本试验旨在探讨12~13月龄湘中黑牛的能量代谢规律与需要量。试验选择30头体况良好、体重 相近的12~13月龄湘中黑牛公牛,采用完全随机试验设计,分为5组,每组6头牛,分别饲喂按我国《肉牛饲养标准》(NY/T 815—2004)提供的预期日增重1.0 kg/d所需净能的70%(Ⅰ组)、85%(Ⅱ组)、100%(Ⅲ组)、115%(Ⅳ组)、130%(Ⅴ组)配制的5种不同能量水平的试验饲粮。采用饲养试验和消化代谢试验测定湘中黑牛生长性能及能量代谢指标,并建立消化能和代谢能需要量预测模型。预试期7 d,正试期50 d。结果表明:湘中黑牛的日增重与消化能采食量、代谢能采食量之间存在高度线性正相关(R²=0.913、R²=0.906);Ⅲ组平均日增重为1 097 g/d,与预期的结果相似;Ⅳ组平均日增重达到最大值(1 250 g/d),能量利用效率最高;总能消化率、总能代谢率和消化能代谢率平均值分别为(67.51±4.35)%、(58.05±4.49)%、(85.92±1.28)%;不同体重和日增重湘中黑牛的消化能、代谢能需要量的回归方程分别为DE=0.648W^0.75+33.12DG;ME=0.506W^0.75+32.12DG。式中,DE为消化能总需要量(MJ/d);ME为代谢能总需要量(MJ/d);W^0.75为单位代谢体重(kg);DG为日增重(kg/d)。湘中黑牛维持消化能和代谢能需要量分别为0.648、0.506 MJ/(kg W^0.75·d),每千克增重的消化能和代谢能需要量分别为33.12、32.15 MJ。表明我国《肉牛饲养标准》(NY/T 815—2004)基本适用于湘中黑牛。

This experiment was conducted to explore the energy metabolism and requirement of 12 to 13-month-old Xiangzhong black cattle. Thirty healthy Xiangzhong black cattle with a similar body weight of (275.67±13.88) kg and aged 12 to 13 months of age were selected and randomly divided into 5 groups with 6 replicates in each group. Beef cattle were fed 5 different levels of energy diets which were formulated according to the expected weight gain 1.0 kg/d of energy required for 70% (group Ⅰ), 85% (group Ⅱ), 100% (group Ⅲ), 115% (group Ⅳ) and 130% (group Ⅴ), respectively. Feeding test and digestion and metabolism test were carried out to measure the growth performance and energy metabolism indexes of Xiangzhong black cattle, and to build the models for predicting the digestive energy requirement and metabolizable energy requirement. Pre-test period was 7 d and test period was 50 d. The results showed as follows: there was a high degree of positive linear correlation between daily gain and digestive energy intake/metabolizable energy intake (R²=0.913, R²=0.906); the average daily gain of group Ⅲ (1 097 g/d) was similar to the expected result; the average daily gain (1 250 g/d) and energy utilization efficiency of group Ⅳ were maximum; gross energy digestibility, gross energy metabolic rate and gross energy digestible energy were (67.51±4.35)%, (58.05±4.49)% and (85.92±1.28)%, respectively; the digestible energy requirement and metabolizable energy requirement of Xiangzhong black cattle could be estimated by the equations:DE=0.648W^0.75+33.12DG; ME=0.506W^0.75+32.15DG. DE represented digestive energy requirement (MJ/d); ME represented metabolizable energy requirement (MJ/d); W^0.75 represented the units of metabolic body weight (kg); DG represented daily gain (kg/d). Overall, the digestible energy requirement and metabolizable energy requirement for maintenance of Xiangzhong black cattle are 0.648 and 0.506 MJ/(kg W^0.75·d), respectively. Digestible energy and metabolizable energy needed per kilogram gain are 33.12 and 32.15 MJ, respectively. China Feeding Standard of Beef Cattle (NY/T 815—2004) is suitable for the Xiangzhong black cattle.