GENETIC PARAMETER ESTIMATES FOR EIGHT WEEK BODY WEIGHT IN A FOUNDATION STOCK OF MALE LINE BROILER CHICKENS

Résumé

The objectives of this study were to estimate heritabilities and genetic correlations for eight week body weight in a foundation stock of male line broiler chickens. A total of 2,086 birds comprising 1500 hens and 586 cocks were used in 3 generations. At hatch, chicks used were wing-banded, weighed and housed on deep litter. Body weights of birds were subsequently taken at 2, 4, 6 and 8 weeks of age. For each generation, data obtained were utilized to estimate heritabilities, genetic and phenotypic correlations from sire component of variance. Selection action (Sel action) statistical software was used to estimate heritability, genetic and phenotypic correlations. Correlations were moderate to high. Heritability estimates for generation 1 ranged from moderate to high 0.34 (CW2) to 0.75 (CW8), low to high for generation 2 (0.17) for CWO and (0.88) for CW8 and positively low for CWO to high for CW8 (0.16 to 0.81) for generation 3. This points to the existence of an appreciable amount of additive genetic variance in the flock and indicates that improvement in the traits can be brought about by intrapopulation selection. The high and positive genetic and phenotypic correlations indicate the pleiotropic action of genes controlling these traits, and that by direct selection for anyone of them; genetic improvement in the others will be realized as correlated responses.