Evaluation of production performance of some economic traits in a synthetic White Leghorn population

Change in mean performance of a synthetic population of a White Leghorn under constant selection over generation was evaluated. The traits studied were body weight at 20, 40, 56 and 72 weeks, age at first egg, egg number up to 40, 56 and 72 weeks and egg weight at 32, 40, 56 and 72 weeks. Over the generations the mean body weight at 20 weeks of age showed an increasing trend, (it is highest in seventh and ninth generation and lowest in sixth generation). The mean value of ninth generation was significantly higher than that of fifth generation, which indicates improvement of mature body weight over generations. Except fifth generation, all other generations showed similar body weight at 40 weeks of age. The comparison of means among five generations indicated significant increasing trend over generations. The age at first egg in the flock remained more or less stable over generations barring seventh generation. The mean value of annual egg production indicated improvement in performance over generations. There was a marked improvement in egg weight at 72 weeks over generations.