Supplementing growing Holstein steers fed a corn-urea diet with a mixture of essential amino acids increases performance

Six ruminally cannulated Holstein steers (550 lb) implanted with Revalor-S were infused abomasally with water or a mixture of six amino acids in a crossover experiment (two 14-day periods) to evaluate effects on nitrogen balance. The mixture was comprised of amino acids that potentially may be limiting in lightweight steers, namely (g/day): lysine (5.3), methionine (3.3), threonine (3.2), tryptophan (1 .0), histidine (2.1), and arginine (5.5). Steers were fed at levels just below ad libitum intake. The diet contained 86% rolled corn, 10% prairie hay, 3% mineral and vitamin premixes, and 1% urea (as-fed). Amino acid infusion increased nitrogen retention by 17.9% over the control, from 27.9 g N/day to 32.9 g N/day. This indicates that implanted steers fed a high concentrate diet are able to respond to amino acid supplementation, suggesting that at least one of the infused amino acids was limiting in the basal corn-urea diet

Performance of lactating cows fed procressed grain sorghum and expeller soybean meal

Forty-four Holstein cows were used to measure milk production responses to dryrolled vs processed grain sorghum and expeller vs solvent soybean meal (SBM) in a 2×2 factorial arrangement of four treatments. Processing of grain sorghum decreased feed intake 5%, but increased milk by 3%, protein by 4%, and efficiency by 7%, with fat being unaffected. Replacement of solvent SBM with expeller SBM had little effect on intake, but increased milk by 3%, fat by 5%, and efficiency by 4%, with protein being unaffected. The processing of grain sorghum seems to be a valuable method to improve its nutritive value for lactating cows. Total milk and fat yield, but not protein yield, were increased in response to feeding expeller SBM in the place of solvent SBM

Dietary molasses enhances ruminal biohydrogenation and partially alleviates diet- induced milk fat depression

Dairy Research, 2008 is known as Dairy Day, 2008Milk fat depression remains a problem on dairy farms, and in recent years, incorporation of distillers grains (typically with solubles added and often dried) has contributed to this problem on some farms. In this study, we evaluated whether molasses could prevent milk fat depression in cows fed a high-risk diet. Replacing up to 5% of dietary corn with cane molasses linearly increased the yield of short- and medium-chain fatty acids in milk, indicating a positive effect on de novo fatty acid synthesis in a milk fat depression environment. Molasses, however, tended to linearly decrease milk yield and linearly decreased milk protein yield, resulting in no net effect on energy- or solids-corrected milk yield. These results indicate that the potential exists for sources of dietary sugar to prevent milk fat depression, but further research is needed to determine when sugar sources might be most effective

Effect of nitrogen supplementation and Zilpaterol-HCl on urea recycling in steers consuming corn-based diets

Cattle have the innate ability to recycle nitrogen absorbed post-ruminally back to the rumen as endogenously synthesized urea. Urea returning to the rumen provides an additional opportunity for ruminal microbes to benefit from nitrogen absorbed postruminally. Urea recycling may provide a significant benefit to cattle when protein requirements of ruminal microbes are high or when large amounts of the dietary protein escape ruminal degradation

D- VS L-methionine utilization by growing steers

Increasing the amino acid supply to the small intestine of growing cattle can increase performance, if specific amino acids are limiting. Although this can be accomplished by feeding rumen undegradable protein, a more economical approach may be supplementing only those amino acids that actually limit performance, but in a form that will bypass the rumen. Methionine (MET) is thought to be a limiting amino acid for growing cattle. DL-MET, a 50 :50 mixture of natural methionine (L-MET) and the unnatural optical isomer (D-MET) is used widely in monogastric rations. Ruminally protected DL-methionine is also available for cattle; however, little information is available about its utilization by growing steers. We studied the efficiency of utilization of D- vs L-MET by growing steers by measuring nitrogen retention of steers postruminally supplemented with graded levels of D- or LMET. Nitrogen retention increased linearly in response to infusion of both L-MET and D-MET, with similar responses for the two isomers. The efficiency of utilization of DMET relative to L-MET was estimated to be 95.5%. In conclusion, D-MET was similar to L-MET in increasing nitrogen retention of growing steers

