Precision Balanced Rations Yield Milk Production and Environmental Benefits. Nutrition and Dairy Fertility

Transcription

1 Dairy Issue 9, Spring/Summer 2006 Precision Balanced Rations Yield Milk Production and Environmental Benefits Nutrition and Dairy Fertility Methionine Supplementation: A Key Factor in Balanced Amino Acid Formulation Practical Considerations for Balancing Lactation Rations for Amino Acids Compliments of:

2 ADM Alliance Nutrition, Inc. Precision Balanced Rations Yield Milk Production and Environmental Benefits by Don Jaquette, Ph.D., Senior Dairy Nutritionist, ADM Alliance Nutrition ADM Alliance Nutrition, Inc N 30th Street, PO Box C1, Quincy, Il The Dairy Performance Edge is a biannual publication of ADM Alliance Nutrition, Inc. Performance Edge is intended to enable us at ADM Alliance Nutrition to help you achieve your production goals and to better serve you. 1 Achieving optimal milk production and good milk components requires a well-balanced ration. A number of commercial software programs are available that can be used to balance rations for dairy cows. ADM Alliance Nutrition has worked closely with the Dalex Corporation for many years, and in the process, has developed a proprietary, customized, stateof-the-art, ration balancing program for dairy cows and heifers. The software program is referred to as the ADM Alliance Nutrition DalexSolutions Program. The National Research Council and other research institutions have established nutrient recommendations for most major nutrients, including protein, amino acids, carbohydrates, energy, fats, minerals, and vitamins. The real challenge is determining how a combination of on-farm ingredients and purchased ingredients/feeds can be put together into a balanced ration to meet a specific set of nutrient recommendations. ANI DalexSolutions is a very powerful tool, which all ADM ANI nutritionists, sales, and dealer personnel have at their disposal to assist dairy producers with ration balancing. The balance of this article will focus specifically on the protein and amino acid portion of the ration. Major advancements have been made in protein nutrition over the past decade. Ultimately, the primary purpose of feeding protein to a dairy cow is to provide nitrogenous compounds to the rumen bacteria and to provide amino acids for absorption in the small intestine. The ANI DalexSolutions software does an excellent job of putting together a package of nutrients that will meet the needs of the rumen bacteria and the cow s amino acid needs. This computer program encompasses a ration balancing platform that includes a dynamic system for predicting protein and amino acid flow to the small intestine, based on ruminal available nitrogen and the digestible organic matter content of the ration. Think Amino Acids, Not Protein Dairy cows require specific quantities of absorbed amino acids, not protein. It is well established that the two most limiting amino acids for milk production are lysine and methionine. The model component of ANI DalexSolutions uses a series of equations to estimate the flow of absorbed lysine and absorbed methionine to the small intestine, based on the quality and quantity of nutrients delivered in the ration. The model provides us with the necessary information to design a custom supplement that will complement on-farm forages, commodities, and grains. To achieve consistently high levels of milk production, it is imperative that the lysine and methionine content of absorbed protein is given close attention. For the most efficient use of amino acids, the ratio of lysine to methionine in absorbed protein should be approximately 3 to 1 based on research and field observations. In addition to highquality RUP (rumen undegradable protein) sources, the use of a synthetic methionine source is sometimes warranted to meet specific amino acid requirements. Without the use of sophisticated software like ANI DalexSolutions, it would be nearly impossible to achieve specific target levels. Manage Nutrients to Cut Waste One of the major goals of on-farm Nutrient Management Plans has been to reduce nitrogen in surface water. To reduce fecal nitrogen output requires a reduction in nitrogen consumption. This is achievable, without negative consequences on milk production, provided the quality of consumed protein and amino acid balance of the ration are monitored. ADM Alliance Nutrition s ration balancing software gives specialists, nutritionists, and sales personnel the ability to reduce nitrogen excretion, while achieving optimum milk yield and optimal milk components. A specific nutrient excretion report, which includes excretion amounts for nitrogen, phosphorus, and potassium, can be generated. As an industry, we must focus on lowering the quantity of crude protein in the ration, while providing an optimal balance of essential amino acids, especially lysine and methionine. Historically, many rations have been balanced with 18% crude protein or greater, with no consideration given to protein quality or amino acid content. With the use of amino acid balancing, rations can be balanced with % crude protein while achieving equal or better performance compared to higher crude protein rations. The lower crude protein rations are healthier for the cow and better for the environment. Summary Over the past 15 years, research studies have provided us with a tremendous amount of insight as to how to feed dairy cows in order to optimize the quantity and quality of amino acids that are absorbed in the small intestine. At ADM Alliance Nutrition, we have been able to incorporate much of this information into new dairy products and feeding programs. A functional ration balancing program is an integral part of putting research results into practice on the farm. The ANI DalexSolutions software is a tremendously powerful program that provides us with the tools we need to provide customized dairy rations that meet the many needs of our progressive dairy customers.

