Repeatability and heritability estimates for egg and chick production, with hierarchical matings, in meat-type chickens

Abstract

Repeatability (r) and heritability (h²) for reproductive traits were estimated from three meat-type chicken populations. One hundred and fifteen females were inseminated with semen of 23 males from three populations under a hierarchical mating system in a first experiment (E₁) and with other 23 males in a second experiment (E₂). Four hatches, or blocks, were produced for each experiment. Estimates of r and h² were obtained by analyses of variance among males, and among females within males within populations and experiments, performed with averages per hen in each hatch. Repeatabilities for egg production (POST) were significant (P < 0.01) and equal to 0.19±0.05 and 0.32±0.04 in experiments E₁ and E₂ respectively. For hatchability of fertile eggs (ECLOD), the h² estimated from male components were 0.14±0.14 (P > 0.05) and 0.26±0.17 (P < 0.05). For hatchability of all eggs set (NASC), the h² (P < 0.05) based on male components were equal to 0.18±0.15 (E₁) and 0.26±0.17 (E₂). The h² estimated from dam components were larger and significant (P < 0.01). The dam estimates for ECLOD were 0.77±0.09 and 0.48±0.20 for E₁ and E₂ respectively, and for NASC, 0.58±0.21 (E₁) and 0.48±0.20 (E₂). The results confirm that ECLOD and NASC tend to present low additive genetic variability.