Effects of energy level on methionine utilization by growing steers

The objective of this study was to evaluate the effect of energy level on amino acid utilization in growing steers. Six ruminally cannulated Holstein steers (503 lb) were limit-fed (6.2 lb/day dry matter) a diet based on soybean hulls (83%), wheat straw (7.6%), and cane molasses (4.1%). The treatments consisted of the infusion of two methionine levels (0 or 3 g/d) and three energy levels (0, 1.3, or 2.6 Mcal ME/day) in a 2 x 3 factorial arrangement. Energy was supplied through ruminal infusion of acetate, propionate, and butyrate and through abomasal infusion of glucose and fat in increasing amounts. No interactions between methionine and energy level were observed. Nitrogen balance was increased by methionine supplementation, indicating that this amino acid limited protein deposition. A linear increase in nitrogen retention was found with the increase in energy. These improvements in protein deposition were related to reductions in urinary nitrogen excretion, reduced plasma-urea concentrations, and greater circulating concentrations of insulin and insulin-like growth factor-I. The results of this study suggest that amino acid utilization can be improved by increasing energy. These effects could be partly explained by variations in plasma concentration of key hormones involved in the control of protein deposition

The effects of rbST (POSILAC®) on heat stressed, lactating, dairy cows

Two hundred cows located on a commercial dairy in Mesquite, NM were used to evaluate response to rbST (POSILAC®) during heat stress in the summer of 1996. Cows were paired by days in milk (average = 153 d at initiation of experiment), parity, and milk yield (average = 92 lb at start of experiment). Prior to initiation of the experiment, all cows received rbST, then rbST treatment was discontinued for one cow from each pair. Milk production was monitored for 4 months. No interactions were detected between lactation number and treatment. Cows maintained on rbST gained .09 of a score (1 to 5scale) less (P\u3c.05) body condition but produced more (P\u3c.05) milk in June, July, August, and September. The average milk productions for rbST-maintained vs rbST-discontinued cows were 80.7 vs 73.5 lb/d in June, 80.1 vs 74.6 lb/d in July, 72.6 vs 67.1 lb/d in August, and 65.1 vs 59.2 lb/d in September. Although rbST-discontinued cows had greater declines in production discontinued cows had greater declines in production persistency was similar between groups during the final 3 months. Under conditions of heat stress, cows maintained on rbST produced 6.2 lb/d more milk than cows for which treatment with rbST was discontinued.; Dairy Day, 1997, Kansas State University, Manhattan, KS, 1997

Characteristic changes of ruminal fermentation in transition dairy cows

Four-ruminally fistulated, multiparous, pregnant Holstein cows were used to delineate changes in ruminal fermentation in dairy cows as they experienced the transition from one lactation to the next. Diets consisted of typical far-off and close-up diets, a late lactation diet containing wet corn gluten feed (20% DM) and an alfalfa hay-corn silage based early lactation diet. Calculated NEL (Mcal/lb), measured crude protein (%), and diet digestibilities (%; based on steers fed at 2% of BW) were: 0.78, 18.7, 74.1; 0.70, 11.5, 66.2; 0.74, 15.6, 71.0; 0.73, 18.4, 70.7 for late lactation, far-off dry, close-up dry, and early lactation diets, respectively. Ruminal measurements were taken on days 72 (late lactation), 51 (faroff), 23, and 9 (close-up dry) before calving and on days 6, 20, 34, 48, 62, 76, and 90 days after calving. Ruminal samples were collected at hours 0, 3, 6, 9, and 12 after feeding on each sampling date. Major shifts in ruminal fermentations occurred when the close-up diet was consumed before calving and in concert with an increase in DM intake during the first 48 days of lactation. Dry matter digestibility increased after cows were switched to the close-up diet and continued this trend through day 6 postpartum. Ruminal pH decreased and total volatile fatty acids, peptides, and free amino acids increased after cows were switched to the early lactation diet. These data support the concept that alterations in ruminal fermentation reflect changes in both diet and intake.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

