NUTRITION IN A NUTSHELL

DNA Q+A

IMPORTANT DNA ITEMS TO REMEMBER:

1.) It is important for all DNA orders to arrive at the lab with proper paperwork.

Neogen receives roughly 20,000 orders a day. Without paperwork, Neogen staffers do not know what customer the order belongs to.

2.) Barcodes are important.

Barcodes are the unique ID for the DNA sample throughout the entire testing process. This ensures that the sample does not get misidentified or put in the wrong account for results.

3.) Be sure to include the full barcode number in DNA orders. Not including the full number, or shortening it to the unique last digits, will delay orders from the beginning processing at the lab. This delay on barcode identification can back up an order up to a week, dependent on volume intake.

4.) Extra samples that arrive at the lab slow down an order.

Do not mail in extra samples that are not included on your association order. All samples must be input at the association level with a DNA order form. Additionally, inform the breed association if any samples are missing, as missing DNA also slows down the testing process.

Q: Can I register an animal if I don’t know the sire of the animal?

A: Yes, breeders can register an animal so long as they know the sire options. First, create a multisire group (MSG) that lists the potential sires. Rather than registering the calf to a sire, choose the MSG as the sire of the animal.

Q: When do I create a DNA order?

A: Breeders create a DNA order form after they have collected the DNA samples and are ready to put the samples in the mail in the following day.

Q: Where can I find the DNA order form?

A: The DNA order form can be found in the member portal in the IBBA Regstr system. Click “DNA” then click “new order.” All animals must be registered prior to submitting DNA.

Q: Who do I include on a DNA order?

A: The DNA order should include all animals that are being submitted on a sample. All animals should be listed in the online Regstr order form.

NUTRITION IN A Nutshell

by Jaymelynn Farney, Beef Systems Specialist, Kansas State University

Cowherd profitability is dependent on several things including the yearly cost of maintaining a cow, percent calfcrop weaned and values for the sale of animals. Reproduction is the most important trait impacting profitability and feed is a major driver of reproductive performance. As such, understanding the factors that influence nutritional requirements and composition of feedstuffs are the key to a profitable cowherd enterprise. Cows have nutritional requirements for energy, protein, water, vitamins and minerals. A series of publications will address these nutritional requirements to provide insight into factors that impact the performance of beef cows.

Nutrition is the process in which animals consume, digest, absorb, and use food for maintenance, growth, fetal development or milk production. Nutrients are the components of feeds that have specific functions within the animal to meet important metabolic processes. Nutrients include energy sources (sugar, starch, cellulose, fat), protein, minerals, vitamins, and water. Nutrient requirements for varying levels of performance have been researched for years and the requirements are published by the National Research Council. These recommendations have been determined to be accurate for groups of cattle. Cattle require nutrients in actual amount (weight) so some math will need to be used to determine if a commercial feed and/or your hay supplement are providing enough of the individual nutrients. When determining the actual amount of nutrients offered in feed an estimate of dry matter needs to be determined. The nutrients are located in the dry part of the feed and are called dry matter (DM). Dry matter is determined by taking a sample of the feed and drying it until there is zero moisture remaining. In general most dry feeds contain seven to 13 percent moisture, molasses is ~25% water, hays are ~15% water, and silages ~65% water. You can also gather exact dry matter by sending your feed to a testing laboratory. ENERGY

The first concept to understand about cow nutrition is

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Maintenance Energy requirement (Mcal/d)

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(continued from page 58) that maintenance requirements have the highest priority. Feed consumed goes first to maintenance then the rest goes towards growth or other productive functions. Maintenance is described as “the amount of feed energy intake that will result in no net loss or gain of energy from the tissues of the animal body.”

