Estimation of model parameters of the Japanese quail growth curve using Gompertz model

Abstract

This study was conducted to describe the growth pattern of Japanese quails with the Gompertz growth model using body weight measurements from an unselected, random bred quail population. The coefficient of determination (R2) was high for both male and female (0.98) indicating that the growth curves of the observed data were adequately described by the Gompertz model. However, male and female Japanese quails did not have identical growth patterns. Generally, females appeared to be heavier than males at all ages and this difference increased with age. Both male and female Japanese quail were 4 % mature at hatch but reached 98 and 96 % respectively, of their mature weights at 12 weeks of age. Thus, males matured faster than females though the latter had higher weights. Asymptotic weight (A) was higher (p<0.05) in females (168.83 g) than males (132.71 g) as was the case with integration constant (B). In contrast, maturity rate (k) was higher (p<0.05) in males (0.3765) compared to females (0.3262). Thus, a strong and negative relationship (–0.7981 and –0.8498 for male and female respectively) between maturation rate and asymptotic weight was observed. Age, weight and maximum gain at point of inflection for male and female Japanese quails were 2.48 vs. 2.91 weeks, 48.82 vs. 62.11 g and, 18.38 vs. 20.26 g res-pectively. Males reached the inflection point at a significantly (p<0.05) earlier age than females. Similarly, they had lower inflection weight and gain than female quail. And it explains difference between males and females Japanese quail in Nigeria.