3 Dairy Issue 9, Spring/Summer 2006 Nutrition and Dairy Fertility It s no secret that good reproductive performance on dairies involves a variety of factors, but often components of reproductive programs get blamed when cows don t get pregnant which may be the wrong thing to focus on. People often focus on just the reproductive part of a program at one point in time, such as synchronizing cows, says Pedro Melendez, DVM, PhD, College of Veterinary Medicine, University of Florida. They focus on GnRH, prostaglandin, timed AI, etc., but aren t looking at what were the situations surrounding parturition and before that, such as did she have difficulty calving, how was the transition and prepartum period management, what was the incidence of retained fetal membranes, hypocalcemia, ketosis, etc. We blame reproductive management, but we often don t look at the other factors that occurred before this time. Jose Santos, DVM, PhD, Veterinary Medicine Teaching and Research Center, University of California, believes it is very important that producers, veterinarians, and nutritionists evaluate reproductive problems not only by paying attention to the reproductive management but also to other aspects, such as nutrition. When cows experience excessive metabolic problems after calving, that will influence subsequent fertility and response to the reproductive program implemented in the herd, he says. Inadequate feeding of transition and early lactation cows that leads to more ketosis, hypocalcemia, displaced abomasum, etc., normally reduces subsequent fertility. In addition, it has been demonstrated that mastitis, which is prevalent early postpartum and can be influenced by nutrition, is negatively associated with conception and pregnancy maintenance in dairy cattle. Unless these problems are corrected, says Santos, it is unlikely that the reproductive program will be successful. Melendez agrees and says studies relating calving-related disorders to fertility found that cows with hypocalcemia or milk fever were six times more likely to develop a retained fetal membrane and probably three times more likely to develop metritis. And indirectly, those cows are more likely to develop ketosis. Finally, we end up with an animal that is cycling very late, so it s very important to pay attention to the basic concept and look back to see what s going on in the transition by Geni Wren, Editor, Bovine Veterinarian Reprinted with permission from Bovine Veterinarian, March period, says Melendez. Nutrition can influence fertility at all stages of the reproductive cycle, but the period between late gestation and first postpartum insemination is probably the most critical. Santos says this is when a cow experiences most of the diseases during the entire lactation cycle and what happens to her in this period will determine how successful the subsequent breeding will be. Melendez echoes that point of view. Starting in the dry-off and transition period, the last 21 days before and after calving are the most important time periods for nutrition. The more deficiencies we have at that time, the more infertility we re going to have in the herd. If we have a dry-off and dry period in bad shape, the transition period won t improve anything. Fertility Problems and Nutrition Nutrition can have remarkable influences on fertility. Inadequate energy intake and/or inadequate body fatness early postpartum can retard resumption of ovulary cycles, which extends the interval from calving to first estrus, reduces conception rates at first postpartum AI, and increases late embryonic losses after first postpartum AI. In addition to energy status, there are some well-characterized effects of nutrition on fertility. Continued on page 3. 2

4 ADM Alliance Nutrition, Inc. 3 Continued from page 2. Nutritional deficiencies, such as antioxidant nutrients (vitamin E and selenium), influence immunity status of the uterus and the ability of white blood cells to kill bacteria that invades the postpartum uterus. This makes the cow more likely to develop retained fetal membranes and metritis, both of which reduce fertility, explains Santos. Another important example is nutritional management during the transition period to prevent subclinical and clinical hypocalcemia. Hypocalcemia can be minimized by manipulating the mineral composition of the prepartum diet (feeding low sodium and potassium diets and including acidogenic salts). Hypocalcemia results in increased blood cortisol concentrations after calving, impairs uterine involution, is associated with increased uterine infections, and reduces fertility. On the other hand, excess of nutrients or dietary components containing toxins can have negative effects on fertility. One example is a diet too high in protein. In order to get milk production of 25,000 lb per lactation, some farms formulate diets too high in crude protein, such as 19 to 20%, says Melendez. But he adds that high protein levels lead to high levels of urea and ammonia in the blood, and studies have demonstrated that high levels of urea will affect the uterine environment and can introduce toxic effects to gametes and the embryo. High-producing lactating dairy cows do not require diets with 19-20% crude protein to achieve production above 26,000 lb, says Santos. What these cows really need is a diet that is balanced for the energy and protein components and provides adequate amounts of metabolizable protein with an adequate amino acid profile. However, producers and nutritionists often conclude that cows need very high crude protein diets. In fact, well-balanced diets that contain 17 to 18% crude protein are enough to provide all the amino acid needs of highproducing cows even in early lactation, explains Santos. The problem is that high-producing cows that consume a lot of feed will also consume a lot of protein, although the diet is presumptively balanced. Even in those cases, urea nitrogen in