Responsed to Genetic Improvement and Heritability of Egg Production and Egg Quality Traits in Japanese Quail (Coturnix coturnix japonica)

Abstract

A study was conducted to determine the egg production, egg quality traits, response to genetic improvement of the egg traits and heritability of the traits in the Japanese quail. The birds used were about 470 chicks purchased at day 14 to serve as foundation stock. They were sexed at day 21 and the females were caged in 28 cages each contain 15 quails constructed in dimension of 60cm x 45cm x 45cm (length x breath x weight). Three birds from each caged were randomly picked at day 35, 42, 49 and 56 in each generation base (Gs), first (G1) and second (G2) and the data obtained were subjected to analyses of variance and realized heritability were obtained as appropriate from the following traits: live body changes in female sexual maturity, body weight gain, egg production, egg quality traits, reproductive traits, realized h2 for the egg traits and egg production in the Japanese quail.The result shows that selection base on high body weight led to the traits to differed significantly (P<0.05) and (P<0.01) by generations, age and sex of quails and significantly affects egg production for base, first and second generations. There were more egg production in first generation than base and second generations. The advances in age for a set of generation led to increase in weekly egg production, selection for body weight for the first generation base on average weekly egg production which was lower than the base and second generation and also as the bird’s advances in age there was improvement in egg traits at day 35, 42, 49 and 56. The percentage death in shell, percentage death in egg and percentage infertility responded positively to selection base on high body weight. The realized h2 of egg number and age at sexual maturity in female quail was very low 0.05 in egg number and 0.23 in age at sexual maturity. There was also low realized h2 values observed in egg width, yolk width, albumen length, shell weight and shell thickness and egg production (0.01 - 0.07). Apart from the age at sexual maturity which h2 is moderate and implies that response to selection for high body weight may be rapid while the low realized heritability obtained for egg number and egg quality traits implies that response to selection for the traits could be slow