Comparison of three fresh cow feeding programs

We evaluated the impact on performance of top dressing a based total mixed ration (TMR) with long-stem alfalfa hay with or without additional dry-rolled corn to the lactating cow diet during the first 5 days postpartum. The three dietary treatments and numbers of cows assigned to each diet were: 1) total mixed ration (TMR; n = 19); 2) TMR + long-stem alfalfa hay (TMR + A; n= 20); and 3) TMR + long-stemmed alfalfa hay + dry-rolled corn (TMR + A + C; n = 20). Top dressing the lactating TMR with long-stem alfalfa hay with or without dry-rolled corn did not reduce the incidence of metabolic disorders in early lactating cows. Six cows, two on each diet, were treated for displaced abomasums. Cows consuming only the TMR lost slightly more body weight during the first 30 days after calving compared to cows fed the other diets. Milk and energy corrected milk (ECM) yields were similar among diets. Fat, protein, and urea nitrogen content in milk were not different among dietary treatments. Lactose content in milk was greater for cows consuming TMR + A than those consuming TMR or TMR + A + C. Concentrations of glucose and urea nitrogen in plasma were not affected by treatment during the initial 5 days of lactation. Concentrations of glucose and urea nitrogen on days 2 and 3 were less for multiparous cows consuming TMR than for multiparous cows consuming TMR + A. Rumen contractions during the first 5 days of lactation were not different among diets. Top dressing the lactating TMR with long-stem alfalfa hay with or without dry-rolled corn was not beneficial in this study. On a dry matter basis, the lactating TMR contained 22% chopped alfalfa hay, 10% corn silage, 20% wet corn gluten feed, 9% whole fuzzy cottonseed, 7.1% expeller soybean meal, 27.4% ground shelled corn, 1.2% molasses, 1.3% Menhaden fishmeal, and 2.0% mineral-vitamin premix. Cows fed diets containing corn silage as the predominant fiber source may respond differently.; Dairy Day, 2003, Kansas State University, Manhattan, KS, 2003

Comlete lactational performance of cows fed wet corn gluten feed and pellet consisting of raw soybean hulls and corn steep liquor

We evaluated the effect of wet corn gluten feed and a novel product containing raw soybean hulls and corn steep liquor on performance in lactating dairy cows. Forty-six multiparous Holstein cows were used in a randomized incomplete block design. Cows were housed in tie stalls for the first 13 weeks of lactation and moved to group pens for the remainder of the study. Cows were blocked by calving date and assigned to control, wet corn gluten feed (20% of diet DM), or the novel product (20% of diet DM). Diets were administered as total mixed rations at the first feeding postpartum. Control contained (DM basis) 30% alfalfa hay, 15% corn silage, 32% corn, 9.3% whole cottonseed, 4.4% solvent soybean meal (SBM), 3.3% expeller SBM, 1.3% fish meal, 1% wet molasses, and 3.7% vitamins/minerals. Wet corn gluten feed replaced 10% alfalfa hay, 5% corn silage, 5% corn grain, and expeller SBM replaced solvent SBM to maintain diet rumen undegradable protein. The novel product replaced 10% alfalfa hay, 5% corn silage, 3% solvent SBM, and 2% corn. Diet crude protein % and energy density (Mcal/lb, NEL) for control, wet corn gluen feed, and the novel product were 18.4, 0.73; 18.2, 0.75; 18.5, 0.73; respectively. Milk, energy corrected milk, dry matter intake, and production efficiency (ratio of milk to DM intake) did not differ among diets during the first 91 days of lactation, but there was a diet by week interaction for production efficiency. Cows fed control were more efficient during the first 2 weeks postpartum than cows fed wet corn gluten feed and the novel product, likely due to increased fat mobilization from adipose tissue because intake as a percent of body weight was less for cows fed control. During weeks 3 through 14 postpartum, wet corn gluten feed and the novel product improved milk, energy corrected milk, and milk component yield, and production efficiency. Inclusion of wet corn gluten feed and the novel product at 20% of dietary DM as a partial replacement for alfalfa hay, corn silage, corn grain, and SBM in diets fed to lactating dairy cattle supported performance during early lactation and improved performance during mid and late lactation. In addition, combining wet corn gluten feed or the novel product with corn silage and alfalfa hay maintained milk fat yields, thereby demonstrating that they can serve as effective sources of fiber when fed at 20% of dietary DM. Improved performance attributed to wet corn gluten feed and the novel product is due to factors other than improved digestibility of the diets. These results indicate that wet corn gluten feed and the novel product can serve as alternative feedstuffs in diets fed to lactating dairy cattle.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002