肉牛不同生长阶段日粮营养物质表观消化率的比较

[目的] 比较不同生长阶段肉牛日粮营养物质表观消化率和日增重,为肉牛养殖日粮配合提供参考。[方法] 按月龄和体重随机选择两组西门塔尔杂交牛,12~15月龄、体重250~300 kg为小体重组,15~18月龄、体重350~500 kg为大体重组,每组10头。日粮根据肉牛体重变化调整,正式试验期分为试验前期和试验后期。以不溶盐酸灰分（AIA）作为内源指示剂,利用点收粪法测定日粮营养物质表观消化率。[结果] 小体重组肉牛在整个试验期的总增重和平均日增重与大体重组肉牛差异显著（P<0.05）;试验前期,小体重组肉牛日粮有机物（OM）、粗蛋白质（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、淀粉和能量的表观可消化量与大体重组肉牛差异显著（P<0.05）,而OM、CP、NDF、ADF、淀粉和能量的表观消化率与大体重组肉牛无显著（P>0.05）差异。[结论] 在试验日粮组成条件下,选取的2个饲养阶段肉牛日粮的营养物质表观消化率没有明显差异,可消化营养物质进食量的增加可提高日增重。

Comparison of Dietary Nutrients Apparent Digestibility in Beef Cattle at Different Growth Stages

[Objective] The dietary nutrients apparent digestibility and daily gain of beef cattle at different growth stages were compared to provide references for ration formulation of beef cattle feeding. [Method] Two groups of Simmental crossbred cattle were randomly selected according to their age and weight. The light weight group comprised of ten 12- to 15-month-old cattle with weights of 250-300 kg. The heavy weight group comprised of ten 15- to 18-month-old cattle with weights of 350-500 kg. The diet was adjusted according to the weight change of beef cattle. The formal test period was divided into early and late test stages. Using ash insoluble in hydrochloric acid （AIA） as endogenous indicator, the apparent digestibility of dietary nutrients was determined by spot fecal collection method. [Result] The overall gain and average daily gain of the light weight group were significantly （P<0.05） different from those of the heavy weight group over the course of the experiment. In the early stage of the experiment, the apparent digestible amount of organic matter （OM）, crude protein （CP）, neutral detergent fiber （NDF）, acid detergent fiber （ADF）, starch, and energy in the diet of light weight group significantly （P<0.05） differed from that of heavy weight group. However there was no significant （P>0.05） difference in the apparent digestibility of OM, CP, NDF, ADF, starch, and energy between the two groups. [Conclusion] Under the conditions of the experimental diet composition, there was no significant difference in the apparent digestibility of dietary nutrients between the beef cattle at the two feeding stages, and the increasing digestible nutrient intake could increase the daily gain.