the blood will be high as a consequence of the high protein intake. Feeding excessive amounts of gossypol is another example, adds Santos. We have shown that feeding cottonseed that results in plasma gossypol concentrations above 5 micrograms/ml reduces conception rates and increases fetal losses, and this is, in part, mediated by reduced embryonic development. When pregnancy gets beyond 25 days, the cow is fairly adept at protecting the conceptus from nutrition-related problems, but even still factors, such as excess copper or iodine, toxic plants, mycotoxins, or fungal-infected silage, can produce abortions. Feeding Heifers Versus Cows There s a vast difference in how heifers utilize and respond to nutritional factors than cows because heifers are still growing, even when calving at 24 months. Because of that, heifers need a diet rich in protein but with moderate energy to avoid getting too fat and risking dystocia when calving. Additionally, the pre-calving cow differs from the heifer in that because she s not still growing, in the transition period she s more likely to develop hypocalcemia. Those animals can be fed acidogenic salts to prevent hypocalcemia, says Melendez. Heifers are less likely to develop hypocalcemia and don t need acidogenic salts. The take-home message is that there should be two different rations one for heifers and one for cows. Melendez adds that first-lactation heifers should continue to be fed in a separate group until the second calving when they become mature adults. Santos agrees that heifers prior to calving should be fed differently than cows. In the last three weeks prepartum, heifers have lower dry matter intake relative to their body weight than cows do. Because they are still growing, their requirements for metabolizable protein is greater

5 Dairy Issue 9, Spring/Summer 2006 and, as opposed to cows, increasing the concentration of crude protein in close-up rations above 13% benefits postpartum performance. The key here is to feed diets that provide adequate metabolizable protein according to the expected intake of the animal, says Santos. Furthermore, prepartum heifers should not be fed acidogenic salts to prevent hypocalcemia as cows are because heifers do not experience this problem and those salts reduce feed intake and might impair the secretion/activity of some regulatory hormones, such as insulin, that are important during transition. Whenever possible, cows and heifers should be fed separately pre- and postpartum, and prepartum, they should be fed diets that are tailored to their nutrient needs. Melendez suggests that the older the animal becomes, the more chronic these nutrition problems can become. If they are not well-fed, they will probably start with some lameness problems, and Nutrition can influence fertility at all stages of the reproductive cycle, but the period between late gestation and first postpartum insemination is probably the most critical. sometimes it s so acute they are culled in the first lactation. They are more likely to develop hypocalcemia, chronic metritis, etc. Using Body Condition Scores Body condition scores (BCS) indicate the energy reserves of the body. Typically, every cow loses BCS after calving. Cows calving in obese conditions or too thin can have decreased fertility later on for different reasons. For example, an obese cow calving at 3.5 to 4 will eat less, develop more retained fat, which can then impact cyclicity. Alternatively, a too-thin cow at calving will not have enough reserves to support milk production. Melendez recommends that at dry-off a cow in general should score at a 3 and gain a 0.25 to 0.5 during the dry period so she will calve at 3.25 to 3.5. Dry cows should never lose body condition score in the dry period, he says. In addition, low energy during the postpartum period can affect the first ovulation and expression of heat. For heifers, preferred scores at calving are a bit lower, such as 3.25, otherwise dystocia problems can occur. Too much fat can affect the birth canal causing more dystocia. Body condition s affect on fertility has a lot to do with the change in score from one time point to another. Studies have demonstrated that between calving and the first days, the cow should not lose more than 1 point of condition. Beyond that, fertility can be affected. A cow may be at 2.5 and gaining weight or a cow may be at 2.75 and losing weight, says Melendez. That cow will have lower fertility even though it has a higher BCS. The change in BCS is more important than just the score itself. When to Body Condition Score Melendez likes cows to be scored at calving, between days post-calving to determine how much condition is lost in the first 100 days, at midlactation, and dry-off. At dry-off, she should score at 2.75 to 3 and be able to recover a quarter or half of a point before calving. Below 2.75 makes it difficult for a cow to gain up to 3.25 by calving time. At calving, heifers and cows should be at 3.25 to 3.75 and not lose more than 0.75 units on the 1-5 scale, says Santos. Cows with low BCS at calving have reduced potential for milk production in the first four to six weeks postpartum. Ketosis and the associated diseases have been negatively associated with conception rates at first postpartum AI. At 60 days postpartum, prebreeding, they should be at 2.75 to 3. This is important because overconditioned animals have less appetite during transition, which makes them more susceptible to ketosis and hepatic lipidosis, says Santos. Cows with BCS less than 2.75 at 60 days postpartum are much more likely to have not experienced any ovulation prior to first postpartum AI (anovular or anestrous cows), which normally reduces conception rates and increase the odds for late embryonic loss, adds Santos. Melendez does not like to see animals below 2.5 at 90 days post-calving. At mid-lactation, she should score at 2.75 to 3. Losing just one body condition