2015 Eng Symposium Proceedings by OSU Animal & Food Sciences

Dr. Kenneth & Caroline McDonald Eng Foundation Symposium Innovations in Intensive Beef Cow Production, Care and Management

Hosted by Oklahoma State University and the Eng Foundation September 17-18, 2015 Skirvin Hilton Hotel Oklahoma City, OK

This conference is being recorded and will be available online following the symposium. Visit the Oklahoma State University Department of Animal Science YouTube page to view the video: https://www.youtube.com/c/OSUAnimalScienceDepartment

The 2015 Dr. Kenneth and Caroline McDonald Eng Foundation Symposium Proceedings Innovations in Intensive Beef Cow Production, Care and Management Oklahoma City, Oklahoma

Dr. Kenneth & Caroline McDonald Eng I’ll share the credit for my good luck It’s a blessing that’s sent from above And if you’re blessed and lucky Share it with those you love –K.S. Eng

AGENDA Thursday, September 17, 2015 1:00 p.m. Welcome and Introductions – Clint Rusk, Oklahoma State University; Larry L. Berger, University of Nebraska; H. Russell Cross, Texas A&M University 1:15 p.m. Opening Remarks – Kenneth S. Eng 1:30 p.m. Confined Cow-Calf Production as a Viable Model for Rebuilding the U.S. Cow Herd Numbers – Don Close, Rabobank, Denver 2:15 p.m. Economics of Alternative Cow/Calf Production Systems – Rick Rasby, University of Nebraska 3:00 p.m. Break 3:15 p.m. Enhancing Ranch Land Ecosystem Services with Semi-confinement Systems – Ryan Reuter, Oklahoma State University 4:00 p.m. “Hands on” Intensive Cow-Calf Producers Discussion North Plains: Dave McClellan, Consultant, Freemont, Nebraska Robert Bryant, Hoop Beef Systems, Cherokee, Iowa Bill Dicke, Consultant, Lincoln, Nebraska South Plains: Roberto Eizmendi, Cactus Feeders Cow-Calf Division, Kansas Ron Crocker, Mason County Cattle Producer, Mason, Texas Jim Simpson, Consultant, Canyon, Texas Round Table Panel Discussion with Questions and Answers – Moderator Kenneth Eng 5:30 p.m. Reception 7:00 p.m. Adjourn

Friday, September 18, 2015 7:30 a.m. 8:15 a.m. 8:30 a.m. 9:15 a.m. 10:00 a.m. 10:15 a.m. 10:15 a.m. 11:00 am 11:45 a.m. 12:00 p.m.

Coffee and Pastries Welcome and Introductions: Moderator – H. Russell Cross, Texas A&M University Non-typical Genetic Effects and Implications for Intensive Systems – Andy Herring, Texas A&M University Strategies to Enhance Cow Efficiency in Intensive Systems – Jason Sawyer, Texas A&M University Break Final Session: Moderator – Larry Berger, University of Nebraska Optimizing Use of Corn Residues for Grazing and Harvest – Jason Warner, University of Nebraska Health Management of Neonatal Calves Born in Confinement Systems – Jared Taylor, Oklahoma State University, Vet Med Questions and Answers Concluding Statements and Looking Ahead – Kenneth S. Eng

TABLE OF CONTENTS Kenneth Eng, Ph.D................................................................................................................................................. 6 Welcome................................................................................................................................................................. 8 Speaker Bios...........................................................................................................................................................11 Confined Cow-Calf Production as a Viable Model for Rebuilding the U.S. Cow Herd Numbers.......................15 Economics of Alternative Cow/Calf Production Systems...................................................................................27 Enhancing Ranch Land Ecosystem Services with Semi-confinement Systems................................................37 Non-typical Genetic Effects and Implications for Intensive Systems................................................................49 Strategies to Enhance Cow Efficiency in Intensive Systems..............................................................................59 Optimizing Use of Corn Residues for Grazing and Harvest.................................................................................75 Health Management of Neonatal Calves Born in Confinement Systems..........................................................87 Intensified Cow/Calf Production in the Southern Great Plains Using Wheat Pasture, Semi-Confinement and Cover Crops: Year 2.........................................................................................................................................99 Sponsorship Ads Elanco.................................................................................................................................................................... 110 Westway................................................................................................................................................................. 111 Multimin................................................................................................................................................................. 111 ABS......................................................................................................................................................................... 112 American Akaushi Association............................................................................................................................. 113 Zinpro..................................................................................................................................................................... 113 Phibro..................................................................................................................................................................... 114 Temple Tag............................................................................................................................................................. 115 Micronutrients....................................................................................................................................................... 116 Dijaide.................................................................................................................................................................... 117 Kemin..................................................................................................................................................................... 117 Biolite..................................................................................................................................................................... 118 Merck Animal Health............................................................................................................................................ 119

KENNETH ENG, PH.D. Welcome each and all of you to our third annual symposium in Oklahoma City, Oklahoma. It’s a fitting location because the city and state has a legendary cattle history. It appears we will have an excellent program and attendance for this year’s symposium. For me, these meetings are a special recognition for my time with Caroline and the love we both had for the industry. As a brief background, during the decade of the 1990’s I began to “wind down” my research and consulting activities and we concentrated on running yearlings and a few cows mostly in New Mexico, Texas and Oklahoma. Beginning in 2002, I told Caroline I wanted to switch to cow-calf operations only and she was “all in” as that fit her “roots and DNA”. As we put together cows in the Southwest, we began to encounter serious drought problems which in some respects became an advantage. It made the purchase of the cows easier and less expensive but of course, we were often short of grass. As a result, we often confined the cows in drylot and this began our original confined cow production concept. We considered the drought bad news but it made putting together a cow herd (over 2000 head) easier and less expensive. When your bad news turns into good luck, you know you’re “on a roll” and

“live on” and remain valuable. New experiences, knowledge and ideas never go “out of style”. Thanks to each of you who have helped expand our knowledge base. Next, a word of caution. In this time of euphoria in the cow business, we should recognize there is a danger of eventual over expansion of the cow herd. With the price levels and weights we are now dealing with, over expansion could lead to catastrophic losses. someone is watching over you. I still have a few of our original cows some of which have had 10 or more calves and when culled and sold as packer cows bring two to three times their original cost. Obviously, the record rains earlier this year (2015) especially in formerly drought stricken Texas and Oklahoma has changed the landscape in the pasture and cattle industry. The combination of great feed and pasture conditions plus a shortage of cattle numbers has kept cow, calf and yearling demand strong. It also means confined cow production is not the necessity it was. However, in some areas we can still maintain a cow in semi confinement more economically than on grass. Furthermore, the lessons learned concerning the efficiency and productivity of intensive cow production will

At last year’s meetings, I introduced my book titled “Started Small and Just Got Lucky”. It’s an autobiographical and historical account of my 50 plus years in the cattle industry with special emphasis on my time with Caroline. It has sold much better than I anticipated and I thank all of you who purchased it. This year I’m introducing a poetry book entitled “Memories of Old Friends, Old Flames, Old Times and The Tales We Can Tell”. It’s mostly poetry with some prose and it relates to the cattle industry and the special people who make our industry so fascinating. I’m hoping you enjoy the book and I’m betting you’ll find either yourself or some of your friends scattered throughout the pages. All profits from the books will go to the Dr. Kenneth and Caroline McDonald Eng Foundation.

ENG Ranch (-K-)

ENG Ranches (-K-) (-C-)

ENG-Pearl River Ranch

Winston, NM 87943

7970 Fredericksburg Rd., #101-377

Columbia, MS

(575) 743-6331

San Antonio, TX 78229

(601) 731-2565

Fax (575) 743-0087

Cell (210) 865-8376

Fax (601) 763-1735

engnm@hotmail.com

ken-eng@hotmail.com

WELCOME On behalf of Oklahoma State University and the Department of Animal Science, it is my pleasure to welcome you to the “Innovations in Intensive Beef Cow Production, Care and Management Symposium”. This annual symposium is the result of Dr. Kenneth Eng’s visionary leadership in the beef industry and his ability to recognize and address the challenges it faces. Although timely and abundant rains have greatly improved the current cow habitat, beef supply is still not able to keep up with demand due to reduced cow numbers and an overall shortage of feeder cattle. Through the Dr. Kenneth and Caroline McDonald Eng Foundation, Dr. Eng has committed nearly $2 million to address timely and relevant beef industry issues by supporting applied cow/calf research initiatives at Oklahoma State University, Texas A&M University and the University of NebraskaLincoln. Dr. Eng’s dedication to research and the beef cattle industry has set a wonderful example for future generations. Beef cow confinement and semiconfinement systems continue to expand throughout the Great

Plains Region as beef cattle producers strive to meet beef demand with declining grazing land resources and increased cost of land ownership. Therefore, the research information being generated by all three universities is timely and applicable. A tremendous advantage and unique aspect of the Kenneth and Caroline McDonald Eng Foundation is the vision to create a forum for academic faculty and students to share results of their research with industry and to encourage industry professionals to share their experiences and needs with the academic community. We are honored to host this year’s

symposium! The mission of the Department of Animal Science at Oklahoma State University is to improve the lives of people through discovery, learning, engagement and application of science-based knowledge and animal products. We are dedicated to serving the beef industry through our teaching, research and Extension programs. The Department of Animal Science offers educational and challenging undergraduate and graduate programs that cover a broad variety of fields including: animal behavior and well-being, food science and safety, genetics and genomics, meat science, nutrition, reproductive physiology and sustainability. We continue to maintain animal facilities for all livestock species and equine for hands-on learning. Our escalating undergraduate enrollment is proof that we continue to attract outstanding students from around the world who benefit from hands-on learning, internships, judging team participation, study abroad programs and undergraduate research that helps them better understand Agriculture and prepares them to be industry leaders.

The challenges and opportunities facing the beef industry are constantly evolving. One of our departmentâ&#x20AC;&#x2122;s primary goals is to lead through effective change by doing our part to assist our clientele in meeting challenges, while exploring opportunities to improve the

beef cattle industry. Thanks to the generous support provided by the Dr. Kenneth and Caroline McDonald Eng Foundation, we are better able to do just that. Thank you for participating in this educational symposium that has the potential to impact the Beef Industry.

We appreciate your attendance at this yearâ&#x20AC;&#x2122;s event! Sincerely,

Clint Rusk, Head Department of Animal Science

SPEAKER BIOS Robert Bryant Hoop Beef Systems

From Cherokee Chronicle Times, Paul Struck, Editor

In 2001, veterinarian and seasoned cattleman Dr. Robert Bryant of Aurelia began to experiment with what would come to be known as the Hoop Beef System®.

Association in Amarillo, Texas, representing cattle feeders in Texas, Oklahoma and New Mexico. He previously held roles with AzTx Cattle Co. in Hereford, Texas; Future Beef Operations in Parker, Colorado; and PHI Marketing Services at Pioneer Hi-Bred International, Inc. in Des Moines, Iowa. Mr. Close is a graduate of West Texas A&M.

Ron Crocker

Mason County, Texas

Originally used to house cows and calves during the harsh Iowa winters, Bryant quickly saw the potential for feeding cattle and managing cows in a controlled environment. He was convinced hoop structures would work for feeding cattle.

Ron Crocker is the managing partner for CA Cattle Company, an intensively managed cow/calf herd located in Mason County, Texas.

Today, approximately 5,000 cows are managed in a Hoop Beef System.

He has spent the last 40 plus years operating ranches and feed yards in Arizona, Australia, New Mexico, Kansas and Texas. Crocker attended Dartmouth College and the University of Arizona with a degree in animal science and business.

Don Close

Rabobank, Denver Don Close is an animal protein analyst at Rabo AgriFinance and Rabobank International in its Food & Agribusiness Research and Advisory (FAR) group. Rabo AgriFinance is a leading provider of financial services to agricultural producers and agribusinesses. Rabo AgriFinance adds value to America’s most successful operations with leading expertise and client-focused solutions, as well as long-term business relationships. Close is responsible for analyzing the beef and protein sectors. Prior to joining Rabo AgriFinance, Close served as market director for the Texas Cattle Feeders

Bill Dicke

Lincoln, Nebraska Bill was raised on a crop and livestock farm in Southwest Nebraska. He attended the University of Nebraska-Lincoln where he obtained a B.S. degree in Animal Science and Agricultural Economics, and a M.S. degree in Ruminant Nutrition. In the early 1980’s, he formed Cattlemen’s Nutrition Services, LLC. Today the firm consults for feedlot and ranch clients in the Northern Plains, Central Plains, and surrounding areas. Cattlemen’s Nutrition Services, LLC also conducts large pen commercial research trials.

Innovations in Intensive Beef Cow Production, Care and Management

Roberto Eizmendi Cactus Feeders

Roberto E. Eizmendi is the General Manager of the Cow-Calf Division of Cactus Feeders, with responsibilities over the development of a confined cow calf operation, including facilities design and construction, acquisition of replacement heifers, safety, health, nutrition, genetic and reproductive programs, risk management, personnel development and cattle marketing. Roberto E. Eizmendi was born in Argentina and graduated from Universidad Nacional del Litoral with a degree in Veterinary Medicine, followed by a Master of Agriculture in Beef Cattle Science from Texas A&M University. Roberto was the recipient of the San Antonio Livestock Show and Exposition Scholarship, the International Good Neighbors Scholarship, and an Academic Excellence Scholarship from Texas A&M University. Roberto E. Eizmendi moved back to the United States in April 2011 joining Cactus Feeders as Assistant Manager of one of Cactus feedyards. Prior to moving to the USA, Roberto was the General Manager of Cactus Argentina, a subsidiary of Cactus Feeders in Argentina with responsibilities over the operation of a feedyard and a packing plant owned by Cactus Feeders in association with Tyson and Cresud (publicly-owned, largest Argentine agricultural company). Previously he worked as the General Manager of Establecimiento Forestagro, an agricultural company in the north part of the country, with activities in farming, cow-calf, stockers and grass finishing steers.

Kenneth Eng Eng Foundation

Dr. Kenneth Eng was born on a farm in Boone County, Nebraska. He received a B.S. from Wayne State, M.S. from the University of Nebraska and Ph.D. in animal nutrition from Oklahoma State University. In 1962 he joined the staff at Texas A&M University for animal nutrition research and later returned to Texas A&M (‘69 & ‘70) on a consulting basis. He soon met Caroline who was born and raised in the Brazos County area and had close family ties to Texas A&M. In 1965 he became Ralston-Purina’s first feedlot Technical Feedlot consultant mainly in the Western United States. Three years later he entered the independent feedlot consulting business and was active in 12

research and consulting in the late 60’s, 70’s, and 80’s. In 1990 Eng began downsizing his consulting business and focused on personal yearling and cow-calf operations. Since Caroline’s death in 2010, he has concentrated on the cow, ranch and farmland investments in Texas, Oklahoma and Nebraska. In early 2012, he shifted his agricultural investments to South Mississippi and Louisiana. Following Caroline’s death, the Dr. Kenneth & Caroline McDonald Eng Foundation was initiated to fund research and education in the areas of cow-calf efficiency and production. The Foundation is funding approximately $2 million in research in the area of beef cow efficiency including dry lot cow production to University of Nebraska, Oklahoma State University and Texas A&M. Grants are also awarded to Wayne State College building projects and Plains Nutrition Council for Research Poster Session awards. Additionally, Eng has authored over 600 articles including Feed Stuffs Beef Bottom Line article for 30 years, 7 books of poetry and 10 calendars. He recently completed an autobiographical and historical account book titled Started Small and Just Got Lucky. In recent years Eng received the Oklahoma State Graduate Student of Distinction Honor, Plains Nutrition Industry Service Award, Feedlot Achievement Industry Award and most recently, the Beef Magazine Trail Blazer Award Honoree.

Andy Herring

Texas A&M University Dr. Herring is a professor in the Animal Science Department at Texas A&M University (2002 to present). He was raised on his family’s cattle and sheep ranch in Texas. He has degrees in animal science (BS - Tarleton State University, 1988), animal breeding (MS - TAMU, 1991) and genetics (PhD - TAMU, 1994). He was a faculty member in the Department of Animal and Food Sciences at Texas Tech University from 1994-2002. Dr. Herring holds a 50% teaching, 50% research appointment. He teaches undergraduate and graduate level classes in beef cattle production and management. His research interests focus on areas to increase production efficiency for cow-calf producers through coordination of breeding systems, environmental resources and marketing strategies. Over the years he and his students have studied genetic influences on beef cow milk production, breed differences for feedlot and carcass characteristics, beef cow reproduction and productivity, animal temperament and immune response.

Innovations in Intensive Beef Cow Production, Care and Management

Dave McClellan Fremont, Nebraska

Dave McClellan is the Owner/ Operator of McClellan Consulting Service, Inc. since 1991 servicing 27 feedlot and cow/calf operations in seven states. McClellan was born June 6, 1946. He received a bachelors degree from Westmar College LeMars, Iowa. McClellan earned his masters degree from the University of Iowa in Iowa City, Iowa. McClellan entered the industry in 1981 as a Territory Manager with Hubbard Milling Co. Mankato, Minnesota. He was in the Presidents Club for Sales Growth in 1982, 1983, and 1984. McClellan was promoted to Regional Manager of Nebraska in 1984. In 1985, McClellan moved to Farr Better Feeds in Duncan, Nebraska to work as a feed nutritionist. He was named the Nutritionist of the Year in 1989 and 1990. He founded McClellan Consulting Service, Inc. as an Independent beef cattle nutritional and management service in 1991 and continues in that capacity today.

Rick Rasby

University of Nebraska Rick Rasby joined the staff at the University of Nebraska in 1986 as Extension Beef Specialist with primary responsibilities in cow/ calf management, reproduction, and nutrition. He received a B.S. from UNL and M.S. and Ph.D. from Oklahoma State University. Since arriving in Nebraska, his extension programs have focused on economical feeding programs incorporating forages for beef cows and evaluation of reproductive performance of the cow herd. He has been instrumental in development of the beef website; http//:beef.unl.edu. His research has been to characterize performance and economics of cow/calf production systems that include corn residue. More recently, his research has focused on the use of grain by-products as supplements for cows and their use in heifer development diets.

and research in beef cattle management at the Noble Foundation. Ryan is currently an Associate Professor of Range Beef Cattle Nutrition in the Animal Science Department at Oklahoma State University. Research interests include forage use efficiency, grazing system management, and using technology to help ranchers make more informed grazing management decisions.

Jason Sawyer

Texas A &M University Dr. Jason Sawyer is an associate professor of beef cattle science in the Department of Animal Science and holds a joint appointment with Texas AgriLife Research. He also serves as associate head for operations for the department and superintendent of the McGregor Research Center. He received a bachelor’s degree in rangeland ecology and management from Texas A&M, and master’s degree and Ph.D. in beef cattle nutrition and management from New Mexico State University. Dr. Sawyer teaches undergraduate and graduate courses in beef cattle science, Stocker and Feeder Cattle Management, Advancements in Beef Production, and Beef Cattle Management, as well as a course in research methods for animal science. Dr. Sawyer’s research interests revolve around beef cattle production systems, with a special emphasis on stocker cattle production systems and upstream and downstream impacts of management inputs. In addition to teaching and research commitments, Dr. Sawyer has managerial responsibility for the department’s AgriLife Research Center at McGregor, Texas, and for a number of other research, teaching, and extension facilities located in and around College Station.

Jim Simpson Canyon, Texas

Oklahoma State University

Jim Simpson is an independent consulting nutritionist headquartered in the Panhandle region of Texas. He currently services approximately 400,000 head of feedlot cattle in the Southern Great Plains and abroad. Prior to forming Simpson Nutrition Services, LLC in 1994, he was the Director of Nutrition for the Friona Industries Feedlot Division and Nutritionist for Hi Pro Feeds in Friona, Texas.

Ryan Reuter received B.S. and M.S. degrees in Animal Science from Oklahoma State and a PhD from Texas Tech. Previous professional experience includes consulting

Jim managed the University of Nebraska Research Facility at Mead, Nebraska in the early 1980’s and the Texas A&M Research Feedlot in the late 1970’s. He is an Individual Sustaining Member of the American Society of Animal Science, past President of the Plains

Ryan Reuter

Innovations in Intensive Beef Cow Production, Care and Management

Nutrition Council, past Secretary of the Ruminant Nutrition Research Council and a former member of the Salmonella Task Force in Washington, D.C. Jim currently serves on the Cattle Health and Well Being Committee with NCBA and the Legislative and Regulatory Committee of the Texas Cattle Feeders Association. Jim received his bachelor’s degree and master’s degree from Texas A&M University. He makes his home in Canyon, Texas.

cow-calf sector of the beef industry. His work has included the utilization and storage of ethanol coproducts for the cowherd, supplementation programs for gestating cows, and most recently the evaluation of alternative (confinement) cow-calf production systems. Warner is a native of southwest Nebraska, and was raised on his family’s cow-calf and diversified dryland farming operation.

Jared Taylor

Oklahoma State University, Vet Med Jared Taylor earned his DVM from Virginia Maryland Regional College of Veterinary Medicine in 2002. Following graduation he practiced mixed animal medicine in southwestern Missouri. Jared left practice to join the Center for Food Security and Public Health at Iowa State University while concurrently pursuing his Master’s in Public Health. Jared subsequently came to Oklahoma State University Center for Veterinary Health Sciences to complete a residency in food animal medicine as well as a PhD. He completed his PhD in December of 2008 and was hired as an assistant professor at OSU CVHS in 2009. Jared was promoted to associate professor in 2015. His major teaching responsibilities are epidemiology and public health although he also developed a food animal production elective and assisted in other courses. Jared’s research focuses on the molecular epidemiology of bacterial species involved in bovine respiratory disease. Jared has been happily married to Wendy Guilliams Taylor for 17 years, and they have 3 children: Alex, Beth and Adam. Jared and Wendy own 210 acres where they raise beef cattle.

Jason Warner

University of Nebraska-Lincoln Jason M. Warner is pursuing a Ph.D. in ruminant nutrition in the Department of Animal Science at the University of Nebraska-Lincoln under the direction of Drs. Rick Rasby and Terry Klopfenstein. He holds a bachelor’s degree (Animal Science & Grazing Livestock Systems) and a master’s degree (Animal Science), both from UNL. Throughout his graduate career, Warner’s research has focused primarily on nutrition and management for the 14

Innovations in Intensive Beef Cow Production, Care and Management

Confined Cow-Calf Production as a Viable Model for Rebuilding the U.S. Cow Herd Numbers Don Close Rabobank, Denver

OUTSIDE IN – CONFINED COW-CALF PRODUCTION IS A VIABLE MODEL FOR REBUILDING THE U.S. COW HERD NUMBERS Don L. Close Senior Analyst Rabobank Food & Agribusiness Research and Advisory (FAR) group • The U.S. cow herd must grow if the industry is going to preserve existing infrastructure and regain lost market share. • Current market conditions are incentivizing expansion in all cow-calf production models, and we expect to see a strong increase in the adoption of more intensive confinement breeding systems. • The three big constraints to expanding cow-calf production are high capital barriers, declining availability of grazable acres, and ageing producers. • The two most applicable production models are converting existing excess feed yard pen space and aligning confinement buildings with conventional row crop producers. • Confined production can help accelerate the rebuilding of the U.S. cow herd and feeder cattle supply, while also offering younger cattle industry entrepreneurs a start in the business.

