本文旨在研究不同比例的苜蓿青饲对波尔山羊瘤胃消化代谢的影响。选取4只体重为（39.80±1.45） kg的装有永久性瘤胃瘘管的波尔公山羊，采用4×4拉丁方设计，4个处理饲粮精料组成相同，粗料组合分别为：100%切碎花生秧（对照组）、85%切碎花生秧+15%苜蓿鲜草（试验Ⅰ组）、70%切碎花生秧+30%苜蓿鲜草（试验Ⅱ组）和55%切碎花生秧+45%苜蓿鲜草（试验Ⅲ组）。试验持续60 d结束。结果表明：1）随着苜蓿鲜草替代比例的增加，干物质（DM）、粗蛋白质（CP）降解率依次升高，且试验Ⅲ组显著高于对照组（P<0.05）；2）中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）降解率随着苜蓿鲜草替代比例的增加有先升后降的趋势，且试验Ⅱ组显著高于对照组（P<0.05）；3）除培养时间为10 h外，随着苜蓿鲜草替代比例的增加各试验组乙酸和丁酸含量均呈先升后降的趋势，丙酸含量如培养时间为8、9 h也有相同的变化趋势；4）除培养时间为9 h外，随苜蓿鲜草替代比例的增加各组瘤胃液氨态氮（NH3-N）含量均逐渐升高，并以试验Ⅲ组最高；5）不同苜蓿鲜草替代比例组瘤胃液pH差异不显著（P>0.05）。结果显示，波尔山羊饲粮中用苜蓿鲜草替代切碎花生秧提高了粗饲料DM、CP、NDF、ADF降解率，瘤胃液挥发性脂肪酸特别是乙酸和NH3-N含量也有增加，以30%苜蓿鲜草替代量为最佳。

The trial was conducted to study the effects of different proportions of fresh alfalfa on rumen digestion and metabolism of Boer goats. Four male Boer goats with an average body weight of (39.8±1.45) kg with permanent cannulas were used in a 4×4 Latin square design. The four treatments were consisted of the same concentrates but with different roughages. The four kinds of roughages were composed of 100% chopped peanut vine (control group), 85% chopped peanut vine+15% fresh alfalfa (group Ⅰ), 70% chopped peanut vine+30% fresh alfalfa (group Ⅱ), and 55% chopped peanut vine+45% fresh alfalfa (group Ⅲ), respectively. The experimental period lasted for 60 days. The results showed as follows: 1) degradability of DM and CP increased gradually with the proportion of fresh alfalfa increased, and their degradability in group Ⅲ were significantly higher than those in control group (P<0.05); 2) degradability of NDF and ADF showed a tendency of increased at first and then decreased with the proportion of fresh alfalfa increased, and degradability of NDF and ADF in group Ⅱ were significantly higher than those in control group (P<0.05); 3) the acetic acid content and butyric acid content increased at first and then decreased with the proportion of fresh alfalfa increased except at 10 h of incubation, and the propionic acid content had the same tendency at 8 and 9 h of incubation; 4) NH3-N content increased gradually with the proportion of fresh alfalfa increased except at 9 h of incubation, and that of group Ⅲ was the highest; 5) there was no significant difference in rumen pH among each group (P>0.05). In conclusion, substitution of fresh alfalfa for chopped peanut vine in the diets of Boer goats can increase the digestibility of DM, CP, NDF and ADF of roughage, and increase the volatile fatty acid contents, especially the acetic acid as well as NH3-N contents. The optimal proportion of fresh alfalfa was 30% in this trial.［Chinese Journal of Animal Nutrition，2011，23（1）：162-170］