不同稻秸添加比例对紫花苜蓿和麦麸混合青贮的影响

Effects on silage quality of mixing different ratios of rice straw with alfalfa and wheat bran

为探讨不同稻秸添加比例对紫花苜蓿和麦麸混合青贮发酵品质的影响,以紫花苜蓿、麦麸及5个不同比例(0、5%、10%、15%和20%)的稻秸分别进行混合裹包青贮,30 d后测定混合青贮饲料的发酵品质、营养品质和有氧稳定性。结果表明:1)稻秸添加组与不添加的对照组pH、可溶性碳水化合物(WSC)、酸性洗涤纤维(ADF)和NH_3-N/TN有显著差异(P<0.05);随着稻秸添加量的增加,pH值、ADF、中性洗涤纤维(NDF)和有氧稳定性递增,粗蛋白(CP)、WSC、相对饲料值(RFV)和V-Score值降低。2)根据V-Score评分可知,0和5%的稻秸添加组发酵品质为优,10%和15%稻秸添加组的发酵品质为良,20%稻秸添加组发酵品质中等。3)青贮30 d开包后,0和5%的稻秸添加组的有氧稳定性分别为64和72 h,10%、15%和20%稻秸添加组的有氧稳定性均大于168 h;有氧暴露4 d后,0、5%、10%和20%稻秸添加组pH值迅速变化,15%稻秸添加组变化相对较小。综上所述,优质混合青贮的推荐稻秸添加比例应小于5%。

To investigate the influence of different ratios of rice straw on the fermentation quality of alfalfa and wheat bran mixed silage, this study conducted a series of experiments in which different ratios of rice straw (0, 5%, 10%, 15% and 20%) were added to the mixed silage and its fermentation quality, nutritional quality, and aerobic stability were analyzed after 30 days. It was found that: 1) There were significant differences in pH, water soluble carbohydrates (WSC), acid detergent fiber (ADF) and NH 3-N/TN between the control group (0) and the other groups (P<0.05). When the ratio of rice straw is increased, the pH, ADF, neutral detergent fiber (NDF) and aerobic stability of the mixed silage tended to increase while the values for crude protein (CP), WSC, relative feed value (RFV) and V-Score decreased. 2) As determined from the V-Score, silage quality for the 0 and 5% treatments was superior, quality of the 10% and 15% treatments was fairish and quality of the 20% treatment was considered to be inferior. 3) After 64 and 72 h aerobic exposure, the 0 and 5% treatments were 2 ℃ above ambient temperature, while the aerobic stability times for the 10%, 15% and 20% treatments were all above 168 h. Furthermore, after 4 days of aerobic exposure, the 0, 5%, 10% and 20% treatments exhibited a rapid change of pH, but for the 15% treatment the pH did not change much. In conclusion, the recommended mixing ratio for incorporation of rice straw into mixed alfalfa-wheat bran silage, is not more than 5% rice straw.