INTRODUCTION Cow-calf producers across the U.S. are feeling pressure from the markets and industry to expand—and expand quickly. The market is right: the weather is improving, and many are starting the process of rebuilding and even expanding herds. However, drought still prohibits rebuilding in some areas, and a 32 million-acre decline in pasture availability over the last ten years is hindering expansion and causing producers to weigh options that require less land. More innovation is paramount to the growth of the U.S. cattle sector. While the key method of U.S. calf production will remain the traditional cow-calf grazing model, a significant part of the expansion will need to incorporate systems for confined calf production. This is due to reduced availability to grass acres and prohibitive competition to purchase or rent pasture. Limited access to capital is also preventing many younger producers from entering the cow business. An alternative production model that reduces initial capital requirements is needed to change that. Confined production systems present an alternative that replaces high capital requirements with intensified

management and labor. Rabobank’s economic evaluation shows that two systems—confined calf production in excess feed yard space and in confinement buildings that are typically built in the Corn Belt—are very competitive compared to conventional production models.

TURNING AROUND THE DECLINE IN COW NUMBERS U.S beef cow inventory has consistently declined since its 1974 peak, as consumer preferences changed and per capita beef consumption began its uninterrupted slide. At the same time, the industry was forced to do more with less, and the feedlot model helped to boost productivity, which allowed the industry to produce the same quantity of beef from an ever-declining breeding base. The cow herd decline accelerated from 2007 to 2012, due to the recession and the impact of higher feeding costs on cattle industry economics as a result of ethanol policy, as well as historic droughts in many cow-calf producing regions in North America. As a result, feeder cattle supplies have been extremely tight, and beef cow inventory in particular has suffered. The subsequent impact was felt across the beef industry, as the number of cattle in the system fell below the level needed to support the existing infrastructure and prompted feed yards and processing facilities to close. Beef cow inventory is the foundation on which the U.S. beef industry is built. Early indications suggest that 2014 saw a modest growth in cow numbers for the first time in years. Beef cow slaughter fell 18 percent, total cow slaughter declined 14 percent, and there was an 8 percent reduction in fed heifer slaughter, suggesting that cows are now being retained for breeding in greater numbers and that herd rebuilding is finally underway. The record price levels in 2014 are encouraging cowcalf operations around the U.S to begin the process of rebuilding herds to pre-drought levels, and, in some cases, operations are even expanding numbers. This expansion is the first step in rebuilding the U.S. beef industry to a point that can support the existing infrastructure. Once the confirmation of cow number recovery is announced in early 2015, Rabobank estimates a 2 percent growth rate in the January 2016 inventory report, based on historical comparisons (see Figure 1). Over the medium term, industry rebuilding will depend on the ability of U.S. cow-calf producers to expand their

Innovations in Intensive Beef Cow Production, Care and Management

herds. For those producers who wish to embark on herd expansion, success depends on three variables: profitability, improving weather conditions, and available land. The outlook for the first two variables appears positive: profitability appears secure for the cow-calf sector, at least for the next few years, and pasture and range conditions seem to have vastly improved in most parts of the country, except in California, Nevada and North Texas. But the availability of suitable breeding land is a more complicated variable involving many factors, Mother Nature not least among them. Over the last ten years, the U.S. has seen a 6.3 percent reduction in grazable acres (see Figure 2). The USDA Census of Agriculture estimates that the U.S. lost, on average, 3 million acres of grazing land a year between the 2002 Census and 2012 Census. That loss has been driven by expansion of row crops, urban sprawl, highfence recreational programs, restricted Bureau of Land Management (BLM) grazing, and even maintenance for BLM horses. While there could be a slowdown in the rate of permanent pasture acres going into row crop, the rate of pasture conversion from other sources shows no signs of slowing at all. If cow numbers are going to increase, by 3 million head to 4 million head despite the simultaneous decline in the number of grazable acres, alternative production models will be required. It is this shift in thinking that has positioned confinement and 18

semi-confinement as a valuable way of expanding cattle numbers in the U.S.

MODELS OF CONFINED COW-CALF PRODUCTION: The implementation of confined and semi-confined cowcalf production programs varies broadly, and no single definition fits all. The two most prevalent production models in the U.S. seem to be adaptation of excess feed yard space and confinement buildings in the Corn Belt. MODEL 1: FEED YARDS The first production model in use today revolves around utilizing a portion of the excess pen space that currently exists in feed yards. This model divides total bunk space to allow 3 feet per cow and calf. This both eliminates crowding and allows space for calves. Some modifications to the existing facilities using this model are required to enhance calf health and well-being, such as lower bunk and water access for calves, a separate area for bedding and shade, and creep gates or other fence spacing to allow a safe zone for calves that is inaccessible to cows. This separate area gives calves a shady place in which to lie down and rest without the risk of being stepped on. An alternative in the feed yard model is to build calf-accessible creep gates that allow calves a completely separate open area. With the current excess pen space, these production units can vary in size, from several hundred cows on the low end to larger units of 3,000 cows to 5,000 cows. A primary benefit of convert-

Innovations in Intensive Beef Cow Production, Care and Management

ing existing feed yard space to cow-calf confinement is that it enables facilities to use existing structures with minimal modifications, while allowing the feed yard to remain a viable entity and sidestep the extreme competition for feeder cattle. MODEL 2: CONFINEMENT BUILDINGS The most prevalent confinement production model is the use of buildingsâ&#x20AC;&#x201D;either linear slant buildings or hoop barns. Hoop barns are especially popular for this method of production because of their cost, efficiency, and air flow dynamics. A common size for the hoop structures is 48 feet wide by 320 feet long. This model typically allows 2 feet of bunk space per cow and can accommodate 150 to 160 cows per unit. When using the confinement buildings production model, it is common to build several units in successive rows to increase head count. Besides providing protection from weather, linear slant buildings and hoop barns provide an extra advantage when it comes to enhancing feed sources on the farm. Consequently, these buildings and housing methods for confined cow production are most widely used in the Corn Belt. Besides being close to intensive row crop production, Corn Belt confinement growers have good regional access to wet DDGs, corn stocks, and other low-cost forage sources. Confinement buildings appear to be the most popular model of confined and semi-confined cow-calf production. The model allows farmers with limited land resources to enhance farm income by generating ad-

ditional revenue from existing resources. A complimentary aspect of the addition of confined feeding to a conventional row crop farm is that the cattle operation gains income credit for the value of the manure. Financial savings for the cattle/farm enterprise can be gained by reducing or, in some cases, even eliminating the purchase of commercial fertilizer and passing the credit back into the cattle operation.

IMPACT: WHY THIS CAN WORK Driving increased efficiency from the cow herd is what makes the confined and semi-confined programs a viable solution to the expansion challenges many cattle operations face. A confined or semi-confined intensive management system allows the operator to tailor feeding programs to the different stages of the animal production cycle. Producers can adjust feeding programs to suit the nutritional and energy needs of cows per trimester of pregnancy, as well as the phases of post-calving and nursing. Additional efficiencies are achieved through the ability to sort cows by their body condition scores and to then adjust feed requirements by groups. This is an option that isnâ&#x20AC;&#x2122;t particularly viable with open grazing. By actively incorporating a consulting bovine nutritionist for ration formulations and nutrition balancing, producers are able to diligently and continually make feed intake adjustments. These adjustments and management systems donâ&#x20AC;&#x2122;t just benefit the animal, but also the financial health of the operation. Programs that are currently using confined, limited feeding state that feed requirements can be reduced

Innovations in Intensive Beef Cow Production, Care and Management

by 10 to 20 percent, depending on where the cow is in the reproduction cycle. The system also appears to offer additional benefits to supply chain partners looking for certain production traits and qualities attributed to the calf crop. A confined system offers opportunities to better manage high-quality calf programs that target specific premium end markets, reducing inefficiencies that exist in the current model and achieving productivity gains through better cow management, artificial breeding, and stock selection for end markets. Under ideal conditions, cows are confined through the majority of their breeding and gestation periods and are then turned out for a 30-day to 90-day calving and calf acclimation period. Upon completion of the acclimation period, the cow-calf pairs or weaned cows return to confinement. For spring calving cows, particularly in the Corn Belt, calving is often delayed until the May/ June window in order to avoid scheduling conflicts with the farm’s planting season. In other cases, calving is moved to fall so cows can calve while grazing seasonal corn stalks.

ENHANCING COW HEALTH AND ANIMAL WELFARE OUTCOMES While a great deal of research is still needed on the implications of a move to confined production for breeding, what limited research there is suggests that cow health can be improved and reproductive life extended. Reduced environmental stress, more complete balancing of the cow’s nutritional requirements on a daily basis, and ready access to cows for improved animal health management regimes clearly offers the potential for improved herd health outcomes and overall productivity gains. While both natural and AI breeding programs are used in confinement programs, the containment of cows facilitates implementation of accelerated AI programs to achieve higher herd productivity. Conception rates and live calf rates under confined production models are also at or above conventional levels because the nutritional requirements of cows can be met consistently throughout the year.

CALF HEALTH ALSO ENHANCED IN CONFINEMENT MODELS Many of the confined cow programs that are in existence today were initiated in the South Plains during the severe drought period of 2011. This expanded in 2012 to include major production areas. Initially, the concept of calving or managing young calves inside a confined area of any kind seemed counterintuitive and generated a great deal of concern over calf health. But once a nursery or rest and retreat area for calves was established, concerns about the possibility of calf injury due to crowding were greatly reduced. 20

One surprising outcome of the confined cow programs is that the prenatal health of the calves is now better than average, since the operations actively balance the cows’ nutritional requirements. In this scenario, calf health in the confined calf crop is, in most cases, exceptional. Calves raised within a confined feeding environment actually start eating and drinking water at an earlier age than conventional pasture-raised calves. This makes weaning, and even early weaning, substantially less stressful on the calves. Finally, confined calves do not have the stress that conventionally raised pasture calves have when they are introduced into the feed yard. Because the confined calves have already adjusted to the noise and conditions of confinement, their adaptability and feed yard performance is often superior to that of conventionally raised calves.

A SOLUTION TO KEEP FARMERS AND FEEDERS IN THE BUSINESS In the U.S. today, one of the most frequently cited barriers to entering the cow business is the high cost of entry. Cow replacement costs are extraordinary, and high land costs are prohibitive. One frequently cited limitation to expansion by existing and entry-level cow owners is the difficulty of finding pasture for sale or for lease at an acceptable price within a reasonable proximity to their existing home or operation. USDA 2012 Census of Agriculture data shows that the average age of U.S. farmers is 58, and the demographic distribution projects the average age to soon exceed 60. A significant percentage of cow owners have reached, or are approaching, retirement age. Current cattle prices may encourage those considering retirement to proceed with liquidation. In spite of exceptional returns, a high price for replacement cows or heifers is daunting and is often a limiting factor for growth. These factors may cause changes in land ownership, but still make entry into the business very difficult. The barriers to entry are just too high, but a confined or semi-confined cow unit could be a path to entry for many young producers. Confined or semi-confined cow units are especially attractive for conventional row crop farmers in the Corn Belt who have family members that want to return to the family farm. The challenge isn’t a new one. How does a farm generate enough income from an established, often land-limited farming operation to generate enough additional revenue for a second income? The addition of a confined cow-calf production unit and the ability to gain greater value from the forage production of the farm may be a viable part of the solution.

Innovations in Intensive Beef Cow Production, Care and Management

TRADITIONAL BREEDING MOST ECONOMICAL, BUT CONFINEMENT ALSO OFFERS GOOD RETURNS

EVEN RETURNS IN WORST-CASE PRICE EXPECTATION WOULD BENEFIT PRODUCERS

Record feeder cattle prices in 2014 have taken the return per cow to historically unprecedented levels in excess of USD 500/head. Without a doubt, market signals are encouraging cow-calf producers to expand, as well as inviting new entrants into the market. In January 2014, the beef cow herd was estimated at 29 million cows, and that number is expected to increase marginally for January 2015.

By using the long-term monthly price series for 400 lb to 500 lb calves in Oklahoma City, a high price scenario was based on the calf price holding at or near the current record price level of USD 3.50/lb and allowed for additional price records to be accomplished. The mid-range price scenario was based on a 38 percent to 50 percent retracement, and the base price scenario was based on prices retracing to levels seen prior to the 2014 rally.

In order to support the existing U.S. beef production infrastructure, Rabobank believes that beef cow numbers need to increase, from between 32 million head to 34 million head over the next few years. Previously, the most aggressive annual rate of rebuilding was just over 5 percent. This occurred in the early 1970s, when total beef cow numbers were between 40 million head to 45 million head. Since that peak in numbers, the annual percentage increase has seldom exceeded 1 percent to 2 percent. In the current circumstances, we expect the herd recovery to take a number of years, so returns to cow-calf production will remain elevated for several years. In a simple cost-of-production benchmarking analysis to help estimate the viability of newer confinement models, two things stand out (see Figure 3). First, breakeven costs per calf are very competitive between geographic regions and production models. Second, all production models offer excellent profit opportunities in the current market environment. In building these benchmarks, a few key assumptions were made. First, we assumed a difference in cow prices by region to reflect market differences. Second, we budgeted for an additional 1 to 2 calves over the life of a cow for cows under the confinement model, to reflect the improved environmental and management conditions. Finally, we assumed that the confined operations would have a 2 percent weaning percentage over a traditional cow-calf system due to nutrition balancing, improved prenatal health of calves, and intensified management. All breakeven calculations were based on a 550 lb early weaned calf, despite the fact that the number of days to weaning differs between confined and conventional production models. Feed costs in the model are based on regional grazing rates and pasture rent between geographic regions. Confined cow feed costs were based on USD 1.00/ head/day on corn stalks and USD 1.75/head/day in confinement. Based on comments from producers, the USD 1.75/head/day may be higher than current feed costs, but allows some room for the movement of feed prices.

Price projections were determined by price histories with standard retracement levels, as well as considerations to the expected breakeven prices of a feeder steer and a fed steer, given the original calf breakeven (see Figure 4). Under the high price scenario, profits in all production models range from USD 660.00/head in conventional North Plains production to an astonishing USD 803.00/ head with a confined older cow. While it is safe to say these returns arenâ&#x20AC;&#x2122;t expected to be sustained, they were realized in 2014. The mid-range price scenario offers a range of returns of USD 220.00/head to USD 363.00/head. Based on the historical returns of less than USD 100.00/head, this is probably a much more realistic expectation and still provides phenomenal returns, historically speaking. The base price scenario provides a range of USD 55.00 loss per head to a USD 88.00 profit per head. This range of return certainly fits with the historical norms. However, there are two considerations to take into account. First, it gives a worst-case scenario that still provides an economic logic to buying cows at the current prices. It also shows that, under the worst-case scenario, returns are not so bad as to force producers out of business.

CONSIDERATION OF SUSTAINABILITY Given the current business environment of the cattle and beef industry, any evaluation of an alternative business model would not be complete without going through a sustainability checklist. That checklist of principles as defined by the Global Roundtable on Sustainable Beef includes the responsible use of natural resources; people and community wellbeing; animal health; food and efficiencies; and innovation. The Rabobank evaluation supports those criteria, and confined cow production meets these criteria. Nonetheless, more intensive production undoubtedly implies additional risk and the need for more hands-on management.

Innovations in Intensive Beef Cow Production, Care and Management

CONCLUSION Increased efficiency from the cow herd and healthier animals is what makes the confined and semi-confined programs viable and valuable. The ability to adjust the nutritional needs of the cow to the pregnancy/post-calving stage, and the ability to sort cows and adjust feed requirements based on their body condition scores isn’t an option with open grazing. Making these adjustments with the counsel of a bovine nutritionist is proving effective in confinement and semi-confinement models. Operations currently using a confined feeding program are showing a 10 percent to 20 percent reduction in feed requirements, depending on where the cow is in the reproduction cycle. This increase in efficiency is an important step in the effort to keep cattle operations as competitive as possible in the changing domestic and international markets. The unparalleled price advance in all classes of cattle and beef in 2014 is a paradigm shift that will take a number of years to fully understand. However, there are a number of developments that are going to reshape the cattle and beef industries in years to come. That list includes a steadily eroding acreage base for natural forage and grass, the unprecedented growth in export developments (especially in China and the Pacific Rim), and escalating GDP growth in a number of developing countries which is increasing the demand for all animal proteins. The global population is expected to reach 9.5 billion by 2050, and we are realizing that only select regions of the world are suitable for beef production. The growth in demand for beef is inevitable, and measures must be taken now to meet that anticipated demand. These measures must consider limited and shrinking availability of land for grazing, and how to use more efficient and sustainable models to produce more beef. These models will be the key to keeping beef a competitive protein in our growing world—and the key to enabling a new generation of beef producers to continue a legacy.

any liability whatsoever for any loss howsoever arising from any use of this document or its contents or otherwise arising in connection therewith. This document may not be reproduced, distributed or published, in whole or in part, for any purpose, except with the prior written consent of Rabobank. All copyrights, including those within the meaning of the Dutch Copyright Act, are reserved. Dutch law shall apply. By accepting this document you agree to be bound by the foregoing restrictions. © Rabobank Utrecht Branch, Croeselaan 18, 3521 CB, Utrecht, The Netherlands +31 30 216 0000 This report has been published in line with Rabobank’s long-term commitment to international food and agribusiness. It is one of a series of publications undertaken by the global department of Food & Agribusiness Research and Advisory. ©2014 - All Rights Reserved. Rabo AgFocus - January 2015

This document is issued by Coöperatieve Centrale Raiffeisen-Boerenleenbank B.A. incorporated in the Netherlands, trading as Rabobank. The information and opinions contained in this document have been compiled or arrived at from sources believed to be reliable, but no representation or warranty, express or implied, is made as to their accuracy, completeness or correctness. This document is for information purposes only and is not, and should not be construed as, an offer or a commitment by Rabobank or any of its affiliates to enter into a transaction, nor is it professional advice. This information is general in nature only and does not take into account an individual’s personal circumstances. All opinions expressed in this document are subject to change without notice. Neither Rabobank, nor other legal entities in the group to which it belongs, accept 24

Innovations in Intensive Beef Cow Production, Care and Management

NOTES DON CLOSE

ECONOMICS OF ALTERNATIVE COW/CALF PRODUCTION SYSTEMS Rick Rasby University of Nebraska

ECONOMICS OF ALTERNATIVE COW/CALF PRODUCTION SYSTEMS Rick J. Rasby3, Jason M. Warner1, Karla H. Jenkins2, and Terry J. Klopfenstein3 1Graduate Student, Department of Animal Science, Lincoln 2Assistant Professor, Panhandle Research and Extension Center, Scottsbluff 3Professor, Department of Animal Science, Lincoln INTRODUCTION Net calf Crop or Number of Calves Weaned per Cow Exposed is an important calculation for commercial cow/calf producers. The greatest loss in potential calves to wean is due to cows not becoming pregnant during the breeding season (Bellows et al., 1979). Body condition of beef females at calving impact reproductive performance during the next breeding season. Body condition of beef females is impacted by feeding/ supplementation strategies. The greatest costs for the cow/calf enterprise are feed costs. Our objective is to review management strategies that impact reproductive performance in beef females because reproductive performance impacts economics of the cow/calf enterprise and to present economics of alternative cow/calf production systems.

IMPACT OF ENERGY AND PROTEIN SUPPLEMENTATION AND BODY CONDITION ON REPRODUCTION Feeding a balanced ration to beef females in the last trimester of pregnancy through the breeding season is critical. Nutritional demands increase from early gestation to lactation (NRC, 2000). Reproduction has low priority among partitioning of nutrients. Thin cows at calving typically remain thin as excess energy in the diet is directed to milk production first. The impact of energy and protein in the ration pre- and post- calving and the inter-relationship with body condition in beef females has been extensively reviewed (Randel, 1990; Short et al., 1990; Dunn and Moss, 1992; Banta et al., 2005; Hess et al., 2005 Whittier, 2005). The common theme among these reviews is that body condition score at calving is related to post-partum interval and re-breeding performance. It is a challenge to increase body condition post-calving or elicit a reproductive response to high energy intake in thin post-partum cows (Spitzer et al., 1995). These data also illustrate the challenge of attempting to increase body condition post-calving on reproductive performance and the need to be proactive to manage body condition pre-calving. A nine-point system is commonly used to condition score beef cows (Wagner et al, 1988). The importance of body condition at the time of calving on subsequent reproductive performance has been documented extensively. Dunn and Kaltenbach (1980) summarized data noting

that body condition at calving and pre-partum weight changes are important factors that affect the length of the post-partum interval in beef cows. Body condition score (BCS) is correlated with several reproductive events such as postpartum interval, services per conception, calving interval, milk production, weaning weight, calving difficulty, and calf survival; which affect net income in a cow-calf operation (Richards et al., 1989; Marston et al., 1995). Spitzer et al. (1995) fed first-calf cows differing in body condition (BCS 6 vs. 4; 1 = emaciated, 9 = obese) to gain either 2.0 or 1.0 lb/d. The percentage of BCS 6 cows in estrus during the first 20 days of the breeding season increased from 40 to 85% when fed to the higher rate of gain, the cows in BCS 4 only increased estrous response from 33 to 50% during the first 20 days of the breeding season when fed to gain at the higher rate. Cows should have an optimum BCS of 5 to 6 at calving be maintained through breeding to assure optimal reproductive performance. The most important factor influencing pregnancy rate in beef females is body condition at calving (Wettemann et al., 2003).

SUPPLEMENTING IONOPHORES ON REPRODUCTIVE PERFORMANCE Feeding an ionophore can influence reproductive performance of beef cows and heifers. Feeding an ionophore to ruminants increases the amount of the volatile fatty acid propionate. Propionate can be converted to glucose and an increase in glucose has a positive impact on the reproductive axis. Cows and heifers fed an ionophore have a shorter post-partum interval (Randle 1990). In addition, when heifers are fed an ionophore age at puberty decreases (Moseley et al., 1977; Moseley et al, 1982) and there are more cyclic before the start of the breeding season and at a lighter body weight (McCartor et al., 1979). These data support the consistent impact of feeding ionophores on beef cattle reproductive performance. However, ionophores are not a substitute for good nutritional management at the producer level.

