装填密度对羊草和苜蓿青贮品质及有氧稳定性的影响

Effect of Filling Density on Quality and Aerobic Stability of Leymus chinensis and Alfalfa Silage

青贮品质和有氧稳定性是影响青贮饲料利用效果的关键因素,本试验旨在研究装填密度对羊草(Leymus chinensis)和紫花苜蓿(Medicago sativa L.)青贮品质、有氧稳定性和微生物数量的影响。本试验以抽穗期的羊草和初花期的苜蓿为原料,青贮密度分别设置为600 kg·m^(-3),700 kg·m^(-3),800 kg·m^(-3),每组3个重复,在青贮60天和有氧暴露8天时取样分析。结果显示,羊草青贮和苜蓿青贮在800 kg·m^(-3)装填密度下的pH值最低,粗蛋白质和可溶性碳水化合物含量最高,乳酸菌数量最多,青贮品质最好。羊草青贮在800 kg·m^(-3)装填密度下有氧稳定性最好,苜蓿青贮在700 kg·m^(-3)装填密度下有氧稳定性最好。有氧暴露后各处理的乳酸菌数量显著下降(P<0.05),酵母菌和好气性细菌数量显著上升(P<0.05),苜蓿青贮有氧暴露后有霉菌产生。

Silage quality and aerobic stability are the key factors affecting the utilization of silage.The aim of this experiment was to study the effects of filling density on silage quality,aerobic stability,and microbial count of Leymus chinensis and Alfalfa silage.In this experiment,Leymus chinensis at the heading stage and Alfalfa at the early flowering stage were used as raw materials.The silage densities were set to 600 kg·m^(-3),700 kg·m^(-3) and 800 kg·m^(-3),respectively,with 3 replicates in each group.Sampling and analysis were carried out at 60 days of silage and 8 days of aerobic exposure.The results showed that Leymus chinensis silage and alfalfa silage had the lowest pH value,the highest crude protein and soluble carbohydrate content,the highest number of lactic acid bacteria,and the best silage quality at 800 kg·m^(-3) filling density.The best aerobic stability was found for Leymus chinensis silage at 800 kg·m^(-3) filling density and for Alfalfa silage at 700 kg·m^(-3) filling density.After aerobic exposure,the number of lactic acid bacteria in each treatment decreased significantly(P<0.05),the number of yeast and aerobic bacteria increased significantly(P<0.05),and mold produced.