BEEF CATTLE PRODUCTION SERIES - PART 2 by TSCRA - The Cattleman Magazine

BEEF CATTLE PRODUCTION SERIES â&#x20AC;&#x201C; PART 2

Breeding Herd Management

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CATTLE HEALTH

BEEF CATTLE PRODUCTION SERIES – PART 2

Breeding Herd Management Table of Contents

4 Set First-Calf Heifers up for Success — Start managing first-calf heifers early in life to set them up for successful calving, timely rebreeding 6 Prepping Heifers and Cows for the Breeding Season 8 Prepping Replacements 11 Set Bulls up for a Successful Breeding Season

The Cattleman, the monthly journal of Texas and Southwestern Cattle Raisers Association, is pleased to partner with Merck Animal Health on a series of seasonal beef cattle health management manuals. Thanks to the generous support of the Merck Animal Health technical services veterinarians, Dr. David Bechtol and several of his colleagues, we are able to provide a blend of easy-to-read articles that educate and inform ranchers about various aspects of beef cattle health management. Calf photo on cover from Santa Gertrudis Breeders International. thecattlemanmagazine.com

Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management 3

Set Them up for Success Start managing first-calf heifers early in life to set them up for successful calving, timely rebreeding By Gary DiGiuseppe

Success with rebreeding heifers after the first calf can depend on how well the rancher has planned in managing the herd following the initial calving and even before the heifers were born. The condition of the rebred heifer “is pretty managementdependent,” says Dr. David Patterson, professor of animal science with the University of Missouri College of Agriculture, Food and Natural Resources, “and that’s often the challenge. “Ideally, I prefer [heifers being bred back] to be in a body condition score (BCS) of 6. That gives them some leeway,” he says, because their body condition can be greatly reduced depending on the availability of feed and on how much milk they produce (heavy milkers will lose more condition, faster). Patterson says the first-calf heifers are “still trying to meet new additional requirements for lactation, and they’re still trying to meet their own requirements for growth because they’re not fully grown yet.” Two researchers, Dr. Sandy Johnson of Kansas State Uni4 Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management

versity and Dr. Rick Funston of the University of Nebraska, make that point in an article written for Veterinary Clinics of North America: Food Animal Practice, entitled “Post Breeding Heifer Management.” They write, “Nutrient demands during late gestation include continuing heifer growth as well as fetal growth. Fetal birth weight increases by 60 percent during the last 70 days of gestation. Timely provision of adequate dietary energy and protein to meet this demand is a key step to having adequate body condition at calving. The importance of prepartum protein and energy level on reproductive performance has been consistently demonstrated. Reproduction has low priority among partitioning of nutrients and consequently; cows in thin BCS often don’t rebreed.” Johnson and Funston also say intake during gestation impacts dystocia (difficult births), calf health and calf survival. Inadequate protein and energy to the dams results in calves more susceptible to cold stress and to being weak and slow thecattlemanmagazine.com

First-calf heifers are feeding their calf and still trying to achieve their own full growth.

to suckle, increasing the risk for the calf to fail to receive antibodies through colostrum. “If heifers are thin at calving, achieving a positive energy balance postpartum is essential for timely return to estrus and pregnancy,” they write. However, they note, caution should be used with feeding excess nutrients before or after calving. It is costly, and cows and heifers with body condition scores greater than 7 have lower pregnancy rates and more calving difficulty than do females with scores of 5 to 6. “Overfeeding protein during the breeding season and early gestation, particularly if energy is limiting, may be associated with decreased pregnancy rates,” Johnson and Funston write. This may be due to a lower uterine pH during the latter part of the estrous cycle in cattle receiving high levels of degradable protein. The negative effects of excess rumen-degradable protein on reproduction are well documented in dairy literature. Patterson says the challenge with 2-year-old females is a longer period of time between calving and the resumption of the estrous cycles when compared to mature cows. If the body condition of the heifers slides following that first calf, a difficult situation becomes worse. The interval can be stretched even longer, increasing the risk that the young cow will not resume her cycle early enough to rebreed during the second breeding season. Choices based on timing Heifers that conceived earliest during their first breeding season are likely to rebreed on time and remain in the herd. Heifers that conceived during the mid — or especially, during the late — part of their first breeding season will calve during the mid or late portion of that first calving period. This leaves those females at a higher risk of failing to rebreed in the next breeding season. Patterson says, “If you maintain a restricted breeding and calving season, then choosing heifers to calve earliest is going to be a big plus in terms of the likelihood of those heifers rebreeding.” Use EPDs to avoid rebreeding delays Another factor to keep in mind is the value of using breeding animals with strong expected progeny differences (EPDs) in key areas. thecattlemanmagazine.com