POST-PARTUM INTERVAL AND CALVING DISTRIBUTION IMPACTS ON CALF PERFORMANCE The post-partum interval in beef females is impacted by age, nutrition/body condition, suckling, dystocia, genetics, and disease (Short et al. 1990). Pre and post-

Innovations in Intensive Beef Cow Production, Care and Management

partum nutrition and body condition impact post-partum interval and reproductive performance during the subsequent breeding season (Houghton et al., 1990). Management strategies that reduce the post-partum interval and increase the proportion of females conceiving at first estrus after calving in commercial cow/ calf enterprises are critical for optimal production and economic efficiency (Wiltbank et al, 1961). Post-partum interval is defined as the interval, usually in days, from calving to the first estrus. For beef females the postpartum interval is between 55 and 65 days (Houghton et al., 1990; Short et al, 1990; Cushman et al., 2007). If the length of gestation is 283 days, a beef female must conceive by 82 days after calving to potentially yield a calf annually. It was determined that heifers that calve during the first 21-d period of their first calving season had increased longevity in the herd compared with heifers that calved for their first time during the second or later calving periods. Average number of years that a beef female remained in a herd was 8.2, 7.6, and 7.2 years for heifers that calved in the first 21 days of their first calving season compared to the second and third 21 day periods of their first calving season (Cushman et al, 2013). Cow longevity in the herd is important for commercial cow/calf producers. Increasing longevity reduces the need for replacement females, reduces labor, reduces the need for high quality feed, increases weaning weight, and increases the number of offspring that are available to be marketed to generate revenue. Through six calvings, beef heifers that calved the first 21 days of their first calving season weaned heavier calves compared to weaning weights of calves from dam that calved during the second or third 21 days of their first calving season (Cushman et al, 2013). Calving distribution, the number of cows calving in 21 day periods during the calving season, is impacted by the nutrition program and therefore body condition at calving, especially for spring-calving cows. Cows that cycle early in the breeding season conceive early in the breeding season, and calve early in the calving season. Twenty-one day calving intervals can be easily calculated if you know when to start the first 21-day interval. Standard Production Analysis Guidelines indicates there are two ways to determine when to start the first 21-calving interval: â&#x20AC;&#x201D;When the third mature cow (3-years-old or older) has calved or â&#x20AC;&#x201D;Start the first 21 day calving period 285 days after the start of the breeding season. Calving Distribution can be impacted easily by monitoring body condition/nutrition prior to calving in springcalving beef herds. Cows that calve in adequate body condition (BCS = 5) breed earlier in the breeding, calve 30

earlier in the calving season, and calves are older and heavier at weaning compared to cows that breed later in the breeding season. Many times a minor change in nutrition management before calving impacts when cows will begin estrous cycles during the breeding season. In a large data set, both male and female calves, from a March calving herd were categorized by when they were born during 21 day periods during the calving season (Funston et al. 2012). Heifer calves that were born during the first 21 days of the calving season were heavier at weaning, more were cycling before the start of their first breeding season, more pregnant during their first breeding season, and more calved during the first 21 days of their first calving season (Funston et al 2012). Male calves born during the first 21 days of the calving season were heavier at weaning, had heavier feedlot finishing weight, did not have greater DMI, had higher marbling scores, had more carcasses that scored a USDA modest marbling score, and generated more income (Funston et al., 2012). Calves born the first 21 days of the calving are older at the time that parameters were measured in these data sets, but these are two extensive sets of data that connect the synergies of reproduction, production, and performance together into attributes that cow/calf producers can strategize management options into production outputs that impact production efficiencies and profitability.

CALF CROP PERCENTAGE Calf Crop Percentage may be the most important production calculation that a cow/calf producer can record. The reason for this statement is that it has both an input and output component. Inputs include genetic selection, nutrition and management, management during the breeding season, management during the calving season and management from calving to weaning. The output component is reproduction and reproduction impacts total pounds of weight that is available to sell at weaning. Percentage calves weaned of females exposed is the number of calves weaned based on the females that were exposed to the bulls to produce the calves that are being weaned. Mathematically it is the number of calves weaned (numerator) divided by the number of females exposed to produce that calf crop (denominator) and this number times 100 to get it to a percentage [(# calves weaned/# cows exposed) x 100]. Sometimes the challenge is that the numbers needed to do the calculation are collected over a year apart so good records are needed. For females that wean a calf in October of 2015, the number of females exposed would be the number of females exposed to a bull during the breeding season in 2014. As an example, 300 cows were exposed to the bull and 255 cows weaned a calf. Calf Crop Percent is 85% ((255 calves weaned/300 cows exposed to the bull) x 100 = 85%). Records indicate 37 cows had no calving records, 6 calves lost at calving, and 2 calves were lost between calving and weaning.

Innovations in Intensive Beef Cow Production, Care and Management

It is the 37 head did not get pregnant during the breeding season because there was no record that they aborted. Using this information, more information can be extracted from these records so that “weak links’ in the production system can be identified. Pregnancy percentage is 87.7% ([(300 - 37)/300) x 100] = (263/300) x 100)], calving percentage is 97.7% [(263 - 6)/263) x 100) = (257/263) x 100], and weaning percent is 99.2% [(257 - 2)/257) x 100 = (255/263) x 100]. Multiplying pregnancy percent x calving percent x weaning percent should be close to 85% (.877 x .977 x .992 = .8499). Cow reproductive performance can be evaluated by age group using the process described above. Some of the challenge is to how to account for pregnant females that enter and leave the herd during the production cycle. There are Standardized Performance Analysis guidelines that outline how to calculate production measures for the cow herd and how to account for pregnant females that enter and leave the herd. SPA guideline can be found on the NCBA website or ask your state beef specialist to help you locate the SPA production guidelines. The greatest loss of calves to wean is due to cows not getting pregnant during the breeding season. Managing body condition for cows in a dry lot should not be an issue because rations delivered to the bunk can be adjusted. Pregnancy rates for cows managed in a dry lot should be at least 90% or greater. The reason for this discussion is that the equation for calculating breakeven cost, total costs are in the numerator and (weaning weight x percent calf crop weaned) is in the denominator.

DRY LOT BEEF COW/CALF ENTERPRISE The dynamics in the beef cattle industry remain volatile with wide swings in the price of grains and forages. The high prices of corn and forages of 2012 and 2013 were followed by lower grain and forage prices in 2014 and 2015. Pasture prices and rental rates were pushed

up in recent years because pastures were converted to row crop (http://agecon.unl.edu/documents/2369805 /10452540/2015+Nebraska+Farm+Real+Estate+Re port.pdf/9669dc53-240d-44ce-8a75-6702773f3453) and this trend appears to be a major factor in the cattle industry for 2014 even with the continued decrease in the beef cow inventory. What options are there to build the nation’s cow herd or add a beef cow/calf enterprise with limited pasture that will no doubt be expensive? The University of Nebraska is currently engaged in investigating alternative options to traditional cow/calf enterprises. The premise is to research cow/calf enterprises that center around the large number of corn acres that are available in many mid-western states. In the Nebraska experiment, composite June/July calving cows were dry lotted for 365 days. Cows are limit-fed a diet of distillers grains and crop residue (either ground corn stalks or wheat straw). The limit-fed rations meet the cow’s nutrient requirements, but cows do not eat to their full capacity. The rations are about 19% Crude Protein and 80% TDN on a dry matter basis, but level of dry matter intake varied depending on stage of production. A supplement was fed that contained an ionophore. While eating these rations, cows maintained weight and body condition when they were gestating or lactating. In addition, calf performance was monitored and performance was similar to what would be expected to cow/ calf pairs managed in a pasture setting. At the University there are extensive data sets on spring calving and early summer (June calving) calving systems to compare to the confinement system. In these systems, records were kept on days grazing vegetative and dormant pasture, days grazing corn residue, and days fed distillers grains, hay, baled residues, and supplements. The prices used for the comparison in 2013 are described in Table 1. Distillers grains and stalks/straw are the major components and due to the

Innovations in Intensive Beef Cow Production, Care and Management

drought in 2012-2013the price of both feed ingredients are high. A different yardage was assessed for cows when they were in the dry lot, grazing stalks or pasture, or fed supplement while on pasture. The â&#x20AC;&#x153;cow costâ&#x20AC;? row in Table 1 represents all other costs in an annual cow budget and includes replacement costs. Percentage of calves weaned of females exposed was held constant across all systems at 90%. In Table 2 the confinement system is compared to three other cow/calf management systems. The June calving herd is a sandhills system that is basically pasture and protein supplement and essentially no hay. The spring-calving herd is a Southeast Nebraska research herd where cow/calf pairs graze pasture in the spring, summer, fall, then cows go to corn stalks followed by hay feeding during calving before grazing spring pasture. The other springcalving herd is like the one described above except during the spring/summer/early fall a distillers grains plus ground residue combination is substituted for half of the pasture consumed daily. The total confinement system breakeven (UCOP) is $0.77/lb greater than the

GSL system with the UCOP for D/H systems between the total confinement and GSL systems. Currently we do not have a full production cycle on the semi-confinement system, but using our best estimates the UCOP is similar to the GSL cow/calf system. The prices of the different feeds used in the 2014 economic analysis are in Table 3. The cost of pasture increased compared to 2013 and cost of distillers and forage decreased. Cow costs increased as a result of female replacement costs being greater in 2014 compared to 2013. Yardage costs were added to each system as noted earlier is also included. Percentage of calves weaned of females exposed was held constant across all systems at 85%. Table 4 includes total annual cow costs, weight at weaning, and base breakeven for each of the systems. Weaning weight is greater for the semi-confinement system as calves grazed with their dam while on corn residue. Annual cow costs for the more traditional spring- and summer-calving herds are similar and less than the total confinement system.

$45/pair/mo

Innovations in Intensive Beef Cow Production, Care and Management

Because of the price of distillers’ grains and residue in 2014, the spring calving system that includes feeding a ration of residue and distillers is the least expensive system in our comparison. Total confinement system is still the most expensive system but, due mainly to feed costs, the gap with more conventional systems narrowed when comparing 2014 to 2013. What is interesting is the semi-confinement system that includes dry lotting and grazing corn stalks is the least expensive of the systems compared. As mentioned, we do not have a full production cycle on the semi-confinement system, but using our best estimates the UCOP is similar to the GSL cow/calf system.

Symposium in Agriculture, (3) Animal Reproduction, pp. 3-18. Ed. H.W. Hawk. Allenheld, Osmun & Co.; Montclair, 1979.

CONCLUSIONS

Dunn, T.G. and C.C. Kaltenbach. 1980. Nutrition and the postpatuum interval of the ewe, sow, and cow. J. Anim. Sci. 51:29-39.

There is a link between nutrition, reproduction, postpartum interval, calving distribution, weaning rate, and economics. So just limiting the discussion to economics doesn’t do justice to the important components that impact economics. Reproductive performance drives Unit Cost of Production for the cow/calf enterprise. Nutrition and body condition have the greatest impact on reproductive performance of beef females. Dry lotting beef cows can and should be used as a drought mitigation strategy. The recent drop in grain and forage prices appear to make it a competitive alternative beef cow/ calf system. When dry lotting cows, consider limit-fed rations because limit-fed rations will usually be cheaper than full-fed rations. Remember, limit-fed rations meet all the cow’s requirements but cows are not fed all that they can eat. Even when rations are limit-fed include yardage in the costs. A semi-confinement system is competitive with other cow/calf systems.

REFERENCES Banta, J.P., D.L. Lalman, and R.P. Wettemann. 2005. SYMPOSIUM PAPER: Post-calving nutrition and management for two-year-old cows. P. Anim. Sci. 21:151. Bellows, R.A., R.E. Short, and R.B. Staigmiller, Research areas in beef cattle reproduction. In Beltsville

Cushman, R.A., M.F. Allan, R.M. Thallman, and L.V. Cundiff. 2007. Characterization of biological types of cattle (Cycle VII): Influence of postpartum interval and estrous cycle length on fertility. J. Anim. Sci. 85: 9: 2156-2162 Cushman, R.A., L.K. Kill, R.N. Funston, E.M. Mousel, and G.A. Perry. 2013. Heifer calving date positively influences calf weaning weights through six parturitions. J. Anim. Sci. 91:4486.

Dunn, T.G., and G.E. Moss. 1992. Effects of nutrient deficiencies and excesses on reproductive efficiency of livestock. J. Anim. Sci. 70:1580-1593. Funston, R.N., J.A. Musgrave, T.L. Meyer, and D.M. Larson. 2012. Effect of calving distribution on beef cattle progeny performance. J. Anim. Sci. 90:5118. Hess, B.W., S. L. Lake, E. J. Scholljegerdes, T. R. Weston, V. Nayigihugu, J. D. C. Molle, and G. E. Moss. 2005. Nutritional controls of beef cow reproduction. J. Anim. Sci. 83: E90-E106. Houghton, P.L., R.P. Lemenager, L.A. Horstman, K.S. Hendrix, and G.E. Moss. 1990. Effects of body condition pre- and postpartum energy level and early weaning on reproductive performance of beef cows and preweaning calf gains. J. Anim. Sci. 68:1438. Marston, T.T., K.S. Lusby, R.P. Wettemann, and H.T. Purvis. 1995. Effects of feeding energy or protein before or after calving on performance of spring-calving cows grazing native range. J. Anim. Sci. 73:657.

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McCartor, M.M., R.D. Randle, and L.H. Carroll. 1979. Dietary alteration of ruminal fermentation on efficiency of growth and onset of puberty in Brangus heifers. J. Anim. Sci. 48:488. Moseley, W.M., M.M. McCartor, and R.D. Randle. 1977. Effects of monensin on growth and reproductive performance of beef heifers. J. Anim. Sci. 45:961. Moseley, W.M., T.G. Dunn, C.C. Kaltenbach, R.E. Short and R. B. Staigmiller. 1982. Relationship of Growth and Puberty in Beef Heifers Fed Monensin. J. Anim. Sci. 55: 2: 357-362 NRC. 2000. Nutrient requirements of beef cattle7th edition rev. ed. Natl. Acad. Press, Washington, DC. Randel, R.D. 1990. Nutrition and postpartum rebreeding in cattle. J. Anim. Sci. 68:853. Richard, M.W., R.P. Wettemann, H.M. Schoenemann. 1989. Nutritional anestrus in beef cows: Body weight change, body condition, luteinizing hormone in serum and ovarian activity. J. Anim. Sci. 67:1520. Short, R.E., R.A. Bellows, R.B. Staigmiller, J.G. Berardinelli, and E.E. Custer. 1990. Physiological mechanisms controlling anestrus and infertility in postpartum beef cattle. J. Anim. Sci. 68:799. Spitzer, J.C., D.G. Morrison, R.P. Wettemann, and L.C. Faulkner. 1995. Reproductive responses and calf birth and weaning weights as affected by body condition at parturition and postpartum weight gain in primiparous beef cows. J. Anim. Sci. 73:1251-1257. Wagner, J.J., K.S. Lusby, J.W. Oltjen, J. Rakestraw, R.P. Wettemann, and L.E. Walters. 1988. Carcass composition in mature Hereford cows: Estimation and effect on daily metabolizable energy requirement during winter. J. Anim. Sci. 66:6.03-612. Wettemann, R.P., C.A. Lents, N.H. Ciccioli, F.J. White, and I. Rubio. 2003. Nutritional-and suckling-mediated anovulation in beef cows. J. Anim. Sci. 81 (E. Suppl. 2):E48-E59. Whittier, J.C., G.P Lardy, and C.R. Johnson. 2005. SYMPOSIUM PAPER: Pre-calving nutrition and management programs for two-year-old beef cows. P. Anim. Sci. 21:145. Witbank, J.N., E.J. Warwick, E.H. Vernon, and B.M. Priode. 1961. Factors affecting net calf crop in beef cattle. J. Anim. Sci. 20:409

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NOTES RICK RASBY

Enhancing Ranch Land Ecosystem Services with Semi-confinement Systems Ryan Reuter Oklahoma State University

ENHANCING RANCH LAND ECOSYSTEM SERVICES WITH SEMI-CONFINEMENT SYSTEMS Ryan Reuter Assoc. Professor - Range Beef Cattle Nutrition, Department of Animal Science Oklahoma State University, Stillwater, OK ABSTRACT Sustainability is a key goal of most Southern Plains ranch enterprises. Two common issues in grazingland management are overstocking and brush encroachment. Keys to addressing these issues are flexibility in cattle management systems that offer ways to reduce grazing pressure at key times of the year, while also potentially improving cattle performance and overall net return. Semi-confinement systems may offer such opportunities.

FOCUS The discussion presented here is focused mainly on Southern Plains ranch country. Some cow/calf production systems have evolved to use semi-confinement successfully in other parts of the country, usually to avoid winter weather. The focus of this paper is to start first from the perspective of improving management of Southern Plains grazinglands, and then explore how semi-confinement cow/calf production might help achieve that goal.

RANCH SUSTAINABILITY A key objective for many ranching operations is sustainability. Ranchers may define sustainability as being able to pass a feasible ranching operation on to the next generation. This is surprisingly close the definition of sustainability offered in Our common future; “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (World Commission on Environment and Development, 1987). Sustainability exists at the confluence of environmental, social, and economic considerations. The environment constrains what is possible to do, economic factors further constrain ranchers to what is feasible to do, and the social aspect constrains ranchers even further to what is permissible to do. All of these constraints exist, with varying degrees of intensity, on grazingland management.

RANCHLAND ECOSYSTEM SERVICES Ranches make up 27% of the US land surface, and are the predominate land use in the Great Plains, Great Basin, and Intermountain West ecosystems in the United States (Figure 1). Some obvious benefits of

ranches are food production and conservation of wildlife habitat, among others. There are also real benefits that some may overlook. For example, ranches produce industrial products, produce water for human use, stimulate rural communities, provide recreation, and preserve the western and cowboy culture. Grazinglands provide these ecosystem services, i.e. the ways in which humankind benefits from ecosystem function, to tens of millions of people. Ecosystem services can be categorized as: • supporting services — basic processes to enable other services — autotroph energy production, soil formation, etc. • provisioning services — supplying products — food, water, raw materials, energy, genetic resources, etc. • regulating services — regulating processes to benefits — carbon sequestration, waste detoxification, disease control, water purification, etc. • social services — non-material benefits — recreation, education, aesthetics, cultural preservation, religious beliefs, etc. Enhancing the ability of ranchlands to provide such services is a worthy goal and benefits both the private rancher and society.

GRASSLAND MANAGEMENT Grazing management is a combination of art and science. Ideal management is producing a desirable balance of ecosystem services in a way that is profitable and enjoyable to the people involved, and ensures welfare of the animals involved. A key factor, maybe the key factor, in grazing management is stocking rate. The degree and timing of defoliation of forage plants drives many processes involved in producing ecosystem services. Too little defoliation can have deleterious effects, such as undesirable plant communities, increased wildfire danger, reduced wildlife habitat value, and others.

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Ultimately, too little defoliation because of too few livestock and too little income, may result in bankruptcy of a ranching enterprise. However, the issue that is far more predominate is that of too much defoliation (Smith, 1940). Often, the defoliation is at the wrong time (Smith & Owensby, 1978). Overgrazing inhibits ecosystem function and reduces production of ecosystem services. Over-defoliation may impair water cycling and soil formation, alter plant communities, and destroy wildlife and aesthetic value. In the short term, overgrazing often increases profit (likely why we commonly observe overgrazing), but it almost always decreases profit in the long run (Shoop and McIlvain, 1971). Protection from overgrazing is a key requirement if sustainability and ecosystem service production of grazinglands are to be improved. This protection is critical during times of stress, such as drought. As climate varies, grazinglands will periodically need protection from overgrazing. Further, Southern Plains grazinglands can benefit from rest from grazing during the late 40

summer (Figure 2). This allows plants to store reserves of nutrients, rebuild tissues, and produce abundant seed (McKendrick et al., 1975; Owensby et al., 1977). Finally, native rangeland ecosystems in the Great Plains evolved under the influence of periodic fire. Periodic fire maintains these systems in the state that produces a desirable balance of ecosystem services. For fire to be effective, adequate forage must be available as a fuel source. In summary, grazinglands are an important ecosystem and in many cases are in need of remediation from overgrazing to optimize their ecosystem service functions. To achieve this, they need: â&#x20AC;˘ protection from overgrazing â&#x20AC;˘ rest during the late summer â&#x20AC;˘ effective periodic fire

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Figure 2. Big bluestem reserve total nonstructural carbohydrate (TNC) at different dates for continuous, season-long and intensive early-stocked pastures (1972-74 average). Asterisk above a date indicates a significant difference )P<.05).

Percent TNC

8 6 4 Intensive May 1-July 15) Continuous (May1-Oct. 1)

From: Owensby et al. (1977)

SEMI-CONFINEMENT A major challenge to providing rangelands those requirements is the fact that to achieve them, the cattle must be moved somewhere else. Rotational grazing systems provide rest to a part of the ranch at a time, and to the entire ranch over time, but these systems have limitations too. They may be expensive and difficult to manage for some ranches. And, ultimately, rotational grazing does not reduce the stocking rate on a ranch, and hasn’t been shown to increase animal production (McCollum et al., 1999). Semi-confinement systems can be an alternative to provide grazinglands the management they need. Semi-confinement here is defined as managing the cowherd, or a part of the cowherd, in a feedlot for a part of the year. Nutrients for the cows during the feedlot period are sourced from off of the ranch. By obtaining outside nutrients, this system does reduce stocking rate. And it provides many other potential benefits. Example – Cattle management To illustrate the benefits semi-confinement may have, an example may be helpful. Our example ranch will consist of 640 acres of native range, stocked with 53 springcalving cows. Calving begins in mid-February and lasts 90 d (Figure 3). Calves are weaned at 205 d of age. The cowherd is grazed on the pasture for 300 days of the year and is fed hay on the pastures for 65 d during late winter. The native grass pastures are stocked year round and are being encroached by eastern red cedar.

While this is admittedly a simplified and somewhat contrived example ranch, it does have features in common with many commercial ranches I have visited, and it illustrates the concept of using semi-confinement to improve grazinglands management well. One issue to note is that the hay feeding period is a major drag on this system. It is essentially a drylot phase, but without any of the benefits of a true drylot. Feed (hay) is hauled out to the cattle where they don’t use it efficiently due to free-choice access (Sparks et al., 2013). The pasture is still exposed to grazing and trampling damage from the cattle which can be significant in wet weather, and disturbs wildlife habitat. The mildly reduced grazing pressure the range receives when cows are being fed hay occurs at a less than ideal time of year. There are numerous ways in which the operational efficiency and the ecosystem services of this example ranch may be improved simultaneously. An alternative cattle management system incorporating semi-confinement is presented in Figure 4. Comparing Figure 3 with 4, we see many differences:

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• Calving - Calving has moved later into the spring, and the calving season has been shortened to 45 d. • Weaning - Calves are now weaned at 135 d of age. Calves need not be sold at this time, but can be retained as stockers/feeders for as long as desired.

Figure 3

Figure 4

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• Feeding - Cows are managed in drylot during the summer and early fall (135 d). • Management and logistics - Calves are born on pasture, but moved into drylot as pairs at a young age. Lactating cows are fed in drylot, and energy intake can be programmed. Calves can be creep fed as desired to improve gain and/or prepare for weaning. Breeding occurs in drylot, making AI easier. Calves can be short-term weaned easily to assist with AI conception. Certainly, some of the management practices shown in the alternative case could be also be implemented without semi-confinement, but in many cases the confinement period makes them logistically easier to implement. And, certainly, there are numerous ways to manage grazing and supplementing of grazing cattle more efficiently without semi-confinement. However, the alternative of a semi-confinement system may fit some rancher’s objectives and constraints better than other options. Pasture management Our example ranch has 3 pastures of approximately equal carrying capacity. Figure 5 illustrates the alternative range management that compliments the new cattle management program. Grazing - Pastures are now grazed from frost (mid November) until July 1. Beginning July 1, all pastures are rested until frost, allowing plants to build root reserves and accumulate fuel for effective prescribed burns (McKendrick et al., 1975). Burning - One pasture is also rested from frost until February. At that time, it is burned. The resting/burning is rotated each year around the three pastures. Stocking rate - The overall stocking rate of the example ranch in the traditional system was 53 cows for 10 months (2 months hay feeding) on 640 acres. That works out to 0.83 AUMs per acre. The alternative

system is the same 53 cows for 7.7 months on the same 640 acres: 0.68 AUMs per acre. One change to notice is that the stocking density during the fall and winter is increased from 12 acres per cow to 8 acres per cow. As a result, the pastures that are grazed will experience greater fall and winter grazing pressure 2 out of 3 years, and then receive a burn. These pastures will, however, have received a late summer/fall rest prior to the increased grazing pressure.

