Correlated response to selection for some egg performance traits in egg line of Japanese quail

Estimation of correlated response to selection in female line of Japanese quail after a short-term selection experiment was conducted. The total number of 547 female (275 selected and 272 control) Japanese quail included in the selection experiment of selection depended on aggregate breeding values based on animal model Best Linear Unbiased Prediction. Correlated selection response estimates were favourable for all the studied traits and significant (–0.38, –9.89, –12.86, –16.64, –5.08 and –8.24) for first egg weight (FEW), age at the first 10 eggs (AGE10), age at first 30 eggs (AGE30), age at first 60 eggs (AGE60), days needed to produce the first 30 eggs (DN30) and the first 60 eggs (DN60), respectively. Estimates of heritability were moderate for egg mass for the first 10 eggs (EM10), the first 30 eggs (EM30), the first 60 eggs (EM60), AGE10 and AGE30 (0.17–0.30), but low for AGE60, DN30 and DN60 (0.01–0.10). Genetic correlations between the selection criteria traits (AFE, BWSM and DN10) and the studied egg production traits were positive and ranged from 0.25 to 0.97, 0.24 to 0.95 and 0.06 to 0.98 for AFE, BWSM and DN10, respectively, whereas phenotypic correlations ranged from 0.12 to 0.89, 0.01 to 0.34 and 0.06 to 0.87 for the same traits. The favourable genetic response obtained for egg traits could be an indicator for improving egg production performance in Japanese quail.