Abstract: This study was conducted to evaluate chemical compositions,fermentation quality,microbial population and in vitro degradability of Sorghum hybrid Sudan grass prepared with Perennial Ryegrass at different mixing ratios silage. The Sorghum hybrid Sudan grass was prepared with and without Perennial Ryegrass at mixing ratios of 10∶0 (A),7∶3 (B),5∶5 (C),3∶7 (D) and 0∶10 (E) on a fresh matter basis and stored for 60 d. The results indicated that there was significant difference on dry matter,acid detergent fibre,neutral detergent fibre and crude protein contents(P<0.05). The pH values of A and E were 4.40 respectively,which were significantly higher than in B,C and D groups (P<0.05). Compared to D and E groups,the lactic acid was significantly lower in A,B and C groups (P<0.05). The acetic acid in E group was significantly greater than that in the other groups (P<0.05) and the highest ammonia nitrogen content was observed in A group (P<0.05). Compared to A and E groups,the count of lactic acid bacteria was significantly (P<0.05) greater in B,C and D groups. In mixed silages,the in vitro dry matter digestibility in D group was significantly (P<0.05) greater than that in B and C groups. In conclusion,the ratio of mixed silage of Sorghum hybrid Sudan grass to Perennial Ryegrass is 3∶7.

Key words: Sorghum hybrid Sudan grass, Perennial ryegrass, Mixed silage, Fermentation quality, Microbial population, Feeding value

摘要： 为研究高丹草(Sorghum bicolor×Sorghum sudanense)与黑麦草(Lolium perenne L.)适宜的混合青贮比例,本试验将不同比例[10∶0(A),7∶3(B),5∶5(C),3∶7(D),0∶10(E)]的高丹草与黑麦草进行混合青贮,室温条件厌氧发酵60 d后测定了青贮的营养成分、发酵品质、微生物数量及体外消化特性。结果表明:随着黑麦草比例增加干物质,酸性洗涤纤维和中性洗涤纤维含量呈下降趋势,粗蛋白质含量呈上升趋势,差异显著(P<0.05);A和E组青贮pH值为4.40,显著高于B,C,D组(P<0.05);D组乳酸含量达到最大值,显著高于A,B,C组(P<0.05);E组乙酸含量最低,显著低于其他各组(P<0.05);A组氨态氮含量最高,E组最低,差异显著(P <0.05)。B,C,D组乳酸菌数量显著高于A和E组(P<0.05);混合青贮中,D组干物质消化率显著高于B和C组(P<0.05)。本试验条件下,高丹草与黑麦草混合青贮适宜比例为3∶7。

关键词: 高丹草, 黑麦草, 混合青贮, 发酵品质, 微生物数量, 饲用价值