苜蓿干草对杜寒F_1的生产性能及瘤胃pH值和氨态氮的影响

Effects of Alfalfa Hay on the Production Performance,Rumen pH,and Ammonia Nitrogen of DuHan Hybrid Sheep F_1

选择45只3月龄左右,体重为(17.77±3.83)kg的健康状况良好的杜寒杂交羊F_1(♂),随机分为5个处理组,用苜蓿(Medicago)干草替代不同比例的粗饲料(按干物质计),即对照组(0%)、试验Ⅰ组(10%)、试验Ⅱ组(20%)、试验Ⅲ组(30%)、试验Ⅳ组(40%),比较5种日粮对杜寒F_1的生产性能、肉品质和瘤胃消化生理指标的影响。结果表明:各试验组的日增重和屠宰率均高于对照组;试验组的料重比均显著低于对照组(P<0.05),但各试验组之间差异不显著;试验组的胸蛋白、肩蛋白、腰蛋白和后腿蛋白均高于对照组,但差异不显著。试验组的眼肌、后腿肌、胸肌的pH值和对照组之间差异也不显著。对照组和试验Ⅰ,Ⅱ组瘤胃pH值呈现先升高后降低,然后再逐渐升高的趋势,试验Ⅲ和Ⅳ组呈现稍微降低,然后急剧降低后逐渐升高的趋势,采食后3 h降到最低值,变化趋势基本一致。对照组和试验组瘤胃中氨态氮和瘤胃pH值的变化一致,并呈现负相关。因此,用苜蓿干草替代部分粗料,可以提高杜寒F_1的生产性能,改善其瘤胃内的发酵状况。

Forty-five healthy DuHan hybrid sheep F1 of three-month-old and weighing （17.77±3.83） kg were allocated to five treatments. DuHan hybrid sheep were fed diets with 0%, 10%, 20%, 30% and 40% alfalfa hay replacing roughage to study the effects of alfalfa hay on production performance, meat quality and rumen digestion physiological indices. Results showed that average daily gain and slaughter rate of tested groups were higher than control. Feed/body ratios of tested groups were significantly lower than control （P〈0. 05）, whereas there was no significant difference between tested groups. The protein percentages of thorax, shoulder, waist and hind leg were higher than control, but there was no significant difference between tested groups. The pH of ocular muscle, hind leg muscle and pectoral muscle had no significant difference between tested groups and control. The rumen fluid pH of control and groups Ⅰ , Ⅱ rose initially then fell, and gradually rose again. The tureen pH of groups Ⅲ, Ⅳ decrease sharply after re- ducing slightly and then rose. The rumen fluid pH reached the minimum value after ingestion three hours. Ammonia nitrogen and rumen pH of both control and tested groups had a consistent change and showed negative correlation. These results showed that alfalfa hay replacing the part of coarse material improved the production performance of DuHan hybrid sheep F1 and ameliorated rumen fermentation conditions.