Genetic parameters of growth, body, and egg traits in Japanese quails (Cotournix cotournix japonica) reared in southern guinea savannah of Nigeria
Objective: This study on Japanese quails was undertaken to estimate heritability values for growth, body and egg traits as well as genetic and phenotypic relationships between these traits in Japanese quails reared in the Southern Guinea Savannah Zone of Nigeria.
Methodology and Results: One hundred and sixty nine (169) pedigree-hatched day-old Japanese quail chicks from 10 sires were used for this study. The data obtained were subjected to variance and correlation analyses as appropriate. Results showed that heritability estimates of body weight at various ages ranged from 0.10±0.02 to 0.82±0.14 while those of body weight gain were mostly moderate (0.19±0.05 - 0.42±0.02). Linear body parameters had moderate to high (0.23±0.13 - 0.49±0.16) heritability estimates except body length which was 0.08±0.15 heritable. Age at first egg (AFE), Body weight at first egg (BWFE) and weight of first egg (WFE) had heritability estimates of 0.48±0.17, 0.56±0.21 and 0.38±0.18, respectively. Phenotypic correlations between body weights at various ages and egg traits were mostly positive and significant (p<0.01) while that of linear body traits were all positive and mostly significant (p<0.01). Genetic relationships between body weights at various ages were all high and positive. AFE correlated negatively with BWFE while WFE had positive correlation with AFE and BWF.
Conclusion and application of findings: The moderate to high heritability estimates obtained for body weight at ages 1-3 weeks indicates that response to selection for body weight at these ages could be rapid while the low heritability estimates of body weight at week 5 and 6 imply that response to selection for body weight at the 5th and 6th week could be slow. It is recommended that selection for body weight or growth rate in Japanese quails should be carried out at early stages of growth, preferably 2-3 weeks of age.
Keywords: Heritability, Genetic correlation, phenotypic correlation, selection, Body measurements