In this study,the effects of weaning stress on blood serum index and body growth at different ages foals were investigated to get the best weaned time.A total of 15 Thoroughbred mare-foal pairs were divided into 3groups(each group,n=5)according to the weaning age.Foals and mares were separated by using the abrupt-weaned method,the changes of 10 blood serum biochemical indices and body weight of foals were measured on pre-weaning day,weaning day and post-weaning day.The results showed as follows:The concentr...