Daidzein Supplementation on Some Blood Biochemical Indexes of Later-lactation Cows under Heat Stress

40 Chinese Holstein cows were selected according to birth,milk yield,and similar lactation and then divided into 4 groups randomly.These cows in 4 groups were fed with basic diet,basic diet plus 200,300,400 mg/day Daidzein,respectively;and the experimental period lasted for 60 days.Blood was collected on Day 0,10,30,60 of experiment via tail vein to isolate serum.The activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP) and gamma-glutamyl transferase(γ-GT) and urea,uric acid and creatinine contents in the serum were measured.Results show that the diets supplemented with DA can significantly reduce serum ALT activity(P0.05),and there is no significant difference in serum ALP,AST,γ-GT activity and UREA,UA,CREA content(P0.05).