|Hammond, Andrew - Andy|
Submitted to: Journal of Animal Science
Publication Type: Abstract only
Publication Acceptance Date: 2/18/1999
Publication Date: N/A
Citation: Hopkins, D.I., Kunkle, W.E., Hammond, A.C., Bates, D.B., Reiling, B.A. 1999. Effects of bypass methionine on the performance of growing cattle fed bermudagrass hay supplemented with molasses-based supplements [abstract]. Journal of Animal Science.77(1):202. Interpretive Summary:
Technical Abstract: We investigated whether the performance response to protein supplements was explained by the total sulfur amino acids (TSAA) in the bypass (UIP) protein. Supplements were formulated to provide 1, 2, 3, 4, or 5 g/d of TSAA (methionine plus cystine) in the UIP from blood-feather meal (BFM, 50:50), corn gluten meal (CGM) and rumen protected methionine (MET) compared to a control supplement. Supplements contained 84% fortified (urea, minerals, vitamins) molasses and 16% corn. Corn was replaced with the respective protein source. Calves averaged 240 kg at the start of the trials. Bermudagrass hay was offered adlibitum and molasses slurries were limit fed at 6 lb/d during the 105 to 120 d trials. Cattle gains increased linearly as bypass TSAA was increased. Each gram of bypass TSAA increased gain 27 g/d. All sources of methionine gave similar results suggesting that the TSAA concentration of the BFM and CGM supplements was the nutrient limiting performance. Dry matter intake averaged 5.8 kg/day and TSAA level and source did not change it. Gain/feed was improved .003 units for each gram of bypass TSAA and all sources of bypass TSAA gave similar results. Cattle fed BFM and CGM supplements had increased BUN (11.5 to 15.5 mg/dl) as the bypass TSAA level increased but cattle fed increasing levels of MET had similar BUN (11.3 mg/dl). This research suggests that TSAA concentration in supplemental UIP is an important factor for growing cattle fed forage based diets.