Abstract: Compared to the non-pregnancy period, the ruminants have largely increased nutritional requirement during pregnancy period. The inappropriate measures of rearing and management always result in the nutritional deficiency of ruminants during pregnancy period. When ruminants are in a state of negative energy balance in late pregnancy period, lipid mobilization occurs, which leads to the transfer of excessive non-esterification fatty acids into liver and causes lipid metabolism disorders of liver, and subsequently results in fatty liver and ketosis.