BENEFITS Some benefits of this alternative system are obvious. • Stocking rate is reduced. • Late summer and early fall rest is provided to all pastures every year. • Improved ability to effectively incorporate prescribed fire is incorporated. — Fuel availability is less variable due to drought • Beef production and cattle welfare are at least maintained, and likely increased. — Calves are born and started on pasture in the late spring (ideal weather). — Technology is more feasible in confinement. AI, feed additives, limit feeding, etc. — Some preliminary data seems to suggest that there may be production benefits in terms of calf growth when cows are fed on a high plane of nutrition in confinement. • Flexibility in management is incorporated. Management flexibility is a key component of sustainability. Many aspects of the semi-confinement system can be fine-tuned for different circumstances and objectives, even as these change over time. • The length of the confinement period can be adjusted to reflect changing climate and range condition.

Figure 5. Alternative semi-confinement system grazing plan.

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• Fire return interval can be adjusted to meet specific range management goals. • The concept could be combined with rotational grazing concepts at a range of rotation intensities, or it can be implemented without cross fencing using the patch burning approach. • Feedstuffs used in confinement can change rapidly to take advantage of market prices. • Programmed feeding of cows in confinement can be used to adjust cow body composition to desired end points. • Confinement facilities can be used at other times of the year to house/develop bulls, develop heifers, manage cull or thin cows, grow calves, receive stockers, feed custom cattle, etc. Facilities to care for cattle are also available in an emergency, such as wildfire.

ECOSYSTEM SERVICES Let’s consider how such a system might improve ecosystem services. An important note is that such improvement would be expected to occur under proper management of this system. Poor management, regardless of production system, can always impair ecosystem services. Supporting services - Through rest and fire, more herbaceous forage is produced and soil is more protected from erosion. Provisioning services - Beef production from the system can be increased. Production of wild foods species (plants and animals) may be increased through restoration of grassland plants. Water consumption by brush species is reduced, helping to recharge surface and groundwater.

Regulating services - Runoff water is cleaner due to more vigorous grass plants protecting soil and filtering runoff. Disease cycles in animals may be broken by changing environments and calving on extensive pastures. Pest burdens such as ticks may be reduced in burned pastures. Carbon may be sequestered at greater rates in grass than brush species. Methane emissions per unit of beef production may be lower due to increased forage and feed quality, and greater production. Social services - Recreation and aesthetic value of rangelands and associated land and water types are improved by restoring the native landscape. Biodiversity is improved. Rural communities and cultures are preserved because the production system is more sustainable.

POTENTIAL PITFALLS • The management logistics are a different set of challenges, and may only fit a subset of ranchers. • Cattle management in confinement may require more knowledge, skill, and time. • Cost of constructing facilities that are durable and address production, environmental and animal welfare concerns. — i.e. facilities that mitigate heat stress on breeding animals; avoid mud accumulation; properly contain and treat runoff water, etc. • Facilities may require CAFO permits. • Cost of purchased feedstuffs may be greater than cost of grass grown on the ranch. As might be expected, many of the potential drawbacks to such a system relate to cost. Costs vary greatly in cow/calf operations, and many assumptions must be

Table 1. Parameters used to calculate the example nutrition cost for two example management scenarios.

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made to illustrate differences in an example such as this. Parameters used to estimate cost of providing nutrition to these example systems are shown in Table 1. Pasture cost is estimated at $15 per cow per month (Doye and Sahs, 2015), which might be a conservative estimate in many situations. Using this pasture value, the alternative system costs about $135 more than the traditional system to feed the cows, or about $11.25 per acre. Other costs may vary between the systems as well. No attempt was made to estimate potential revenue or net return due to the variability in weaning management that may be employed in these systems, and because data is limited as to the potential benefits to cattle production from semi-confinement feeding, range improvement, etc. Before adopting a semi-confinement strategy, ranchers should carefully consider and budget their own expected costs for any such system they might employ.

Smith, E. F., and C. E. Owensby. 1978. Intensive-Early Stocking and Season-Long Stocking of Kansas Flint Hills Range. J. Range Manag. 31:14–17. Sparks, J. D., S. K. Linneen, and D. L. Lalman. 2013. Effects of bale feeder type, monensin supplementation, limit feeding, and hay ammoniation on hay waste, intake, and performance of beef cattle. Oklahoma State Univ. Anim. Sci. Res. Reports. World Commission on Environment and Development. 1987. Our common future. Oxford University Press, Oxford; New York.

SUMMARY The example described here illustrates how semi-confinement could be used to achieve a goal of improving ecosystem services through incorporating more late-season rest of native range. However, the real key may be to consider the flexibility afforded a grassland manager by the concept of semi-confinement. This approach could be used to explore alternative management strategies for different kinds of ranches that may have different goals.

LITERATURE CITED Doye, D., and R. Sahs. 2015. Oklahoma Pasture Rental Rates: 2014-15. Oklahoma Coop. Ext. Curr. Rep. CR216. McCollum, F. T., R. L. Gillen, B. R. Karges, and M. E. Hodges. 1999. Stocker Cattle Response to Grazing Management in Tallgrass Prairie. J. Range Manag. 52:120–126. McKendrick, J. D., C. E. Owensby, and R. M. Hyde. 1975. Big bluestem and indiangrass vegetative reproduction and annual reserve carbohydrate and nitrogen cycles. Agro-Ecosystems 2:75–93. Owensby, C. E., E. F. Smith, and J. R. Rains. 1977. Carbohydrate and nitrogen reserve cycles for continuous, season long and intensive early stocked Flint Hills bluestem range. J. Range Manag. Arch. 30:258–260. Shoop, M. C., and E. H. McIlvain. 1971. Why Some Cattlemen Overgraze-and Some Don’t. J. Range Manag. 24:252–257. Smith, C. C. 1940. The Effect of Overgrazing and Erosion Upon the Biota of the Mixed-Grass Prairie of Oklahoma. Ecology 21:381–397. Innovations in Intensive Beef Cow Production, Care and Management

NOTES RYAN REUTER

Non-typical Genetic Effects and Implications for Intensive Systems Andy D. Herring Texas A&M University

NON-TYPICAL GENETIC EFFECTS AND IMPLICATIONS FOR INTENSIVE SYSTEMS Andy D. Herring John K. Riggs â&#x20AC;&#x2122;41 Beef Cattle Professor Department of Animal Science, Texas A&M University, College Station INTRODUCTION All traits in livestock have some degree of genetic influence, and anything not attributed to known genetic origin is designated as environmental influence. The type of production system and its associated conditions can result in wide variation in regard to performance levels of traits and their associated economic values. Interactions between genetic background and production environment are known to exist for many beef cattle production traits, and the most desired genetic type of animal in one production system may be undesirable for other systems. They ability to capitalize on the most desirable genetic influences occurs when the entire production system is evaluated, not just one component. In recent years, several non-typical types of genetic effects have been documented in several mammal species, and the study of these types of influences has not yet received much consideration in beef cattle production system discussions. This paper lays the ground work to begin considerations of these types of effects and how they may be uncovered and/or utilized in intensive beef cattle production systems.

INTERACTIONS CONSIDERATIONS IN PRODUCTION SYSTEMS Intensive cow-calf production systems offer unique opportunities over traditional management strategies. Some extremes in production system settings and considerations are provided in Table 1. Genetic improvement for any trait is a function of its heritability, its potential level of heterosis, and the production environment in which it occurs. Not all animals and not all traits have the same values in all production settings.

It is typically recommended that breeding animals be selected relative to the production environment in which their progeny are evaluated. In the conventional U.S. beef supply chain, there are two distinct challenges to application of this theory: (1) many sires and bloodlines deemed desirable (and/or popular) are utilized in cow herds with very different production conditions, and (2) the vast majority of calves are evaluated for feedyard performance in a different geographical and nutritional environment than the cow herds from which they originate. Both of these present challenges to efficiency of genetic improvement from a whole systems perspective. Numerous instances of genotype by environment (G x E) interactions have been documented in various beef cattle production traits. The majority of the focus for G x E interactions has been with the breed as the genotype, but the concept can be extended to families within breed, and potentially even to genotype at the individual gene level. Many types of environmental interactions (E x E) are known to exist relative to beef cattle production (for instance the degree of performance difference of using growth implants over no implant when nutrition is restricted vs. when at a high plane, etc.). However, another type of interaction can also impact beef cattle production efficiency: genotype x genotype (G x G) interactions. Where these types of interactions exist, they have high chance of being undetected and have potential to contribute unrecognized variability (i.e. noise) to production systems. Fetal programming is the concept that in utero environmental influences have the potential to alter phenotypes later in life. If the environmental influence on that

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animal also affects its germline (cells and tissues that produce eggs and sperm), this environmental influence may also be passed onto its progeny; the altered phenotype is not expected to persist beyond the progeny unless the germline is permanently altered. Epigenetics is the term used to describe the concept that heritable variation in a trait is possible without changes in DNA sequence of the gene products (the DNA sequence of the gene itself is the same, but the expression of the gene is variable). Variable expression of genes through fetal programming and imprinting are known to be influenced by methylation and acetylation of DNA sequence in mammalian species. It is now widely documented in humans and rodent species that substantial genetic variation exists beyond the DNA sequence level (the same DNA sequence of a gene can result in variable expression). Genes and their regulatory elements may be influenced at the DNA gene coding level by presence of methyl groups (methylation) or in histone proteins involved with DNA extension and compaction (methylation and acetylation). These processes result in epigenetic or epigenomic influences. One widely recognized epigenetic process known to occur in mammals is genetic or genomic imprinting, and this is where the gene is expressed differently when it is inherited from the male vs. female parent. In cattle and many mammalian species the IGF2 gene and its receptor IGF2R are related to body composition and growth and are known to be imprinted. Figure 1 illustrates the concept of characterizing parent-of-origin effects for performance traits. For many years, there was large variability observed in birth weights and other traits of cloned cattle, which was perplexing as clones are genetically identical for their nuclear DNA. However, it has been recognized that methylation patterns can produce some of this phenotypic variation. For example, Long and Cai (2007)

demonstrated that DNA methylation was disrupted at a known imprinted gene (IGF2R) in cloned Holstein cattle; de Montera et al. (2010) showed large variation in methylation within genotype of cloned cattle, including more methylation variability within genotypes than across genotypes. Parent-of origin effects are not necessarily due to imprinting as they can be cause by maternal influences (and/or paternal influences theoretically), and in many instances the parent-of-origin effect may be confounded with a breeding strategy; therefore, understanding of the root cause(s) of these differences is important for full utilization and understanding of potential applications. Through intensive production systems, the nutritional variability can be separated from the genetic variability if a uniform, standardized nutritional program and other components such as health management are provided. If individual animal identification and pedigree information is known, there is potential for more complete description (and therefore prediction) of performance phenotypes, which in turn can lead to increased economic values. The number one problem that cattle breed associations have with producer field data is the improper recognition and description of contemporary groups. Feedyards are used to designation of contemporary groups (they are called pens); connection of contemporary groups from calf birth to harvest (or mature cow production) along with pedigree information and animal identification in intensive systems provides potential for complete separation of genetic and environmental influences, and, potential use of data. The continual reduction in costs to obtain genotypes and the higher density SNP platforms available on animals make its potential use more realistic, but only knowing genotypes on one generation of animals is typically not cost effective. It has become more widely accepted that parent-of-

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origin effects are important for many complex traits in humans and rodent model species, particularly regarding health and body composition; Lawson et al. (2013) provided a recent review of this scientific literature. Stridh et al. (2014) investigated inheritance of a multiple sclerosis-like disease in rats (experimental autoimmune encephalomyelitis), and stated 37–54% of all detected disease-predisposing loci depended on parental transmission. The authors also stated that accounting for parent-of-origin enabled more powerful and precise identification of novel risk factors and increased the disease variance explained by the identified factors by 200 to 400%. Mott et al. (2014) documented epigenetic effects of some genes on weight in mice that had life-long influences, and, these authors also stated that the number of interactions of imprinted loci with nonimprinted loci (which would generate many more parent-of-origin influences) was more important than the number of imprinted loci. Among interspecies crosses of mice, the species source of X chromosome and imprinting of loci on autosomes (non-sex chromosomes) have been associated with differences in placenta weight and birth weight (Vrana et al., 2000; Duselis and Vrana, 2010).

PARENT-OF-ORIGIN EFFECTS CONSIDERATIONS IN CATTLE There have been a limited number of studies to evaluate imprinting/parent-of-origin effects in beef cattle, but the few found in the literature are discussed here. Engellandt and Tier (2002) evaluated estimation of variance components of carcass composition in 2,744 German Gelbvieh bulls due to “imprinting.” These scientists modeled sire as a random uncorrelated effect (in a similar way to how maternal effects are modeled in genetic evaluations) and found 14 to 16% influence of paternally expressed genes for internal fat and meat yield traits. Neugebauer et al. (2010) evaluated parentof-origin effects on carcass traits in 65,233 German Simmental bulls where they incorporated two additive genetic effects per animal (paternal and maternal patterns). They then estimated breeding values on each animal as a sire and as a dam, and assumed the difference in two estimated breeding values was due to imprinting. Of 25 traits, 10 showed significant “imprinting” effects with influence of 8% to 25% of the additive genetic variance. Tier and Meyer (2012) evaluated large datasets (over 90,000 records) of ultrasound carcass traits in Australian Angus and Hereford heifers and bulls between 300 and 700 days of age. In both breeds significant influence was attributed to parent-of-origin effects, and these explained from 12 to 45% of the total genetic variation with all traits showing influences of paternal and maternal origins in both sexes. Fina et al. (2012) reported paternal imprinting effects in a Spanish breed to account

for 13% of the phenotypic variance in weaning weight. It has been known for many years and in many locations that reciprocal crosses of Bos indicus and Bos taurus produce very large differences for calf birth weight and gestation length (Bos indicus-sired calves much larger, with males much heavier than females, see Table 2).

This historically was attributed to maternal uterine effects of Bos indicus vs. Bos taurus females. However, this same phenomenon occurs in calves produced by embryo transfer (Amen et al., 2007; Dillon et al., 2015). Additionally, Dillon et al. (2015) modeled a potential interaction involving the X chromosome source and an autosomal gene locus that helped explain birth weight differences similar to results reported in interspecies crosses in mice. Other types of cattle reciprocal crosses do not exhibit this large of an effect, but the potential to better characterize birth weight and the implications of selecting for “curve-bender” bulls exists. In many cases, the relative variation in birth weight as evaluated by CV is larger than weights later in life. Birth weight variation in cattle may be as or more useful in study of other production traits than it is for description of calving ease. We have also observed potential differences among Bos indicus-Bos taurus crosses beyond the F1 generation that warrant further investigation. The genetic difference between crossbred animals that are F1 crosses and those that are F2 is that F1 animals are heterozygous across all loci where the foundation breeds have different alleles, and the F2 animals should have 50% of their gene loci heterozygous (25% homozygous for one breed and 25% homozygous for the other breed). For example, F1 Angus-Hereford cattle have one allele from Angus origin and the other allele is from Hereford origin, and their breed composition is 50% Angus and 50% Hereford. However, in mating F1 males to F1 females, the resulting F2 progeny are still 50% Angus and 50% Hereford, but not all the alleles of breed origin are packaged the same as in the F1. Traditional animal breeding and quantitative genetics theory has assumed the F1 animals (and/or heterozygous genotype) where the Angus allele was inherited from the sire and Hereford allele came from the dam was equal to the reverse case of a Hereford allele inherited from the sire and an Angus

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allele from the dam. The validity of this assumption when crossing breeds and even within breeds needs to be studied. Table 3 illustrates birth weights and weaning weights among F2 Brahman-Hereford calves produced at McGregor. When these crosses were being made, it was assumed that alternate F1 parent types and alternate F2 types were equal. As a result, not all of these crosses were produced in the same years, and the number of animals per F2 type are rather small. However, the differences in birth weights among the two sexes is always provide fair comparison, and it can be seen that potential differences in size and growth may exist due to the foundational parent of origin. Anecdotal evidence by many cattle breeders is that some family lines and/ or individual sires are better for producing daughters or better for producing sons. Evaluation of both sexes for as many traits as possible provides for a more complete picture about desirability of different types of animals in a whole production system context.

Table 4. provides raw means for weights of F2 and F3 Nellore-Angus steers born 2009-2012 from the McGregor Genomics Project from some recent, preliminary analyses. Production of all types of calves was balanced across years, although the number of animals of all four F2 types is not equal. Only preliminary analyses have been conducted on these data to this point; however, it appears that some potential inheritance

patterns could exist in these data. The relative rankings among these calves changed dramatically from birth weight to weaning weight to weights at a year of age and beyond. There also appears to be more differences among marbling scores than among fat thickness (data not shown) in these cattle. We have genotype data on these and other cattle and will investigate potential parent-of-origin effects at the individual gene level. Information uncovered on these various Bos indicusBos taurus crosses may provide avenues for potential study in other breeds, and, may provide for more comparative genetic studies across mammalian species.

SUMMARY Epigenetic influences on several complex traits in humans and rodent model species have been widely documented. It is possible that at least some variation in cow herd level traits that have been attributed to environmental differences may be due to some epigenetic influences. Intensive cow-calf systems have potential to better characterize the environmental inputs over traditional systems, and potential to better describe and capitalize on particular genetic influences most desirable for a particular production environment. This can be beneficial from both industry and research scenarios. Large intensive systems involved in production of commercial cattle have more potential to describe genetic differences in breeds than exist from purebred/seedstock operations. If there are ways to genetically characterize (and therefore more precisely predict) individual animal performance, this would allow more precision in matching genetics-management-market combinations. The continual reduction in costs to more thoroughly genotype animals will provide for more opportunities to study potential parent-of-origin effects in beef cattle production systems; however, only having one generation of animals makes it impossible to know which allele was inherited from which parent. It is recommended that pedigree information and individual animal identification be incorporated into intensive systems regardless of the goals or types of cattle involved. Effective utilization of genetic information in livestock production systems is a multi-generational concept, and this has

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been much more heavily emphasized and utilized in the global pork and poultry industries than it has in beef cattle.

Long, J.E., and X. Cai. 2007. IGF-2R expression regulated by epigenetic modification and the locus of gene imprinting disrupted in cloned cattle. Gene 388:125-134.

ACKNOWLEDGEMENTS

Mott, R., W. Yuan, P. Kaisaki, X. Gan, J. Cleak, A. Edwards, A. Baud, and J. Flint. 2014. The architecture of parentof-origin effects in mice. Cell 156: 332–342.

Valuable interdisciplinary discussions, data interpretations and considerations have been contributed by my colleagues Drs. Jim Sanders, Clare Gill, David Riley, Penny Riggs and Jason Sawyer. Maintenance of breeding herds and collection of numerous cattle phenotypes associated with the McGregor Genomics Project would not be possible without support from Texas A&M AgriLife Research and the Beef Competitiveness funding program. Some data are based upon work that is supported by the National Institute of Food and Agriculture, USDA Hatch Project TEX08937.

REFERENCES

Neugebauer, N., I. Räder, H.J. Schild, D. Zimmer, and N. Reinsch. 2010. Evidence for parent-of-origin effects on genetic variability of beef traits. J. Anim. Sci. 88:523532. Stridh, P., S. Ruhrmann, P. Bergman, M.T. Hedreul, S. Flytzani, A.D. Beyeen, A.Gillett, N. Krivosija1, J. Öckinger, A.C. Ferguson-Smith, and M. Jagodic. 2014. Parent-oforigin effects implicate epigenetic regulation of experimental autoimmune encephalomyelitis and identify imprinted Dlk1 as a novel risk gene. PLoS Genet 10(3): e1004265.

Amen, T.S., A.D. Herring, J.O. Sanders, and C.A. Gill. 2007. Evaluation of reciprocal differences in Bos indicus x Bos taurus backcross calves produced through embryo transfer: I. Birth and weaning traits. J. Anim. Sci. 85:365-372.

Tier, B., and K. Meyer. 2012. The effect of imprinted genes on carcass traits in Australian Angus and Hereford cattle. Proc. Assoc. Advmt. Anim. Breed. Genet. 19:6366.

Boenig, L. 2011. Heterosis and heterosis retention for reproductive and maternal traits in Brahman x Hereford crossbred cows. Texas A&M University. M.S. Thesis.

Vrana, P. B., J. A. Fossella, P. Matteson, T. Del Rio, M. J. O’Neill, and S. M. Tilghman. 2000. Genetic and epigenetic incompatibilities underlie hybrid dysgenesis in Peromyscus. Nature 25:120–124.

de Montera, B., D. El Zeihery, S. Müller, H. Jammes, G. Brem, H.D. Reichenbach, F. Scheipl, P. ChavattePalmer, V. Zakhartchenko, O.J. Schmitz, E. Wolf, J.P. Renard, and S. Hiendleder. 2010. Quantification of leukocyte genomic 5-methylcytosine levels reveals epigenetic plasticity in healthy adult cloned cattle. Cellular Reprogramming 12:175-181. Dillon, J.A., D.G. Riley, A.D. Herring, J.O. Sanders, and R.M. Thallman. 2015. Genetic effects on birth weight in reciprocal Brahman–Simmental crossbred calves. J. Anim. Sci. 93: 553-561. Duselis, A. R., and P. B. Vrana. 2010. Aberrant growth and pattern formation in Peromyscus hybrid placental development. Biol. Reprod. 83:988–996. Engellandt T., and B. Tier. 2002. Genetic variances due to imprinted genes in cattle. J. Anim. Breed. Genet. 119:154-165. Fina, M., L. Varona, J. Piedrafita, and J. Casellas. 2012. Sources of sire-specific genetic variance for birth and weaning weight in Bruna dels Pirineus beef calves. Animal 6(12):1931-1938. Lawson, H.A., J.M. Cheverud, and J.B. Wolf. 2013. Genomic imprinting and parent-of‑origin effects on complex traits. Nature Reviews Genetics 14:609-617. Innovations in Intensive Beef Cow Production, Care and Management

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Strategies to Enhance Efficiency in Intensive Systems Jason E. Sawyer Texas A&M University

STRATEGIES TO ENHANCE EFFICIENCY IN INTENSIVE SYSTEMS Jason E. Sawyer Associate Professor & Associate Department Head Superintendent, McGregor Research Center Levi A. Trubenbach, Graduate Assistant; Lonisa Early, Graduate Assistant; Jessica Baber, Graduate Assistant; Caleb Boardman, Graduate Assistant; Tryon A. Wickersham, Associate Professor Department of Animal Science, Texas A&M University, Texas A&M AgriLife Research, College Station, TX INTRODUCTION Sustainable intensification has been proposed as a necessary element of increasing global protein supplies in the face of decreasing land availability (FAO, 2011; Sawyer and Wickersham 2014). Solutions are required that can simultaneously improve protein yields while enhancing resource stewardship, increasing the economic viability of beef production for new and existing producers, and ensuring resilience of food production systems to market and climatic shocks. A primary strategic aim of the Animal Science program at Texas A&M University and of Texas A&M AgriLife Research is to discover, develop and deploy sustainable solutions for beef production systems. Innovative intensification of cow-calf systems offers sustainable solutions to these challenges, and through the support of Texas A&M AgriLife Research and the Kenneth and Caroline McDonald Eng Foundation, strategies for intensification of cow-calf systems are being developed.