score can affect her fertility, says Melendez. Most BCS loss after calving occurs in the first 40 to 60 days; scoring immediately prior to calving or at 40 to 60 days postpartum will allow the producer to evaluate how his/her fresh cow program is. At mid-lactation, the producer can decide if cows should be fed differently or not if he/she wants to manage cows based on BCS, suggests Santos. At this point, there still is time to avoid overconditioning or to improve low BCS by moving cows to different groups if different rations are fed to the lactating herd. Lastly, the measurements taken at dry-off and immediately prior to calving will allow the producer to evaluate the dry cow program. For lactating dairy cows, a key factor beyond nutrition that will influence BCS is the interval from calving to conception. Cows that become pregnant early in the postpartum period rarely will be overconditioned when they go dry, explains Santos. However, they can be on the thin side. On the other hand, cows that have prolonged lactations because of poor reproduction are more likely to be overconditioned at next calving. Continued on page 5. 4

6 ADM Alliance Nutrition, Inc. 5 Continued from page 4. Heat Stress, Nutrition, and Fertility Heat stress is the most important environmental factor influencing fertility of lactating dairy cattle. Once the body temperature of the cow rises above 40 C (~104 F), fertilization and early embryonic development are impaired. At this point, there is not much that you can do in terms of nutritional management to improve fertility, says Santos. What you really have to do is to provide adequate cooling to avoid hyperthermia. University of Florida research demonstrated that cells under thermal stress are more prone to oxidative stress, which harms cell membranes, and indicated that one possible mechanism by which heat stress influences fertility is by causing more cellular damage to the embryo because of oxidative stress. However, it s not been demonstrated that there is any benefit to increasing the supply of antioxidant nutrients (vitamin E, B-carotene) on conception rates of heat-stressed cows. Because heat stress negatively influences feed intake, it might be prudent to increase the energy content of the diet to offset reduced feed intake and minimize energy deficit that impairs reproduction, says Santos. However, one might be cautious because cows under heat stress are more likely to develop lameness, which can be exacerbated by hotter diets. In addition, Melendez s research demonstrated that high urea nitrogen in the milk of cows reduced fertility when associated with heat stress. This indicates that diets that are unbalanced in protein can be more detrimental to fertility during heat stress. Nutrition and Expression of Estrus Textbooks used to say estrus lasts 18 hours, but today s cows don t seem to be reading those old books. Today you can see a cow in estrus for just two hours, says Melendez. They are completely different today, as is nutrition and the high levels of production we now have. One of the first things affected by poor nutrition is going to be the expression of estrus. Poor nutrition, especially inadequate energy intake, can lead to extended postpartum anestrus, so diets that cause excessive body weight loss can reduce expression of estrus. In addition to that, I am not aware of any research that has evaluated the effect of specific nutrients on intensity, expression, and rates of estrus detection in lactating dairy cows, says Santos. We and others have demonstrated that 10 to 20% of the postpartum cows and 20 to 50% of the postpartum heifers have not cycled until 60 days postpartum, and these numbers are highly influenced by body condition score. So, if cows and heifers are underfed early postpartum or experience more postpartum problems that lead to reduced BCS, they will have extended period of lack of estrus expression. Furthermore, recent studies by Milo Wiltbank s group at the University of Wisconsin have demonstrated that intensity and duration of estrus are negatively correlated with level of milk production. This is one reason today s cows are less likely to be seen in estrus. The increase in milk production has changed, to some degree, the biology of the cow and this has made estrus detection more difficult. Investigating Problems A dairy has to have good records to begin with in order to know when reproductive problems are abnormal. A major indicator of fertility in the herd is the pregnancy rate, which is conception rate x heat detection. Conception rate is affected by nutrition and other factors, says Melendez. When conception rate drops 5 to 6%, that s a red flag. Pregnancy rate changes over time because of seasonality, but when you compare summer-tosummer, winter-to-winter, that number is very important and can indicate problems. When investigating fertility problems on a dairy, Melendez suggests to first look at the dairy s management in general, heat detection, cow comfort, and other factors. When looking at nutritional influences, work with the nutritionist and see the interactions with rations, the levels of energy, protein, NDF, ADF, nutrients, etc., and see if there have been changes, to start slowly expose the different pieces of the puzzle. Today, there are many useful diagnostic tools that can point you in the right direction when analyzing nutrition problems. One way is to measure

