Genetic evaluation of the performance of Japanese quails

A study was undertaken on the body weights of 2926 Black and Brown Japanese quails (Coturnix coturnix japonica) selected for high 6-weeks body weight in two generations. The overall least squares mean body weights at hatch, 1, 2, 3, 4, 5 and 6 weeks age were 8.19±0.01, 28.60±0.09, 62.17±0.18, 102.49±0.27, 133.34±0.32, 163.84±0.37 and 190.67±0.39 g, respectively. The effects of strains, generations and hatches were significant (P<0.01) at all the ages, while the influence of sex was significant on body weights from 1 to 6 weeks age. The chicks of Black strain were superior to Brown strain by 1.50 to 4.59 g. The chicks in second generation were better to those of first generation by 4.60 to 30.94 g and females weighed higher than males by 1.00 to 14.26 g. The estimates of heritability for body weights ranged from 0.04±0.10 to 0.99±0.24 in Black strain and from 0.10±0.22 to 0.59±0.20 in Brown strain. The genetic correlations between body weights at various ages ranged from −0.32±0.60 to 0.99±0.01 in Black and from 0.71±0.12 to 0.99±0.01 in Brown strains. The selection differentials in males were higher than in females and the expected genetic gain ranged from 4.52 to 10.34 g in males and from 8.12 to 20.86 g in females. A substantial genetic gain in body weights was obtained in the two generations of selection for high 6-week body weight.