Dairy Research, 2011 is known as Dairy Day, 2011Ninety-six lactating Holstein cows were used to determine the effects of using commercial
supplements to supply additional lysine and methionine in diets containing large proportions
of corn by-products. Cows were assigned to 1 of 8 pens. Pens were offered rations formulated
to differ in metabolizable lysine and methionine supply. The study was divided into 2 periods.
During period 1, cows received similar diets, but the treatment diet supplied supplemental lysine
and methionine. During period 2, the treatment diet was modified to reduce dietary crude
protein. Feed intake and production were monitored daily, and milk components were analyzed
3 days per week for 4 weeks. Diet did not alter feed intake or milk production. During period
2, dietary crude protein and milk urea nitrogen (MUN) were decreased without sacrificing
performance

Block, E.

Bradford, Barry J.

Brouk, Michael J.

Mullins, C.R.

Smith, John F., 1962-

Weber, D.

K-State Research Exchange

10Nutrition and FeedingEffects of Supplementing Methionine and Lysine  in a Lactation Diet Containing High Concentrations  of Corn By-products C. R. Mullins, D. Weber, E. Block, J. F. Smith, M. J. Brouk, and B. J. BradfordSummaryNinety-six lactating Holstein cows were used to determine the effects of using commercial supplements to supply additional lysine and methionine in diets containing large proportions of corn by-products. Cows were assigned to 1 of 8 pens. Pens were offered rations formulated to differ in metabolizable lysine and methionine supply. The study was divided into 2 periods. During period 1, cows received similar diets, but the treatment diet supplied supplemental ly-sine and methionine. During period 2, the treatment diet was modified to reduce dietary crude protein. Feed intake and production were monitored daily, and milk components were analyzed 3 days per week for 4 weeks. Diet did not alter feed intake or milk production. During period 2, dietary crude protein and milk urea nitrogen (MUN) were decreased without sacrificing performance.Key words: by-product, lysine, methionine, milk yieldIntroductionCost of protein sources combined with environmental regulations demands more efficient use of dietary protein. Formulating for metabolizable protein (MP) has provided some progress in this area while possibly improving production. Formulating for an adequate MP supply may, however, still fail to meet the requirements of the cow if the dietary amino acid profile is not considered.By-products from corn biofuel production are often used to provide protein and energy in lacta-tion diets. In 2010, of the nutritionists and veterinarians who formulate rations and completed a survey, 92% used distillers grains or considered using them. Many other by-products of corn milling also are fed to dairy cattle, including corn germ meal, corn bran, corn meal, and corn gluten feed. Like corn grain, these by-products are low in lysine, so it is not surprising when nutrition models predict that diets containing large concentrations of corn by-products do not supply enough lysine to support the demands of high milk production. Many lactation diets also do not supply adequate methionine; thus, lysine and methionine are often the first-limiting amino acids in lactating cow diets.The objective of this study was to evaluate the effects of supplementing commercial rumen-protected amino acids in a diet that was predicted to have marginally deficient lysine and methionine supply. The products used to provide the additional amino acids contained lysine embedded within calcium salts of fatty acids (Megamine-L, Arm & Hammer Animal Nutri-tion, Princeton, NJ) and the isopropyl ester of 2-hydroxy-4-methylthio-butanoic acid (HMBi; MetaSmart, Adisseo Inc., Antony, France), a methionine precursor.11Nutrition and FeedingExperimental ProceduresNinety-six lactating Holstein cows (33 first lactation; 63 second or greater lactation) that aver-aged 186 days in milk were enrolled in this study. Cows were assigned to 1 of 8 identical pens with 12 free stalls in each pen. Cows were divided into pens evenly based on milk production, parity, and pregnancy status. Cows were moved into pens on May 3, 2010, and the study began on May 10, 2010, allowing for a 1-week adaptation period. During the adaption period, all pens received a common diet.The study consisted of two 28-day treatment periods. During period 1, cows were offered either of 2 rations that were formulated to differ in metabolizable amino acid supply (Table 1). Dur-ing period 2, the treatment diet was modified to decrease dietary crude protein and further increase lysine and methionine supply. Treatment diets were assigned