A Cost-Benefit Analysis of Cultivating Forage to Raise Dairy Cattle in Saibei Precinct,Zhangjiakou City Effect of Chinese herbal medicine on milk production, antioxidant capacity and immunity of dairy cows Effects of metallothionein on expression of lymphocyte apoptosis genes and the HSP70 gene of dairy cattle under heat stress Effect of exogenous metallothionein on blood GSH-Px and CAT gene expression in dairy cattle Effects of exogenous metallothionein on milkability and anti-oxidative status in dairy cattle