体外产气法评定全株玉米青贮与谷草的组合效应研究

试验采用体外发酵产气法对全株玉米青贮（WCS）与谷草（MS）的组合效应做出评价。WCS与MS分别以100：0、80：20、60：40、50：50、40：60、20：80、0：100的比例组合，每个比例设3个重复。利用体外产气法分析不同组合对体外发酵24、48、72 h的产气量（GP）、pH、氨态氮（NH₃-N）、挥发性脂肪酸（VFA）、微生物蛋白（MCP）及干物质消失率（DML）的影响，计算单项组合效应指数（SFAEI）及多项组合效应指数（MFAEI）。结果显示，不同比例的全株玉米青贮与谷草在发酵24、48、72 h时产气量差异显著（P<0.05），两种饲料组合后WCS80组的产气量最优；DML随着MS含量的增加呈下降趋势，但是WCS80组的DML与WCS100组较接近，WCS100和WCS80组的MCP含量显著或极显著高于其他各组（P<0.05；P<0.01）；各组间挥发性脂肪酸浓度差异显著（P<0.05）；在WCS与MS的不同比例组合中，发酵24、48、72 h的MFAEI均以WCS80组最大，分别为0.5517、0.5094和0.9860。通过MFAEI评定，WCS与MS的最佳配比为80：20。

Evaluation of Associative Effect of Whole Corn Silage and Millet Straw by Gas Production Technique in vitro

This research adopted fermentation gas production method in vitro to evaluate the associative effect of whole corn silage (WCS) and millet straw (MS).The WCS was mixed with MS in the proportion of 100:0,80:20,60:40,50:50, 40:60,20:80 and 0:100 with 3 replicates per group.The gas production,pH,ammonia nitrogen (NH₃-N), volatile fatty acids (VFA), microbial crude protein (MCP) and dry matter loss (DML) for 24,48 and 72 h of varying forage combinations were analyzed.Single factor associative effects index (SFAEI) and multiply factors associative effects index (MFAEI) of different combinations were calculated. The results showed as follows:There were significant differences of gas production among different combinations (P<0.05),and the best combination was the WCS80 group. With creasing of the content of MS,DML decreased,but the DML of WCS80 and WCS100 were similar (P>0.05). The MCP concentration of WCS100 and WCS80 was extremely significantly or significantly higher than other groups (P<0.05;P<0.01). The VFA concentration showed significant differences among different combinations (P<0.05).Among the different combinations of WCS and MS,the MFAEI of WCS80 was the largest,and that were 0.5517,0.5094 and 0.9860 at 24,48 and 72 h,respectively. The best combination of WCS and MS was 80:20.