randomly to pens. Cows were fed once daily at 110% of the expected intake. Amounts of feed delivered and refused were recorded on days 19, 20, 21, 26, 27, and 28 of each period. The total mixed rations were ana-lyzed for dry matter (DM) on those days. Samples of all dietary ingredients were collected on days 19, 21, 26, and 28 and composited into 1 sample per period for wet chemistry analysis.Cows were milked 3 times daily in a milking parlor, and milk yields were recorded at each milk-ing. Milk samples were collected from every milking on each Monday, Wednesday, and Friday throughout the experiment. Milk samples were analyzed for component concentrations.Results and DiscussionIn formulating experimental diets, the strategy was to maintain large concentrations of corn by-products within diets; therefore, the control diet (Table 1) contained 26.7% wet corn gluten feed (WCGF) on a DM basis. The period 1 treatment diet was similar to the control; the pri-mary differences were replacement of 190 g/cow of the calcium salts of fatty acids (Megalac-R, Arm & Hammer Animal Nutrition) with a source of calcium salts of fatty acids embedded with lysine (Megamine-L), and addition of 14 g/cow of HMBi. As expected, most nutrient concen-trations were similar across treatments (Table 1); however, predicted supplies of metabolizable lysine and methionine were slightly elevated in the amino acid-supplemented group (Table 2).Period 1 feed intake and production responses for both diets are shown in Table 3. Mean DM intake was 58.6 lb/day and mean milk yield was 88.4 lb/day, with means of 3.10% fat and 3.06% protein. No treatment effects were observed for any of the traits measured. Milk protein yield, the variable of greatest interest, was numerically smaller (P = 0.54) for the amino acid-supplemented diet compared with the control (2.67 vs. 2.71 ± 0.04 lb/day). For period 2, the treatment diet was modified such that 3.6% WCGF was replaced with corn silage, expeller soybean meal was decreased from 4.9 to 2.2% of diet DM, and more Megamine-L and HMBi were added. These changes resulted in a decrease in dietary crude protein from 17.9% to 17.1%, with similar predicted lysine and methionine supply compared with the period 1 treatment diet (Table2).Performance of cows fed the 2 diets during period 2 is shown in Table 4. Consistent with the decrease in dietary crude protein, milk urea nitrogen (MUN) was decreased (P < 0.001) in the amino acid-supplemented group (10.8 vs. 12.5 ± 0.2 mg/dL) without affecting milk produc-tion. During this period, mean DM intake was 53.8 lb/day and mean milk yield was 78.9 lb/day, with means of 3.18% fat and 3.04% protein. Beyond dietary treatment effects on MUN, 12Nutrition and Feedingno effects were observed for any production traits measured. As in period 1, milk protein yield was numerically smaller (P = 0.20) for the amino acid-supplemented diet compared with the control (2.18 vs. 2.25 ± 0.04 lb/day). Results from this study did not support the hypothesis that increasing lysine and methionine supply would increase production of cows fed a corn by-product-based diet. A number of pos-sible explanations could explain the lack of a response. One possibility is that the products used to provide supplemental methionine and lysine did not increase post-ruminal supply of these amino acids. Past research, however, has indicated that the amino acid sources used in this study are partially protected from ruminal degradation. The efficacy of HMBi to deliver metabolizable methionine is further supported by production responses showing HMBi supplementation in-creases milk protein when production seems to be limited by metabolizable methionine supply.Another possibility accounting for why lysine and methionine supplementation did not in-crease production is that something else was first-limiting in this scenario. Our study narrowly focused on lysine and methionine because substantial research has supported the focus on a lysine and methionine deficiency in diets similar to those fed in our study. Energy intake also could have been limiting even though all nutrition model predictions indicated a positive en-ergy balance.A third possibility is that the model predictions, which were used to suggest a lysine limitation in the control diet, were wrong. From these results, determining whether this was because of inaccurate predictions of metabolizable lysine supply and/or lysine requirements is impossible.Results from this study demonstrated little response to supplementing the rumen-protected amino acids lysine and methionine. Given the results, the diet fed to control cows likely was not deficient in these amino acids, or the supplemental amino acid products that were