Energy requirements are split into two broad categories: energy for maintenance and energy for gain. The net energy system is what nutritionist use to formulate diets for cattle. This system takes into account gross energy intake (energy from consumption of feed) and removes losses of energy (fecal, urine, gas, and heat) that are not used for tissue utilization and/or accretion. Energy requirements for maintenance and gain are based on megacalories (Mcal) which is 1,000 kilocalories or 1 million calories. Note that NEm includes energy for pregnancy and lactation in addition to maintenance of weight, whereas NEg represents energy for body weight gain and fat. Energy requirements for cows are influenced by cow weight, level of milk production, stage of production, breed, weather, physical activity, and body condition. A yearly energy requirement for a 1,300 lb. cow with peak milk of 20 lb. and a calf birth weight of 80 lbs. is illustrated in Figure 1. Specifically cattle that fall into these categories have a higher demand for megacalories such as heavier body weight, heavier milking ability, lactating, larger pastures to walk longer distances, hilly terrain, cold weather environment, or are a Bos taurus breed. PROTEIN

Energy and protein metabolism in the ruminant animal is linked in many ways. To maximize rumen microbial efficiency the microbes need adequate protein and energy substrates to generate volatile fatty acids and microbial crude protein. Cattle have specific energy demands as well as demands for protein or more specifically dietary nitrogen (N). Proteins are nitrogen containing molecules that are needed to generate amino acids. Amino acids are the building blocks of muscle development in cattle. Proteins that are consumed by cattle first go to the rumen where some proteins are degraded by the microbes to make microbial crude protein (MCP). This fraction of protein degraded by the microbes is labeled rumen degradable protein (RDP). There is a portion of protein that “by-passes” or is protected from ruminal degradation and is called rumen undegradable protein (RUP). The combination of MCP and RUP make up the metabolizable protein (MP) requirement of cattle.

This concept of protein delivered to cattle is fairly easy to comprehend, however, ruminants are amazing animals that can utilize nitrogen in varying sources and can recycle urea to meet daily demands for N. This recycling effect is evident in studies that have proven that cows on mature (low CP) pasture can be supplemented three times per week with a protein supplement and perform as well as cattle receiving a daily protein supplement.

Protein requirements are additive with requirements based on weight, milk production, and pregnancy. In general the trend for periods of high protein demand is similar to the energy schematic shown in Figure 1. The daily pounds of protein required based on a year for a 1,300 lb. cow is shown in Figure 2. WATER

Water is an essential nutrient for cattle, and is often considered the most important nutrient. Water is in all cells of the body. Up to 70% of the weight of cattle is composed of water. Water is essential for regulation of body temperature, growth, reproduction, lactation, digestion and metabolism to

Protein requirements (lb/d)

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Maintenance Pregnancy Lactation Total FIGURE 2: YEARLY PROTEIN REQUIREMENTS FOR 1,300 LB. COW WITH PEAK MILK OF 20 LB. AND AN 80 LB. CALF BIRTHWEIGHT.

(continued from page 60) name a few things. All essential functions of the animal have water involvement. Even though water is essential, there is still minimal information about water requirements for cattle as requirements are confounded by multiple factors.

Some factors that impact water intake include dry matter intake, lactation yield, temperature (both external and water temperature), diet type, and water quality. To try and simply, a greater dry matter intake generally increased water intake; except sometimes in summer when dry matter intake may be low but water intake is high and sometimes in extreme cold when dry matter intake is increased yet water intake is low. In those situations, environmental temperature plays a greater role in water consumption than dry matter intake. Water intake is similar for each class of cow weight and production stage up to temperatures of 40°F. As temperature increases above this value, water intake is increased linearly by 0.85 lb. per 1°F above 40°F. Additionally, cows with a higher milk production require more water, thus a higher intake than cows that have a lower milk production. In general, a guideline is that cows will drink 0.9 lb. of water for each 1 lb. of milk produced. One gallon of water weighs 8.53 lbs. For diet type, high roughage diets, in particular dry roughage diets will increase water intake. One the other hand for cattle consuming high moisture forages such as silages, green-chop feeds, or lush green-growing pasture water intake is lower. High salt diets will increase water intake. High protein diets will increase water intake. On the same note, very low quality, high fiber diets will also lead to an increase in water intake to help with mucus production for digestion and more water to help with moving high fiber manure through the digestive tract.

