不同相对饲养水平对西藏岗巴绵羊生长性能、屠宰性能和器官发育的影响

Effects of Different Relative Feeding Levels on Growth Performance,Slaughter Performance and Organ Development of Tibetan Gamba Sheep

本试验旨在研究不同相对饲养水平下西藏岗巴绵羊的生长性能、屠宰性能和器官发育的表征,以评估西藏岗巴绵羊养殖生产价值。选用体况、体型一致的36只健康的1周岁黑岗巴绵羊公羔,平均体重(17.94±0.91)kg,随机分为6组,每组6个重复,每个重复1只羊。参照NRC(2007)中的绵羊代谢能和蛋白质维持需要量,以不同倍数设计各组饲粮的代谢能和蛋白质水平。Ⅰ组:体重20 kg、平均日增重(ADG)100 g/d需要量的0.8倍;Ⅱ组:体重20 kg、ADG 100 g/d需要量的0.9倍;Ⅲ组:体重20 kg、ADG 100 g/d需要量的1.0倍;Ⅳ组:体重20 kg、ADG 200 g/d需要量的0.8倍;Ⅴ组:体重20 kg、ADG 200 g/d需要量的0.9倍;Ⅵ组:体重20 kg、ADG 200 g/d需要量的1.0倍。预试期10 d,正试期70 d。结果显示:Ⅵ组试验羊的终末体重、净增重、平均日增重与Ⅴ组无显著差异(P>0.05),但显著高于其余5组(P<0.05);Ⅰ组料重比显著高于其余5组(P<0.05);饲料成本随相对饲养水平的升高而显著上升(P<0.05)。Ⅵ组的宰前活重、胴体重和净肉重显著高于其余5组(P<0.05);Ⅲ组和Ⅴ组的宰前活重无显著差异(P<0.05),但二者显著高于Ⅰ组、Ⅱ组和Ⅳ组(P<0.05);Ⅲ组、Ⅳ组、Ⅴ组间净肉重无显著差异(P>0.05),但显著高于Ⅰ组和Ⅱ组(P<0.05);Ⅵ组腹脂重显著高于Ⅰ组、Ⅱ组和Ⅴ组(P<0.05)。Ⅵ组肝脏重量和指数显著高于其余5组(P<0.05);6个试验组间心脏、肺脏和肾脏重量及指数无显著差异(P>0.05);Ⅵ组瘤胃重量及指数显著高于其余5组(P<0.05),网胃和瓣胃重量及指数显著高于Ⅱ组、Ⅳ组(P<0.05)。结合饲料成本以及实际养殖经济效益,推荐按照0.9倍的NRC(2007)中体重20 kg、ADG 200 g/d绵羊的代谢能和蛋白质需要量配制饲粮,西藏岗巴绵羊可获得较好的生长性能和屠宰性能。

The purpose of this experiment was to study the characterization of growth performance,slaughter performance and organ development of Tibetan Gamba sheep under different relative feeding levels,so as to evaluate the production value of Tibetan Gamba sheep.Thirty-six healthy male black Gamba sheep lambs with the same body condition and body size[average body weight(BW):(17.94±0.91)kg]were selected and randomly divided into 6 groups with 6 replicates per group and 1 sheep per replicate.According to the metabolizable energy and protein maintenance requirements of sheep in NRC(2007),the dietary metabolizable energy and protein levels of each group were designed with different multiples.GroupⅠ:0.8 times of requirement for 20 kg BW and 100 g/d average daily gain(ADG);groupⅡ:0.9 times of requirement for 20 kg BW and 100 g/d ADG;groupⅢ:1.0 times of requirement for 20 kg BW and 100 g/d ADG;groupⅣ:0.8 times of requirement for 20 kg BW and 200 g/d ADG,groupⅤ:0.9 times of requirement for 20 kg BW and 200 g/d ADG;groupⅥ:1.0 times of requirement for 20 kg BW and 200 g/d ADG.The pre-trial period lasted for 10 days and the experimental period lasted for 70 days.The results showed as follows:the final body weight,net gain,average daily gain of sheep in groupsⅤandⅥhad no significant differences(P>0.05),while groupⅥwas significantly higher than the other 5 groups(P<0.05);the ratio of feed to gain in groupⅠwas significantly higher than that in the other 5 groups(P<0.05);the feed cost increased significantly with the increase of relative feeding level(P<0.05).Live weight before slaughter,carcass weight and net meat weight in groupⅥwere significantly higher than those in the other 5 groups(P<0.05),while the live weight before slaughter in groupsⅢandⅤhad no significant difference(P<0.05),but they was significantly higher than that in groupsⅠ,ⅡandⅣ(P<0.05);there was no significant difference in net meat weight among groupsⅢ,ⅣandⅤ(P>0.05),but they was significantly higher than groupsⅠandⅡ(P<0.05);the abdominal fat weight of groupⅥwas significantly higher than that of groupsⅠ,ⅡandⅤ(P<0.05).The liver weight and index of groupⅥwere significantly higher than those of the other 5 groups(P<0.05);there were no significant differences in heart,lung and kidney weights and indexes among the 6 test groups(P>0.05);the weight and index of rumen of groupⅥwere significantly higher than those of the other 5 groups(P<0.05),and the weights and indexes of reticulum and omasum were significantly higher than those of groupsⅡandⅣ(P<0.05).In conclusion,combined with feed cost and actual breeding economic benefits,it is recommend that diet prepared according to 0.9 times the metabolizable energy and protein maintenance requirements of sheep with 20 kg BW-200 g/d ADG in NRC(2007),Tibetan Gamba sheep can obtain the better growth performance and slaughter performance.