本试验旨在研究高能饲料对热应激条件下奶牛的生产性能和生理指标的影响及对其机理的探究。选择33头处于热应激期泌乳中期的荷斯坦奶牛，随机分为对照组和处理Ⅰ、Ⅱ。处理Ⅰ、Ⅱ饲喂对不同的高能饲料，分别为烘烤大豆和油菜籽，对照组饲喂常规饲料。结果表明：使用高能饲料对奶牛的干物质采食量没有影响；处理Ⅰ试验期的产奶量比对照组高3.27% (P<0.05)，处理Ⅰ、Ⅱ试验期产奶量比试验前分别提高了2.28%和7.31%，而对照组则略有下降；使用高能饲料对乳成分基本没有影响；不同处理间的直肠温度相近，但处理Ⅰ呼吸频率极显著高于对照组(P<0.01)，两处理的心跳次数显著高于对照组(P<0.05)。说明这两种高能饲料能够提高产奶量，对缓解奶牛的热应激有一定作用。

This experiment was conducted to study the effects of high energy feed on physiologic indices and production performance of cows under heat stress and its mechanism. Thirty three lactating Holstein cows was used in the experiment and divided into three groups randomly with 11 cows in each group. The cows in control group were fed basal diets, those in treatmentⅠwas supplemented with roast soybean, and those in treatmentⅡwas supplemented with rapeseed. The results showed that the high energy feed had no effect on the dry matter intake of cows. The milk yield of treatmentⅠhad significant (P<0.05) increase by 3.27% compared with that of control group. Milk yield of treatment ⅠandⅡboth increased by 2.28% and 7.31%, respectively compared with that before experiment, however, the control group had slight delclining. The high energy feed had no effect on the milk composition basically. The rectal temperature of different treatments was similar, the breath frequency of treatment Ⅰwas significantly (P<0.05) increased compared with that of the control group, and the two treatments had significant higher heartbeat times (P<0.05) compared with control group. It was concluded that the two kinds of high energy feed could increase milk yield and relieve the heat stress of the cows in a certain degree.