牦牛犊牛生长后期能量消化代谢及生长需要量研究

Study on Energy Digestion and Metabolism and Growth Requirement of Yak Calves in Later Growth Stage

本试验旨在研究牦牛犊牛生长后期能量消化代谢及生长需要量。选择健康、出生日期接近、平均体重(60.44±4.59)kg的大通牦牛犊牛(公牛)21头,随机等分为3组,即初期屠宰组(平均体重73.61 kg,IS组)、中期屠宰组(平均体重81.96 kg,MS组)、末期屠宰组(平均体重96.53 kg,FS组),每组7个重复,每个重复1头犊牛。预试期15 d,正试期60 d。所有牦牛犊牛均单栏饲喂,自由采食,自由饮水。当犊牛平均体重达到73.61、81.96、96.53 kg时进行消化代谢、气体代谢和屠宰试验。结果表明:1)随着牦牛犊牛体重增加,宰前活重和空腹体重显著增加(P<0.05)。2)随着牦牛犊牛体重增加,干物质、钙和磷表观消化率显著降低(P<0.05),中性洗涤纤维表观消化率显著增加(P<0.05)。IS组无机物、氮和酸性洗涤纤维表观消化率显著高于MS组和FS组(P<0.05)。3)随着牦牛犊牛体重增加,总能、粪能、尿能和消化能显著增加(P<0.05),总能代谢率和消化能代谢率显著降低(P<0.05)。IS组和MS组代谢能和总能消化率显著高于FS组(P<0.05)。4)FS组氧气消耗量和二氧化碳排出量显著高于IS组和MS组(P<0.05)。5)FS组和MS组肌肉和皮的能量总量显著高于IS组(P<0.05),FS组毛的能量总量显著高于IS组和MS组(P<0.05)。6)平均日增重在100.00~500.00 g/d的生长净能为1.19~5.95 MJ/d,生长净能需要量模型为:log10能量=0.9106+0.9898log10空腹体重。综上所述,本试验根据牦牛犊牛生长后期能量的消化代谢特征,建立了牦牛犊牛生长后期生长净能需要量的回归模型,获得了能量需要量营养参数,为牦牛犊牛的科学饲养提供了参考依据。

The purpose of this experiment was to study the energy digestion and metabolism and growth requirement of yak calves in later growth stage.Twenty-one healthy Datong yak calves(bulls)with similar date of birth and average body weight of(60.44±4.59)kg were randomly divided into three groups:initial slaughter group(average body weight of 73.61 kg,IS group),middle slaughter group(average body weight of 81.96 kg,MS group),final slaughter group(average body weight of 96.53 kg,FS group),there were 7 replicates in each group and 1 calf in each replicate.The pre-trial period was 15 days and the trial period was 60 days.All yak calves were fed in single pens,free feeding and drinking water.When the average weight of calves reached 73.61,81.96 and 96.53 kg,the digestion and metabolism,gas metabolism and slaughter tests were carried out.The results showed as follows:1)with the body weight of yak calves increased,the body weight before slaughter and empty body weight were significantly increased(P<0.05).2)With the body weight of yak calves increased,the apparent digestibility of dry matter,calcium and phosphorus was significantly decreased(P<0.05),and the apparent digestibility of neutral detergent fiber was significantly increased(P<0.05).The apparent digestibility of inorganic matter,nitrogen and acid washing fiber of IS group was significantly higher than that of MS group and FS group(P<0.05).3)With the body weight of yak calves increased,the gross energy,fecal energy,urinary energy and digestive energy were significantly increased(P<0.05),and the total energy metabolic rate and digestive energy metabolic rate were significantly decreased(P<0.05).The metabolic energy and total energy digestibility of IS group and MS group were significantly higher than that of FS group(P<0.05).4)The oxygen consumption and carbon dioxide output of FS group were significantly higher than those of IS group and MS group(P<0.05).5)The total energy of muscle and skin of FS group and MS group was significantly higher than that of IS group(P<0.05),and the total energy of hair of FS group was significantly higher than that of IS group and MS group(P<0.05).6)The net energy for growth when average daily gain of 100.00 to 500.00 g/d was 1.19 to 5.95 MJ/d,and the model of net energy requirement for growth was:log10 energy=0.9106+0.9898 log10 empty body weight.In conclusion,according to the digestion and metabolism characteristics of energy of yak calves in late growth stage,the regression model of net energy requirement for growth of yak calves in late growth stage is established,and the nutrient parameters of energy requirement are obtained,which provides a reference for scientific feeding of yak calves.