BACKGROUND AND RATIONALE The purpose of this article is to describe the development and evaluation of strategies for cow-calf system intensification. The conceptual framework and rationale for strategy identification and evaluation will be described, and progress and future direction will be discussed. Previously, we have described a model system in which intensification of cow-calf systems through confinement feeding during a portion of the production cycle could increase production per acre and improve net income (Sawyer et al., 2013; Trubenbach et al., 2014). In the envisioned system, cows are confined from weaning until 30 d prior to calving. This also points to an initial strategy for intensification – system mapping and model construction. The ‘map’ is the conceptualization of production flow including a period(s) of intensive management, in this case confined feeding. The ‘model’ may be as straightforward as a quantitative representation of the map, a budget, or a description of feed requirements drawn from the mapped system. Such tools allow for the identification of leverage points or critical

elements that must be addressed for a solution to be viable. Ultimately, end users must be capable of implementing these strategies in a variety of settings and under a wide array of capital constraints and managerial capacities. There are technical, operational, and managerial limitations to implementation of these strategies. Technical limitations include inadequate description of requirements in these systems, or of the capacity to forecast diet caloric value. Operational limitations include space and capital constraints, equipment limitations, and feed manufacturing and delivery logistics. Managerial limitations include knowledge application, but also include potential pitfalls or ‘unintended consequences’ on other production parameters. Evaluation of implementation strategies and their impact on animal health and long-term productivity is required to minimize risk from adopting these systems. Summarizing these evaluations into effective decision support tools provides producers at several scales with the capacity to determine feasibility and develop tactical solutions for implementation. Ultimately, validation of strategies at production scale is necessary and provides the platform for continued innovation. The objectives of this article are to provide a brief description of a program of work designed to address the elements described above; to provide a report of progress to date, building upon previous reports to the symposium; and to discuss proposed efforts for continuance in developing innovative and sustainable production strategies.

STRATEGY DEVELOPMENT: PROGRESS AND PATH FORWARD Elements of our strategy development plan can be broadly categorized as:

Innovations in Intensive Beef Cow Production, Care and Management

1) Conceptualization and model development 2) Identification of leverage points and strategies 3) Identification of limits to implementation and solutions 61

4) Development of decision support tools and strategy recommendations 5) Validation through production CONCEPTUALIZATION Conceptualization consists of problem identification, framing of high-level objectives and desired outcomes, and system mapping. During this phase, key initial conditions were established; most importantly, we considered a scenario in which: – Cow-calf operation already in existence, – Based on grazing systems consistent with balancing forage supply and demand – Utilized supply and demand of calories as a fundamental means of tracking ranch level production capacity The importance of this condition is that it considers continuation of utilization of the ranch asset; it is not aimed at development of a confinement-only system. Despite this condition, results from downstream experimentation and development are likely to yield information that is beneficial even in a confinement-only system. This concept was developed and described previously (Sawyer et al., 2013). An initial system map (model) based on energy demand, according to currently accepted nutrition models (NRC, 2000), was developed to identify the likely least-cost period for confined feeding of cows, and to evaluate the potential increase in production capacity that would result assuming a viable solution could be identified. Budgets were developed and scenarios were evaluated to identify leverage factors (Sawyer et al., 2013). IDENTIFICATION OF LEVERAGE POINTS Two critical leverage points were identified, based on their capacity to impact the financial outcome of intensive management scenarios. First, optimizing variable costs by maximizing the efficient use of purchased feeds was clearly the most influential factor in the financial evaluation. A second leverage point, reducing capital costs and total fixed costs per cow (or per cwt. calf produced) was also identified as a priority. Strategies to optimize use of purchased feeds. In beef cattle, diet digestion increases with intake restriction (Galyean et al., 1979; Boardman et al., 2015); our results suggest that this effect may be greater with more energy dense diets (Trubenbach et al., 2014). These observations create a challenge: standard methods of diet evaluation do not account for these dynamics, and thus diets cannot be formulated to effectively capture these benefits. Increasing energetic utility of feedstuffs with limited value for human consumption is a key feature 62

of a sustainable solution for cow-calf intensification. Because ionophores typically increase the effective caloric value of diets without directly affecting digestibility, the combination of limit feeding and ionophore application in these systems could further increase the caloric value of diets in intensive cow-calf systems. Limit-fed systems also confer a metabolic advantage, likely resulting from both alterations in ruminal fermentation (Armstrong and Blaxter, 1961; Trubenbach et al., 2014) and visceral organ mass (Reynolds et al., 1991; McLeod and Baldwin, 2000). The magnitude of improvement may be related to diet energy density (Trubenbach et al., 2014). These effects are not adequately described by standard models of nutritional requirements. Capturing the efficiency gains by defining management approaches to reduce maintenance requirements of cows fed in confinement systems is a key element of enhancing both sustainability and viability of these systems. The additive effects of limit feeding and ionophore application on diet utilization, coupled with potential reductions in absolute maintenance requirements, suggest that efficiencies during the confinement feeding period can be enhanced. Based on these foundations, manipulation of diet energy content through feeding management, and the potential to alter cow energy requirements are key strategies for gaining efficiencies in the system. An experimental model was developed to provide a platform for evaluating these strategies. Briefly, primary evaluation trials have been designed as completely randomized designs with pregnant cows fed individually in Calan gate feeding systems. These experiments have utilized approximately 56 animals with four treatments. In these trials, frequent collection of BW and condition score data, along with ultrasound measures of body composition have been utilized to estimate changes in retained energy according to NRC (2000) and have also been evaluated using other relevant and published equations. These methods and calculations were described for an initial experiment (Trubenbach et al., 2014). Although the precise estimates vary depending upon the equations utilized, equation selection has not impacted the magnitude of treatment differences nor the precision with which treatment effects are estimated. For this article, the NRC (2000) equations are considered as the industry benchmark. Additionally, in these trials ADIA is used as an internal marker to describe diet digestibility. Bomb calorimetry is utilized to define GE of diets, feces, and the marker is used to describe apparent DE. The suggested ratio of 0.82 is used to estimate ME content. We have defined “limit feeding” relative to cow daily maintenance requirements according to NRC (2000). Arguably, with reference to voluntary DMI, all of the

Innovations in Intensive Beef Cow Production, Care and Management

treatments and strategies that we have evaluated could be described as ‘limit-fed’, as cows are not being fed ad libitum on any treatment. In the initial experiment reported by Trubenbach et al. (2014) treatments consisted of a 2×2 factorial arrangement; cows were fed to achieve 80% or 120% of predicted daily NEm requirement using a TMR formulated to provide either 1.64 Mcal/kg NEm or 1.12 Mcal/kg NEm (as fed basis). As anticipated, digestibility of the high energy density diet was greater than for the low density diet (P < 0.01). Restricting intake of either diet resulted in an increase in digestion (P < 0.01). While numerically, the improvement in digestion due to intake restriction appeared to be greater for the high density diet, no interaction was detected (P = 0.43). These results were reported (Trubenbach et al., 2014) and are described here for convenience of the reader. In a companion study using ruminally cannulated steers fed the same diets at an equivalent rate on a metabolic BW basis, an interaction was observed. In that experiment, measures of digestion were minimal affected by intake restriction for cattle fed the low energy density diet, but restriction increased measures of digestion in steers fed the high energy density diet (Table 1). While these outcomes differed in statistical analysis, they are directionally similar, and suggest that intake restriction may be a viable means of enhancing dietary caloric value, but that the magnitude of this benefit may be dependent on diet formulation. In the initial cow feeding trial, estimates of fasting heat

production (NEm requirement) were made based on HE estimates by difference (IE – RE = HE), with IE estimated based upon observed levels of DE intake and RE estimated by equation based on BW and compositional change measured via ultrasound. A comparison could not be made based upon level of intake (the derivation of FHP is a regression function, requiring both intake level observation to estimate FHP for cows on a given diet). Feeding the lower density diet resulted in estimates of FHP similar to those predicted by NRC, but feeding the higher energy density ration resulted in an apparent reduction in NEm requirement of approximately 26% (Trubenbach et al. 2014). A second cow feeding trial (Table 2) was conducted as described above, with a 2×2 factorial treatment arrangement. Cows in the second trial were fed the highenergy diet utilized in the first experiment, fed at 80% or 120% of daily NEm requirement estimated by NRC (2000) with either 0 or 200 mg/d monensin. Monensin is known to alter fermentation profiles, effectively increasing the caloric value of diets. We hypothesized that this effect would be additive with effects of intake restriction observed in the initial cow trial, yielding additional increases in apparent efficiency. Monensin had little impact on measures of digestion (P > 0.18), and there were no intake level × monensin interactions (P > 0.18). As in the first cow feeding trial, restricting intake improved measures of digestion (P < 0.01), suggesting that this is a reliable strategy for enhancing diet caloric value. While these increases may be modest (3 – 5%), they are meaningful when formu-

Innovations in Intensive Beef Cow Production, Care and Management

lating to a specific energy target and underestimation of these effects would lead to overfeeding in a confinement scenario targeted at maintenance. In a companion trial using cannulated steers under the same treatment structure, effects of intake restriction on digestibility were confirmed, and lack of effect of monensin inclusion was also affirmed. Monensin did have anticipated effects on acetate to propionate ratio, regardless of intake level, indicating that the additive performed as expected. (data not shown). Due to the presumed mode of action of monensin to affect dietary energy value, inability to measure these effects through diet and feces calorimetry is not surprising. Rather, it was expected that monensin addition would increase RE across intake levels. When RE was estimated, however, there was neither a measured effect of monensin nor a monensin Ă&#x2014; intake interaction (P > 0.65) (Figure 1). Estimates of NEm requirements based on HE for diets with and without monensin were similar, but were approximately 18% below the 77 kcal/ EBW0.75 baseline requirement described by NRC, and approximately 24% below the model predicted requirement for cows in this study (adjusted for age, environment, and days in gestation). This estimate is consistent with the observation that cows fed at 80% of predicted maintenance requirements had RE not different than 64

zero after 56 days, and is similar to estimates obtained in the initial experiment. The lack of an apparent effect of monensin may be explained by evaluating the pattern of BW change throughout the trial (Figure 2), as BW change is the largest driver of RE as estimated in this experiment. Notably, cows fed monensin at the 80% intake level had a more modest initial decline in BW, although ultimately achieving a similar stasis point. This may have resulted in an effective slower adaptation to the new plane of nutrition, and thus slower reduction in maintenance requirement. This observation suggests that utilizing ionophores in intensive cow-feeding systems may be warranted, but that the timing of implementation may affect the outcome. Additional exploration of this strategy is needed. A third cow feeding trial was conducted, using the same general methods, to define the relationship between degree of energy restriction (relative to NRC predicted requirement) and change in maintenance requirement. A graded treatment structure was applied, with cows fed at 70, 85, 100, or 115% of predicted maintenance requirements. Table 3 provides diet formulated values and target intake levels for this trial. Table 4 describes the observed RE and HE estimates across intake levels. While overall RE values are lower for the cows fed at 115% relative to the observations of cows fed at 120%

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in the prior experiments, it is important to note that cows in Trial 3 were in the last trimester of pregnancy rather than the second trimester, as in the first two cow trials. Accounting for the large demand of the fetus yields reduced RE estimates. Importantly, a regression of HE on deviation from NRC predicted energy provision suggests that each 1 percentage unit reduction in feeding level results in a 40 kcal/d reduction in NEm required. 66

Comparing cattle fed at 70% vs. those fed at 115% (a 45 unit delta) yields an estimated reduction in daily NEm requirement of 24%. This is consistent with the change in requirements observed in the previous trials, in which a 40 unit span of energy provision existed. Importantly, these initial results suggest that the reduction in requirements due to intake restriction is a robust, repeatable strategy for reducing feed requirements in confine-

Innovations in Intensive Beef Cow Production, Care and Management

ment cow feeding systems. Results from the third trial also suggest that an equation to predict the adjustment in NEm requirement as a function of intake target relative to NRC predicted requirements can be developed to aid in precision feeding for these systems. Strategies to reduce fixed costs per unit. While not a nutritional management problem (directly), strategies to reduce capital expense and thus fixed costs are important to the viability of strategic intensification. By definition, intensification typically imposes higher inputs and thus costs. However, mitigating fixed cost increases, or finding mechanisms by which variable cost increases are at least partially offset by fixed cost reductions, offers a viable strategy for enhancing the overall viability of the system. A common strategy for reducing fixed costs (e.g., land costs in a ranching operation) is to increase the units over which the costs are evaluated. Increasing headcount is one strategy, if number of cows is the unit of measure for fixed cost analysis. A more accepted measure might be units of output (cwt of calf weaned) so that the fixed cost portion of unit cost of production can be defined. In our conceptual model, we have assumed no per cow productivity impacts due to intensification. Clearly, this is an area in which validation is required, however, it is reasonable to assume that is other strategies for feeding are successful, cows will not be fed below nutrient requirements during confinement, and thus, no decline in productivity as a direct result of deployment of these strategies is expected. Under this assumption, increases in headcount are equivalent to increases in output. As described in Sawyer et al. (2013), the conceptual model utilizing 120 d of confinement feeding may yield approximately 35% increase in headcount without increasing forage utilization. Therefore, fixed costs may be expected to decline in general. Adding a confinement feeding system imposes additional capital expense, however, due to increased infrastructure and equipment requirements. Re-evaluation of the conceptual model, with cows in confinement for 1/3 of the year, suggested a strategic modification that might reduce infrastructure requirements by 67%. This strategy involves reducing required one-time feeding capacity to 1/3 of original concept; rather than feeding 100% of the cows for 1/3 of the year, 1/3 of the cows will be fed for 100% of the year in a systematic rotation. This concept (nicknamed â&#x20AC;&#x153;Red, White and Blue Management Systemâ&#x20AC;?) is detailed in Figure 3. Several mechanisms for cost reduction are anticipated under this strategy. First, because only 1/3 of the cows are in confinement systems at a given time, total equipment expenditure is reduced, infrastructure requirements are reduced, and labor requirement may be reduced. Second, shifting to multiple breeding seasons

may allow for a reduction in the total size of the bull battery, resulting in reduced capital outlay for breeding assets. Reducing the duration but increasing the frequency of calving seasons may reduce labor requirements and is likely to improve labor efficiency, as opportunities for specialization are greater in this system. Finally, the multiple calving seasons have been shown to reduce cow replacement costs above any single season in warm climates (Payne et al., 2009). We have established a cow herd to be operated under the Red, White and Blue system. Due to required transition from a dedicated spring calving system into the multiple season system, and to reduce selection bias, we elected to establish this herd using calves weaned from a spring calving herd and age sorted into the three groups for initial breeding. Calves from 2 successive years were entered into this system, with a target herd size of 250 females in production (approximately 83 per sub group). After establishment, replacements will be drawn only from within the Red, White and Blue System to keep it exclusive of the conventional system operated alongside. At the time of the Symposium, the Red group has weaned the first calf crop, the white group has calves at side and has completed the second breeding season, and the Blue Group is calving. While no results are yet available because a full cycle has not yet been completed, we felt it important to include this progress update relevant to this strategy. LIMITATIONS TO IMPLEMENTATION Implementation of intensive feeding systems may have a number of impediments. Capitalization of infrastructure is an important consideration, as dilution of fixed costs is a critical constraint for most extensive cow-calf operations, primarily due to land values. Thus, addition of fixed assets to support an intensification strategy must be carefully considered, and strategies to optimize this use of capital should be considered. Thus, the Red, White and Blue strategy can be viewed both as a leverage point or a solution to a barrier to implementation. Incorporating logistics into formulation models. Tactical limitations also exist. Feeding relatively low energy density diets as total mixed rations (TMR) creates logistics challenges, as less tonnage can be delivered per load and the cost per load and equipment cost per cow may increase in spite of a decrease in apparent ingredient cost. It is difficult to implicitly incorporate logistics considerations into formulation solutions, as delivery costs per load are location specific, ingredient characterization rarely includes information relevant to this specification, and methods to predict and formulate for ingredient interspersion are computationally complex and generally unavailable. To begin to address these challenges, we devised a

Innovations in Intensive Beef Cow Production, Care and Management

method to assess bulk density of ingredients, and in one additional step using the same equipment, to assess the ‘void space’ among particles in a standardized manner. The estimation of void space provides a proxy value from which interspersion potential can be estimated in a blending problem. Briefly, a cylinder 15 cm in diameter and 1.2 m in length as constructed with a removable closure on one end. The cylinder was filled without packing with a given ingredient until completely filled. A weighted disk 14.5 cm in diameter was placed at the top of the cylinder and allowed to compress the sample. The weight of the disk provided the only compression force. Once compressed, the vertical distance of travel (length of compression stroke) was recorded. The sample was removed in toto and weighed. Bulk density was computed as a function of mass and total cylinder volume. The difference between total cylinder volume and compressed sample volume was considered ‘void space’ or the space available for interspersion. Several common roughage and concentrate ingredients were evaluated (see Table 5). Sorghum × sudangrass hay was processed in a vertical mixer for different lengths of time to assess the effect of degree of processing on bulk density; generally, bulk density increased and void space decreased linearly with increasing processing time (P < 0.05; data not shown). Interspersion was tested by filling the cylinder completely with uncompressed roughage, then predicting void space given previous observations, and computing the mass of a concentrate ingredient required to fill the void space as a function of the concentrate ingredient bulk density. This amount was added, mixed into the roughage and the volume of the resulting mixture was measured. This method proved quite capable of predicting final volume and mass of blends with disparate bulk density and particle size. As an initial application, maximum payload of a vertical mixer given different proportions of either wheat straw or alfalfa combined with corn to maximum volume of the mixer were computed (Figure 4). Note that at 25%

roughage inclusion, predicted maximum load size is over 4-fold greater when alfalfa is used as the roughage source versus wheat straw. This effectively increases number of loads and thus delivery costs by over 4 times if a constant number of animals are to be fed. This gap widens if a constant daily amount of NEm is to be delivered. By estimating the variable costs of processing on a per load basis, and the indirect expense of depreciation per load, the total delivery cost differential can be computed and used as an additional formulation element, facilitating optimization of diet formulation and ingredient selection. Alternate feed delivery methods. In most intensive feeding scenarios, handling roughage ingredients offer the most complexity and cost. As indicated above, roughage inclusion, particularly of very low bulk density roughages, may increase logistical complexity and cost of delivery. Producers operating at smaller scales may not be able to justify the capitalization of equipment. Approaches that do not employ TMR may be valid in these settings. A trial was conducted to evaluate delivery of diet components in different packages. A diet formulation similar to that used as the high energy density diet in the trials described previously was formulated. Individually fed cannulated steers were provided one of four treatments: TMR, the diet fed as a TMR; -2S, the diet fed as separate roughage and concentrate packages, with concentrate package fed 2 h prior to roughage; +2S, roughage and concentrate fed separately, with concentrate provided 2 h following roughage; and 12S, components fed separately with concentrate fed 12 h following roughage. Steers were limit fed to mimic mean rates of DMI in cow trials; i.e., diet was offered at NRC predicted maintenance level. Little effect of treatment was observed on measures of ruminal fermentation or function. Mean ruminal pH was not affected by treatment, but a time × treatment interaction was observed (Figure 5). The driver of this interaction was a displacement effect; the post-prandial decline in ruminal pH occurred after concentrate

Innovations in Intensive Beef Cow Production, Care and Management

Figure 4.

feeding, regardless of the relative timing of roughage feeding. Thus, steers receiving 12S displayed a countercyclical decline in ruminal pH relative to those fed other treatments; however, if compared relative to the timing of concentrate feeding rather than roughage feeding, 70

this difference is obviated. Importantly, no steers experienced ruminal pH values below 6, suggesting that risk of acidosis may be relatively low when implementing these strategies.

Innovations in Intensive Beef Cow Production, Care and Management

CONCLUSION AND NEXT STEPS

DEVELOPMENT OF DECISION SUPPORT TOOLS Cumulative results suggest that optimal strategies likely include high energy density rations fed at substantially restricted rates. While results to date suggest that acidosis may be a relatively low risk, optimal energy density has not been defined, and these events may be ‘threshold events’, in which risk may increase precipitously once a critical threshold is passed. In a similar manner, while the strategies evaluated to date are promising, development of decision support tools requires more quantitative designs so the functional equations can be described in order to truly optimize strategies to local conditions. Near term experiments are planned to accomplish these objectives and move toward development and release of decision aids for cow-calf intensification. Initially, describing the response surface of maintenance requirements across a functional range of energy density × intake combinations is vital to accurately predicting requirements and moving toward precision programmed feeding. Defining a similar response surface for diet digestion as a function of the same two variables is also important, so that the combination of these feeding management strategies can be implemented most efficiently. Once defined, these outcomes can be accommodated in the bulk density model to facilitate decision making considering logistic constraints of bulky ingredients. Ultimately, by defining each of these relationships in terms of caloric value, outcomes can be predicted at the system level using the initial concept and model that includes the calories produced directly by the ranch forage base in addition to exogenous (purchased) calories. A suite of decision aids with a common variable (energy) describing both system requirements (energy demand) and resource availability (energy content of diets) can be devised. This is effectively expanding the concepts of the Net Energy System to the system level rather than the individual animal level. VALIDATION Experimental results, the strategies derived from them, and the decision support mechanisms developed to facilitate implementation must be validated. In our view, validation must, and will, occur through production. The Red, White, and Blue system provides the validation platform necessary for this critical step, as well as a platform in which to test refinements to strategy, identify new or unforeseen limitations and barriers, and inform subsequent models and tools development.

While substantial progress is being made to develop innovative strategies for the sustainable intensification of cow-calf production systems, new targets have already emerged. Within the next 24 months, we will execute or initiate at least 6 additional experiments and complete the first 2 cycles of the Red White and Blue project. These will include quantitative response surface designs to define dynamics of energy requirements and diet digestibility, assessment of the thresholds for acidosis risk and triggers in these systems, efforts to define the potential impacts of these management strategies on fetal development and programming, and the potential impact of maternal transfer of immunity and neonatal calf vitality. It is our near term objective to begin to devise simple decision aids to hasten implementation of these strategies. With a longer view, we aim to utilize the evaluation of these systems to more effectively define valid and quantitative measures of sustainability, and to make effective progress toward the key objectives defined by Texas A&M AgriLife Research and the Department of Animal Science for the development of Sustainable Solutions for Beef Production Systems. We gratefully acknowledge the continued support of the Kenneth and Carolyn MacDonald Eng Foundation, and of the Texas A&M AgriLife Research Sustainable Solutions Seed Grant Program, which has allowed effective multiplication of the Foundation support to produce faster, greater outcomes with an aim toward near term impact.

LITERATURE CITED Armstrong, D. G., and K. L. Blaxter. 1961. The utilization of the energy of carbohydrates by ruminants. Eur. Assoc. Anim. Prod. 10:187. FAO. 2011. The state of the world’s land and water resources for food and agriculture (SOLAW) – Managing systems at risk. Food and Agriculture Organization of the United Nations, Rome and Earthscan, London. Galyean, M. L., D. G. Wagner, and F. N. Owens. 1979. Level of feed intake and site and extent of digestion of high concentrate diets by steers. J. Anim. Sci. 49:199203. McLeod, K. R., and R. L. Baldwin. 2000. Effects of diet forage:concentrate ratio and metabolizable energy intake on visceral organ growth and in vitro oxidative capacity of gut tissues in sheep. J. Anim. Sci. 78:760-770. Nutrient Requirements of Beef Cattle: Seventh Revised Edition. 2000. National Academies Press, Washington, D. C.