7 Dairy Issue 9, Spring/Summer 2006 urine ph in cows fed acidogenic salts prior to calving to prevent hypocalcemia. In addition, producers can evaluate ketones in milk by using strips to determine if changes in prevalence of subclinical ketosis early postpartum, says Santos. Other tests Adequate balances of major and minor trace minerals and vitamins play important roles in health as well as reproductive efficiency. that can be used that are associated with the nutritional status of the herd are plasma concentrations of nonesterified fatty acids and ketones in late gestation and early lactation, and milk urea nitrogen (MUN) during lactation. Melendez says high MUN indicates too much protein, and studies have indicated too high MUN might impair fertility. Obviously, keeping good records of occurrence of disease events is important to evaluate if the health of the herd has not deteriorated. In addition to these tools, producers, veterinarians, and nutritionists should do the common things that normally improve production, such as evaluating forage quality, suggests Santos. Melendez says monitoring transition cows after calving for 20 days in a separate group is one way to head off problems, then after 21 days, they can go to the milking ration. But we need to monitor those animals for the first 20 days, he says. In Florida, the university s Food Animal Group is monitoring temperature after calving within the first 10 days to see if cows have a fever, which is a red flag for metritis. Melendez says, We re monitoring ketone bodies by taking urine or milk samples to see if they are ketotic. If they are, the more likely they are to develop an LDA. It s a fresh cow program, and it s helped a lot to diagnose these problems at this time. Other nutrition and management factors come into play in the relationship with fertility. Cow comfort, heat abatement, bunk space, ration mixing, etc., need to also be considered, as is quantity and quality of water. Dry matter content of the TMR is very important as well, says Melendez. Veterinarians and nutritionist need to look at the dry matter content during times of wet weather, or when forages and feeds are wet so they can adjust rations to get the proper dry matter intake. Santos believes it is critical that veterinarians and nutritionists work together. By working together, we will be able to make more educated decisions and complement each other on our expertise in problem solving, he says. The most important thing to remember is that nutrition and fertility is a highly complex relationship, says Melendez. And everything is related. Trace Minerals and Fertility Adequate balances of major and minor trace minerals and vitamins play important roles in health as well as reproductive efficiency. For example, calcium is involved in any physiological and molecular process. Selenium is very important in preventing retained fetal membranes before calving. Zinc, especially in bulls, is important for semen quality. In general, says Pedro Melendez, DVM, PhD, every nutrient in the end is related to fertility. Trace minerals, such as copper, selenium, and zinc, influence the immune system of the cow by being part of enzymes that promote cell integrity at the level of membrane or cytoplasm. This is important for proper postpartum uterine health. Also, vitamins such as E and A have complementary effects to some of these trace minerals an example is vitamin E and selenium working together as scavengers of free radicals at the membrane and cytoplasm, respectively, and they are both important for proper reproductive performance. However, feeding these trace minerals and vitamins in excess of the daily requirements is unlikely to improve reproduction, notes Jose Santos, DVM, PhD. In fact, excess of some of these trace minerals, such as copper, can be detrimental to fertility. Nutrition and Bull Fertility Nutrition is important in dairy bull fertility. Overconditioned bulls can be lazy and not want to mount cows. Thin bulls may have poor semen quality. The problem is that on dairies using bulls, the bulls consume the same diet as the cows. These diets contain more energy and protein than they need and also contain other ingredients that might be detrimental to bull fertility. Bulls fed lactating rations normally become overconditioned, and the fat accumulated in the neck of the scrotum can impair thermoregulation of the testes, which is critical to sperm viability, says Jose Santos, DVM, PhD. In beef cattle, young bulls fed an excess of energy after puberty showed reduced sperm reserves in the epididymus and increased testicular degeneration. Lactating rations can also contain considerable amounts of cottonseed and cotton by-products, which are the source of gossypol. Most lactating cows will consume diets with 500 to 1,000 ppm of total gossypol, most of it in the free form if from whole cottonseed, leading to intakes of 15 to 30 g of gossypol/cow/day. These amounts of gossypol are detrimental to bull fertility as they increase testicular degeneration and sperm abnormalities and might reduce libido, says Santos. One option is to rotate bulls continuously from the lactating group to a group in which the energy and protein content of the ration is more adequate and contains no gossypol. However, this requires more breeding bulls in the herd. 6

8 ADM Alliance Nutrition, Inc. Methionine Supplementation: A Key Factor in Balanced Amino Acid Formulation by Dwain Bunting, Ph.D., Ruminant Marketing & Technical Support, ADM Animal Health & Nutrition Division 7 The Bottom Line Like non-ruminants, lysine and methionine are the most limiting amino acids for milk protein secretion and are generally the only amino acids considered in ration formulation software for dairy cattle. Because a synthetic, rumen bypass lysine product is currently not available in North America, heat-treated soy and animal protein products remain the primary sources of supplemental bypass lysine in the ration. In contrast, synthetic bypass methionine products (such as the ADM Stimerall products) can be readily purchased. In balanced rations, supplemental methionine not only increases total milk production and protein concentration but also typically increases milk fat concentration. In addition, the use of supplemental methionine in amino acid balanced rations allows for lower ration crude protein levels, which reduces ration cost and environmental impact. Focus on Feeding