Estimation of Genetic Parameters for Growth Traits in Two Routine and Ascites Inducing Conditions for Ascites Syndrome in a Commercial Broiler Line

In the present study, phenotypic data including the live bodyweights and the growth rate characteristics of broiler chickens were collected from two offspring generation of 47 and 71 sires of a Commercial Broiler Line respectively and then were separately entered for estimation heritability and statistical calculating the correlation of growth-related traits under conditions routine breeding were used under inducible cold stress for ascites syndrome. Later on, the estimation of heritability for growth related traits was done using UNIVARIATE analyzes and calculation of genetic and phenotypic correlations of these traits with MULTYVARIATE analysis using AREML procedure of WOMBAT software. The heritabilities of growth-related traits varied from low to high in two routine and inducible cold stress condition (from 0.08 to 0.76(and most of it was generally early in the growth period and showed a decreasing trend with age, similar trends were observed in the results in both generations. Phenotypic correlations were lower than genetic correlations at all weeks. With increasing age, genetic and phenotypic correlations for all traits showed a decreasing trend. These results suggest that in addition to the greater influence of non-genetic factors in reducing the share of incremental genetic variance of the total variance, the occurrence of ascites in the last few weeks (especially in cold stress conditions) has reduced the heritability of growth-related traits. The observation of the present report indicated there is no high significant genetic correlation between growth-associated traits between routine temperature conditions and under cold-inducible stress existed, this phenomenon makes messages and conclusion responsible candidate gene for both conditions could not be the same. Outputs about moderate to high estimates for the heritability of the investigated traits indicate that genetic selection can lead to an improvement in such growth characteristics.