Patterson says if ranchers are doing a good job of managing the genetics of their herd for calving ease and watching birth weight, then they are doing a great deal to “ensure that those first-calf heifers calve with relative ease and very little difficulty. That’s probably one of the biggest considerations right at calving for the first breeding season.” When the heifers experience dystocia with their first calves, the postpartum interval between calving and the resumption of cyclicity is extended. “We’ve seen a pretty significant reduction in the incidence of calving difficulty since producers have begun to pay more attention to calving ease EPD, in terms of direct calving ease and/or birth weight EPD of the service sires to which those heifers are bred,” he says. “The data would indicate that the postpartum interval is going to be extended based on the severity of the difficulty she experienced. So, anything that can be done to limit both the incidence and the severity of calving difficulty will really contribute to reproductive success going into that second breeding season.” Pelvic size is highly heritable When considering heifers entering their first calving period, calf birth weight and pelvic area are the 2 most influential factors in determining calving ease or difficulty. If the heifer is nutritionally restricted during the developing period to the extent that her pelvic growth or skeletal growth has been limited, that could contribute to an increased incidence and severity of calving difficulty. Pelvic area is a heritable trait, so it is important to know that sires may influence whether the pelvic area of a heifer is abnormally small or abnormally structured in a way that leads to calving difficulty. This is where pre-breeding exams of yearling heifers going into their first breeding season can head off future problems. Patterson notes the number of Texas herds with Brahman influence. For females of that parentage, he says calving difficulty is not an issue in general, but nutritional management is. The drought and environmental extremes over the last few years can further complicate efforts to maintain heifers at body condition scores favorable to rebreeding. Johnson and Funston note the results of a study of a group of heifers that delivered their first calves. These females had Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management 5

Use breeding animals with strong expected progeny differences (EPDs) in key areas. been fed to achieve body condition scores of 4, 5 or 6 at calving and were targeted to gain either 1 or 2 pounds a day. “The magnitude of response to energy level was greater for BCS 4 heifers than those with greater BCS on the proportion of heifers initiating estrous cycles early in the breeding season,” they report. “However, even with increased postpartum energy, the pregnancy rates of thin, primiparous (first pregnancy) cows may not be acceptable.” Adding fat to the ration should be viewed with caution. Johnson and Funston say that supplemental fats can increase diet energy density and avoid the negative effects like rumen acidosis sometimes experienced with cereal grains in high roughage diets. “Beef animals apparently have the ability to store certain fatty acids,” they say, “supported by studies in which fat supplementation discontinued at calving resulted

in a positive effect on reproduction.” But there appears to be no benefit, and in some cases there is a negative effect, from feeding supplemental fat after calving, especially when it was also fed prior to calving. Patterson says that maintaining body condition on a younger cow is based on nutrient partitioning. Reproduction is fairly far down on the list of priorities for a young cow with her first calf if her nutrient requirements are not being met. “She’s still trying to satisfy her own requirements relative to growth and maintenance plus lactation. That’s the difference between the younger female and the mature female,” Patterson says, adding that the manager of the mature cows is considering cow maintenance and lactation, while the manager of the younger cows with their first calves must manage for the added requirement for growth. ❚

Prepping Heifers and Cows for the Breeding Season By Glenn Rogers, DVM MS, DABVP (Beef Cattle), Holt River Ranch

While the more immediate concern during calving season is maximizing the number of live calves, it is also time to plan for the next breeding season. Body condition at calving has been shown to be highly correlated with cow rebreeding success. Maintaining or even increasing body condition in cows and first-calf heifers prior to calving is usually more economically feasible than trying to increase body condition during lactation. Heifers should be in body condition score 6 at breeding, and cows should calve with a body condition score of at least 5. In addition to monitoring herd body condition, the herd’s immunization program should be considered. A basic principle of immunology is to immunize prior to a disease challenge. Vaccinating heifers 30 to 60 days prior to the start of the breeding season allows a peak immunologic response from vaccination to occur early in the breeding season and early pregnancy. This is a time when many reproductive diseases can have their greatest effect.

