Abstract: To study the effects of chitosan on biochemical indicators in cows′ blood during summer. 30 Chinese-Holstein dairy cows were randomly divided into treatment group and control group, each group had 15 cows.Took additives feeding contrast experiment.The result showed that:after adding chitosan, cortisol,P,glucose in cows′ blood were very significantly improved(P＜0.01), thyroxine, potassium, chlorine, calcium were significantly improved(P＜0.05), aspertate aminotransferase, creatine kinase were very significantly descended(P＜0.01),pH were significantly descended(P＜0.05). The research suggests that the utilization of chitosan has obvious effect in regulating of cows′ endocrine and fluid balance during summer.

Key words: dairy cattle, summer, chitosan, biochemical indicators, heat stress