生长期秦川牛能量代谢规律与需要量研究

摘要

This experiment was conducted to investigate the energy metabolism and requirement of growing Qinchuan cattle. Thirty healthy growing bulls of Qinchuan cattle with similar body weight [ ( 336. 33 ± 18.28) kg] were selected and randomly divided into 5 groups with 6 heads in each group. Cattle were fed 5 di⁃ets with different levels of energy, which were formulated according to 85. 0% ( group Ⅰ) , 92. 5% ( groupⅡ) , 100.0% ( group Ⅲ) , 107. 5% ( group Ⅳ) and 115. 0% ( group Ⅴ) of net energy for the expected weight gain of 900 g/d [ China Feeding Stantard of Beef Cattle( NY/T 815—2004) ] , respectively. Feeding test and digestion and metabolism test were carried out to measure the growth performance and energy metabo⁃lism indexes of growing Qinchuan cattle, and to build the models for predicting the digestive energy require⁃ment and energy metabolism requirement. Pre⁃test period was 10 days and test period was 42 days. The results showed as follows:average daily gain of groupⅢ(880.15 g/d) was lower than the expected resuthe aver⁃age daily gain (1 160.10 g/d) and energy utilization efficiency of group Ⅳ were maximum; the average val⁃ues of gross energy digestibility, gross energy metabolic rate and digestive energy metabolic rate were (76.44± 3.23)%, (66.75±3.16)% and (87.31±0.54)%, respectively; the digestive energy requirement and metabo⁃lizable energy requirement of growing Qinchuan cattle could be estimated by the following equations: DER=0.778W0.75 + 37. 05ADG; MER=0. 668W0.75+33. 49ADG [ DER represented digestive energy requirement ( MJ/d) , MER represented metabolizable energy requirement ( MJ/d ) , W0.75 represented metabolic body weight ( kg) , and ADG represented average daily gain ( kg/d) ] . Overall, the digestive energy requirement and metabolizable energy requirement for maintenance of growing Qinchuan cattle are 0. 778 and 0.668 MJ/(kg W0.75·d), respectively. Digestible energy and metabolizable energy required for per kilogram of body weight gain are 37.05 and 33.49 MJ, respectively.%本试验旨在研究生长期秦川牛能量代谢规律与需要量。选择30头体况良好、体重[（336．33±18．28） kg]相近的生长期秦川牛公牛，随机分为5组，每组6头牛，分别饲喂按我国《肉牛饲养标准》（NY／T 815—2004）提供的预期平均日增重900 g／d 所需净能的85．0％（Ⅰ组）、92．5％（Ⅱ组）、100．0％（Ⅲ组）、107．5％（Ⅳ组）、115．0％（Ⅴ组）配制的5种试验饲粮。采用饲养试验和消化代谢试验测定秦川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10 d，正试期42 d。结果表明，Ⅲ组秦川牛平均日增重为880．15 g／d，较预期的结果略低；Ⅳ组平均日增重达到最大值（1160．10 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（76．44±3．23）％、（66．75±3．16）％、（87．31±0．54）％；秦川牛的消化能和代谢能需要量的回归方程分别为：DER ＝0．778W0．75＋37．05ADG；MER ＝0．668W0．75＋33．49ADG[ DER为消化能需要量（ MJ／d），MER为代谢能需要量（ MJ／d），W0．75为单位代谢体重（ kg），ADG为平均日增重（ kg／d）]。综合得出，生长期秦川牛的维持消化能和代谢能需要量分别为0．778、0．668 MJ／（ kg W0．75·d），每千克增重的消化能和代谢能需要量分别为37．05、33．49 MJ。