Effect of High Temperature in Summer on Production Performance and Blood Biochemical Parameter of Holstein Cows in Central Hebei Plain
The experiment aimed to explore the effect of high temperature in summer on the production per-formance and blood biochemical indexes of Holstein cows in the central Hebei plain,and to provide relevant theo-retical basis for the study of alleviating heat stress in dairy cows.The experiment was conducted in three stages:non-hot season stage,early hot season stage,the late hot season stage.The changes of blood routine,antioxidant capacity,endocrine and immune function indexes of Holstein cows in this plain were studied.The results indicated that with the increase in environmental temperature,the dry mater intake,milk fat and protein content of dairy cows decreased significantly(P＜0.01),milk production fell by 0.74 kg(P＜0.05),while the respiratory rate in-creased significantly(P＜0.01).Blood parameter analysis showed that the levels of WBC,RBC,PLT,LY and MO decreased significantly in the late hot season(P＜0.05),while PCT,HGB,HCT,MCV increased signifi-cantly(P＜0.01).In addition,with the increase in temperature,ACTH and thyroxine both showed a significant increase(P＜0.01),while GLU content decreased significantly(P＜0.01).During the hot season,T-AOC in-creased significantly(P＜0.01),the content of SOD decreased significantly(P＜0.05)in the late stage of hot sea-son.In conclusion,the significant changes in the above indicators can be considered as key factors sensitive to heat environment in the central Hebei plain.It provides a reliable theoretical basis for early formulation of prevention and control measures and screening of stress-tolerant individuals.
high temperatureHolstein cowsbiochemical indicatorsmilk production performanceheat stress
万方数据
维普