6 Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management

The replacement heifer pre-breeding vaccination program is the foundation for establishment of lifetime herd immunity and the logical first step in improving herd vaccination programs. Heifers generally have less immunity to common reproductive diseases than mature cows. Substantial carryover effect in cow herd immunity occurs when an initial, sound pre-breeding health management program for heifers is implemented. With shorter, controlled breeding seasons, cows can be vaccinated after calving and before breeding. Even in herds with extended breeding seasons or where the choice is made to not implement pre-breeding vaccination in the mature cow herd, improvements in heifer pre-breeding management can usually be successfully implemented. Vaccination against IBR, BVD, leptospirosis and vibrio should be administered. Failure to vaccinate at the correct time may result in decreased reproductive performance, even when the best products available are used. ❚

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2 Giralda Farms – Madison, NJ 07940 – merck-animal-health-usa.com – 800.521.5767 Copyright ©2015 Intervet, Inc. d/b/a Merck Animal health, a subsidiary of Merck & Co., Inc. All rights reserved 10/15 BV-SG-54399 Stromberg, B.E., et al., Cooperia punctata: Effect on cattle productivity? Vet. Parasitol. (2011), doi: 10.1016/j.vetpar.2011.07.030

Prepping Replacements By Gary DiGiuseppe

How should the producer protect replacement heifers from illness and reproductive disorders? And are there different regimens that that can be followed? Mark Spire, D.V.M., retired technical services manager for Merck Animal Health, says in developing a replacement heifer from weaning up until first calf, you are really looking at 2 entities. “At weaning time,” Spire says, “we have to concern ourselves with respiratory disease control. Most of the agents that we would take in a typical vaccine can also cause a reproductive side effect that we can protect against later on.” There will be more on this later in this article. Spire says the standard vaccine in a basic program would be a 5-way viral vaccine. This controls infectious bovine rhinotracheitis (IBR or “red nose”), bovine viral diarrhea (BVD) types 1 and 2, bovine respiratory syncytial virus (BRSV), and parainfluenzia-3 virus (PI-3). Those are the most common pathogens out there from a viral side. “At weaning time,” he says, “we will also want to look for other protections, primarily against our respiratory bacteria. 8 Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management

That’s going to have us use a Mannheimia product, potentially Mannheimia with leukotoxin in it — the toxin that produces and causes most of the lung damage — and then against Pasteurella multocida. Those 2 are our most frequent pathogens, and recent diagnostics have told us that P. multocida is really isolated more frequently around weaning time than Mannheimia is.” In addition, the heifer will need boosters. She should have received initial vaccines at branding against the blackleg (Clostridium) family of bacterial diseases. Spire says, “Typically, we use a 7-way component at weaning time as a booster vaccine. This gives us a heifer that’s vaccinated out through the weaning process.” 30 days ahead of first breeding season Preparation for the heifer’s first breeding season should begin about 30 days in advance. “Now we’re switching from respiratory control to reproduction control,” Spire says. Protection continues against red nose, the IBR virus, and the BVD family, types 1A, 1B, and 2A. “If we use a comprehensive viral vaccine at weaning, we can come back now and thecattlemanmagazine.com

Preparation for the heifer’s first breeding season should begin about 30 days in advance.

booster it,” he says. “Now she’s coming up on a year of age or slightly over, maybe 13 months. That will booster off quite well at that point in time, but we also want to add some other components to this.” Among those will be a comprehensive vaccine against leptospirosis, an organism that can cause both infertility and abortions. Spire recommends a vaccine for lepto that gives good cross protection to other strains that may not be in the vaccine. In addition, the animal should receive protection against Campylobacter, commonly known as vibrio, which can be transmitted as a venereal disease from an infected bull into the heifer pool. “By doing these things 30 days ahead of time,” Spire says, “any adverse effects that we potentially might have had on cycling, where she’s coming into heat and going out of heat, that can tend to be caused by an IBR vaccine and a BVD vaccine are far enough away that those are of no consequence anymore. “The summer after the heifer has entered her first breeding season, she should be left alone from a vaccine standpoint. In fall when she’s pregnancy checked, the emphasis shifts from protecting the first pregnancy to protecting a later term pregnancy and preparing her for the calving season. Spire says while respiratory virus protection does not need to receive boosters at this time, the lepto vaccine does not have a long duration of immunity that will provide protection in a high percentage of animals. “The first-calf heifer should also receive a scours vaccine if there’s been a scours problem in previous heifer calving groups. In addition, “At this point in time, we would want a comprehensive vaccination program that would include rotavirus and coronavirus, E. coli and Clostridium perfringens types C&D, at a minimum. In a 7-way vaccine that we may have used back at weaning time you would have C. perfringens in it. Those are typically of short duration, but by giving it at this point in time we are actually boostering it at that fall preg check,” Spire points out. Quality colostrum With these late-term vaccinations, the animal is on the road to making good quality colostrum with high antibody levels against common diseases. thecattlemanmagazine.com

