Abstract: 20 Bayinbuluk sheep Lambs was designed to be weaned early at 40 and 60 days respectively, it was aimed at studying the gain of weaning lamb of fed with two milk replacers (20%,22%) , analyzed the content of IGF-Ⅰ,INS,T3 and T4 in serum of early weaning lamb. There were four experiment groups (group A, B, C,D: weaning at 40 or 60 days ,two milk replacers with different crude protein)and one control group(fed by milk of ewe).The results showed that the average daily gain(ADG), experiment group was higher than control group, and Group B＆D(22%) were significantly higher than control group(P＜0.05). Among experiment groups, the ADG of Group B＆D(22%) were higher than Group A＆C(20%),as for the two milk replacers ,there was no significant deviation between two weaned age for the ADG. AS for the content of IGF-Ⅰand INS in serum, experiment group was higher than control group, and the content of IGF-Ⅰof Group B(weaning at 40 days, 22%) was significantly higher than control group(P＜0.05), the content of INS of Group B＆D (22%CP)were significantly higher than control group(P＜0.05). Among experiment groups, the content of IGF-Ⅰof Group B was higher than Group A, C and D; asfor the content of T3,T4, there was no significant deviation between experiment group and control group.It was feasible for Bayinbuluk lamb to wean at 40 and 60 days. Moreover, fed with milk replacer of 22% crude protein level was better.

Key words: Bayinbuluk sheep; gain; hormone; early weaning.