Heritability estimates of growth curve parameters and genetic correlations between the growth curve parameters and weights at different age of Japanese quail

This study was carried out to estimate heritabilities of growth curve parameters, and phenotypic and genetic correlations among growth curve parameters and also between weights at different of age and growth curve parameters of Japanese quail. Progeny from random mating of 42 sires and 168 dams were used. Growth curves for individual quail were fitted using Gompertz model. Mean estimates of growth curve parameters (A, B and K) for male + female were 245, 3.399 and 0.055, respectively. Heritability estimates for the parameter A were 0.351 and 0.176 from paternal half-sibs (PHS) and full-sibs (FS), while heritabilities of parameter B were 0.263, 0.328 and 0.393 from PHS, FS and maternal half-sibs (MHS), respectively. Heritability estimates of K from PHS, MHS and FS were 0.316, 0.329 and 0.322, respectively. Phenotypic and genetic correlations between the parameter A and B acid between B and K were generally positive while the correlations between A and K were negative. Phenotypic correlations between the parameter A and weights at different ages were generally negative, but it reached to the level of 0.452 at 6 week of age. Genetic correlations were higher than phenotypic correlations and they increased by age of quail from 0.107 to 0.571 based on FS. Phenotypic and genetic correlations between the parameter B and weights at different ages were negative for the first thrice weeks of age and positive after that age. The highest genetic correlation be tween the parameter B and weights at different ages was at hatching. Phenotypic and genetic correlations between the parameter K and weights at different ages were generally positive except for hatching weight. Breeding aspects of growth curve parameters are discussed.