The next time she would be processed in a comprehensive vaccination program would be 4 to 6 weeks pre-calving, but Spire says, “That is keyed upon the fact that we’re dealing with a nice tight calving group that’s typically not spread over more than 60 days. Ideally, our heifers are calving in 30 to 45 days in a well-managed heifer breeding program.” To generate the maximum antibodies to deliver to the calf through the colostrum, the heifer needs to receive the highest possible level of protection. It takes about 2 weeks from the time of vaccination to get to the peak blood levels of antibodies that can be transferred into the colostrum. About 2 weeks before calving, a heifer is going to start passing those antibodies into her colostrum. Spire concludes, “There’s a timing issue there, and that’s why we’re looking at vaccinations at 4 to 6 weeks pre-calving to get the maximum level.” The timing also works for a heifer that calves at the end of the group’s 60-day window. So far, the heifer has received a number of vaccinations at critical times — boosters for respiratory control, boosters and initial vaccinations for pre-breeding challenges, and boosters and initial vaccinations at the time of preg checking to protect late pregnancy and starting to build high-quality colostrum. What is left is pre-calving boosters. Spire says the producer can apply boosters for scours where appropriate, and for clostridials if that is an issue in the herd. But it is not mandatory. He says, “If we don’t have a scours problem or calves dying from bloat or scours at 6 to 12 weeks of age, scours vaccines and clostridial vaccines with perfringens C&D probably won’t be added into the program, so you don’t have to have anything working in fall except lepto protection.” Trichomoniasis vaccination timing One other component of the vaccination schedule that is not traditionally in the first fall vaccines for females that are less than yearlings, is trichomoniasis. Spire says whether the animal needs 1 or 2 doses depends on the product. If it is a 2-dose vaccine, the last dose should be applied no sooner than 2 weeks before the start of the breeding season. The first one can be administered 4 to 6 weeks earlier than that. ➤ Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management 9

About 2 weeks before calving, a heifer is going to start passing those antibodies into her colostrum. Reproductive side effects of vaccinations Earlier, we referred to vaccinations that can cause reproductive side effects. Spire says an example of that would be modified live vaccines for viruses. To work, the viruses have to replicate well in the body. He says, “If we have a naive heifer that doesn’t have good antibody titers already existing, or hasn’t been exposed to natural disease or to the vaccine, those viruses can go to the ovary, the oviduct and the rest of the reproductive tract and cause an inflammation that will last about 7 to 10 days. That can throw her off cycle and cause some other consequences. That’s why we don’t recommend using the modified live virus at the same time you’re going to use a synchronization product in them, because it can upset that cycling mechanism and cause infertility for about one cycle.” In addition, the adjuvants placed in killed vaccines to make them work and the animals respond to them can also have side

10 Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management

effects that may last up to 10 days; therefore, those vaccines should be applied before instead of at the time of breeding. “It takes a full 2 weeks, and sometimes up to 4 weeks, before we get antibodies from killed vaccines up to the protective level that we need, so timing of administration is important,” he says. “Also, if we start using ‘gram-negative’ vaccines, which are common around cattle operations — they can be pinkeye, haemophilus, Pasteurella/Mannheimia, vibrio, lepto or Bangs’ vaccines — too many of those types of vaccines given at the same time to heifers around the time of breeding can cause release of a product called endotoxin that’s inherent in those types of vaccines.” The effects of endotoxins can be cumulative and throw the heifers off cycle, so those types of vaccines should be applied at least a month ahead of the breeding season or the beginning of a synchronization program. ❚

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Set Bulls up for a Successful Breeding Season Good development of young bulls and a good health program for any age bulls go a long way toward helping them do their job in the pastures. By Gary DiGiuseppe

