Abstract: This study was aimed to analyze the effects of different cotton stalk levels on free gosspol content and apparent digestibility in sheep during fattening period.Designed by single factor random test single factor randomized trial,the similar weight of 60 Small-tailed Han sheep were randomly divided into 6 groups,every group had 10 sheep.The diet was prepared for free feeding based on same energy and same nitrogen content.The control group ck1 did not add cotton stalks and cottonseed meal,the control group ck2 added cottonseed meal,and 20% to 50% cotton stalks were added to 20%,30%,40% and 50% groups,respectively,with a total period of 70 days,of which the pre-test period was 10 days and the feeding test was 60 days.On the 50th day of the trial period,the fecal samples were collected for 24 h using the full-fee method.The acclimation period was 5 days,and the samples were collected continuously for 5 days,weighed and recorded for 3 days.On the 55th to 60th day,the daily feeding amount and the remaining material amount of each group of test sheep were recorded,and the average dry matter intake was calculated.The results showed that expect for ck1 group,the 20% group had the lowest free gossypol residue,which was extremely significantly different from ck2,30%,40% and 50% groups (P<0.01).The apparent digestibility of dry matter,CP,EE,Ca,P and Ash increased with the increase in the proportion of cotton stalk.The addition ratio of 20%-50% had no significant effect on fecal output and the apparent digestibility of NDF and ADF (P>0.05).The results suggested that cotton stalk could be used as raw material for fattening sheep production,it was advisable to consider cotton stalk addition at about 20% which based on the data of free gosspol content and apparent digestibility.

Key words: cotton stalk; sheep; free gosspol residue; apparent digestibility