The Studies On The Energy And Protein Requirements In Male Lambs Of Mutton Sheep At 20-35kg

Thirty hornless Dorset×Small Tail Han sheep crossbred F2 which fixed athwart cross,at the age of 3 month with mean weight about 18kg and non-castrated male kids were selected to study.The diet was made to granulation TMR based on recommendation of nutrients requirements of NRC(2007). Energy and protein metabolism rules and requirement factorial models of mutton sheep at the growth of 20-35kg were systematically studied by the feeding test,digestion-metabolism experiment and comparative slaughtering test. The results showed that:①T he digestibility of DM,EE,NDF and ADF of mutton sheep at the growth of 20-35kg were 85.19±0.58%,73.78±2.10%,61.79±3.25% and 31.34±3.76% respectively;②T he digestibility of energy was 60.61±3.09%,the metabolizability of gross energy(ME/GE) and digestible energy(ME/DE) were 51.86±3.45%,85.95±1.30%. The digestibility of protein was 65.88±3.63%,the utilization of net protein was 29.36±3.17%;③T he metabolizable energy requirements and net energy requirements of mutton sheep for maintenance were 240.44KJ/kgW0.75·d and 335.47 KJ/kgW0.75·d, the partial efficiency of use of ME for NE below maintenance was 0.72, the partial efficiency of use of ME for NE below growth was 0.418,the requirements of net energy for growth were 9.19 to 12.05MJ/kg of EBW; the net protein requirements of mutton sheep for mainten- ance were 270.455mg N/kgW0.75·d and 1.69g CP/kgW0.75·d, the requirements of net protein for growth was 171.99g/kg of EBW;④T he net energy requirement of mutton sheep at 20-35kg can be estimated by the factorial models as follows: NER=240.44KJ/kgW0.75·d+ NEg; Log10(ER)=0.217+1.483Log10(EBW); EBW=-1.809+0.943SBW.The metabolizable energy requirement of mutton sheep at 20-35kg can be estimated by the factorial models as follows: MER=335.47 KJ/kgW0.75·d+ NEg/0.418; Log10(ER)=0.217+1.483Log10(EBW); EBW=-1.809+0.943SBW.The net protein requirement of mutton sheep at 20-35kg can be estimated by the factorial models as follows: NPR=1.69g/kgW0.75·d+ NPg; Log10(NR)=2.261+Log10(EBW ); EBW=-1.809+0.943SBW.