Growth Curve Fitting of Hubei Black-head Goats with Different Sex

The growth curve of Hubei black-head goats from 0 to 24 months were fitted with three nonlinear models including Gompertz, Logistic and Von Bertalanffy. The results showed that the three growth curve models had good fitting for Hubei black-head goats(R20.99). The optimal models of different sex were different. For rams, the Gompertz model fitted best(R2=0.999 32), with the growth turning points of 20.823 kg of body weight at 6.21 months of age. The Gompertz model equation for rams was W=56.604 9 e-2.885 1exp(-0.170 5 t). For ewes, Von Bertalanffy model fitted best fitting(R2=0.998 12), with the growth turning points of 13.221 kg of body weight at 4.17 months of age. The Von Bertalanffy model equation for ewes was W=44.619 3×(1-0.643 3e-0.157 5t)3.