热应激对奶牛血液中内毒素含量和抗氧化指标的影响

选用16头健康的中国荷斯坦奶牛,随机分为两个处理（夏季组和冬季组）,每个处理8个重复,每个重复1头牛。当夏季组奶牛牛舍温湿度指数（THI）〉72的时间连续达到15d,冬季组牛舍THI〈72的时间连续达到15d时,颈静脉采血15mL制备血清,检测血清中内毒素、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）的活性,以及丙二醛（MDA）的含量。结果表明：夏季热应激可导致奶牛血清内毒素、MDA含量极显著升高,SOD和GSH-Px活性极显著和显著（P〈0.05）下降。

The effect of heat stress on the endotoxin content and redox in the serum of dairy cattle

16 healthy Holstein cows were divided into the summer group（in August） and winter group（12 months）,each treatment with eight repetitions,a cow each repetition.Summer,when the dairy cow-house temperature and humidity index（THI）72 up to 15 consecutive days,winter,when the cow-house THI72 up to 15 consecutive days,15 mL jugular vein blood was taken.Endotoxin level in plasma,Superoxide Dismutase（SOD）,total antioxidant activity（TAP）,glutathione peroxidase（GSH-Px） activity,and malondialdehyde（MDA） content in plasma were detected.The results show that：in summer,cow plasma endotoxin,MDA content highly increased significantly（P0.01）,SOD activity highly decreased significantly（P0.01）,TAP and GSH-Px activity decreased significantly（P0.05） in winter.