饲料蛋白质组分对泌乳奶牛乳脂率和乳蛋白的影响

本试验研究采用粗蛋白质相同而蛋白质组分水平不同的四种日粮(日粮粗蛋白质中瘤胃未降解蛋白质(RUP)比例由35.9%逐步提高到40.9%,其他营养成分基本保持一致),选择32头处于中产水平的荷斯坦奶牛,根据产奶量、胎次和泌乳日龄按配对法随机分为四组,研究了不同蛋白质组分水平的日粮对奶牛乳脂率、乳蛋白率和乳蛋白质产量的影响规律。结果表明,粗蛋白质相同而蛋白质组分水平不同的日粮对奶牛乳脂率、乳蛋白率和乳蛋白产量没有显著的影响(P>0.05),但乳脂率有下降的趋势,乳蛋白产量有增加的趋势。

Effects of Feed Protein Fractions on Milk Fat and Milk Protein of Lactating Dairy Cow

The objectives of this study were to determine the effects of rations with different level of protein fractions on milk fat,milk protein and milk protein yield in lactating cows.Four rations with equal crude protein and different protein fractions(the ratio of rumen undegraded protein in crude protein was added from 35.9% to 40.9%)were used in this experiment.Thirty-two Holstein cows in middle lactation were selected and divided into four groups randomly in pairing with milk yield,ages and days in milk.The result indicated that it was not great effects of rations with equal crude protein and different protein fractions on milk fat,milk protein and milk protein yield in lactating cows(P>0.05),but there was a decreasing trend for milk fat and a increasing trend for milk protein yield.