You don’t drive your pickup without checking the oil and tires. The same principle applies to your bull. That is according to Mark Spire, D.V.M., retired technical services manager for Merck Animal Health. He points out that ranchers have a huge investment in their breeding bulls. Each bull is typically needed to service about 25 females. “If you look at the price of cows today, it’s not uncommon to have $1,500 a head in a cow. The total cost for a year is between $900 to $1,000,” says Spire. That means you can have $60,000 tied up in a single bull’s performance. “Take the time and spend the money to make sure that bull is in peak condition at the start of the breeding season,” Spire urges. Start with physical soundness The bull should have good, sound feet and legs and a correct gait that shows their hips are well. Both eyes should be clear and functional. Spire explains, “Those bulls have to get out, and they have to move. They have to be able to mount and breed the cows. They have to see them. Bulls depend so much on eyesight to thecattlemanmagazine.com

watch cows’ behavior, to pick them out and decide whether to have physical contact with them.” He says ranchers should avoid any bulls with “lumps and bumps” — that is, symptoms of diseases like lump jaw (actinomycosis) or wood tongue (actinobacillosis), or signs of abscessed teeth or arthritis in the neck, which will impact how the bull is able to graze and maintain itself. The bulls should start the breeding season with a body condition score (BCS) of about 6. Bull BCS is assessed the same way it is on cows, by measuring the fat cover over the ribs and along the hips, while taking into account the differences in male and female builds. BCS ranges from 1 (gaunt) to 9 (obese). “That bull condition score will drop off very rapidly early in the breeding season,” says Spire, “so if we start them off too thin, that will impact semen quality.” Reproductive soundness checks — vet or DIY? The bull’s reproductive equipment should also be checked out. Spire breaks down those examinations into 2 categories — the $40 exam performed by the vet, or the $2 version you Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management 11

Older bulls are efficient. Make sure they have good locomotion, no problems seeing and are in good physical shape. can conduct yourself, “where you just make sure that they are functional and doing what they should,” he says. That includes looking at the feet and legs, making sure that there is no swelling in the scrotum, and watching the bull breed the cows for the first few days after he’s turned out in order to make sure he can mount a cow and fully extend his penis. The more expensive exam, he says, is more appropriate on newly purchased bulls, and on yearlings developed from your own herd. With the yearlings, it is critical that their scrotal circumference is adequate for their weight, breed and age. The industry standard is about 30 centimeters (cm) in diameter at puberty, with testicles no more than 10 percent different in size from one another and with good tone. “Then I like to extend them,” Spire says, “because there are several things that we’ve seen come out of bulls in development centers, and just as bulls mature. Things like tears, hair rings and frenulums (folds of tissue that restricts the organ) on the penis can end up causing damage that can limit a bull’s ability to breed. Warts on the penis are also very important to look for during the examination, when a bull is being extended. A more detailed examination will allow close examination of the prepuce for scarring, adhesions and strictures.” Another potential issue to watch for is seminal vesiculitis. The seminal vesicles are accessory sex glands within the bull and add fluid to the semen. They can become inflamed and sometimes infected. Spire says when bulls are grouped, fed together and developed, they can pass bacteria to each other that can cause the condition. In addition to affecting the bull’s semen quality, this can produce an irritation that affects the animal’s ability to mount. 60 days before breeding season Spire recommends these examinations be conducted 60 days ahead of the breeding season. If problems are detected with the feet or with the penis or seminal vesicles, they can be addressed without causing an interruption to breeding. If the BCS is too high or low, 60 days will afford enough time to change that, as well. “I like to have yearling bulls at the start of the breeding season at a minimum of 1,100 pounds,” Spire says. “If I start getting bulls that are too heavy, I want to exercise them and cut out the carbs —generally, just the kinds of recommendations you’d make for humans who want to change their physiques.” 12 Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management

If the bulls are too thin, the producer can make the diet richer, as well as search for other factors that could be causing the condition, like parasites. And don’t forget hornfly control. Spire says, “You have to remember that every one of those hornflies is going to feed multiple times a day, and when they have 1,000 to 1,500 flies on them, that’s a lot of irritation that will take their mind off breeding and make them worry more about trying to get flies off of them. The blood loss from feeding flies is significant.” A 2-year-old bull coming into his second breeding season should be at about 80 percent of his mature body weight. Spire says there is a physiological reason to make sure the bull is that well developed — at 2 years old, they lose their central incisor teeth and cannot graze as efficiently before the next set of teeth come out. “Because of muscle mass, they need to have a pretty good protein load coming through them,” he notes. “They’re actually a lot more difficult to maintain than heifers.” Also, beginning at 60 days prior to the breeding season, a new bull can be caught up with the herd’s animal health program. Spire recommends a PI (persistent infection) test for BVD, and a test for trichomoniasis. A purebred operator will also want to make sure that an animal is free of Johne’s disease and leukosis before introducing him into the herd. “In both the yearlings and the 2-yearolds, I like to make sure I deworm them before the start of the breeding season,” he says. “I don’t emphasize deworming for mature bulls as much as I do my younger bulls.” Three weeks before breeding, his regimen calls for a booster for virus vaccines, vaccines for leptospirosis and genital campylobacteriosis (vibrio) and, depending on the prevalent risk factors, a trich vaccine as well. The trich vaccine for bulls, Spire says, is “reasonably” effective. “You get some assurance with it. The problem we have with bulls is that the cow can carry the trich or the vibrio organism. A bull can pick it up during breeding and then, because it takes a while for the vaccine to get into the secretions and kill the organism, he can take organisms from an infected cow into several clean cows after breeding an infected cow, and before the vaccine would have time to work.” While the vaccine may prevent bulls from carrying a chronic infection from trich or vibrio, they still can be carriers, so cow herd management and bull testing is recommended Spire says weanling bulls should be put on a comprehenthecattlemanmagazine.com

