Twelve fat-rump sheep was divided randomly into 3 groups which consist of 4 each,and fed with 3 levels of metabolizable energy(120,100 and 80% of recomended content of NRC(1978)).

• 选择体重年龄相近，经产大尾寒羊空怀母羊12只，随机分成3组，每组4只，分别按NRC（1978）推荐绵羊维持代谢能需要量的120%25，100%25和80%25供给。