Effects Of Castration On Production Performance Of Hu Sheep

To investigate the effects of castration on production performance of Hu lambs,60 male Hu lambs were randomly divided into three groups: control group(CK,N=20),3-day old castrated group(QS3,N=20),56-day old castrated group(QS56,N=20).All lambs were weaned at 49 d and the transition period was 4 weeks,the pre-trial period was 2 weeks,while the trial period was 14 weeks.The growth performance,feed intake,nutrient digestibility and utilization,testosterone,slaughter performance and meat quality were detected.The main results as follows:(1)Effect of castration on growth performance of lambs: In control group,the body weight,average daily gain and feed conversion efficiency was significantly higher than group QS3 and QS56(P<0.05),however,there was no difference between group QS3 and QS56(P>0.05).(2)Effect of castration on nutrient digestibility and utilization of lambs: The feed intake,feed energy intake,N intake and digested energy was significantly higher than QS3 and QS56(P<0.05),but the acid washing fiber digestibility in control group was significantly lower(P<0.05).There was no difference among three groups in DM,NDF,OM and energy digestibility,N retention(P>0.05).(3)Castration at 3-day old significantly decreased testosterone concentration compared to control and QS56 groups(P<0.05).In control group,the testosterone concentrations at 13-week,18-week and 23-week old were significantly higher than 8-week old(P<0.05).(4)Effect of castration on slaughter performance of lambs: In control group,weight of carcass,tail fat,kidney,liver and heart were significantly higher than groups QS3 and QS56(P<0.01).The Spleen index in control group was significantly lower than groups QS56(P<0.05).There was no difference among three groups in slaughter rat,backfat thickness,weight of spleen,lung and Index of heart,lung and kidney(P>0.05).(5)Effect of castration on meat quality of lambs: The drip loss and value of a*,b* at 24 h in groups control and QS3 were significantly higher than group QS56(P<0.05).However,there was no difference among three groups in waster loss,cooking loss and shear force(P>0.05).In conclusion,castration at 3-day and 56-day old significantly decrease the production efficiency,whoever,there was no contribution to the meat quality.It is recommended to castrate at 3-day and 56-day old when used Hu lambs in wethers mutton production.