Use of general and restricted selection indices for the improvement of Rhode Island Red

The data for the present investigation were obtained from the performance records of 740 pullets, progenies of 198 dams and 50 sires from 3 hatches of a RIR strain maintained by a commercial poultry breeding organization. Genetic and phenotypic variances and covariance of body weights at 20 and 40-weeks of age (20-WKBW and 40-WKBW), Age at sexual maturity (ASM), egg production up to 40-Weeks (EP) and 35-Week egg weight (EW) were computed from sire component of variance and covariance for use of constructing 26 general and 7 restricted selection indices in various combinations. On the basis of expected response in aggregate genetic worth (ΔH) and correlation between index and aggregate genetic worth (R_IH), index I₁ which included all the five traits was adjusted to be best index followed by index I₄ (20-WKBW, 40-WKBW, EP and EW). The ΔH and R_IH values of index I₁ and I₄ were 47.80, 46.922 units and 0.400, 0.398 respectively. The expected genetic change in individual traits due to index I₁ would 20.482 g, -26.471 g, -0.208 days, 0.399 egg and -0.844 g, per generation. The restricted selection indices were found to have lower efficiencies compared to general selection indices.