不同蛋白质水平补饲料对早期断奶犊牦牛生产性能和胃肠道发育的影响

摘要

This study was conducted to evaluate the effects of supplementary diets containing different levels of protein on performance, blood indexes and gastrointestinal development of early-weaned yak calves. Forty-eight healthy female Datong weaned yak calves aged about 3 months [(90 ± 5) days of age] were selected and assigned randomly to four groups with four replicates in each group and 3 heads per replicate. Yaks in con-trol group were grazed only, and those in experimental groups were grazed and fed isoenergetic ( net energy for gain=5.6 MJ/kg) supplementary diets contained 17%, 18% and 19% crude protein ( CP) , respectively. The pre-experiment lasted for 7 days, and the experiment lasted for 60 days. The results showed as follows: con-trast with control group, 1) the average daily gain were significantly increased by supplementary, and that in 17%, 18% and 19% supplementary groups was increased by 28.87%, 47.47%, 28.61% ( P<0.05) , respec-tively;2) the supplementary significantly increased the concentration of serum urea nitrogen, and that in 17%, 18% and 19% supplementary groups was increased 10.57%, 16.64% and 21.84% (P<0.05), respectively;3 ) the absolute weight and the relative weight of rumen and large intestine were significantly enhanced by sup-plementary diet containing 18% CP (P<0.05), and the villus height of duodenum, caecum and colon, and villus height/crypt depth of duodenum and caecum were significantly improved, too ( P<0.05) . These results indicate that supplementary diet is contributed to improve the production performance and gastrointestinal devel-opment of early-weaned female yak calves, and the optimal CP level is 18%.%本试验旨在探究不同蛋白质水平补饲料对3月龄早期断奶犊牦牛生产性能、血液指标和胃肠道发育的影响。选取3月龄(90±5)日龄]健康大通母犊牦牛48头,随机分为4组,每组4个重复,每个重复3头。对照组犊牛全放牧,试验组犊牛在放牧基础上分别补饲不同蛋白质水平(粗蛋白质水平分别17%、18%、19%)的3种等能量(增重净能5.6 MJ/kg)饲粮。预试期7 d,正试期60 d。结果表明：1)与对照组相比,补饲能够显著提高犊牦牛的平均日增重,17%、18%和19%补饲组分别提高了28.87%、47.47%和28.61%( P<0.05)。2)与对照组相比,补饲显著提高了血清尿素氮浓度(P<0.05),17%、18%和19%补饲组分别增加了10.57%、16.64%、21.84%( P<0.05)。3)与对照组组相比,补饲料粗蛋白质水平为18%时,显著提高了瘤胃和大肠的绝对重量和相对重量( P<0.05),显著提高了十二指肠、盲肠、结肠的绒毛高度以及十二指肠和盲肠的绒毛高度/隐窝深度( P<0.05)。因此,补饲能够提高早期断奶母犊牦牛生产性能和促进胃肠道发育,早期断奶母犊牦牛的补饲料的适宜粗蛋白质水为18%。