Factors affecting the nutritive value of the diet and the composition of rumen fluid of grazing sheep and cattle
Factors affecting the nutritive value of the diet and the composition of rumen fluid of grazing sheep and cattle
复制标题
放牧羊、牛日粮营养价值及瘤胃液成分的影响因素
DOI：
10.1071/ar9760691
复制
发表时间：
1976
影响因子：
1.9
通讯作者：
J. Sanson
中科院分区：
文献类型：
--
作者：
J. Langlands;J. Sanson
的消化率和氮含量的饮食和绿色部分的饮食，和浓度的个别挥发性脂肪酸在瘤胃中的羊和牛放牧在一起的五个Phalaris tuberosa牧草不同的饲料供应。绵羊和牛分别为5月龄和6月龄。连续5个月每月进行一次测量，在此期间，动物在牧场之间轮换。牧草的可用性，结构和组成的测量进行了主成分分析，从正交变量描述牧草组成的计算。回归分析表明，这与日粮营养价值和瘤胃液成分有关。绵羊选择的日粮消化率和氮含量高于黄牛，这是因为绵羊选择的日粮含有较多的绿色物质，而绵羊选择的绿色物质消化率和氮含量较高。绵羊日粮的营养价值随绿色饲料的供应而变化，牛的营养价值随绿色饲料的供应和提供的饲料的体积而变化。牛是更敏感的绿色材料的数量的变化，绵羊和牛之间的差异，在饮食的营养价值减少的数量的绿色材料和饲料的体积增加。牛瘤胃液中乙酸的比例高于绵羊，其它挥发性脂肪酸的比例低于绵羊。这些差异通常与选择性放牧的差异有关。
The digestibility and nitrogen content of the diet and of the green fraction of the diet, and concentrations of individual volatile fatty acids in the rumen were measured in sheep and cattle grazing together on five Phalaris tuberosa pastures varying in forage availability. The sheep and cattle were aged 5 and 6 months respectively. Measurements were made at monthly intervals for 5 consecutive months during which animals were rotated between pastures. Measurements of forage availability, structure and composition were subjected to a principal components analysis from which orthogonal variables describing pasture composition were calculated. These were related to the nutritive value of the diet and the composition of rumen fluid by regression analysis. Diets selected by sheep were of higher digestibility and nitrogen content than those selected by cattle, because they contained more green material and the green material selected by the sheep was of higher digestibility and nitrogen content. The nutritive value of the diet of sheep varied with the availability of green forage, and that of cattle with both the availability of green and the bulk of forage on offer. Cattle were the more sensitive to changes in the quantity of green material available, and differences between sheep and cattle in the nutritive value of diets were reduced as the quantity of green material and the bulk of forage increased. The rumen liquor of cattle contained proportionately more acetic acid, and the proportions of other volatile fatty acids were less than in sheep. These differences were generally associated with differences in selective grazing.