补饲苜蓿干草对蒙贝利亚×荷斯坦杂交犊牛瘤胃内环境和胃肠道发育的影响

Effects of Alfalfa Hay Supplementation on Rumen Internal Environment and Gastrointestinal Development of Montbeliard×Holstein Crossed Calves

本试验旨在研究补饲苜蓿干草对蒙贝利亚×荷斯坦杂交犊牛(以下简称蒙×荷杂交犊牛)瘤胃内环境和胃肠道发育的影响。选择健康的初生蒙×荷杂交犊牛20头,随机分为饲喂颗粒化开食料的对照组和额外添加苜蓿干草的试验组,每组10头犊牛。试验期为10周,第8周断奶。对照组和试验组犊牛从第3天起采食开食料,试验组犊牛从第15天起额外添加苜蓿干草。试验期间,分别于犊牛28、56和70日龄晨饲后4 h采集瘤胃液,测定pH及挥发性脂肪酸、氨态氮含量;于56日龄晨饲后4 h,以颈静脉放血方式屠宰犊牛,采集内脏及胃肠道样品,测定内脏和胃肠道发育指标以及肠道消化酶活性。结果表明:1)与对照组相比,试验组的瘤胃液乙酸比例显著增加(P<0.05),丙酸比例显著降低(P<0.05),丁酸比例有降低趋势(P=0.057),但pH、乙酸/丙酸及氨态氮、总挥发性脂肪酸含量无显著差异(P>0.05)。2)日龄对瘤胃液pH、丙酸和丁酸比例、乙酸/丙酸及总挥发性脂肪酸、氨态氮含量有显著影响(P<0.05)。3)2组之间肠道消化酶活性及内脏器官和胃肠道发育指标均无显著差异(P>0.05)。由此可见,补饲苜蓿干草显著影响了蒙×荷杂交犊牛瘤胃液乙酸、丙酸比例,但对内脏器官和胃肠道发育无不良影响。

This experiment was conducted to study the effects of alfalfa hay supplementation on rumen internal environment and gastrointestinal development of Montbeliard×Holstein crossed calves.Twenty healthy newborn Montbeliard×Holstein crossed calves were randomly divided into control group fed with pelleted starter and ex⁃perimental group supplemented with alfalfa hay,with 10 calves in each group.The trial period was 10 weeks,weaning at 8 weeks.All the calves were fed starter from day 3,and calves in experimental group were supple⁃mented with alfalfa hay from day 15.During the trial,collected the rumen fluid after morning feeding 4 hours of calves at 28,56 and 70 days of age,respectively,and measured the pH and volatile fatty acids and ammo⁃nia nitrogen contents;at 56 days of age,calves were slaughtered with jugular vein bloodletting at 4 h after morning feeding,the internal organs and gastrointestinal tract samples were collected to determine organs and gastrointestinal tract development indexes and intestinal digestive enzyme activities.The results showed as fol⁃lows:1)compared with the control group,the rumen fluid acetate proportion of experimental group was sig⁃nificantly increased(P<0.05),the propionate proportion was significantly decreased(P<0.05),the butyrate proportion showed a decreasing trend(P=0.057),and the pH,acetate/propionate and ammonia nitrogen and total volatile fatty acid contents were no significant differences(P>0.05).2)The days of age significantly af⁃fected the pH,propionate and butyrate proportions,acetate/propionate and ammonia nitrogen and total volatile fatty acid contents in rumen fluid(P<0.05).3)There were no significant differences on intestinal digestive enzyme activities and organs and gastrointestinal tract development indexes between 2 groups(P>0.05).In conclusion,the alfalfa hay supplementation has significant effects on the proportions of acetate and propionate in rumen fluid but has no adverse effects on organs and gastrointestinal tract development of Montbeliard×Hol⁃stein crossed calves.