Analysis and Fitting of Growth Curve in Daiyun Goat

To study the early growth of Daiyun goat,a Fujian local goat breed,the body weight and body size of lambs from zero to six months after birth were measured.Three kinds of nonlinear models of Von Bertalanffy,Gompertz and Logistic were used to investigate the growth curve,respectively.Male and female Daiyun goats growed the fastest during the first month,while the growth rate went down during the second to fifth month,then rose up during the fifth to sixth month.The results showed the growth curve fitted well with these three models and the R2 was above 0.97,but the Von Bertalanffy model was much closer to the actual observed values.The fitting parameters of Von Bertalanffy model between genders were also compared,the results told that male Daiyun goats showed higher body weight than female Daiyun goats for each month,but the male Daiyun goat showed lower inflection age,inflection point weight than the female ones.The Von Bertalanffy model equation for male and female Daiyun goat was W = 20038.421(1-0.485e-0.227t)3 and W = 21272.581(1-0.510e-0.198t)3,respectively.