Fitting and Comparison of Body Weight Growth Curves of Xingyi Duck

The growth curves of Xingyi duck were separately fitted by Logistic,Von Bertalanffy and Gompertz nonlinear growth models according to measured body weight values of young male and female ducks to provide the reference basis for standardization breeding and variety selection of Xingyi duck.The results showed that the body weight of 0~4 weeks old Xingyi duck was in the rapid increment period and the growth rate of female duck was higher than male duck,but the week-growth rate of 6~10 weeks old Xingyi duck slowed down gradually and the week-growth rate of male duck was higher than female duck.Three nonlinear growth models all could better fit body weight growth curves of Xingyi duck and the fitting effect of Gompertz model was the best in three nonlinear growth models.The fitting models for male and female duck were 1404.492e-4.079exp(-0.382t) and 1301.985e-4.324exp(-0.433t) respectively.Three rational breeding stages of 0~4 weeks,5~10 weeks and 11 weeks to adult were divided according to the change regulation of body weight and fitted growth curves.