Water temperature can also impact water intake. In some studies where water was cooled for British-cross cattle in the summer, intake was increased and subsequently average daily gain was improved. However, for Brahman x British cross cattle, cooling water did not impact intakes or gains. Brahman x British cross cattle had the same performance whether water was cooled in the summer or heated in the winter. The influence of water temperature on consumption has been variable in the current literature. Water can be consumed in multiple states – liquid or frozen. Cattle can use snow to meet water demands. They prefer liquid water, but in instances where cattle do not have access to liquid water they will use the snow to replace drinking water. Water quality is another area that can influence water intake. Water quality can have impacts on water intake, performance, and health of cattle. There are several indicators of water quality that can be tested at laboratories. MINERALS

Mineral nutrition might be the most complicated and least understood component of ruminant nutrition especially in grazing animals. The reason behind this is that mineral content of forages are constantly changing throughout the year and free choice mineral supplement intake of cattle is highly variable. Minerals are required by ruminant animals for nearly all normal body functions such as: growth, bone development, energy utilization, hormone secretion, fertility, muscle contractions, nerve transmission, enzyme function, intake, gain, milk production, etc. Therefore, understanding and meeting minimal requirements of minerals become important in beef cattle operations. Cattle have requirements for minerals based on age and stage of production. There are two main categories of minerals that are classified based on the amount required in the diet: macrominerals and microminerals (also known as trace minerals). Macrominerals are included in large amounts within the diet and are often reported as a percentage of the diet (salt, calcium, phosphorous, magnesium, potassium, and sulfur). Microminerals are included in minute amounts being reported as parts per million (ppm; zinc, copper, manganese, selenium, cobalt, iodine, iron, nickel, molybdenum). Deficiencies in trace minerals can result in tremendous losses in performance of cattle and can cause clinical deficiencies. However, more commonly subclinical deficiencies occur manifested as reduced pregnancy rates, rough hair coats, hoof issues, retained placenta, low libido, and poor calf performance.

Sources of minerals for cattle include forage, supplemental feeds, and water. Accounting for and balancing all these components will allow producers to meet animal absolute requirements. Often times we use free-choice minerals to meet 100% of the animals requirements, yet with increasing prices, working with a nutritionist and feed company can help develop a mineral program that is lower cost for your operation. To further complicate the mineral discussion, there are multiple forms of each mineral type that can be offered to cattle: inorganic, organic, or injectable. Each chemical form of the mineral responds differently in the animal and is a consideration in mineral supplement decisions. In general, oxide forms of inorganic minerals are the lowest in bioavailability of mineral form while sulfates and chlorides are more bioavailable and more palatable. Bioavailability indicates how well the mineral is absorbed from the rumen and available in circulation. Organic forms of minerals are more bioavailable than inorganic forms, but this primarily impacts trace minerals. Organic forms of minerals are often more expensive than inorganic forms so producers must make specific decisions as to whether the extra expense is worth the greater investment. There is also interactions between minerals that need to be accounted for. For example, some minerals have positive interactions were one mineral is needed to increase absorption of the other (selenium and vitamin E), whereas others are negative (copper, molybdenum, and sulfur). Organic forms of minerals are often only found in trace minerals and are generally more expensive than inorganic forms. There are certain scenarios where organic trace minerals may pay to be included in the diet.

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Injectable trace minerals is a class of mineral that is becoming very popular. Injectable trace minerals are easy to administer, provide a specific amount of trace mineral, and producers know that every animal receives the trace mineral. Due to the highly variable animal-to-animal intake of free choice minerals, the concept behind injection of minerals allows those animals that do not consume mineral to meet recommended levels.

Many of the injectable trace minerals have been used at stressful periods such as weaning and breeding. These products have shown benefits to production in animals that are deficient in minerals. Many of the important trace minerals can be stored in the animals liver. In research projects where no advantage was found for the injectable trace minerals, the cattle included in these studies had sufficient reserves of trace minerals and had previously been on a high plain of mineral nutrition and care.

