Abstract: In order to reasonably utilize forage recourse of Tibet, the fermentation qualities of mixed perennial ryegrass and alfalfa silages were researched through following treatments: CK (100% perennial ryegrass), L (85% perennial ryegrass+15% alfalfa), M (75% perennial ryegrass+25% alfalfa), H (65% perennial ryegrass+35% alfalfa). After ensiling 7, 24 and 45 days, the silage silos were opened in triplicate and examined the quality of silage. Alfalfa addition increased the crude protein content of mixed silage (P<0.05). Adding proper alfalfa promoted the lactic acid fermentation of the mixed silages. Especially, lactic acid content of M treatment was higher than other treatments during ensiling (P<0.05), and its butyric acid content was lower than CK and L treatment during ensiling process (P<0.05). All silages had low butyric acid contents and NH₃-N/TN. And V-Scores indicated good fermentation quality. It was suggested that mixed 25% alfalfa was best for balancing the nutrient of perennial ryegrass and improving fermentation quality.

Key words: Perennial ryegrass, Alfalfa, Mixed ensilage, Fermentation quality

摘要： 为合理利用西藏牧草资源,研究多年生黑麦草(Lolium perenne L.)和紫花苜蓿(Medicago sativa L.)混合青贮饲料的发酵品质,以筛选出适宜的混合比例。设100%多年生黑麦草(CK),85%多年生黑麦草+15%紫花苜蓿(L组),75%多年生黑麦草+25%紫花苜蓿(M组),65%多年生黑麦草+35%紫花苜蓿(H组)4个处理组,分别于青贮7,24和45 d后开窖进行品质鉴定。结果表明:适当添加紫花苜蓿提高了粗蛋白含量(P<0.05),促进了乳酸发酵,特别是M组在整个青贮过程中的乳酸含量都高于其他组(P<0.05),且青贮终点的丁酸含量低于CK和L组(P<0.05);所有青贮饲料的丁酸含量和NH₃-N/TN都较低,V-Score评分显示各组的发酵品质良好。从营养均衡和发酵品质的角度出发,建议以25%紫花苜蓿混合青贮较为适宜。

关键词: 多年生黑麦草, 紫花苜蓿, 青贮, 发酵品质