不同加工方式制作桑枝饲料的营养价值及用于肉牛饲养的瘤胃降解特性

Nutritional Value of Mulberry Branch Feed from Different Pro-cessing Methods and Degradation Characteristics in Rumen of Beef Cattle

以冬季剪伐的桑枝条为原料,分别采用粉碎方式和膨化方式加工制作桑枝饲料,通过化学分析方法和尼龙袋法评价2种桑枝饲料的饲用价值。测定膨化桑枝饲料和粉碎桑枝饲料中的粗蛋白质含量均较高,质量分数分别达到7.97%、7.43%,且差异极显著（P〈0.01）;膨化桑枝饲料中的粗纤维、中性洗涤纤维、酸性洗涤纤维的含量极显著低于粉碎桑枝饲料（P〈0.01）。根据RFV饲料评定标准评定膨化桑枝饲料的等级为3级,高于粉碎桑枝饲料。将装有永久性瘤胃瘘管的30月龄云南云岭牛作为供试肉牛,测定2种桑枝饲料营养物质在肉牛瘤胃中的降解率,结果是膨化桑枝饲料营养物质的降解率极显著高于粉碎桑枝饲料（P〈0.01）。研究结果表明,桑枝饲料中的粗蛋白含量较高,采用膨化方式加工的桑枝饲料的营养价值以及在肉牛瘤胃中的降解率均更高,可作为反刍动物的粗饲料。

Taking mulberry branches cut in winter as raw materials,mulberry branch feed was made using grinding method and puffing method. The feeding values of two kinds of mulberry branch feeds were evaluated by chemical analysis method and nylon bagging method. The crude protein content of puffed mulberry branch feed and ground mulberry branch feed was as high as 7. 97% and 7. 43% respectively,showing significant difference（ P〈0. 01）. The contents of crude fiber,neutral detergent fiber and acidic detergent fiber in puffed mulberry branch feed were significantly lower than those in ground mulberry branch feed（ P〈0. 01）. According to relative feed value（ RFV） evaluation standard,puffed mulberry branch feed was rated as grade 3, which was higher than ground mulberry branch feed. The degradation rate of nutrients from puffed mulberry branch feed in rumen of Yunnan Yunling cattle with installation of permanent rumen fistula at age of 30 months was significantly higher than that from ground mulberry branch feed（ P〈 0. 01）. These results show that mulberry branch feed has high CP content,andthe nutritional value and degradation rate of mulberry branch feed processed by puffing method are satisfactory,which could be used as coarse fodder for ruminants.