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Payne, C.A., B.H. Dunn, K.C. McCuistion, S.D. Lukefahr, and D. Delaney. 2009. Predicted financial performance of three beef cow calving seasons in South Texas. Prof. Anim. Sci. 25:74-77. Reynolds, C. K., H. F. Tyrrell, and P. J. Reynolds. 1991. Effects of diet forage-to-concentrate ratio and intake on energy metabolism in growing beef heifers: whole body energy and nitrogen balance and visceral heat production. J. Nutr. 121:994-1003. Sawyer, J.E. and T.A. Wickersham. 2014. Does intensification improve sustainability? Dr. Kenneth and Caroline McDonald Eng Foundation Cow-Calf Symposium, San Antonio, Texas. Pg. 79-90. Sawyer, J.E. and T.A. Wickersham. 2013. Defining value and requirements in cow rations: What is a calorie worth? Dr. Kenneth S. and Caroline McDonald Eng Foundation Symposium, Lincoln, NE. Trubenbach, L.A., T.A. Wickersham, G.E. Carstens, and J.E. Sawyer. 2014. Managing energy requirements in confined cows. Dr. Kenneth and Caroline McDonald Eng Foundation Cow-Calf Symposium, San Antonio, Texas. Pg. 17-26.

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NOTES JASON SAWYER

Optimizing Use of Corn Residues for Grazing and Harvest Jason Warner University of Nebraska

OPTIMIZING THE USE OF CORN RESIDUES FOR GRAZING AND HARVEST IN INTENSIFIED COW-CALF PRODUCTION SYSTEMS Jason M. Warner1, Karla H. Jenkins2, Rick J. Rasby3, and Terry J. Klopfenstein3 1Graduate Student, Department of Animal Science, Lincoln 2Assistant Professor, Panhandle Research and Extension Center, Scottsbluff 3Professor, Department of Animal Science, Lincoln

INTRODUCTION Conventional cow-calf production systems are dependent on forage resources for grazing or hay production. If such traditional forages become limited or unavailable, other feedstuffs must be utilized to maintain the beef cow-calf enterprise in an intensively managed (confinement) system. While grain commodity prices have fluctuated recently, many dynamics have increased land values and initiated the conversion of traditional forage acres to grain crop production, particularly throughout the Midwest and Northern Great Plains. Although traditional forage production in these regions has decreased, the availability of alternative forage in the form of corn residue is growing as a result of increased corn production. Therefore, corn residues represent a valuable forage resource for beef cattle production systems in areas where grain production is abundant. Our objectives with this report are to review the changes in cattle inventory, land use trends and forage production, present the composition and nutritional value of corn residue, and discuss the utilization of residues in intensified cow-calf systems using either grazing or harvesting.

CATTLE INVENTORY There has been much discussion within the industry regarding the declining cattle inventory. Clearly, cattle inventories have decreased overtime for a myriad of reasons including the fact that the industry has become more efficient with fewer animals. Regardless, many have questioned what the long-term implications will be if the cattle industry continues to downsize. While the total U.S. beef cow inventory has declined by about 15 million hd since 1975, cow numbers actually increased by approximately 650,000 hd or 2% nationwide from 2014 to 2015 (USDA, 2015). This small increase is likely due to increased heifer retention and decreased beef cow harvest permitted by favorable weather conditions. However, changes in beef cow inventories appear to be region specific and influenced to an extent by land use practices. For example, the U.S. beef cow herd shrunk by about 2.4 million hd between 2006 and 2011 (MacDonald et al., 2014). Interestingly, nearly 50% of that inventory reduction occurred in the

Midwest and Northern Great Plains states including Nebraska, Kansas, Missouri, Iowa, South Dakota, and others farther north and east. This implies that traditional forage resources necessary for cow-calf production may be changing in areas which favor grain crop production.

LAND USE TRENDS, ECONOMICS AND FORAGE PRODUCTION Although grain prices have fluctuated during the past 2-3 years, corn and soybean prices have generally been high over the last decade as a result of demand from the biofuel industry (Wright and Wimberly, 2013). Corn prices essentially doubled from 2006 to 2011. This has prompted an accelerated conversion of grassland to cropland throughout the major corn production areas of the United States. As reported by Wright and Wimberly (2013), grassland transformation to crop production between 2006 and 2011 was primarily in the eastern half of North and South Dakota with similar grassland conversion patterns observed in Nebraska. However, South Dakota and Iowa contained areas with the highest concentration of land use change from grassland to corn/soybean production, with 451,000 and 376,000 acres converted in those states, respectively. The total net decrease in grassland during this time period was over 1.3 million acres in the entire region (N. Dakota, S. Dakota, Nebraska, Minnesota, Iowa). On an annual basis, conversion rates averaged between 1 and 5.4% per year. In addition to elevated crop prices, risk management programs such as federal crop insurance and disaster relief may also encourage producers to convert grassland to cropland. In many instances, once grasslands are tilled for crop production, they may never be reestablished for pasture or hay production, particularly if fences and watering sources are removed. As economic fundamentals work, a shortage of pasture and land for hay production leads to increased prices during periods of high demand. Low cattle inventories have led to record high cattle prices resulting in increased demand for pasture and other grasslands, particularly now as interest in expanding the cowherd has grown due to improved moisture conditions in

Innovations in Intensive Beef Cow Production, Care and Management

most cow-calf production areas. Pasture rental rates in Nebraska have increased by approximately 40% on average from 2006 to 2012 (MacDonald et al., 2014). In 2014, pasture rental rates ($ per cow-calf pair per month) averaged $46 across all regions of Nebraska (range of $32 to $60) (Jansen and Wilson, 2014). The average value of tillable and non-tillable grazing land in Nebraska increased by 14 and 24%, respectively, between 2013 and 2014 (Jansen and Wilson, 2014). The same trend of increasing pasture prices can be found in other states as well. A 2015 Iowa survey demonstrated pasture rental fees averaged $22 per AUM or $34 per pair per month, up from $10.70 per AUM in 2005 (Plastina et al., 2015). In South Dakota, cash rental rates for pasture/rangeland have increased between 35 and 64% depending on region between 2009 and 2014 (Janssen et al., 2014). While surveys only represent what is reported by participants, these data provide evidence that pasture rental fees have strengthened in areas where pasture acreage has decreased. On a national basis, total acreage harvested for all hay production decreased about 4.5 million acres from 2005 to 2015 (USDA, NASS). During the same time period, total hay production in the U.S. decreased 10.7 million tons. The national average price for all hay increased approximately 85% ($96 to $178/ton) during the last decade (USDA, NASS). In Nebraska, total hay production declined about 900,000 tons from 2002 to 2012. In Iowa and South Dakota, total hay production has decreased 2.26 and 1.77 million tons, respectively, from 2002 to 2012. Regarding only alfalfa hay, total acres harvested in the U.S. declined 3.9 million acres, while alfalfa hay production decreased 14 million tons (USDA, NASS). However, over the same decade, U.S. corn production increased 1.7 billion bu, and area harvested grew by 19.2 million acres. This increase in corn production (1.7 billion bu) equates to 26 billion lb (DM) of residue produced. These changes in hay and corn grain production over time reflect the conversion of grassland to cropland in certain areas and validate that traditional forage resources (pasture, hay land) are diminishing while forage derived from crop residue is

expanding. As corn and residue production continues to increase, the possibility of removing a portion of the residue for forage becomes more evident because high amounts of residue can impede crop establishment in high production areas (Wienhold et al., 2013).

CORN RESIDUE COMPOSITION AND QUALITY Digestibility of corn residue varies by individual plant part and the proportion of parts within the entire plant differs as well. Thus, quality of either grazed or harvested residue is ultimately a function of which parts of the corn plant are consumed. Previous (FernandezRivera and Klopfenstein, 1989; Gutierrez-Ornelas and Klopfenstein, 1991) and more recent data (Wilson et al., 2004; McGee et al., 2012) have demonstrated these differences. As reported by McGee et al. (2012), the husk is the most digestible component of residue followed by the leaf blade and leaf sheath (Table 1). Observations indicate that these portions of the plant are also apparently palatable and consumed first by cattle. Digestibility of the stem and cob are relatively poor. As a percentage of the total plant (DM), the stem comprises the greatest proportion followed by the leaf, cob, and leaf sheath (Table 1). Husks are produced in smaller proportions, although it is the most digestible component of the corn plant aside from the grain. Additional data suggest an average of 15.5 lb of leaf and husk are produced per bushel of grain yield (range = 13.1 to 19.4 lb) (Musgrave et al., 2011). Certainly there is variation, but if cattle graze with 50% efficiency, then 8 lb (DM) of leaf and husk available for grazing per bushel of yield is a sound estimate for stocking rate. Another factor contributing to corn residue quality is the amount of residual grain remaining after harvest. Gutierrez-Ornelas and Klopfenstein (1991) reported 2 to 8% residual grain left in the field. This amount has likely declined to approximately 1.0 to 1.5% with improvements in harvesting efficiency, and hybrid resistance to diseases and insects. Down corn is typically an issue only in fields that have experienced wind or hail damage.

Innovations in Intensive Beef Cow Production, Care and Management

GRAZING CORN RESIDUE Provided winter weather is favorable, grazing is typically the most economical method of utilizing corn residues by beef cattle (Ward, 1978). During periods of dry weather, the grazing period may last 120 to 150 days throughout the fall and winter, which could represent significant savings over feeding harvested forages to meet the nutrient requirements of the cowherd. Certainly, there is always risk with grazing cornstalks as snow cover or moisture may require supplemental hay feeding or premature removal of cattle from fields. As noted by Ward (1978) it is critical for producers to have an emergency feed supply, such as hay, available if needed. Along with weather conditions, other factors such as the proximity of cowherds to cornfields, fencing, water, labor, and the willingness of producers to rent cornfields can also influence the economics of cornstalk grazing. Being nearby cornfields and therefore having less expense associated with transporting cattle would be an advantage for an intensively managed cowherd located in the corn belt region. Aside from weather and logistics, determining an appropriate stocking rate is the most critical aspect of a residue grazing program, because it influences both animal performance and the amount of residue remaining in the field after grazing. Stocking rate impacts the quantity of residue available for grazing per animal (Wilson et al., 2004). Consequently, the amount of higher quality plant parts (husk, leaf) available for grazing will be influenced by stocking rate which ultimately dictates overall diet quality. Cows grazing cornstalks at a high stocking rate either lost or maintained body condition score (BCS), while those grazing at a lower stocking rate maintained body condition (McGee et al., 2013). Similar results were reported by Gigax et al. (2011) with pregnant cows or heifers, suggesting that performance generally increases as stocking rate decreases. This is because cattle have selective grazing patterns and will prefer to consume grain first, followed by husks and leaves and will only eat cobs and stem if forced. Digestibility of residue fields decreases throughout the grazing season due to initial consumption of the higher quality plant parts, trampling, and other losses. Residue digestibility decreases at a greater rate as stocking rate increases (Wilson et al., 2004). As discussed by Wilson et al. (2004), this concept demonstrates how corn residue differs from other grazed forages. While the quality of native grasses declines throughout the grazing season, digestibility of individual residue components does not change over time, although quality of the entire field does change for the aforementioned reasons. Further, all of the forage is available at the beginning of grazing; there is no additional forage growth throughout the season. Corn residue (husk and leaf) yield is directly related to grain yield. Experiments conducted by UNL researchers have

demonstrated approximately 8 lb (DM) of leaf and husk available for consumption is produced per bushel of grain yield (Musgrave et al., 2011; McGee et al., 2012). Given a grain yield of 150 bushels per acre, one acre of residue could maintain one 1200 lb cow for about 50 days or one 550 lb calf for approximately 110 days. For every bushel of corn grain produced, there are approximately 45 lb (DM) of total residue and 16 lb (DM) of leaf and husk produced. We recommend stocking at a rate to remove only 8 lb (DM) of leaf and husk. Therefore, if stocking rate is appropriate, less than 12% of the total residue is removed by grazing if the digestibility of the leaf and husk is 55-60%. Some producers remain apprehensive that grazing corn residue will negatively impact subsequent crop yields, which is certainly a reason why some residue fields go unutilized. Concerns regarding soil compaction when the ground is thawed and wet, nutrient removal, and disappearance of ground cover are all common issues. Ten years of data from an irrigated field managed in a corn/soybean annual rotation in eastern Nebraska indicated no difference in subsequent corn yield when residue is not grazed or grazed in either the fall/winter or spring (Drewnoski et al., 2015). Soybean yields from the same field were improved by grazing corn residue the previous fall, but were not different if residue was grazed in spring or not grazed. Additional data collected from an irrigated field maintained in continuous corn production in western Nebraska show no difference in yield between not grazing or grazing residue the previous fall (Drewnoski et al., 2015). Whether or not a protein and/or energy supplement is necessary for cows grazing cornstalk residue will depend on stage of production, cow age, BCS, and stocking rate. A 1200 lb spring-calving cow grazing cornstalks during mid- to late-gestation has a CP requirement of 6.0 to 7.5% and a TDN requirement of 45 to 56% (DM) (NRC, 1996). Crude protein values for cornstalk residue have been reported from 2.2 to 7.8% (Wilson et al., 2004), with IVDMD values of 33 to 59% depending on plant part (McGee et al., 2012). Therefore, the ability of residue to meet the protein and energy requirements of gestating cows will be influenced largely by stocking rate because of its influence on the proportion of plant parts consumed. In a large study conducted over several years, supplementing gestating spring-calving cows grazing irrigated cornstalks with a dried distillers grain based cube did not influence cow BW, although BCS at calving was greater for supplemented cows (5.6 vs. 5.4, P = 0.02) (Warner et al., 2011). However, supplementation did not impact the percentage of females cycling prior to breeding, pregnancy rates, or calf weaning weights. Cows in this study were â&#x2030;Ľ 3 years of age, were in adequate BCS (â&#x2030;Ľ 5.0) prior to cornstalk grazing, and stocking rate was assigned such that cows only consumed leaves and husks. Similar results were reported

Innovations in Intensive Beef Cow Production, Care and Management

by Larson et al. (2009) with 3-5 year old spring-calving cows suggesting that cornstalk residue may be of sufficient quality for mature, gestating cows in adequate BCS that graze at an appropriate stocking rate. Cows that have lost BW and BCS during summer and enter the fall cornstalk grazing period in a negative plane of nutrition will likely require supplementation to regain condition prior to calving. Initiating a supplementation program 90 to 120 days pre-calving allows adequate time for body condition to be regained at less expense as opposed to waiting until the beginning of calving when nutrient requirements greatly increase. Pregnant heifers grazing cornstalks will also require supplementation to enable females to continue to grow and develop prior to having their first calf. Summer or fall-calving cows that graze cornstalks with calves at side will require supplementation because of increased

nutrient demand for lactation. This is an area UNL is currently researching because incorporating winter cornstalk grazing into an intensive cow management system appears to be economical. In this study, summer-born cow-calf pairs either remained in drylot pens and were limit-fed a complete diet (Table 2), or grazed winter cornstalks with supplementation (Table 3). Within each location, all calves were weaned on a common date at the end of the cornstalk grazing period. Although pregnancy rates were adequate (â&#x2030;Ľ 90%) among treatments, cows at ARDC lost BW and BCS (Table 4) while grazing cornstalks. At ARDC, calf ADG was greater for calves that remained in drylot pens (Table 5). In previous work (Griffin et al., 2010), lactating August-calving cows grazing cornstalks lost about 150 lb and 1.0 BCS unit during winter while receiving 1.0 lb (DM) per pair daily of a 28% CP supplement, indicating additional energy and protein may be necessary for cows to maintain

Innovations in Intensive Beef Cow Production, Care and Management

BW and BCS. Weaned calves grazing cornstalks also require protein supplementation to achieve acceptable BW gains.

RESIDUE HARVESTING METHODS Essential for an intensively managed cow-calf system is an economical source of forage when cows are being fed a complete mixed diet. Aside from the opportu-

nity to graze corn residue following harvest, increased corn production also allows for residue to be harvested as either silage or baled cornstalks. While harvesting corn silage may be less common for conventional cow-calf operations, it enables producers to store feed in advance of when it is needed and provides an excellent source of energy for lactating cows or growing calves, if harvested and stored correctly. When priced relative to corn, silage may be competitive with other

Innovations in Intensive Beef Cow Production, Care and Management

forages on a per ton DM basis and a more economical source of energy. Harvesting corn as silage may also afford flexibility for an integrated cow-calf/crop production system. Alternative forages (wheat, rye, triticale, brassicas) can be seeded into corn silage ground after harvest and grazed in either fall or spring provided adequate forage growth is achieved (Drewnoski, 2014). Alternative crops following silage harvest will produce high quality forage (â&#x2030;Ľ 65% TDN) which can complement the nutrient requirements of summer/fall-calving cows or weaned calves. These crops can also help extend the grazing season earlier in the fall or later into the spring beyond that normally provided by grazing corn residue. Baling cornstalks after grain harvest is a common method of harvesting corn residue. Raking the residue into windrows before baling results in greater yield per acre, but reduces forage quality because a greater proportion of stems are collected. Conventionally raked and baled residue removes a greater proportion of total residue from the field and increases soil contamination in the bale. Residue is critical for protection from erosion and provides soil nutrients for future crops, so maintaining a balance between removing residue for forage and leaving an amount sufficient for soil health and productivity is important. Currently, commercial equipment manufacturers are researching new residue harvesting technologies, with the main objective being to alter the proportion of plant parts in the finished bale. Preliminary data (Updike et al., 2015) indicate both yield of harvested residue per acre and digestibility of the bale would be influenced. Adoption of this technology may aid in maintaining a balance between forage quality and yield when harvesting baled residue.

CONCLUSIONS Changes in land use present both challenges and opportunities for the beef industry. While increasing corn production is related to the decline in traditional forage acres, residue from corn production represents a forage resource becoming more abundant. The nutritional quality of corn residue is influenced by the proportion of plant parts consumed. Grazing cornstalks during fall/winter presents an opportunity for intensified cowcalf systems to capitalize on an economical forage and different methods for mechanically harvesting and storing residue for use in complete diets are evolving. Designing intensified cow-calf systems that are integrated with crop production will be essential for the beef industry in an era of increasing crop production.

LITERATURE CITED Drewnoski, M. 2014. Secondary forage crops, opportunities and challenges in corn and soybean fields. University of Nebraska-Lincoln Husker Beef Nutrition Conference Proceedings. 82

Drewnoski, M. E., L. A. Stalker, J. C. MacDonald, G. E. Erickson, K. J. Hanford, and T. J. Klopfenstein. 2015. Effect of corn residue removal on subsequent crop yields. NE Beef Cattle Rep. MP101:53-55. Fernandez-Rivera, S., and T. J. Klopfenstein. 1989. Yield and quality components of corn crop residues and utilization of these residues by grazing cattle. J. Anim. Sci. 67:597-605. Gigax, J. A., C. D. Buckner, L. A. Stalker, T. J. Klopfenstein, and S. J. van Donk. 2011. Effect of stocking rate on animal performance and diet quality while grazing cornstalks. NE Beef Cattle Rep. MP94:33-34. Griffin, W. A., D. C. Adams, L. A. Stalker, R. N. Funston, J. A. Musgrave, T. J. Klopfenstein, and G. E. Erickson. 2010. Effect of calving season and wintering system on cow performance. NE Beef Cattle Rep. MP93:5-7. Gutierrez-Ornelas, E., and T. J. Klopfenstein. 1991. Changes in availability and nutritive value of different corn residue parts as affected by early and late grazing seasons. J. Anim. Sci. 69:1741-1750. Jansen, J. and R. Wilson. 2014. 2014 Nebraska farmland values and rental rates. University of Nebraska-Lincoln Extension Cornhusker Economics. Online. Available: http://agecon.unl.edu/documents/2369805/5842081/7-2-14.pdf Janssen, L., K. Dillivan, and B. McMurtry. 2014. South Dakota agricultural land market trends 1991-2014. The 2014 SDSU South Dakota farm real estate survey. South Dakota State University Extension. Online. Available: http://igrow.org/up/resources/03-7000-2014.pdf Larson, D. M., J. L. Martin, D. C. Adams and R. N. Funston. 2009. Winter grazing system and supplementation during late gestation influence performance of beef cows and steer progeny. J. Anim. Sci. 87:11471155. MacDonald, J. C., G. E. Erickson, and T. J. Klopfenstein. 2014. Update on residue research. University of Nebraska-Lincoln Husker Beef Nutrition Conference Proceedings. McGee, A. L., J. L. Harding, S. van Donk, T. J. Klopfenstein, and L. A. Stalker. 2013. Effect of stocking rate on cow performance and grain yields when grazing corn residue. NE Beef Cattle Rep. MP98:36-37. McGee, A. L., M. Johnson, K. M. Rolfe, J. L. Harding, and T. J. Klopfenstein. 2012. Nutritive value and amount of corn plant parts. NE Beef Cattle Rep. MP95:11-12. Musgrave, J. A., J. A. Gigax, L. A. Stalker, T. J. Klopfenstein, M. C. Stockton, and K. H. Jenkins. 2011. Effect of corn

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hybrid on amount of residue available for grazing. NE Beef Cattle Rep. MP94:22-23. NRC. 1996. Nutrient requirements of beef cattle. 7th rev. ed. Natl. Acad. Press, Washington, D. C. Plastina, A., W. Edwards, and A. Johanns. 2015. Cash rental rates for Iowa 2015 survey. Iowa State University Extension and Outreach. Online. Available: https://www. extension.iastate.edu/agdm/wholefarm/pdf/c2-10.pdf United States Department of Agriculture National Agricultural Statistics Service. Quick Stats. Online. Available: http://quickstats.nass.usda.gov United States Department of Agriculture. 2015. January 1 cattle inventory report. National agricultural statistics service. Online. Available: http://usda.mannlib.cornell. edu/usda/current/Catt/Catt-01-30-2015.pdf Updike, J. J., J. L. Harding, T. J. Klopfenstein, and J. C. MacDonald. 2015. Effect of harvest method on In Vitro digestibility of corn residues. NE Beef Cattle Rep. MP101:62-63. Ward, J. K. 1978. Utilization of corn and grain sorghum residues in beef cow forage systems. J. Anim. Sci. 46:831-840. Warner, J. M., J. L. Martin, Z. C. Hall, L. M. Kovarik, K. J. Hanford, and R. J. Rasby. 2011. The effects of supplementing beef cows grazing cornstalk residue with a dried distillers grain based cube on cow and calf performance. Prof. Anim. Sci. 27:540-546. Wienhold, B. J., G .E. Varvel, V. L. Jin, R. B. Mitchell, and K. P. Vogel. 2013. Corn residue removal effects on subsequent yield. NE Beef Cattle Rep. MP98:40-41. Wilson, C. B., G. E. Erickson, T. J. Klopfenstein, R. J. Rasby, D. C. Adams, and I. G. Rush. 2004. A review of corn stalk grazing on animal performance and crop yield. NE Beef Cattle Rep. MP80-A:13-15. Wright, C. K., and M. C. Wimberly. 2013. Recent land use change in the Western Corn Belt threatens grasslands and wetlands. Proc. Natl. Acad. Sci. 110:41344139.

