Genetic characterization of a White Leghorn population for some production traits

Data on 1445 White Leghorn pullets of 40 sires and 320 dams were used for estimation of means, heritabilities and correlations (genetic, phenotypic and environmental) from sire, dam and full sib components of variance and co-variance. Themean values for egg production measured as number of eggsup to 280 days of age, 32 week egg weight, age at sexual maturity and 20 week body weight were 73.91 eggs, 41.92g, 161.87 days and 1039.79g, respectively. The heritabilities of these traits were low to medium. The heritability estimates from sire, dam and ‘sire+dam’ components of variance ranged between 0.181±0.069 to 0.200±0.06l for egg production up to 280 days of age, 0.219±0.087 to 0.31 0±0.097 for egg weight, 0.250±0.087 to 0.309±0.093 for age at sexual maturity and 0.310±0.102 to 0.904±0.098 for body weight at 20 weeks of age. Sire component of heritability estimate was less than that of dam component except for egg weight. Egg numbers with egg weight and ASM with 20 week body weight were seen to be negatively associated both on genetic and phenotypic levels. The genetic and phenotypic correlations of egg weight with ASM and 20 week body weight and of egg number with 20 week body weight were positive. The phenotypic correlations irrespective of directions were statistically significant except for egg number with body weight at 20 weeks of age. The environmental correlations were mostly similar in direction to their respective genetic correlations.