热应激对红安格斯牛、抗旱王牛及红抗杂交牛生理指标和血液生化指标的影响

The effect of heat stress on physiological and blood biochemical indexes of Red Angus cattle,Droughtmaster cattle and Red Angus×Droughtmaster hybrid cattle

为了探讨不同品种(品系)肉牛的耐热性,试验根据体况、月龄相近的原则分别选择红安格斯牛、抗旱王牛及红抗杂交牛(红安格斯牛×抗旱王牛F1)母牛各12头,在热应激及非热应激状态下测定直肠温度、呼吸频率等生理指标,采集血样对血液生化指标进行测定和分析。结果表明:热应激期试验牛只处于轻度热应激与中度热应激之间,红安格斯牛、抗旱王牛及红抗杂交牛直肠温度差异不显著(P>0.05),红安格斯牛呼吸频率显著高于抗旱王牛(P<0.05);红抗杂交牛血清天门冬氨酸氨基转移酶活性显著低于红安格斯牛(P<0.05);抗旱王牛T4含量显著高于红抗杂交牛(P<0.05);其他血液生化指标红安格斯牛、抗旱王牛及红抗杂交牛间差异不显著(P>0.05)。说明在轻度热应激条件下红抗杂交牛具有较好的耐热性能。

In order to investigate the heat tolerance of beef cattle of different breeds(lines),according to the principle of similar body condition and month age,12 Red Angus cattle,Droughtmaster cattle and Red Angus×Droughtmaster hybrid cattle(Red Angus cattle×Droughtmaster cattle F1)were selected respectively.The rectal temperature and respiratory rate were measured under heat stress and non-heat stress respectively.Blood samples were collected to measure and analyze their blood biochemical indexes.The results showed that in heat stress period the experimental cattle were between mild and moderate heat stress,the rectal temperature of Red Angus cattle,Droughtmaster cattle and Angus×Droughtmaster hybrid cattle had no significant differences(P>0.05),the respiratory rate of Red Angus cattle was significantly higher than that of Droughtmaster cattle(P<0.05).The activity of aspartate aminotransferase in serum of Angus×Droughtmaster hybrid cattle was significantly lower than that of Red Angus cattle(P<0.05).T4 content in Droughtmaster cattle was significantly higher than that in Angus×Droughtmaster hybrid cattle(P<0.05).Other serum biochemical indicators were not significantly different among Red Angus cattle,Droughtmaster cattle and Angus×Droughtmaster hybrid cattle(P>0.05).The results suggested that Angus×Droughtmaster hybrid cattle had better heat resistance under mild heat stress.