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NOTES JASON WARNER

Health Management of Neonatal Calves Born in Confinement Systems Jared Taylor Oklahoma State University, Vet Med

HEALTH MANAGEMENT OF NEONATAL CALVES BORN IN CONFINEMENT SYSTEMS Jared D. Taylor, DVM, MPH, PhD, DACVIM, DACVPM Associate Professor, Oklahoma State University Center for Veterinary Health Sciences Successful operation of a cow-calf operation requires cows to deliver live, viable calves, which are appropriately managed to become suitable for progression into other production segments (stocker, feedlot, etc.). In general, cow-calf producers are quite capable of achieving this goal, with a reported pre-weaning mortality rate of less than 6% (National Animal Health Monitoring System, 2008). This death-loss was reported to be nearly equally split between mortality at or immediately following birth, and later death (44.5% and 55.5%, respectively). However, these data were derived exclusively from grazing based cow operations. While the objectives of a confinement operation are essentially the same, the challenges are notably different from range operations. To achieve the same rate of success (or better) as seen in grazing environments requires overcoming the obstacles inherent to confinement and realizing the full benefits of the advantages.

DYSTOCIA The first challenge in this process is delivery of a live calf. Dystocia is the primary cause of stillbirth or perinatal death for grazing beef cows (National Animal Health Monitoring System, 2008).Selection for calving ease is essential for reducing dystocia of heifers. In general, mature cows have a relatively low dystocia rate, primarily due to malposition of the calf. Dystocia in cows can become a more significant issue if management of the environment contributes to delays in progression of labor. It has been shown that moving beef heifers from a grazing environment to a confinement environment with continuous presence of a person increased dystocia and stillbirth (Duffy, 1981). It has also been shown that moving dairy cows to maternity pens after labor has begun will prolong labor (Proudfoot et al, 2013). This research, while not directly applicable to typical practices in a confinement operation, highlights concerns regarding how cows will respond to calving in confinement. Cows instinctively seek seclusion and isolation as parturition approaches (Proudfoot et al, 2014). An inability to separate from the herd, close contact or observation by pen riders, or moving cows to different pens during the birthing process all pose a risk of delaying progression of delivery. Such delays pose a notable risk for stillbirth. But even if the calf is eventually delivered alive, hypoxia, acidosis, and other complications can have long-lasting impacts, as those calves are slower to rise and suckle. Such calves are at greater risk of passive transfer because of this delay in suckling (see below). Moreover, acidotic calves may have impaired absorp-

tion of colostral antibodies, although the finding has not been consistent (Weaver et al, 2000). Successful, rapidly progressing calving requires an environment in which cows can be comfortable, at ease, and undisturbed. This requires, at a minimum, adequate space for cows to isolate themselves within the pen. When a structure was constructed inside the maternity pen to allow cows to seclude themselves (while potentially still being able to see other cows), dairy cows showed a preference for calving within the structure (Proudfoot et al, 2014). Creation of a temporary structure or some other means of providing â&#x20AC;&#x153;privacyâ&#x20AC;? may be beneficial in a confinement operation, particularly for cows that are nervous or have had inadequate time to acclimate to a confinement environment. Pen riders should be well trained in normal birthing behavior and recommendations for when to intervene. While it is imperative that assistance be provided early enough to protect the life and health of the calf, there is a balance to be maintained in allowing nature to take its course vs. intervening. In general, only 2% of cows should require assistance (a larger percentage of heifers will need help- up to 10%). If assistance is needed significantly more frequently than these rules of thumb, it should be determined whether intervention is being instigated too aggressively, if something is interfering with appropriate progression, or some other issue is present (excessive calf birthweight, etc.). Proper management of dystocia would require greater length of time than available in this forum to discuss. But great resources are available, including online @: http://pods.dasnr.okstate.edu/docushare/dsweb/Get/ Document-9389/E-1006web2014.pdf

COLOSTRUM INTAKE Adequate colostrum intake is essential for providing calves with immune components necessary for fighting off disease-causing pathogens ubiquitous in the environment. The most important component of colostrum is considered to be antibodies (primarily IgG), although other important immune factors are also present. The amount of antibodies absorbed equals: (concentration of antibodies in colostrum) x (volume of colostrum consumed) x (percent of antibodies absorbed)

Innovations in Intensive Beef Cow Production, Care and Management

Failure to absorb adequate antibodies is termed failure of passive transfer (FPT), and can result from one or more of the following problems: 1. Poor quality colostrum 2. Inadequate intake of colostrum 3. Inadequate absorption of colostrum Quality of colostrum generally has two componentsAdequate presence of antibodies, and absence of excessive load of bacterial contaminants. Bacterial contamination is unlikely to occur in the udder, and if present, will result in notably abnormal appearance of the colostrum. Contamination is more likely to be an issue if teats are very dirty, or if colostrum is collected from the cow and stored (inappropriately) before being administered to the calf. The presence of large number of bacteria in the gut at or prior to colostrum consumption decreases absorption of antibodies (James, 1978; Gelsinger et al, 2015) and potentially increases risk for scours (Gelsinger et al, 2015). Concentration of antibodies in the colostrum can be measured with a colostrometer or with a Brix refractometer. It is important to recognize, though, that these instruments are most commonly used for dairy cattle, which produce much larger volumes of milk, with lower concentration of antibodies compared to beef cattle (Guy et al, 1994). Therefore, colostrum that is considered “marginal” to “acceptable” from dairy cows may be inadequate for beef cows because calves are not going to voluntarily suckle the large volume that would be required (obviously this can be offset by milking out the cow and administering to the calf, but this is time consuming and labor intensive). Colostrum production is a process that begins several weeks before calving and ends abruptly at the time of calving (McGuirk and Collins, 2004). That means that there is, in essence, a limited amount of colostrum each cow can and will produce, and any loss of that colostrum results in less available for calves. Leakage of colostrum prior to calving should be very minimal in most beef cows. However, it can occur, resulting in loss of colostrum and increased risk of FPT in the calf. A more significant concern for loss of colostrum would be from mis-mothering. If a cow is suckled prior to delivery, the colostrum consumed will not be replaced. Dominant cows claiming calves of others, as well as calves suckling from cows other than their dam both present the opportunity for loss of colostrum in a prepartum cow with FPT likely for her calf once it is born. The percent of antibodies absorbed is heavily influenced by the amount of time that passes between birth and consumption of colostrum (Weaver et al, 2000). Absorption of antibodies from colostrum requires presence of special cell receptors in the gut of the calf. These receptors are only present for a brief period of time following birth; absorption is considered optimal in the first four hours after birth, with a notable decline 90

after 12 hours of age. Generally it is considered that absorption capabilities are gone by 24 hours after birth, although some absorption ability remains up to 36 hours if prior feeding does not occur (Weaver et al, 2000). A variety of other factors have been investigated regarding impact on absorption of antibodies from colostrum (sucked from a nipple vs. tube-fed, metabolic status of the calf, etc.). While some of these things have been “statistically significant,” overall this work has shown that the most important thing to do is get clean, goodquality colostrum into calves quickly. It is difficult to make recommendations on colostrum management for confinement cow calf operations because nearly all research has been related to dairy cattle. Nonetheless, the following should give a good start on ensuring appropriate colostrum intake and minimizing FPT. • Cows should be watched closely to ensure no cross-suckling or mis-mothering takes place, particularly prior to calving. This should include proper ID to match up cow with calf • Assistance should be provided to cows not progressing in labor, either due to true difficulty in delivery or simply apprehension • Calves should be monitored closely for ability to sit sternal within 15 minutes of birth. Calves that fail to attain sternal recumbency by this time have been found to be at greater risk for FPT (Murray et al, 2015) • Cows with large teats, extremely large udders, or poor udder confirmation present a challenge for calves to suckle. Such cows should be monitored closely to ensure the calf is able to find teats, “latch on,” and suckle for an adequate time. Otherwise, the cow should be milked and the calf tube-fed or provided an alternative source of colostrum • Calves that have not been observed to rise and suckle (or at least demonstrate intention to suckle) within 4 hours of birth need to be prioritized for intervention • Operations with a history of FPT should consider testing of colostrum for quality (either periodically or on a systematic, on-going basis). If a calf is deemed to be at risk, a variety of intervention(s) are available to combat FPT. The first, and in most cases, preferred, option would be milking of the dam and delivery to the calf (either via a bottle or through esophageal tube feeder). However, this requires moving the dam to a restraint facility, is time consuming, and extremely labor intensive. Moreover, it may be very difficult to achieve in less than ideal conditions (i.e., when inclement weather is already stressing labor and facilities). If colostrum collection is practiced, it should be administered to the calf immediately after collection.

Innovations in Intensive Beef Cow Production, Care and Management

Alternatives to collection from the dam include use of colostrum from other cows, or a commercially available colostrum replacement. If colostrum is collected from other cows, it needs to be handled correctly. That includes sanitary practices in collection, and either administration immediately after collection; rapid cooling and storage in refrigerator for no more than 5 days; or freezing (can be stored for up to one year). Each 30 minutes that colostrum is allowed to sit at room temperature equates to a doubling of the number of bacteria in the colostrum. Thus, even good quality colostrum will spoil rapidly and will do more harm than good when administered to a calf. My expectation is that few, if any, operations would choose to collect colostrum from their cows, but would instead acquire colostrum from dairy sources. Such a practice offers the benefit of a steady supply without investment of labor. However, quality control measures need to be in place to ensure that the product purchased is of good quality. The worst case scenario is purchase of low-quality colostrum which introduces novel diseases/organisms to the operation environment. If purchasing colostrum, it is preferable to purchase it as a frozen product, in single use volumes, derived from only one cow per serving (as opposed to pooled, where colostrum from many animals is combined). Purchase of fresh colostrum requires keeping the product cool from purchase until feeding, with storage no greater than 5 days. Use of pooled colostrum has been shown to lead to consistently lower antibody concentrations as opposed to use of good-quality colostrum from a single animal (Weaver et al, 2000). If purchasing from a dairy, ensure that the farm tests their colostrum and that all offered for sale is high-quality. Some dairies choose to pasteurize colostrum. Pasteurization greatly reduces the bacterial contamination present, which extends the length of time it can be stored at refrigerated temperature. Perhaps counterintuitively, pasteurization actually increases the absorption of antibodies (Gelsinger et al, 2015; Elizondo-Salazar et al, 2011). Finally, pasteurization also reduces the likelihood of introducing novel pathogens into the operation. As such, if the option exists, pasteurized colostrum is certainly preferable to non-pasteurized. Colostrum that has been refrigerated or frozen must be warmed prior to feeding. This is best done in a warm water bath (water temperature between 100-120 degrees). It is essential that progress be monitored closely, as this temperature is ideal for bacterial growth. Therefore, colostrum should be fed as soon as it reaches the appropriate temperature (~98-104°F). Storage of colostrum in small batches (1 to 2 quarts, no more than 4 quarts) facilitates more rapid thawing and warming. A microwave can also be used for warming but must be done on low power with short intervals to avoid overheating. Overheating colostrum damages antibodies and changes the consistency to pudding, making administration impossible. If some is becoming warm

while portions still remain frozen, the liquid should be separated before further heating of the frozen to prevent overheating of what is thawed. As stated above, colostrum from dairy cows typically has a lower concentration of antibodies as compared to that from beef cows. As such, a larger volume is required. A typical recommendation is at least 3 quarts within the first 6 hours, with another feeding of at least 2 quarts at 12 hours of age. These are relatively large volumes for a calf to consume via bottle feeding, although it is achievable for many calves (Chigerwe et al, 2009). It has been suggested that absorption is improved in calves allowed to suckle milk from a bottle as opposed to being tube-fed. However, a difference was only seen when low quantity of antibodies was provided (Godden et al, 2009); when appropriate quantities are provided, no benefit is seen to bottle feeding over esophageal feeder (Elizondo-Salazar et al, 2011; Godden et al, 2009). Of course, greater training and expertise is required to administer via esophageal feeder due to the risk of inducing fatal pneumonia if the tube is inserted into the trachea rather than the esophagus. Operations should thus feel free to administer either via tube feeding (which is rapid and ensures adequate intake, but requires greater skill), or via bottle. However, if a calf fails to consume adequate volume from a bottle, tube feeding may still be necessary. Commercial products are available to assist in avoiding FPT. These can either be derived from colostrum or from plasma collected from cattle at slaughter. It is imperative to recognize an enormous distinction between products labeled as “colostrum replacement products” as opposed to “colostrum supplements.” Products labeled as supplements do not have adequate antibodies to prevent FPT alone and are intended to provide supplemental antibodies to the calf that also consumed colostrum. However, supplements are not needed when highquality colostrum is used, and combining supplements with poor quality colostrum often results in poorer absorption of antibodies than use of either high quality colostrum or colostrum replacement products (Jones and Heinrichs, 2011). As such, there is generally limited indication for use of supplements. In contrast, high-quality replacement products will have a minimum of 100 grams of antibodies per serving, and are intended to provide enough antibodies to provide adequate passive transfer by themselves. While these products are not as good as maternal colostrum at matching antibodies to the agents most likely to be encountered on a given operation, they are comparable to maternal colostrum in terms of amount of antibodies absorbed. They are also a much better source of nutrition than supplements, which is another critical factor in ensuring a healthy, vigorous calf. As such, if good quality colostrum is not available, or one is worried about disease transfer in colostrum (and pasteurization is not an option), colos-

Innovations in Intensive Beef Cow Production, Care and Management

trum replacements are the preferred means of ensuring passive transfer. When using such products, it is essential to follow directions. Volume to be mixed and number of feedings recommended can vary; failure to follow directions can result in FPT. The same rules apply for colostrum replacement products as for colostrummaintain cleanliness, get an appropriate amount in the calf, and do so as soon as possible. In general, calves should receive 150-200 grams of antibodies. If this requires two feedings, both should be administered by 12 hours of age.

equivalence in a number of parameters when navels were treated with 7% iodine, 4% chlorhexidine, 10% trisodium citrate, and a 0.1% chlorine-based product (Robinson et al, 2015). Unfortunately, this study did not include a negative control group. Most other literature on veterinary navel dipping is from observational studies. However, a large, systematic review found that chlorhexidine has been found to reduce infections in human neonates in developing countries (Imdad et al, 2013). This, along with the cited veterinary studies, supports the benefit of some treatment of navels.

PERI-PARTURIENT MANAGEMENT

Umbilical infection has been reported to affect between 1% and 14% of dairy calves, with much of the variation likely attributable to under-diagnosis (Grover and Godden, 2011). Dipping was able to reduce the rate of infections by up to 2/3 compared to no dipping (Grover and Godden, 2011). While recommendations vary, I advocate that attention be given to a calf’s umbilicus within 30 minutes or birth, or as shortly thereafter as possible. If more than a couple of inches of umbilical remnant hangs below the skin, clip the tissue with clean and sanitized scissors and dip or spray the stump immediately after. I personally prefer spraying, although complete and adequate coverage is more difficult. If dipping, ensure that the cup containing the dip is emptied after each calf and cleaned regularly. I believe that the choice of product used is less important than promptness and adequate coverage. As long as one is applying a safe, hypertonic, disinfecting compound within a couple of hours of birth, benefit is likely to be realized.

While ensuring colostrum intake is the most important task to accomplish after a calf is born, other steps should also be taken to protect the calf’s health. The unifying goal of these is limiting exposure to pathogens. Calving on grass is preferred to dirt, which is preferred to mud. Weather events are uncontrollable, but these logical conclusions should be accommodated, when possible. If calving in inclement weather is expected, plan to calve in areas of the yard that provide best drainage. Regardless of the environment, calves are going to encounter microorganisms shortly after birth. Older calves tend to be the worst multipliers of pathogens and thus the greatest risk to susceptible newborns. The Sandhills calving system addresses this by moving out of pastures cows that haven’t calved within the first 10 days to 2 weeks of entering the pasture. In this system, calves stay in the pasture where they were born, while limiting the age span of calves within any pasture. That means newborns are not being exposed to an area contaminated by a bunch of 30 day old calves. If your facilities are conducive to a similar system, pathogen buildup and transmission can be greatly reduced. At the very least, cows should be accurately staged for pregnancy and grouped in as tight a calving interval as possible. The most direct routes for pathogens to enter a calf are orally or through the umbilicus. Protecting against oral inoculation hinges on cleanliness of the environment in general, and specifically of the teats of the cow (or feeding equipment, if colostrum is administered). The risk posed by inoculation via the umbilicus can be reduced by minimizing exposure to pathogens, disinfection of the tissue, and speeding the natural desiccation process as much as possible. A number of products have been used for dipping navels, including iodine-based products (7% tincture or lower concentrations), chlorhexidine, alcohol, or proprietary products (Navel Guard, VetOne, Boise, ID; Super 7+, Vetericyn/ Innovacyn, Rialto, CA). Use of a commercial product was found to be effective in reducing umbilical infections compared to not dipping navels (Grover and Godden, 2011).The product was numerically superior but statistically no different from varying concentrations of iodine dip (Grover and Godden, 2011). Another study found 92

VACCINATION I intentionally place vaccination as my final point, and I won’t even address treatment of calves. Too often, producers and veterinarians are searching for an answer in a bottle, believing that the correct vaccination or treatment protocol will eliminate their problems. And if a commercial product doesn’t work, we must need an autogenous vaccine or a compounded drug! This approach is rarely successful, and it frequently distracts from the management issues that can have a meaningful impact. Thus, I have chosen to focus on the management issues first. Vaccination of cows in late-stage pregnancy is a commonly employed strategy to attempt to minimize scours in calves born to those cows. It has been shown that such vaccination results in production of antibodies by the cow, and delivery and absorption of these antibodies by the calf. Some evidence suggests that vaccination can be protective (Rousic et al, 2000), or at least part of an effective program for reducing calf scours (Meganck et al, 2015). However, other studies have found limited to no benefit of vaccination of cows in terms or reducing frequency of scours in calves (Kohara et al, 1997; Waltner-Toews et al, 1985). I consider the practice to be

Innovations in Intensive Beef Cow Production, Care and Management

a reasonable thing to do when management permits it, but it should not be viewed as a panacea. As always, be certain to follow the label, as typically these products require at least two doses be administered to previously unvaccinated animals, and administration may need to occur fairly late in gestation. Products are also available that are administered orally to calves immediately after birth to stimulate active immunity (rather than relying on the passive immunity acquired through colostrum). These products necessitate delaying colostrum intake since the antibodies in colostrum can inactivate the vaccine and prevent it working. Such requirements make these products very management-intensive, and aren’t an approach I would advocate. Vaccination of calves for respiratory disease is advocated by some in dairy calves. Intranasal modified live viral vaccines such as InForceTM 3 or similar appear to provide local immunity even in the face of maternal antibodies. Anecdotally, they also have minimal negative impact on calves (i.e., no “sweats”). These vaccines can be given within the first week of age, and even as early as day 1. However, it still requires some time for immunity to develop, so these are most effective for respiratory disease beginning 3 weeks of age or later. As always, management aspects impacting disease should be first priority, meaning ensuring good ventilation in their micro-environment.

MONITORING Adherence and success of all SOPs should be assessed through routine monitoring efforts. Adequacy of passive transfer can be assessed through measurement of total protein in the serum of calves. Total protein (TP) content of the blood is not equivalent to antibodies. However, it correlates very well, allowing this simple procedure to be very reliable assessment of colostrum intake and absorption. Measurement of TP entails collecting blood from calves between two and five days of age. Assessment prior to two days of age may result in underestimation of acquired antibodies, as peak concentration isn’t reached until approximately 32 hours after birth (Stott et al, 1979). Delay in collection beyond five days can complicate interpretation, as greater variation develops over time depending upon endogenous production of proteins, consumption of immunoglobulins, hydration status, etc. Blood can be collected from any access point although the jugular vein is generally the easiest source. It should be collected into a red-top tube (a sterile tube with no anticoagulant) or a plain capillary tube. The blood should then be allowed to clot prior to separation of sera from the cells via centrifugation. Inhibition of clotting by presence of an anticoagulant means that the protein fibrinogen remains in the sample. Presence of fibrinogen alters the cut-points for interpretation of passive transfer, and can distort finding in the presence of inflammation (which increases fibrinogen

production). After separation, serum is evaluated via refractometry to assess the TP of the sample. Historically, optical refractometers have been used, but recent research has validated Brix refractometers (Deelen et al, 2014; Elsohaby et al, 2015). The value deemed to best represent “adequate passive transfer” vs. FPT is open to debate. Historically, dairy-based references have stated that 5.2 gm/dL (as determined by optical refractometer) is an acceptable target (Chigerwe et al, 2009). More recent work has shown that 5.5 gm/dL is an achievable goal, and a better target. Less work has been done looking at beef calves. Research from South Dakota recommended a cutoff of 5.5 gm/dl (Courtney et al, 2000). However, this was in calves approximately one to three days of age. Thus, it is possible TP levels continued to increase after sampling for calves sampled earliest in life. More importantly, work has shown that, in general, more is better. That is, even calves that have “adequate” passive transfer are at greater risk of disease than those that have higher levels of antibodies (Waldner and Rosengren, 2009). Therefore, the goal should be not to achieve “adequate,” but to maximize. My experience suggests that >5.5 gm/dL (optical refractometer; ~8.3% on a Brix) should be achievable for nearly all calves, and should be the minimum value considered acceptable for calves born without complications and from cows with good udder confirmation. The majority of calves should be above 6.0 gm/ dL. Routine monitoring should not only be designed to ensure these goals, but also to establish trends. If an apparent decline is observed over time, interventions should be taken based upon that trend rather than waiting until values become unacceptable. It is important to recognize that much of the value of measuring TP is at the herd level, not the individual calf level. On occasion, calves will test unexpectedly low, with no readily apparent explanation. Managers and employees should not focus excessively on these instances. Instead, focus should be on the typical values observed and the trend in values over time. In range situations, it has been estimated that 6% (Waldner and Rosengren, 2009) to 12.8% (Courtney et al, 2000) of beef calves suffer from FPT (one study reported as high as to 19% (Filteau et al, 2003), but management practices were not consistent with standard North American practices). In these reports, illness or death was up to three times more likely in calves diagnosed with FPT. These findings do more to highlight the importance of passive transfer than give a target for performance. Benchmarks aren’t readily available for beef cattle but it has been recommended that <10% of calves suffering FPT should be an achievable goal in dairy calves (Chigerwe et al, 2009). This would seem like a reasonable target for an operation just beginning to monitor TP in calves. If TP monitoring identifies issues in passive transfer, monitoring of colostrum quality may be indicated.

