泌乳期奶牛热应激与防治措施研究进展

Research progress on heat stress and prevention measures of lactating cows

泌乳期是奶牛重要的生理阶段,影响着奶牛乳产量、再次发情及实际使用年限。良好的饲养管理措施会提高奶牛的使用年限,增加饲养场的经济收益。夏季持续高温,外界环境温度超过奶牛本身所能够调节上限时,机体产生热应激,引起奶牛采食量、乳产量和奶品质降低等,严重时出现休克或死亡。发生热应激时,奶牛肠道、神经-内分泌及免疫系统均产生应激反应,且分泌的激素及神经递质互为调理作用。文章综述了热应激对泌乳期奶牛血液生理生化指标、生产性能、免疫功能、抗氧化能力、肠道的影响及其作用机制,并提出物理、营养调控、药物及添加剂方面的防控措施,以期为降低热应激对泌乳期奶牛的危害及提高乳产量提供参考。

Lactation is an important physiological stage of dairy cows,which affects milk yield,reestrus and actual service life of dairy cows.Good feeding management measures will improve the service life of cows and increase the economic benefits of feedlots.In summer,when the temperature of the external environment exceeds the upper limit that the cow can adjust,the body will produce heat stress,resulting in the decrease of feed intake,milk yield and milk quality of the cow,and in severe cases,shock or death.When heat stress occurs,the intestinal tract,neuroendocrine and immune systems of dairy cows all produce stress responses,and the secreted hormones and neurotransmitters regulate each other.The article reviewed the effects of heat stress on blood physiological and biochemical indexes,production performance,immune function,antioxidant capacity and intestinal tract of lactating cows and its mechanism,and proposed prevention and control measures in terms of physical,nutritional regulation,drugs and additives,in order to provide references for reducing the harm of heat stress on lactating cows and improving milk yield.