中文摘要：

就稻草（RS）与苜蓿（MSL）混合瘤胃体外发酵组合效应进行整体评定。采用单因子试验设计,体外批次培养48 h,应用经改进的组合效应多项指标综合指数（IMFAEI）对RS分别添补0、20%、40%、60%、80%与100%MSL（MSL0、MSL20、MSL40、MSL60、MSL80与MSL100）在12、24与48 h研究瘤胃体外发酵的组合效应。各组各时间点的pH值6.75～6.88,NH3-N 3.11～28.74 mg/100 ml,微生物氮2.91～14.57 mg/ml,48 h各组累计产气量与总挥发性脂肪酸分别为120.1～162.4 ml/g OM与41.51～55.45 mmol/l。各组的IM-FAEI自高到低的排序为：MSL60（1.271 1）、MSL40（1.260 3）、MSL20（0.826 5）与MSL80（0.633 3）。本研究RS与MSL适宜添补量为40%～60%。

英文摘要：

To overall evaluation research the associative effects of rice straw（RS）supplemented with Medicago sativa L.（MSL） on in vitro fermentation parameters.48 h in vitro batch in cubation was practiced ina single-factor randomized design to investigate the associative effects of RS mixed with varying MSL levels of 0,20%,40%,60%,80% and 100%（MSL0,MSL20,MSL40,MSL60,MSL80 and MSL100） on in vitro fermentation traits at 12,24 and 48 h individually,and the improved multiple-factors associative effects index（IMFAEI） was used.The range of parameters of various groups at different time was：pH 6.75～6.88,NH3-N 3.11～28.74 mg/100 ml,MN 2.91～14.57 mg/ml.48 h cumulative gas production and total volatile fatty acids were 120.1～162.4 ml/g OM and 41.51-55.45 mmol/l individually.The IMFAEI ranked from greatest to least in the following order： MSL60（1.2711）,MSL40（1.2603）,MSL20（0.8265）,and MSL80（0.633 3）.40%～60% MSL is the optimal volume supplemented to ruminant RS basal diet.