Innovations in Intensive Beef Cow Production, Care and Management

Colostrum quality can be assessed by a colostrometer or a Brix refractometer (the same instrument as can be used for measuring TP). It is imperative to remember that antibody intake equals: (Antibodies per ml of colostrum) x (Quantity of colostrum consumed) The scale on a colostrometer considers 50 gm/Liter to be good quality. However, that is assuming consumption of approximately 10% of the calf’s body weight (which frequently necessitates use a an esophageal feeder to get that volume into the calf). In contrast, colostrum from beef cattle may be nearly twice as concentrated (~95 gm/Liter). If colostrum quality approaches 50 gm/L, the cow may not produce, nor the calf consume, enough colostrum to meet the calf’s needs. As always, be certain to read the instructions on using this instrument, as temperature of the colostrum greatly influences the reading that the colostrometer provides. If using a Brix refractometer, measurements of ~26% to 26.3% should be expected (equivalent to 95 gm/Liter), with 22.5% indicating a high volume is required. Readings below 22% should be considered low quality, and not be used. Additional monitoring parameters can include evaluation for umbilical infections and complications associated with such infections. Such assessment requires palpation of the navel area, not simply visual appraisal from a distance. In general, umbilical remnants should not be painful, and should decrease in size over the course of the first several days of life. Specific evaluation criteria can be found in a study by Grover and Godden (Grover and Godden, 2011). Clearly, not every calf needs to be caught and evaluated. But it is inadequate to rely simply on visual appraisal of calves in the pen. If a calf responds to modest pressure on the umbilical stump, if a “knot” remains palpable in a calf more than a few days old, or a hernia/body wall defect is present at the area of the umbilicus, it is likely an infection is or was present. Discovery of an umbilical infection should lead to evaluation of the individual calf for treatment; but more importantly, occurrence of infection in more than 2-5% of calves should prompt reevaluation of umbilical care, colostrum management, and general hygiene.

CONCLUSION Calving and subsequent management of calves in confinement presents unique challenges compared to typical cow-calf or even dairy environments. However, the same concepts apply. Cows should have a comfortable, non-stressful environment for calving. Intervention should be provided promptly when warranted, but not to an excess- if more than 2% of cows require assistance, management practices should be evaluated. Calves require appropriate quantity of quality colostrum as 94

soon after birth as possible. Navels should be dipped, and hygiene emphasized on all matters. It must be recognized that health is achieved by creating a favorable balance of exposure and immunity. If exposure to pathogens is minimized, not all calves with FPT will become ill. Calves raised in confinement, even under good management, are likely to encounter a heavier pathogen load than range calves. That means that to avoid severe health risks, you need to do better than what is reported in range calves. Moreover, if exposure becomes excessive, even “adequate” passive transfer will not protect from illness. That means that hygienic practices are essential to avoid overwhelming young calves. We all know that it is impossible to create what the general public would consider a “hygienic environment” in a feedlot-type operation. However, efforts to protect calves from heavy exposures will ultimately be far more fruitful than intensive focus on vaccines, medications, or even colostrum.

LITERATURE CITED Chigerwe, M., Tyler, J.W., Summers, M.K., Middleton, J.R., Schultz, L.G., Nagy, D.W. 2009. Evaluation of factors affecting serum IgG concentrations in bottlefed calves. Journal of the American Veterinary Medical Association. 234:785-789. Courtney, A., Epperson, W., Wittig, T., Pruitt, R.J., Marshall, D.M. 2000. Defining failure of passive transfer in South Dakota beef calves. AES 113th Annual Report 2000. Deelen, S.M., Ollivett, T.L., Haines, D.M., Leslie, K.E. 2014. Evaluation of a Brix refractometer to estimate serum immunoglobulin G concentration in neonatal dairy calves. J. Dairy Sci. 97:3838-3844. Duffy, J.H. 1981. The influence of various degrees of confinement and supervision on the incidence of dystokia and stillbirths in Hereford heifers. New Zealand Veterinary Journal. 29:44-48. Elizondo-Salazar, J.A., Jones, C.M., Heinrichs, A.J. 2011. Feeding colostrum with an esophageal feeder does not reduce immunoglobulin G absorption in neonatal dairy heifer calves. Professional Animal Scientist. 27:561564. Elsohaby, I., McClure, J.T., Keefe, G.P. 2015. Evaluation of digital and optical refractometers for assessing failure of transfer of passive immunity in dairy calves. J. Vet. Intern. Med. 29:721-726. Filteau, V., Bouchard, E., Fecteau, G., Dutil, L., DuTremblay, D. 2003. Health status and risk factors associated with failure of passive transfer of immunity

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in newborn beef calves in Quebec. Canadian Veterinary Journal. 44:907-913. Gelsinger, S.L., Jones, C.M., Heinrichs, A.J. 2015. Effect of colostrum heat treatment and bacterial population on immunoglobulin G absorption and health of neonatal calves. J. Dairy Sci. 98:4640-4645.

Keyserlingk, M.A.G. 2013. Effect of moving dairy cows at different stages of labor on behavior during parturition. Journal of Dairy Science. 96:1638-1646. Proudfoot, K.L., Jensen, M.B., Weary, D.M., von Keyserlingk, M.A. 2014. Dairy cows seek isolation at calving and when ill. J. Dairy Sci. 97:2731-2739.

Godden, S.M., Haines, D.M., Konkol, K., Peterson, J. 2009. Improving passive transfer of immunoglobulins in calves. II: Interaction between feeding method and volume of colostrum fed. Journal of Dairy Science. 92:1758-1764.

Robinson, A.L., Timms, L.L., Stalder, K.J., Tyler, H.D. 2015. Short communication: The effect of 4 antiseptic compounds on umbilical cord healing and infection rates in the first 24 hours in dairy calves from a commercial herd. J. Dairy Sci.

Grover, W.M., Godden, S. 2011. Efficacy of a new navel dip to prevent umbilical infection in dairy calves. Bovine Practitioner. 45:70-77.

Rousic, S.l., Klein, N., Houghton S., Charleston, B. 2000. Use of colostrum from rotavirus-immunised cows as a single feed to prevent rotavirus-induced diarrhoea in calves. Veterinary Record. 147:160-161.

Guy, M.A., McFadden, T.B., Cockrell, D.C., Besser, T.E. 1994. Regulation of colostrum formation in beef and dairy-cows. Journal of Dairy Science. 77:3002-3007. Imdad, A., Bautista, R.M., Senen, K.A., Uy M.E., Mantaring, J.B. III, Bhutta, Z.A. 2013. Umbilical cord antiseptics for preventing sepsis and death among newborns. Cochrane Database Syst. Rev. 5:CD008635. James, R.E., Polan, C.E. 1978. Effect of orally administered duodenal fluid on serum proteins in neonatal calves. J. Dairy Sci. 61:1444-1449.

Stott, G.H., Marx, D.B., Menefee, B.E., Nightengale, G.T. 1979. Colostral immunoglobulin transfer in calves I. Period of absorption. J. Dairy Sci. 62:1632-1638. Waldner, C.L., Rosengren, L.B. 2009. Factors associated with serum immunoglobulin levels in beef calves from Alberta and Saskatchewan and association between passive transfer and health outcomes. Canadian Veterinary Journal. 50:275-281.

Jones, C. and Heinrichs, J. 2011. http://extension.psu. edu/animals/dairy/nutrition/calves/colostrum/das11-180

Waltner-Toews, D., Martin, S.W., Meek, A.H., McMillan, I., Crouch, C.F. 1985. A field trial to evaluate the efficacy of a combined rotavirus-coronavirus/Escherichia coli vaccine in dairy cattle. Canadian Journal of Comparative Medicine. 49:1-9.

Kohara, J., Hirai, T., Mori, K., Ishizaki, H., Tsunemitsu, H. 1997. Enhancement of passive immunity with maternal vaccine against newborn calf diarrhea. Journal of Veterinary Medical Science. 59:1023-1025.

Weaver, D.M., Tyler, J.W., VanMetre, D.C., Hostetler, D.E., Barrington, G.M. 2000. Passive transfer of colostral immunoglobulins in calves. J. Vet. Intern. Med. 14:569577.

McGuirk, S.M., Collins, M. 2004. Managing the production, storage, and delivery of colostrum. Veterinary Clinics of North America, Food Animal Practice. 20:593603. Meganck, V., Hoflack, G., Piepers, S., Opsomer, G. 2015. Evaluation of a protocol to reduce the incidence of neonatal calf diarrhoea on dairy herds. Preventive Veterinary Medicine. 118:64-70. Murray, C.F., Veira, D.M., Nadalin, A.L., Haines, D.M., Jackson, M.L., Pearl, D.L., Leslie, K.E. 2015. The effect of dystocia on physiological and behavioral characteristics related to vitality and passive transfer of immunoglobulins in newborn Holstein calves. Canadian Journal of Veterinary Research-Revue Canadienne De Recherche Veterinaire. 79:109-119. Proudfoot, K.L., Jensen, M.B., Heegaard, P.M.H., von Innovations in Intensive Beef Cow Production, Care and Management

NOTES JARED TAYLOR

Intensified Cow/Calf Production in the Southern Great Plains Using Wheat Pasture, Semi-Confinement and Cover Crops: Year 2 Jarrod Cole Oklahoma State University

INTENSIFIED COW/CALF PRODUCTION IN THE SOUTHERN GREAT PLAINS USING WHEAT PASTURE, SEMI-CONFINEMENT AND COVER CROPS: YEAR 2 Jarrod Cole, Adam McGee, Corbit Bayliff, Miles Redden, Clint Rusk, Jason Warren, Gerald Horn, Ryan Reuter, and David Lalman Departments of Animal Science and Plant and Soils Science, Oklahoma State University, Stillwater, OK INTRODUCTION This report summarizes the second year’s results of an ongoing systems project described in detail by Lalman et al., 2014. The objective of this experiment is to document the economic and production outcomes of an extensive cow/calf enterprise utilizing native rangeland alone compared to an intensified system utilizing native rangeland, semi-confinement combined with winter wheat pasture and a summer cover crop on the wheat acreage. The second year of cow and pre-weaning calf performance data is summarized along with the first year’s steer progeny feedlot performance and carcass data.

MATERIALS AND METHODS YEAR 1 STEERS, FINISHING PERIOD Steer calves produced during the first year of the experiment entered the feed yard following 30 days of grazing sorghum-sudan grass (INT) or native rangeland (EXT). This portion of the experiment was conducted at the Willard Sparks Beef Research Center, just west of Stillwater, Oklahoma. Fall born Angus and Angus X Hereford calves (n = 39; BW = 773 ± 80.1) were penned based on their original pen assignment and fed in two pens per replicate group (12 pens total. 6 per treatment). Calves were processed upon arrival and fed a starter ration for ten days before initiation of a gradual ration concentrate step-up program. The INT system steers were sold on day 158 (January 27) and EXT on day 178 (February 16). YEAR 2 COW AND CALF PERFORMANCE Fall calving Angus and Angus x Herford cows (n = 93; BW = 1285 ± 163; BCS = 5.6 ± 0.7) were maintained in two forage system treatments: extensive (EXT) or intensive (INT). Following year one all pregnant and healthy cows remained in the same respective treatment and pasture management groups. Eight cows from EXT and eight cows from INT were culled for standard management practices such as poor udder structure, failure to become pregnant and old age. In order to maintain

stocking rate for EXT system or increase stocking rate for INT system, pregnant cows of similar genetics and management were added to each pasture group. These replacement cows were allotted by BW and age to maintain similar age and mature body weight among treatments. Cows assigned to the EXT treatment were continuously grazed with year-around access to 13.4 acres of open native rangeland for each cow/calf pair. This is considered to be a low stocking rate in this region and should provide adequate forage through the winter and with little supplemental hay required except in the case of severe drought. Only during severe inclement weather were cattle fed prairie hay (5.5% CP, DM basis). Dried distillers grain (32% CP, DM basis) was provided to the EXT cows and calves through the winter at a rate of 4 lb/pair/day and 3 lb/pair/day during late fall and early spring. Supplement feeding rate for EXT managed cows was designed to provide adequate rumen degradable protein while grazing low quality, dormant forage. The feeding rate was not increased to meet energy requirements because fall-calving cows typically compensate for winter weight loss during the spring and summer, to the point where they can become over-conditioned. The INT system was designed to reduce the land area required per cow/calf pair and increase production either through increased calf weaning weight, increased reproductive efficiency, or both. Cows assigned to the INT system were fed prairie hay (5.5% CP, DM basis) and mineral supplement in a dry lot through the winter period beginning December 4, 2014. During this time, INT cows had access to 0.8 acre of wheat pasture per cow/calf unit. On Monday, Wednesday and Friday each week, cows were allowed to graze wheat pasture for four hours. Because of excessive cow body condition as of January 3, the limit grazing period was reduced to three hours of grazing time per day. On February 4, limit grazing was decreased even further to two days per week with a three-hour grazing time each day. Calves were allowed continuous access to wheat through creep gates throughout the winter and spring. Beginning April 3, cows and calves were given free-choice access to wheat pasture. The graze-out period continued through May 1 when most of the wheat forage had been consumed. The INT cows were moved to native rangeland

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on May 1 with a stocking rate of 6.5 acres of open native rangeland per cow/calf pair. Experimental pasture groups assigned to both treatments grazed their respective native rangeland pastures from May 1 through June 18 when the cattle were gathered and calves were weaned. Red River ® crabgrass seed and N fertilizer was broadcasted on the wheat acreage on March 13. Sustained heavy rainfall through mid-June resulted in excellent crabgrass establishment and growth in approximately 65% of the area within each paddock. Crabgrass establishment and growth in the remaining area was nonexistent or delayed due to extended flooding of the lower areas within the paddocks. Calves from within the three INT replications plus additional yearling calves were returned to the cropland to graze the cover crop from June 22 through approximately August 15. After cover crop (INT) and native range grazing (EXT) through mid-August, steer calves will be shipped to a feedlot for finishing and heifers returned to native rangeland. The cover crop will be terminated and planted back to wheat in September to repeat the limit-grazing system for cows the following winter. During winter grazing, cow and calf wheat consumption was estimated during the 3-hour / 3-day and 3-hour / 2-day limit grazing period on 4 different occasions, 2 occasions for each limit grazing schedule: January 16, February 20, March 20, and 27. Each day, 2-4 cow/calf pairs from the same pasture were randomly selected. An individual BW was recorded immediately prior to turnout on wheat pasture. Cows were separated from their calves by a fence during the collection period to prevent nursing. Cows and calves were closely monitored during the grazing period, if defecation occurred

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fecal material was immediately collected in plastic bags and later weighed on an electronic scale. After planned grazing time had expired, cattle were gathered immediately and body weight was recorded. While the cows and calves were grazing wheat, forage samples were collected in the grazing area to determine wheat dry matter content. The following equation was used to determine wheat consumption: Wheat Consumption = (Final Weight, lb – Initial Weight, lb + Fecal Weight, lb) * Wheat DM, % Forage samples were collected once a month in all of the pastures to evaluate forage availability. The samples were weighed, and placed in a drying oven at 115ºF for 72 h, and then weighed again to determine DM content of the forage.

RESULTS AND DISCUSSION YEAR 1 STEERS, FINISHING PERIOD Entering the feedlot August of 2014, steer calves previously managed in the INT system weighed significantly more (P < 0.01; Table 1) compared to EXT-managed steers. In an attempt to finish the treatment groups at a common biological (back fat) end point, steers from the INT system were harvested 20 days sooner than the EXT steers. However, EXT system steers still had less (P < 0.01) back fat compared to INT steers. Consequently, back fat was used as a covariate in the performance and carcass data analyses to adjust to a common biological end point. Our expectation was that steers from the EXT system would outperform INT system calves as compensation

Innovations in Intensive Beef Cow Production, Care and Management

resulting from reduced weight gain during the winter. Surprisingly, steers from the INT system gained substantially faster with similar feed intake. This resulted in improved (P < 0.01) feed efficiency for the INT system steers. Compensatory weight gain varies according to duration and extent of dietary restriction (White et al., 1987). According to White et al. (1987), compensatory gain should take place early during the recovery period. Indeed, some compensation may have occurred in EXT system steers during the summer grazing period prior to feed yard entry (Lalman et al., 2014). However, during this late-summer grazing period, the treatment groups were grazing different forage species with different forage availability. Therefore, whether differences in late-summer grazing performance are due to compensatory growth or simply due to grazing system cannot be determined. Regardless, the dramatically improved performance of INT system steers was unexpected. Recall that these effects are not due to differences in in-utero nutrition as the cows were managed similarly until after the calving season when cows were divided into their respective treatment groups.

This excessive BCS prompted consideration of practical methods to reduce caloric availability to INT system cows in order to improve system efficiency and reduce annual cow costs. We chose to modify the INT system in two ways. First, throughout the course of the 2014/2015 winter period, cowsâ&#x20AC;&#x2122; wheat pasture limitgrazing time was reduced as described in the materials and methods section above. Secondly, the stocking density was increased from one acre per cow calf unit to 0.8 acre per cow/calf unit. On average, wheat pasture forage availability (Figure 1) was also lower in Year 2 compared to Year 1, resulting in further restriction of cow caloric intake during winter in the INT system. However, also shown in Figure 1, native rangeland forage availability was abundant throughout the wintering period for EXT system cows and calves. A prescribed burn was executed in late March in all experimental

There were no differences in marbling or HCW between systems (Table 2). However, yield grade was improved (lower) and REA was increased in the INT system steers (Table 2). YEAR 2 COW AND CALF PERFORMANCE Cows from the INT system entered the calving season of 2014 in excessive BCS (7.2, Lalman et al., 2014).

Innovations in Intensive Beef Cow Production, Care and Management

103

)

native rangeland pastures. In addition, precipitation was abundant beginning in April 2015 and continuing through June resulting in abundant native rangeland forage availability for both treatment groups during the spring and summer grazing period. Cows from both systems lost weight during the winter period although EXT system cows lost considerably more body condition (P = 0.02; Table 3). As expected, calves from the INT system gained at a faster rate and were substantially heavier (P ≤ 0.05) in April, May and at weaning in June. In fact, at the end of the limit-grazing period, compared to EXT system calves, INT system calves weighed an additional 102 lb in Year 2 whereas this difference was 53 lb in Year 1. Our observation was that creep grazing behavior began sooner and was more aggressive in Year 2. Increased calf performance was observed in Year 2 even though cows had less time grazing wheat and less forage available. Wheat forage intake was measured during several 3-hr grazing bouts. Results from the grazing bouts are separated into two categories: grazing 3 d/wk and 2 d/ 104

wk. During each grazing period, on average, the cows consumed 9.9 lb (0.8% BW) and 18.2 lb (1.6% BW) of forage DM, 3 d/wk and 2 d/wk, respectively. Calves consumed 1.4 lb (0.3% BW) and 2.7 lb (0.5% BW) of forage DM during the 3 d/wk and 2 d/wk grazing bouts. It appears that cows may have the ability to increase forage consumption and “fill up” to compensate for the reduction in grazing time. In addition, wheat forage DM availability increased over time through late-winter and early spring. Consequently, increased wheat forage DM intake during the 2-days per week 3-hour grazing bouts could be due to more aggressive grazing behavior when time on wheat was further restricted, greater forage availability or both. The wheat forage ranged from 27-48% DM across pastures and collection days. A mixture of sorghum-sudan, cow peas and sun hemp were planted as a cover crop in Year 1. A portion of the cover-crop forage was grazed and excess forage was harvested for hay. The excess forage produced within each paddock (replication) was fed to the same group of cows during winter in Year 2. Hay bales were

Innovations in Intensive Beef Cow Production, Care and Management

weighed on an electronic scale before being placed in basket-style ring feeders. Prairie hay disappearance average 15.5 lb DM per cow/calf pair each day when fed simultaneously with sorghum and 22.5 lb DM/pair/ day when fed alone. Sorghum disappearance averaged 14.5 lb DM/pair/day, but was preferred over the prairie hay because it was consumed completely before the prairie hay. No hay was fed during the grazeout period. The first week of May INT system cows were returned to native rangeland pastures with a higher stocking rate than Year 1 (6.5 ac/cow-calf pair compared to 7.8 ac/ cow-calf pair). During the late spring, treatment group rate of weight gain was no different for cows or calves (P=0.35 and P=0.59, respectively). Different situations may have different effects on calf performance. Similar to the grazeout period, Year 1 and 2 produced different results. The difference may be in response to the altered prescribe burn timing. In Year 1, burning took place in April, both systems were placed on regrowth at the same time. In Year 2, EXT system cattle began grazing fresh native regrowth, from the March prescribed burn, on the 16th of April, two weeks before the INT system cattle.

IMPLICATIONS In this ongoing experiment, INT system steer progeny produced during the first year gained at a faster rate and more efficiently, in the feedlot, compared to steers produced in the EXT grazing system. Hay produced from year 1 summer cover crop reduced the need for purchased hay during the second winter in the INT system. Even though the INT system was further intensified during Year 2, beef production measured as calf weaning weight was substantially greater compared to the EXT system.

LITERATURE CITED Lalman, D. L., J.R. Cole, A.L. McGee, C.L. Bayliff, M.D Reden, G.W. Horn, J.G. Warren. 2014. Intensified cow/ calf production in the southern great pains using winter wheat pasture, semi-confinement and cover crops. Kenneth and Caroline McDonald Eng Foundation Symposium. Proceedings Paper. Pgs. 61-67. White, T.W., F.G. Hembry, P.E. Humes, A.M. Saxton. 1987. Influence of wintering weight change on subsequent pasture. J. Anim. Sci. 64:32-35.

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NOTES JARROD COLE

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Essential your operation. Essential to to you you and andEssential yourEssential operation. to youtoand youyour and operation. your operation.

FAST FACTS PROTECT YOUR HERD’S PERFORMANCE Research shows internal parasites can cost a producer over $190 per head over the lifetime of each animal in lost performance1. Safe-Guard goes straight to the gut to kill internal parasites where they live.

ADD SAFE-GUARD – ADD POUNDS Choose Safe-Guard Because: Internal parasites threaten performance -Reduce average daily gain (ADG) -Reduce feed intake -Can impair the immune system of cattle Safe-Guard features broad-spectrum activity against internal parasites Cooperia is now confirmed as the most prevalent internal parasite in U.S. cattle herds (NAHMS 2009, 2010) Internal parasite (Cooperia) resistance to macrocyclic lactone compounds (endectocides) was confirmed in 2004 and continues to grow2 In a peer-reviewed published study, calves infected with macrocyclic lactone-resistant Cooperia had 7.4% less average daily gain and 5.4% less feed intake3 Safe-Guard eliminates these resistant parasites3 (98.1% effective)

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Important Safety Information: Safe-Guard EN-PRO-AL Molasses Block: RESIDUE WARNING: Cattle must not be slaughtered within 11 days following last treatment.

Safe-Guard Protein Block: RESIDUE WARNING: Cattle must not be slaughtered within 16 days following last treatment.

A withdrawal period has not A withdrawal period has not been been established for this product in pre-ruminating calves. established for this product in pre-ruminating calves. Do not use in calves to be processed for veal. Do not use in calves to be processed for veal.

Safe-Guard mineral, feed through products and liquid feed: RESIDUE WARNING: Cattle must not be slaughtered within 13 days following last treatment. For dairy cattle, the milk discard time is zero hours. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal.

Safe-Guard drench and paste: RESIDUE WARNING: Cattle must not be slaughtered within 8 days following last treatment. For dairy cattle, the milk discard time is zero hours. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal.

Consult your local veterinarian for assistance in the diagnosis, treatment and control of parasitism. Economic analysis of pharmaceutical technologies in modern beef production, John D. Lawrence and Maro A. Ibarburu, Iowa State University, 2007. Gasbarre, L.C., Smith, L.L., Lichtenfels, J.R., Pilitt, P.A., 2004. The identification of cattle nematode parasites resistant to multiple classes of anthelmintics in a commercial cattle population in the US. Proceedings of the 49th American Association of VeterinarParasitologists. Philadelphia, July 24-28 (Abstract 44). 3 Stromberg, B.E., et al., Cooperia punctata: Effect on cattle productivity? Vet. Parasitol. (2011), doi: 10.1016/j.vetpar.2011.07.030 1 2

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