日粮精料水平对牦牛和黑白花牛营养物利用率的影响

The influence of dietary concentrate level on nutrients utilization of holstein,yak

2 5月龄的牦牛和 15月龄的黑白花牛各 3头 ,于消化代谢笼内进行三期的消化代谢试验 ,以测定日粮精料水平对牦牛和黑白花牛营养物利用率的影响及两种牛对营养物消化代谢之差异。三期试验所用日粮的精粗比分别为 2 0∶80 ,5 0∶5 0 ,和 80∶2 0。所有动物自由采食 ,自由饮水。用全收集法收集粪尿 ,常规法分析饲料和粪尿样品中的粗蛋白 (CP) ,钙 (Ca)和磷 (P)。结果表明 ,两种牛在营养物消化率及能量代谢方面无差异 ,在低精料日粮条件下 ,牦牛对日粮中的CP ,Ca和P的利用率高于黑白花牛。黑白花牛的CP ,Ca和P贮留随精料水平上升而迅速上升 ,而牦牛的CP和Ca贮留几乎不受精料水平的影响。在干物质 (DM )消化率方面两种牛间无差异 ,它们的DM消化率均随日粮精料水平升高而升高。黑白花牛的DM采食量随精料水平升高而升高 ,牦牛对精料粗料比为 5 0∶5 0的日粮有最高的采食量。这些结果表明 ,牦牛和黑白花牛的消化道的消化吸收功能无差异 ,牦牛对高粗料型日粮中的营养物的利用率高于黑白花牛。

month-old yaks and 3 15-month-old Holsteins,all caged in metabolic sac,were subjected to 3-stage digestion and metabolism trials for the determination of the influence of dietary concentrate level on nutrient utilization of yak and Holstein and of the differences of nutrient digestion and metabolism between yak and holstein.Dietary concentrate level(expressed by the ratio of concentrate versus roughage)used in 3-stage experiments were 20∶80,50∶50 and 80∶20 respectively.all the animals were accessed to food and water ad.libitum.Total collection method was used in digestion and metabolism trial and convenient method was used to analyze the crude protein(CP),Calcium (Ca),phosphorus(P),dry matter (DM) and energy(E).No difference on nutrient digestions and energy metabolism was found between yak and holstein,and higher( P <0 01)efficiency of CP,Ca,and P utilization was found in yak than in holstein under high roughage diet condition.CP,Ca and P retention in holstein increased rapidly( P <0 01)with concentrate level,while those in yak was almost unaffected by dietary concentrate level.As far as DM intake of holstein increased( P <0 01)with concentrate level,but DM intake of yak reached the highest point when fed 50∶50 diet.all these results suggested that the nutrient digestion efficiency of the digestive tract between yak and holstein was similar,the sensitivity of yak to the change of diets was far lower than the sensitivity of holstein.