Abstract: The associative effects of oat hay and Kobresia tibetica, K. alpine-Stipa aliena, K. alpine, S. purpurea, K. alpine under different proportions (0:100, 25:75, 50:50, 75:25 and 100:0) were evaluated by in vitro gas production technique in Yushu region. The best combination of oat hay and natural forage was determined by investigating the gas production and its influence on fermentation process. Results showed that the optimal proportions of oat hay and K. tibetica, K. alpine, K. alpine miscellany, K. alpine-S. aliena, S. purpurea were 75:25, 75:25, 75:25, 25:75 and 50:50, respectively. It did not cause the disorder of rumen microbial flora when pH was about 6.56~7.02. These combinations did not have significantly associative effects on pH value. The NH₃-N concentrations of rumen microbial growth were about 9.12~15.68 mg·100 mL^-1. Both acetic acid and propionic acid produced by tested combinations had no significant difference compared with that produced by single pasture. The CH₄ yields of tested combinations had no highly significant difference compared with that of single pasture. All tested combinations did not improve CH₄ productions.

Key words: In vitro gas production technique, Associative effects, Yak, Natural pasture, Oat hay

摘要： 以牦牛为瘤胃液供体动物,采用体外产气法评定燕麦(Arrhenatherum elatius)青干草与玉树地区藏嵩草(Kobresia tibetica)、高山嵩草-异针茅(Kobresia alpine-Stipa aliena)、高山嵩草、紫花针茅(Stipa purpurea)、高山嵩草杂类5种草地型分别按100:0, 25:75, 50:50, 75:25, 0:100比例两两搭配后的组合效应,通过产气量结合干物质消化率确定最优组合搭配并探讨对发酵产物的影响。结果表明:根据产气量结合干物质消化率得出最优组合:燕麦青干草分别与藏嵩草、高山嵩草、高山嵩草杂类以75:25比例组合搭配最好;燕麦青干草与高山嵩草-异针茅以25:75比例搭配最好,与紫花针茅以50:50比例搭配最好。pH在6.56~7.02范围内,没有造成微生物区系紊乱,组合效应对pH影响不明显;NH₃-N浓度在9.12~15.68 mg·100 mL^-1之间,适于瘤胃微生物生长;牧草组合后产生的乙丙酸累积量与单一牧草产生的无显著差异;牧草组合后CH₄产量与单一牧草的CH₄产量无极显著差异,组合效应并没有提高CH₄产量。

关键词: 体外产气法, 组合效应, 牦牛, 天然牧草, 燕麦青干草