Evaluation of pure and crossbred parent stock pullets: 1. Egg weight, body weight and sexual maturity

Abstract

The relationships between egg weight, body weight and sexual maturity and their inheritance were  studied in the Fl of two grandparent strains or laying birds. Each strain had two lines. Data used for analyses comprised bodyweight at firstegg,30weeks and 40 weeks of age (BFE, 830 and B40); weight of first egg (WFE), weight of egg at 30 weeks and 40 weeks (W30, W40) and age or birds at first egg (AFE). Phenotypic correlations between AFE and BFE, AFE and WFE and between WFE and BFE were 0.45 and 0.40; 0.96 and 0.11, 0.65 and 0.85 for male and female lines respectively. While AFE generally showed additive inheritance which was sire  influenced, BFE and WFE were line dependent. The crossbred groups however, appeared to be at advantage over the purebreds in respect of these three traits.

Key words: Parent stock, pullets, egg weight, body weight, sexuaJ maturity.