为研究饱和脂肪酸对高温环境条件下泌乳中期奶牛呼吸、体温和能量平衡的影响.选择产后150 ～210 d的中国荷斯坦奶牛48头,根据产奶量、分娩时间和胎次分为对照组(SFA0)、1.5％ (SFA1.5)和3％( SFA3)饱和脂肪酸试验组.试验期间牛舍最小湿热指数(THI)在72以上.结果表明饱和脂肪酸可以显著提高奶牛产奶量、乳脂和干物质含量(P＜0.05),降低14:00牛的直肠温度(P＜0.05),但试验组之间差异不显著,添加量对14:00奶牛的直肠温度的效应呈显著的二次关系(P＜0.05),呼吸频率试验牛之间差异不显著.SFA0、SFA1.5和SFA3.0组的能量平衡分别为1.49 Mcal/d、0.27 Mcal/d和1.22 Mcal/d,差异不显著.日粮添加饱和脂肪酸降低了泌乳中期热应激奶牛日高温时间的体温,对呼吸频率和能量平衡无影响.%The objective of this study was to investigate the effect of saturated fatty acids on body temperatures, respirations and energy balances of mid - lactating dairy cows under heat stress. For the experiment, forty eight post-partum Chinese Holstein cows( 150 ~210 days after parturition) were selected and divided into three groups according to milkability, parturition time and calving number for comparison. The animals were fed with the fodder containing (SFAO) ,1.5%(SFA1.5)and 3% (SFA3)saturated fatty acid for group l(control) ,group 2(SFA1.5)and group 3 (SFA3) , respectively. The minimum THI in the cowshed was normally more than 72 during experimental period. The result showed that the milkability, milk fat content and total solid content were obviously raised by saturated fatty acid ( P <0.05),which also cut the rectal temperatures(P <0.05)of 14:00 h cows. However,there was no obvious difference on rectal temperatures between test groups. The rectal temperatures of the tested dairy cows showed a quadratic relation due to the amount of added saturated fatty acid(P<0.05) ,but there was no remarkable effect on respiration rates. The calculated energy balances were 1.49 Mcal/d,0. 27 Mcal/d and 1. 22 Mcal/d for group 1,group SFAO, SFA1.5 and SF A3.0, which showed no remarkable difference. In summary, saturated fatty acids improved milkability and milk components and reduced peak rectal temperatures of mid - lactation heat - stressed dairy cows.
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