Effect of dietary supplementation with yeast chromium on dairy cows during non-stress period

To study the effects of dietary supplementation for yeast chromium, sixty dairy cows with an average daily milking 26.00 kg at 170 day after calving were divided into 5 groups, the milk yield and component were evaluated, and the plasma hormones were assessed- The level of supplementation was 0.35, 0.70, 1.05 and 1.40 mg ·kg-1as yeast chromium in concentrates for treatment Ⅰ, Ⅱ, Ⅲ, Ⅳ, respectively, and non-chromium applied was control group.Results showed that:Ⅰ There were no significant effects on daily milking, fat corrected milk (FCM), and the content of milk fat, protein, and solid compounds (P0.05) for all treatment groups.Ⅱ The chromium content in milk was lower than 0.30mg · kg-1, which met the national standard for fresh milk (NY 5045-2001).③ Comparing with control group, FT3 content in treatment Ⅳ was reduced significantly (P 0.05), but observed only a tendency of decreasing in treatment Ⅰ,Ⅱ,Ⅲ (P0.05).Moreover, supplementation of chromium had no significant effects on FT4, cortisol and insulin (P0.05).