the Rumen The objective of feeding cows for high production is to optimize rumen fermentation. The better the fermentation, the more microbial protein produced. Microbial protein is the primary source of protein for absorption in the intestine and contains a profile of essential amino acids that is almost perfect for milk production. Microbial growth in the rumen is primarily the result of the amount and the rate of carbohydrate digestion in the rumen. Carbohydrates that have faster rates of fermentation, like flaked grains or sugars, tend to increase the synthesis of microbial protein more than feeding slowly fermenting carbohydrates, like dry corn or milo. However, too much highly fermentable carbohydrate can reduce rumen ph, dry matter intake, and milk production. Feeding strategies that result in maximum rumen microbial growth must first promote healthy rumen conditions (less acidosis) and increased dry matter intake. Optimum rumen fermentation is reached mainly through providing the proper balance of both the amounts and the types of carbohydrate and protein. Most modern ration formulation programs contain models that attempt to predict and/or optimize metabolizable protein production. Metabolizable protein is the total absorbable protein that reaches the intestine and is the combination of microbial protein produced in the rumen and bypass protein from feedstuffs. These models attempt to estimate microbial protein production based on feed nitrogen (ammonia and peptides) and carbohydrates that are available for fermentation in the rumen. In addition, these models attempt to estimate the bypass of the protein and amino acids in feed ingredients, taking into account how the feed intake of the cow will influence passage of feed ingredients out of the rumen. Although these models are valuable tools for understanding the value of bypass amino acid technologies, the primary value of these programs is their ability to help achieve optimal rumen fermentation. The Cornell-Penn-Miner model and the ADM Alliance Nutrition In balanced rations, supplemental methionine not only increases total milk production and protein concentration but also typically increases milk fat concentration. DalexSolutions Program are two software programs that have been successfully used to optimize rumen fermentation and metabolizable protein supply for the dairy cow. For Cows... Amino Acids = Lysine and Methionine Although other amino acids are suggested as having potential importance, lysine and methionine requirements continue to be the focal point of amino acid formulation for high-producing dairy cows. The practice of balancing for lysine and methionine has continued to grow in spite of recent problems with sourcing of premium high protein ingredients, especially those rich in lysine. As mentioned previously, a viable source of synthetic bypass lysine is currently not available. BSE issues have limited the usage of blood and other animal proteins and hurricane Katrina wiped out most of the current fish meal inventory. Shortages of these protein sources are particularly problematic for formulating rations for highproducing herds. These ingredients are not only good sources of lysine and methionine but most are rich in all amino acids and have very high levels of protein bypass. Even without using premium sources of bypass protein, substantial improvements in lysine and methionine balance can still be achieved with high-quality vegetable proteins, synthetic bypass methionine, and increased focus on rumen output. The level of total protein, bypass protein %, and lysine and methionine as a % of bypass protein in some typical protein sources are shown in Table 1. As shown, no single protein source is adequate for balancing the requirements for both lysine and

9 Dairy Issue 9, Spring/Summer 2006 methionine, which is why the use of multiple protein sources almost always results in higher milk production. Although heat-processed soy protein ingredients are not as high in lysine as blood meal, they are still much higher in lysine than grain-based ingredients such as ethanol byproducts. As a rule, high levels of milk production cannot be reached without the inclusion of high-quality vegetable proteins that have been processed for higher protein bypass. Depending on the technical expert or formulation platform involved, the relative balance of lysine and methionine may be described using a slightly different format, including grams of each amino acid, their percentage of the metabolizable protein, their percentage of essential amino acids, etc. However, in all cases, the global strategy is directed to achieving a lysine to methionine ratio of about 3:1. This is the practical measure of amino acid balance that should be kept in mind when evaluating feedstuffs and dairy feeding programs. Methionine and Fat Metabolism Although lysine is primarily involved in protein metabolism, methionine has important roles in both protein synthesis and fat metabolism. Depending on whether the cow is dry or lactating, as much as 1 /3 of the methionine consumed by the cow may be used for the synthesis of choline and other intermediates with roles in fat metabolism and transport. Primarily because of the importance of methionine, when cows are fed rations balanced for lysine and methionine during the complete transition period, milk production responses to amino acid-balanced rations are much greater than when given later in lactation. Research studies have shown that blood fatty acid and ketones levels decrease when rations were supplemented with methionine during the transition period. Interestingly, the benefit of supplemental methionine on fat metabolism appears to continue well after the transition period. Even in circumstances where milk production does not appear to increase in response to balancing for amino acids, milk fat concentration is frequently increased. In fact, increased milk fat is