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sive vaccination and growth program. If they are weaned at 600 pounds, they need to gain 500 pounds by the start of the breeding season. That requires a daily gain of about 2.5 pounds. Considerations for your bull development program When several bulls are being developed, Spire suggests maintaining them on a group pasture with salt, water and feed spread out. “I want those bulls to exercise and get hardened up and ready for the start of the breeding season,” he says. “Nothing’s worse than an out-of-shape, overweight bull that that’s been confined to a small area that is suddenly turned out on the open range with 30 head to breed. That’s asking too much from them and we will frequently see conception rates suffer.” If you are developing your own bulls, Spire says they should come from the top 10 percent to top one-third of the calf crop. “We want to have the most weight on them that we can at weaning time,” he says. “It’s just cheaper in the long run. We don’t really have to push them or worry as much about having reached puberty in time for their first breeding season.” Development, growth and body condition are extremely important in yearling bulls. By their nature, younger bulls have a high “mount-to-service” ratio — they spend more time jumping the cows than they do actually breeding them. This leads to wasted energy and inefficiency in breeding, so paying attention to body condition at the start of their first season is vital. Older bulls are more efficient. The important thing is to

14 Merck Animal Health BEEF CATTLE PRODUCTION SERIES – PART 2 Breeding Herd Management

make sure the bull has good locomotion, no problems seeing and that he is in good physical shape. Running bulls together prior to the season will also allow them to establish a social hierarchy. It reduces the risk of fighting and injury. If animals unfamiliar with each other are abruptly placed together during the breeding season, a lot of bull power is wasted. For that reason, Spire discourages running old bulls and young bulls together, preferring instead to match groups by weight, size and age. Unlike older bulls, 2-year-olds are still putting on weight and need to be on a higher plane of nutrition from the time that they are pulled off after their first breeding seasons. “I don’t like to overwork young bulls,” Spire says. “In some situations, depending on the pasture, we can run old bulls in a 1:40 male-to-female ratio. With younger bulls, we tone that down to about a 1:25 ratio.” He prefers to pull 2-year-olds off the cows after 60 days, but no more than 90 days, by which point they will have lost quite a bit of weight. Spire says, “If we run from the spring breeding season into the summer grass, the nutritional quality of those grasses goes down. We have lower protein and energy in those forages, and those bulls just aren’t going to condition well on them. “This will limit the amount of breeding season in which we’re running them. Get them in where you can start conditioning and managing them as a group again to get them up to where they need to be when they become 3-year-olds. After 3 years of age, we can be a little more frugal with them on nutrition than we are with younger animals.” ❚

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Take care of BRD with Once PMH® IN, the first and only intranasal vaccine that delivers dual bacterial pneumonia protection for healthy cattle of all ages, including calves as young as 1 week of age.

Talk to your veterinarian or animal health supplier about Once PMH IN. Always read, understand and follow product label and use as directed. merck-animal-health-usa.com • 800-521-5767 Copyright © 2016 Intervet Inc., doing business as Merck Animal Health, a subsidiary of Merck & Co., Inc. All rights reserved. 54670 1/16 BV-Once IN-51131-B

Approved for healthy cattle 1 week of age or older Dual protection against Mannheimia haemolytica and Pasteurella multocida, the leading causes of early-onset BRD Adjuvant-free, intranasal application that’s easy to use and easy on cattle

Choose Once PMH IN And never choose again

BEEF CATTLE PRODUCTION SERIES â&#x20AC;&#x201C; PART 2

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