Sire-Hatch Interaction Effects on Juvenile Body Weight and Weight Gain in Chickens

The objectives of this study were to evaluate the importance of sire-hatch interaction on the juvenile body weight and weight gain in broiler chickens and to check the biasness in heritability estimates of these traits due to the interaction.The data were collected from 4, 062 female chickens belonging to 281 sire groups of four breeding populations over 4 generations. The traits analysed were body weight at six and nine weeks of age and body weight gain from six to nine weeks of age. Statistical analyses were first made on the basis of within-flock and generation and then pooled over all flocks and generations. The statistical analysis employed was least squares of two-way mixed model with interaction in which hatches were assumed to be fixed and sire groups were assumed to be random.Statistically significant interactions were detected in six- and nine-week body weights and weight gain. The pooled estimates of the interactions explained 4.22%, 2.83% and 2.66% of the total phenotypic variations of those traits, respectively. These amounts of variability corresponded to 28.55%, 23.08% and 33.00% of the sire components, respectively. This suggests that the heritability estimates of those traits in broilers were overestimated.