probably the most consistently observed positive response to inclusion of synthetic bypass methionine sources in the ration. This is primarily due to the role of methionine in fat transport in the liver. The ADM Stimerall family of methionine supplements was developed to take advantage of the unique properties of both ruminally-available and bypass methionine sources to alter milk volume and/or components according to the goals of the producer. High bypass Stimerall products are used in rations directed toward greater milk production and milk protein concentration, whereas Stimerall products targeting increased milk fat take advantage of methionine sources with greater ruminal availability. Cost of Amino Acid Supplementation The amount of supplemental bypass methionine required to balance a deficient ration is about 5 to 10 grams per cow daily. Natural sources of methionine, such as corn gluten meal or animal proteins, supply methionine at a cost of about 3 to 4 per gram of absorbed methionine. Synthetic rumen-protected methionine products typically supply methionine at less than 2 per gram of absorbed methionine or about 10 to 20 per cow daily. The amount of supplemental bypass lysine required to balance a deficient ration is about 10 to 20 grams per cow daily. Natural sources of lysine, such as heat-treated soy or animal proteins, supply lysine at a cost of about 1.5 to 2 per gram of absorbed lysine, which is roughly equal to or higher than the cost of a hypothetical synthetic bypass lysine source. Market conditions for synthetic bypass lysine products have not been favorable to-date; however, the increased usage of high-methionine ethanol byproducts (Table 1) and the cost of animal proteins may improve the economic viability of potential synthetic bypass lysine technologies. Table 1: Composition of Protein Sources (DM basis) with High Levels of Rumen Bypass Protein Sources with High Lysine Sources with High Methionine Heat-Treated Soybeans Expellers Soybean Meal Blood Meal Corn Gluten Meal Fish Meal Distillers Grains Dry matter, % Crude protein, % Bypass protein, % of CP Lysine, % of bypass protein Methionine, % of bypass protein

10 ADM Alliance Nutrition, Inc. Practical Considerations for Balancing Lactation Rations for Amino Acids by Ryan S. Ordway, Ph.D. Dairy Technical Support Specialist ADM Alliance Nutrition, Inc. 9 Concept of Limiting Amino Acids It is well known that methionine (Met) and lysine (Lys) are the two most limiting amino acids (AA) for maximizing milk and milk protein production in lactating dairy cows. This is largely because of their low concentrations in feed protein as compared to their concentrations in milk and ruminally synthesized bacterial protein (Table 1). Some dairy nutritionists are unaware of the amino acid content of commonly used feeds, let alone the amino acid content of bacterially synthesized crude protein, milk, or lean muscle tissue. However, when the amino acid content of commonly used feeds is compared to the amino acid content of the end products of feed digestion (e.g., bacterial protein, muscle tissue, and milk), it is readily apparent why Met and Lys are the two most limiting amino acids in dairy cow rations. The NRC (2001) suggested concentrations of Lys and Met in metabolizable protein (MP) for maximal use of MP for milk and milk protein production are 7.2 and 2.4%, respectively. However, under almost all circumstances, these concentrations cannot be achieved. Therefore, more practical recommendations for Lys and Met in MP of 6.6 and 2.2%, respectively, have been suggested (Schwab et al., 2003). These concentrations can generally be achieved in corn-based rations by using a combination of high-lys protein supplements (e.g., blood, fish, and processed soybean meals) and a rumen-protected Met (RPMet) product along with limiting intake of rumen-undegraded intake protein (RUP) to requirement levels. Not using a RPMet product requires the mix-and-matching of protein supplements to achieve the desired Lys:Met ratio in MP of 3:1 and, as a result, lowers the concentrations of both Lys and Met in MP that are achievable (Schwab et al., 2003). Amino Acid Content of Feeds The amino acid content of milk, lean muscle tissue, bacterially synthesized crude protein, and common feeds are summarized in Table 1. This data clearly demonstrates that the amino acid content of most feeds used in typical dairy rations are too low in Met and Lys to meet the requirements for milk production and lean tissue growth. It is also clearly evident that bacterially synthesized crude protein is a rich source of amino acids and is perhaps, the most complete source of amino acids for meeting the needs of the dairy cow for milk production and lean tissue growth. Unfortunately, the high producing dairy cow cannot synthesize sufficient amounts of bacterial protein to satisfy the requirements for maintenance of body tissue and milk production. To help satisfy these requirements additional amino acids should be included in lactation rations. Unfortunately, supplementing additional amino acids in dairy rations is not an easy task, because rumen microorganisms tend to utilize ruminally available amino acids found in feed for their own needs. To overcome rumen breakdown, nutritionists can incorporate into dairy rations feedstuffs that have the ability to remain undegraded in the rumen, allowing passage to the small intestine for absorption. For reasons beyond the scope of this article, only a limited number of feedstuffs are available that can provide the needed amounts of Lys and Met to meet the needs of the high producing dairy cow. Because Met is available synthetically, this article will focus on the need for finding feedstuffs that will supply sufficient amounts of Lys to meet the needs of high producing dairy cows. Many dairy nutritionists and producers are currently utilizing distillers grains, a protein-rich byproduct, in dairy