used did not efficiently escape ruminal degradation.13Nutrition and FeedingTable 1. Ingredient and nutrient composition of diets fed to lactating Holstein cowsDietary treatmentItem Control Amino acid  supplemented  (period 1)Amino acid  supplemented  (period 2)Ingredient, % of dry matterCorn silage 23.4 23.4 27.8WCGF1 26.7 26.6 23.0Alfalfa hay 18.5 18.7 19.0Cottonseed 5.4 5.3 5.6Ground corn grain 14.2 14.2 14.7Ground milo 2.7 2.7 2.8Expeller soybean meal2 4.9 4.9 2.2Fish meal, Menhaden 0.3 0.3 0.3Calcium salts of fatty acids3 0.7 … …Megamine-L4 … 0.7 1.2HMBi5 … 0.04 0.18Micronutrient premix6 3.3 3.3 3.4NutrientDry matter, % as-fed 55.6 55.6 52.9Crude protein 17.8 17.9 17.1Neutral detergent fiber 33.3 32.9 30.6Crude fat 4.7 4.5 4.7Starch 24.0 23.5 25.6NFC7 37.6 37.9 41.1Ash 6.9 6.8 6.7NEL, Mcal/lb8 0.76 0.76 0.79Calcium 0.83 0.79 0.94Phosphorus 0.54 0.53 0.50Magnesium 0.35 0.33 0.33Potassium 1.41 1.42 1.30Sodium 0.42 0.44 0.441 Wet corn gluten feed (Sweet Bran, Cargill, Inc., Blair, NE).2 Soybest (Grain States Soya, Inc., West Point, NE).3 Megalac-R (Arm & Hammer Animal Nutrition, Princeton, NJ).4 Calcium salts of long-chain fatty acids plus lysine monohydrochloride (Arm & Hammer Animal Nutrition).5 Isopropyl ester of 2-hydroxy-4-methylthio-butanoic acid, MetaSmart (Adisseo Inc., Antony, France).6 The premix consisted of 41.6% limestone, 32.5% sodium bicarbonate, 6.50% Diamond V XP (Diamond V Mills, Inc.), 5.40% trace mineral salt, 5.40% magnesium oxide, 5.20% vitamin E premix, 1.66% 4-plex, 0.93% Se premix, 0.36% vitamin A premix, 0.16% vitamin D premix, 0.05% EDDI, and 0.21% Rumensin 80 (Elanco Animal Health, Greenfield, IN).7 Nonfiber carbohydrates; calculated as dry matter − (crude protein + NDF + crude fat + ash).8 Estimated according to NRC (2001). Nutrient Requirements of Dairy Cattle, 7th rev. ed., National Research Council. Natl. Acad. Sci., Washington, DC.14Nutrition and FeedingTable 2. Predicted metabolizable lysine and methionine supplies as a percentage of predicted metabolizable pro-tein supply by 3 different models and predicted metabolizable lysine:methionine ratio  Dietary treatmentControlAmino acid  supplemented (period 1)Amino acid  supplemented  (period 2)Item Lysine Methionine Lysine Methionine Lysine MethioninePredicted supply (g/day)NRC (2001) 191 65 206 67 200 69CNCPS 5.0 181 64 197 66 197 70CNCPS 6.1 165 62 194 67 188 68% of metabolizable proteinNRC (2001) 6.3 2.2 6.8 2.2 7.2 2.5CNCPS 5.0 6.1 2.1 6.6 2.2 7.1 2.5CNCPS 6.1 5.3 2.0 6.0 2.1 6.5 2.3Lysine:methionine1NRC (2001) 2.92 3.07 2.90CNCPS 5.0 2.84 2.99 2.81CNCPS 6.1 2.66 2.89 2.771 Calculated based on g of predicted amino acid supply.Table 3. Effects of supplementing lysine embedded within calcium salts of fatty acids1 and HMBi2 on perfor-mance of lactating Holstein cows in period 1Dietary treatment Item Control Amino acid  supplemented  (period 1) SEM P-value Dry matter intake, lb/day 58.2 58.9 1.10 0.65Yield, lb/dayMilk 88.2 88.2 1.5 0.98Milk fat 2.68 2.75 0.07 0.59Milk protein 2.71 2.66 0.04 0.54Milk lactose 4.29 4.31 0.09 0.96Energy-corrected milk3 84.0 84.7 1.5 0.81Milk fat, % 3.07 3.12 0.06 0.59Milk protein, % 3.08 3.04 0.04 0.51Milk lactose, % 4.88 4.88 0.03 0.97MUN, mg/dL 13.9 14.3 0.2 0.251 Megamine-L, Arm & Hammer Animal Nutrition, Princeton, NJ.2 The methionine precursor isopropyl ester of 2-hydroxy-4-methylthio-butanoic acid (MetaSmart, Adisseo Inc., Antony, France).3 Energy-corrected milk = (0.327 × milk yield) + (12.86 × fat yield) + (7.65 × protein yield).15Nutrition and FeedingTable 4. Effects of supplementing lysine embedded within calcium salts of fatty acids1 and HMBi2 on performance of lactating Holstein cows in period 2Dietary treatment Item Control Amino acid supplemented (period 2) SEM P-value Dry matter intake, lb/day 53.9 53.5 0.9 0.91Yield, lb/dayMilk 79.2 78.1 1.3 0.51Milk fat 2.29 2.33 0.07 0.65Milk protein 2.24 2.18 0.04 0.20Milk lactose 3.59 3.52 0.07 0.36Energy-corrected milk3 84.0 84.7 1.5 0.81Milk fat, % 3.12 3.23 0.06 0.59Milk protein, % 3.05 3.02 0.04 0.59Milk lactose, % 4.85 4.84 0.04 0.87Milk urea nitrogen, mg/dL 12.5 10.8 0.2 <0.0011 Megamine-L, Arm & Hammer Animal Nutrition, Princeton, NJ.2 The methionine precursor isopropyl ester of 2-hydroxy-4-methylthio-butanoic acid (MetaSmart, Adisseo Inc., Antony, France).3 Energy-corrected milk = (0.327 × milk yield) + (12.86 × fat yield) + (7.65 × protein yield).

Effects of supplementing methionine and lysine
in a lactation diet containing high concentrations
of corn by-products

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Effects of supplementing methionine and lysine in a lactation diet containing high concentrations of corn by-products

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