中文摘要：

通过化学成分分析和活体外人工瘤胃发酵法，对3种玉米（高油玉米HOCll5、普通玉米3138及青贮专用玉米）及3个籽粒成熟期（2／4乳线期（ML）、3／4ML和4／4ML）的秸秆青贮品质进行了比较。结果表明：随籽粒成熟期的延长，HOCll5和3138青贮秸秆的品质及青贮发酵品质均下降，而青贮专用玉米各期的发酵品质均良好。其中HOCll5的NDF和木质素含量以3／4ML为最高（P〈0．05），ADF含量无显著变化（P〉0．05），3138的NDF、ADF和木质素含量在成熟期上呈明显的二次曲线增加趋势（P〈0．01），干物质（DM）和NDF消化率明显降低（P〈0．05），而青贮专用玉米秸秆的NDF、ADF和木质素含量在成熟期上呈显著的下降趋势（P〈0．01），48h的DM消化率有明显的增加（P〈0．05）。由此得出HOCll5和3138玉米秸秆在2／4ML具有较佳的青贮效果，而青贮专用玉米的最佳青贮期可延长至籽粒3／4ML或4／4ML。

英文摘要：

This study was conducted to evaluate the nutritional value and fermentation in vitro of three kind of silage including high oil corn variety 115 （HOC115）, typical corn variety 3138 and a special silage corn variety by compar- ing their chemical components and gas production, taking different maturity stage of kernels （2/4, 3/4 and 4/4 milk line; ML） into account. The results showed that for the variety of HOC 115 and 3138, their silage fermentation quality were decreased as the mature period increasing, while the special silage corn variety had better quality in all the pe- riods. A significant difference was observed in the contents of NDF and lignin of HOC 115 at different mature stages （P 〈 0.05） and the highest contents were in the 3/4 ML, whereas the content of ADF had little change （P 〉 0.05）. The contents of NDF, ADF and lignin of typical corn variety 3138 were quadratically increased as maturity increasing （P 〈 0.01）, as well as the digestibility of DM and NDF. In contrast to HOC115 and 3138, the special silage corn variety had high DM digestibility （P 〈 0.05）, less contents of NDF, ADF and lignin （P 〈 0.01） with advanced maturity stage of corn kernels. It was concluded that 2/4 ML was the best silage period for HOC 115 and 3138, and 3/4 or 4/4 ML for the special silage corn as well.