Study on growth fitness models of the lambs of Poll Dorset and Borderdale

The early growth process of lambs from 0 to 8 month old Poll Dorset and Borderdale was studied by fitting of Mitschetrlich,Gompertz and Logistic models.The results showed that all the fitnesses(R~(2)) of three models were above 0.98,among which the Gompertz model had both highest R~(2)value and best prediction effectiveness of body weight.The parameters of maximum body weight,inflection age,body weight at inflection age,instantaneous relative growth rate(K),relative growth rate(RGR) and instananeous growth rate(GR)were estimated with Gompertz model,as the results,the growth of male lamb was more rapid than that of female,while the early growth of Poll Dorset was higher than that of Borderdale.