Investigation of nonlinear models to describe long-term egg production in Japanese quail

In this study, long-term egg production was monitored in a Japanese quail flock, which had not undergone any genetic improvement, for 52 wk as of the age of sexual maturity. The study aimed to detect some traits with respect to egg production, to determine the cumulative hen-housed egg numbers, and to compare goodness of fit of different nonlinear models for the percentage of hen-day egg production. The mean age at first egg was 38.9 d and the age at 50% egg production was 45.3 d. The quail reached peak production at 15 wk of age (wk 9 of egg production period) when the percentage of hen-day egg production was found to be 94%. The cumulative hen-housed egg number for 52 wk as of the age of sexual maturity was 253.08. The monomolecular function, a nonsigmoid model, was used in the nonlinear regression analysis of the cumulative egg numbers. Parameters a, b, and c of the monomolecular model were estimated to be 461.70, 473.31, and 0.065, respectively. Gamma, McNally, Adams-Bell, and modified compartmental models, widely used in hens previously, were used in the nonlinear regression analysis of the percentages of hen-day egg production. The goodness of fit for these models was compared using the values of pseudo-R², Akaike's information criterion, and Bayesian information criterion. It was determined that all the models are adequate but that the Adams-Bell model displayed a slightly better fit for the percentage of hen-day egg production in Japanese quail than others.