rations due to its increasing availability and favorable cost. However, a common misconception about distillers grains exists; this being that distillers grains are Producers who fine-tune amino acid balance in lactating rations can reap the dividends of higher milk protein and milk production. high in Met content. This misconception often prompts nutritionists and producers to feed more bypass Lys in order to maintain a balanced Lys to Met ratio. It is important to note that distillers grains are not necessarily high in Met content, but rather it is simply that distillers grains are low in Lys content. In fact, the Lys content of distillers grains is still higher than the Met content, but overall, is low compared to other Lys-rich feeds, such as blood meal, fish meal, and soybean meal. Do not balance dairy rations when using distillers grains with the misconception that they are a rich source of RUP Met. Plant Proteins Versus Animal Proteins The use of plant protein sources versus animal protein sources as supplemental Lys sources for dairy rations needs evaluating. As shown in Table 1, animal protein sources, such as blood meal and fish meal, are much more concentrated sources of RUP-Lys compared to plant protein sources. It is extremely difficult to attain high levels of Lys required to meet the needs for milk and milk protein production of high producing dairy cows using only plant protein sources due to their relatively low content of Lys compared to animal protein sources. However, several inherent limitations exist when using animal protein sources. With the recent U.S. documented cases of bovine spongiform encephalopathy (i.e., Mad Cow disease), the use of animal proteins in rations for food animals or lactating animals has come under scrutiny by the government and general public. Beyond the negative public perception, problems associated with feeding animal proteins include the large variations that can exist in crude protein content, RUP content, RUP-digestibility, and amino acid content. Although these same problems exist when using plant protein sources they are of even greater concern with animal proteins. Also, palatability is often a concern when feeding animal proteins. Moderate levels of animal proteins can often be fed without a problem; however at

11 Dairy Issue 9, Spring/Summer 2006 Table 1: A Comparison of the Essential Amino Acid Composition of Body Lean Tissue, Milk, and Ruminal Bacteria with that of Some Common Feeds 1 (Adapted from Schwab and Ordway, 2005) Item Lysine Methionine Histidine (% of CP) Lean tissue Milk Bacteria Alfalfa silage Corn silage Grass silage Barley Corn Oats Wheat higher levels, dry matter intake is often depressed. To improve handling characteristics and increase RUP characteristics, animal proteins are dried. Differences in drying procedures can greatly impact product quality. Products that are dried too long will have high RUP values, yet will have a low RUP-digestibility, and the Lys will be unavailable for Brewers grains Canola meal Corn DDG w/sol Corn gluten meal Cottonseed meal Soybean meal Sunflower meal Blood meal Feather meal Fish meal Meat meal use by the animal. Insufficient drying will result in low RUP values, enabling greater rumen degradation that prevents its passage to the small intestine for absorption and use by the animal. These two scenarios commonly occur with blood and meat and bone meal products where the method of processing has a significant impact on quality. Consequently, quality control is extremely important when processing animal proteins for use in dairy rations. The ADM Alliance Nutrition Response While ADM Alliance Nutrition recognizes that blood meal is the most concentrated source of Lys available, ADM researchers and feed technology scientists realize the potential quality control limitations of using blood meal as a source of digestible Lys. Unfortunately, poor quality control and improper processing techniques involved in producing blood meal may compromise expected performance in increasing milk protein production. Equipped with this knowledge, ADM researchers applied extensive analytical research protocols to determine the nutritional content of blood meal from various suppliers. The process identified variations related to plant location and processing methods used in the blood meal manufacturing process. The results of ADM s research efforts enabled ADM Alliance Nutrition to Amino acid values for lean tissue, milk, and ruminal bacteria are from O Connor et al. (1993) and amino acid values for feeds are from NRC (2001). enhance the quality control of inputs, which ensure the proper amino acid content of feed ingredients is maintained on a continual basis. The result ADM Alliance Nutrition can apply scientific knowledge and skill to formulate feed products and dairy rations which provide consistent quality and value, enabling dairy cows to perform to their genetic potential. The ADM Alliance Nutrition Solution ADM Alliance Nutrition developed the Dairy Solutions 6:1 Base to provide a 6:1 Lys to Met ratio. This ratio supplies the optimal balance of amino acids to compliment the growing use of distillers grains used in today s dairy rations. The stringent quality control processes used in the manufacture of Dairy Solutions 6:1 Base provides ADM Alliance Nutrition dairy customers with the assurance that lactating cows receive the required amino acids for optimal milk and component production. The feeding of high-quality ingredients offers dairy producers the best return on their feed investment. Producers who fine-tune amino acid balance in lactating rations can reap the dividends of higher milk protein and milk production. To obtain information concerning ADM Alliance Nutrition s dairy products and programs, contact your local ADM Alliance Nutrition representative or dealer, or call ADM Alliance Nutrition at

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