Genetic Evaluation of Egg Production Curve Parameters and Their Association with Some Economical Traits in Quail

The aim of this study was to estimate of (Co)variance components for egg production curve parameters and their genetic correlation with some economic traits using of the best function for describing egg production curve in wild strains of quail. For this purpose, the daily records of quail egg production during the first 20 weeks were used for fitting egg production curve. Five nonlinear functions including nonlinear logistic, incomplete gamma (Wood), modified compartmental, modified gamma, and logistic (Nelder) were fitted by R computer program, and the best function was determined based on the goodness of fit criteria. After selecting the best model, the production curve parameters for each of quails was calculated and their genetic correlation with age and weight of puberty, egg number, total egg production and the average egg during the first 20 weeks were estimated. The genetic correlation between traits was estimated using of a two-trait animal model and Gibbs sampling method by Gibbs3f90 software. Based on the goodness of fit criteria, the Modification of Wood was selected as the best function. Heritability estimates for the rate of production decrease was higher than the rate of production increase (0.231 in comparison with 0.148) and the heritability for weight of puberty was estimated higher than the age of puberty. Also, the heritabilty of egg number was estimated higher than the sum and average egg weight among the studied production traits. The highest and lowest genetic correlation was observed between the rate of production decrease and the rate of production increase (-0.764) and the rate of production increase with weight of puberty (-0.031), respectively. The results of the study indicate that the sum and average egg weight and age of puberty could be considered in selection objective to improve the egg curve parameters.