7～10月龄杂交肉牛蛋白质需要量及其代谢规律的研究

Protein requirements and metabolisms in the cross-bred beefs of 7～10 month old

选择18头健康、体重（183.58±7.89）kg的6月龄利木赞×鲁西黄牛杂交生长牛，采用饲养试验、消化代谢试验和尼龙袋试验，研究了7～10月龄生长牛的蛋白质需要量及其代谢规律。试验结果表明，本试验日粮的粗蛋白质对7～10月龄生长牛的消化率、沉积率和瘤胃降解率分别为75.93%、35.28%和56.28%。生长牛在7～10月龄时的维持粗蛋白质需要量为6.46 g/kgW0.75.d，增重的粗蛋白质需要量为463.42 g/kg。生长牛在7～10月龄时期，其粗蛋白质需要量（RCP，g/d）、可消化粗蛋白质需要量（RDCP，g/d）和瘤胃降解蛋白质需要量（RDP，g/d）可按下式计算：RCP=6.46W0.75＋463.42△W；RDCP=4.91W0.75＋351.87△W；RDP=2.76W0.75＋198.04△W。

Feeding trial, digestion-metabolism experiment and nylon bag test were conducted to study the protein requirements and metabolism in 18 cross-bred （ Luxi Limousin） beef cattle. The result showed the protein digestibility of the diet by the beef was 75.93% ; the deposit rate of the protein was 35.28% ; the rumen degradable rate was 56. 28%. The crude protein requirement for maintenance was 6. 46 g/kg W^0.75 d, and the crude protein requirement for gain was 463.42 g/kg. The crude protein requirement （RCP, g/d）, digestible crude protein requirement （RDCP, g/d）, rumen degradable protein requirement （RDP, g/d） of beef cattle can be calculated according to the following formula：RCP=6.46W0.75＋463.42△W;RDCP=4.91W0.75＋351.87△W;RDP=2.76W0.75＋198.04△W.