estimation of heritability and genetic and phenotypic correlation between egg quality and body weight traits in native fowls of fars

a total of 2000 records of egg quality of 746 birds and body weight data from 17th generation of fars native fowl breeding station were used to estimate the genetic parameters of egg quality and body weight traits. six univariate animal models with different random effects were fitted for each trait. a model with direct additive genetic and maternal permanent environmental effects was the most appropriate model for mature weight. for body weight in 12th week, the model with direct additive genetic, maternal genetic and maternal permanent environmental effects was suitable. the model with direct additive genetic and maternal genetic effects was appropriate for albumen diameter, yolk weight and egg weight. for other traits, the simple animal model with direct animal additive genetic effect was the best model. estimates of heritability were ranged from 0.02 (yolk weight) to 0.23 (albumen index) for internal egg quality and were ranged from 0.01 (egg weight) to 0.43 (egg shell strength) for external egg quality traits. these parameters were estimated 0.03, 0.07 and 0.18 for mature weight, body weights at 8th and 12th weeks, respectively. genetic correlations between egg quality and body weight traits ranged from -0.79 to 0.80. in conclusion, selection based on the body weights at 8th and 12th weeks increases the egg weight, egg width and egg shape index. selection for body weight in 12th week would increase the albumen weight and yolk diameters.