饲用油菜与紫花苜蓿混合青贮品质研究

Quality of the mixed silage of forage rape and alfalfa

本试验旨在为油菜饲料化的实际运用提供理论数据和技术支撑,选取盛花期的饲用油菜(Brassica napus L.)和紫花苜蓿(Medicago sativa L.)为原料,探究二者混合青贮对其营养和发酵品质的影响。饲用油菜和紫花苜蓿盛花期进行刈割后按鲜重比0∶10、3∶7、5∶5、7∶3和10∶0的比例进行混合青贮。分别在发酵第5、10、20、40和60 d时开罐分析营养成分和发酵特性的动态变化,结合V-Score评分法和模糊隶属函数法对混合青贮饲料品质进行综合评价,探讨二者混合青贮的适宜比例。结果表明,饲用油菜和紫花苜蓿单独青贮组发酵品质整体较差。随着紫花苜蓿混合比例的增加,混合青贮饲料的感官品质评分逐步提高。混合青贮饲料的粗蛋白、可溶性碳水化合物和乳酸含量均出现不同程度的提升,pH值、氨态氮/总氮和丁酸含量出现一定程度降低。饲用油菜和紫花苜蓿混合比例为3∶7时处理效果较好,发酵60 d时pH值(3.95)、氨态氮/总氮(4.16%)含量显著低于对照组(P<0.05),乳酸(96.46g·kg^(-1)DM)显著最高(P<0.05),其V-Score评分为良好(80.07),隶属函数值最大(0.7649),可以作为饲用油菜和紫花苜蓿混合青贮的适宜配比方案。

In order to provide theoretical data and technical support for the practical application of forage rape,this experiment selected forage rape(Brassica napus L.)and alfalfa(Medicago Sativa L.)during full flowering period as raw materials to explore the effects of mixed silage on its nutrition and fermentation quality.Silage materials were mixed according to the ratio of fresh weight 0∶10,3∶7,5∶5,7∶3 and 10∶0.The silage cans were opened at 5,10,20,40 and 60 days after ensiling to determine the dynamic changes of fermentation index and nutrient content.The results showed that the overall quality of forage rape and alfalfa silage alone was poor.With the increase of alfalfa addition ratio,the sensory quality score of mixed silage gradually improved.The contents of crude protein,soluble carbohydrate and lactic acid of mixed silage increased to varying degrees,while the pH value,NH3-N/TN and butyric acid content decreased to a certain extent.It is better to mix and store forage rape and alfalfa at a ratio of 3∶7.At 60 days of fermentation,the pH value(3.95)and a NH3-N/TN(4.16%)content were significantly lower than those in the control group(P<0.05),and lactic acid(96.46g·kg-1DM)was significantly the highest(P<0.05).The V-score was good(80.07)and the membership function value was the highest(0.7649),which could be used as the appropriate proportion scheme for mixed silage of forage rape and alfalfa.