大豆异黄酮对奶牛产奶量及乳成分的影响

为研究大豆异黄酮对奶牛产奶量和乳成分的影响，选用32头产奶水平相近的荷斯坦奶牛，随机分成A、B两组。试验分为两个阶段，第一阶段A组在基础日粮中添加Da400mg·kg^-1，B组饲喂基础日粮，持续15d。第一阶段试验结束后，两组均饲喂基础日粮，持续20d。第二阶段A组奶牛饲喂基础日粮（A’组），B组奶牛在基础日粮中添加Da200mg·kg^-1（B＇组），持续15d。结果显示，A组奶牛产奶量略高于B组，表明饲喂大豆异黄酮在一定程度上能提高产奶量；但A’组奶牛产奶量极显著低于B组（P〈0．01），可能由于添加Da剂量过大导致内源性激素水平下降所引起的。同时与A’组相比，B’组乳蛋白略有提高，脂肪含量极显著升高（P〈0.01）。

Effect of Daidzein on Milk Yield and Components of Dairy Cow

In order to study the influence of daidzein on cows, 32 Holstein dairy cows with similar milk productivity were assigned randomly to A and B groups. The experiment included two stages. In the first stage, cows in A group were fed with 400 mg·kg^-1 daidzein for 15 days, meanwhile B group were fed with the basic diet. Then the A and B groups were all fed with the basic diet for 20 days. The second stage of the experiment followed, the A group were fed with the basic diet （A＇ group）, but the B group were fed with 200 mg＇kg-1 daidzein （B＇ group） for 15 days. The results showed that the milk yield of the A group were higher than the B group, it sug gested that daidzein could increase the milk yield to a certain extent. But the milk yield of the A＇ group were significantly lower than the B group （P〈0.01）, it seemed that the dose of added daidzein was so high that the level of intrinsic hormones declined. At the same time, contrasted with A＇ group, lactoprotein in B＇ group was increased while milk fat percentage evidently increased.