Abstract: he early bodyweight of White Muscovy with different gender were measured, and three nonlinear curves of Logistic, Von Bertalanffy and Gompertz model were used to fit the growth curve in this study. The results showed that White Muscovy grown slowly before the age of 4 weeks, but the male Muscovy showed higher growth rate than female duck after this stage. The Gompertz model generated the best effect concerned with goodness of fit(R2), residual sum of squares(E), and suitability of χ2 test. Further more, the fitting parameters of Gompertz model between genders were compared, the male Muscovy showed higher initial weight, mature weight, largest weight gain per week and inflection point weight and lower initial growth rate than female Muscovy . The inflection age of male Muscovy was 7.03 weeks and female Muscovy was 5.37 weeks, respectively. The relative growth rate of male Muscovy was lower than female before 4 weeks but higher after 4 weeks and the difference of absolute growth rate was high between genders.

Key words: White Muscovy; growth curve; bodyweight; model; fitting