Developing a mineral feeding strategy is important to evaluate in feeding programs to manage for costs. Phosphorous evaluation is a very important mineral to evaluate as it is one of the most expensive in the mineral mixture. It also is unpalatable and can drive voluntary intake of minerals. Often in the spring and early summer on warm season grasses there is high levels of phosphorus in the grass and this causes cattle to consume less of the mineral, which reduces their intake of important trace minerals. A lower phosphorus mineral at this time will help save money and might help with a more consistent intake. VITAMINS

Vitamins are required to sustain normal body function and life processes of beef cattle. Vitamins are classified into two categories: fat- and water-soluble vitamins. The fatsoluble vitamins include A, D, E, and K. The water-soluble vitamins are the B vitamins and vitamin C. It is important to understand the differences in these two forms: fat-soluble vitamins can be stored by the animal while water-soluble are generally synthesized by the rumen bacteria on a daily basis and generally do not need to be supplied in the diet. Vitamins are unique from other nutrients in the fact that a portion of the nutrients are synthesized by microbes and do not need to be fed to the animal. Vitamins are also unique in that requirements are listed as international units (IU). This is an important distinction because IU is a unit of measure that describes the potency or biological activity of a product.

Deficiencies in vitamin A have been associated with lateterm abortions retained placenta, stillborn calves, and increased calf scours. As such, the most important time to include vitamin A in cow rations is in the last trimester through the first couple of months of lactation. To minimize calf scours intake needs to be 30,000 to 45,000 IU daily of vitamin A and the actual requirement of vitamin A for pregnant cows is 1269 IU/lb. of dry feed intake and for lactating cows is 1769 IU/ lb. of dry feed intake.

Little research has found deficiencies in vitamin D in beef cows, especially since vitamin D is naturally synthesized in cattle that have exposure to sunlight or are consuming sun-cured hays. Cattle that have direct sunlight exposure or are fed at least 3-4 lbs. of sun-cured hay daily do not require supplementary vitamin D. Many times A, D and E are sold in one “vitamin pack” but vitamin D is not necessarily needed unless the cattle are completely in a confined covered facility.

Vitamin E is important to help with selenium and vitamin A absorption, aids in immune function, and is an antioxidant important in cellular metabolism. Calves born to cows that are vitamin E deficient can be born with white muscle disease (also a symptom of low selenium). Vitamin E requirements vary widely depending on diets, with higher vitamin E required if the diet is high in sulfur-containing amino acids, selenium, or includes oil from corn, linseed, or soybeans. Even though there is not a specific recommendation for vitamin E in beef cows, the Nutrient Requirements of Beef Cattle book lists a range of vitamin E levels; 6.8 to 27.2 IU/lb. of dry feed intake. Vitamin K does not need to be supplied to beef cattle.

Vitamin B is a water-soluble vitamin that is synthesized by rumen microbes to meet the animal’s requirements and thus does not need to be added to the feed for mature animals. Baby calves do not have a functioning rumen with microbes and do not synthesize vitamin B or K. The class of cattle in a beef operation that may benefit from vitamin B supplementation is the preruminant or very young calf, especially the bottlefed calf. There are nine B-vitamins that have been useful in specific calf situations. Milk is high in B-vitamins so a healthy dam and calf that is consuming milk should be receiving adequate B-vitamins. The bottle-fed calf has requirement for B-vitamins in the milk replacer. The B-vitamin, thiamin, could be deficient in high sulfur diets and in some feedlot studies supplying additional thiamin could help manage polioencephalomalacia (PEM). There is no need to include vitamin C in the beef cow diet.

Sources of vitamins include forages and feeds (A, E, K), some are synthesized in the rumen (B and K), some are synthesized from the sun (C, D), and some are injectable (A, B, C, D, E). Many green forages such as alfalfa are high in vitamin A so the amount to supplement may be fairly low if feeding this forage or grazing lush, green forages. However, vitamin A can degrade in harvested forages, especially in hays that are over a year old. Dormant warm season grasses are low in vitamin A, which becomes an issue for spring calving cows as this forage does not meet cow requirements. One good thing in regard to vitamin A is that cows can store vitamin A in the liver for up to four months (but the range is two to four months depending on storage supply) which can provide a slight cushion during vitamin A deficient diets. Few grains, except for corn, contain appreciable amounts of vitamin A. Silage is not a good source of vitamin A.

For an in depth assessment of best nutrition practices, I suggest you visit with your local nutritionist to develop a whole herd nutrition plan.