Selection indices for improving commercial strain of White Leghorn

Data recorded on 559 pullets progeny of 149 darns mated with 58 sires from single hatch of a commerical strain of White Leghorn, maintained by a poultry breeding organization were used in this investigation. The body weight at 12 and 36 weeks of age, age at sexual maturity, egg production upto 280 days of age and egg weight at 32 weeks of age, averaged as 820.06±3.75 g, 1616.97±6.78 g, 147.13±0.37 days, 108.56±0.52 eggs and 52.43±0.12 g, respectively. The heritablity estimates computed from sire component of variance of the above traits were 0.52±0.15, 0.59±0.16, 0.43±0.14. 0.38±0.13 and O.53±0.15 respectively. Sixteen multitrait selection indices constructed using the above five traits in different combinations were evaluated. On the basis of rIH (0.41) and ΔH (44.98 units) values, the index I1, comprising of all the five traits was found to be most efficient. The reduction in ΔH values due to noninclusion of different traits in the index revealed that 36 week body weight, 12 week body weight, egg production, egg weight and age at sexual maturity were relatively less important in the given order. Further it was observed that selection based on the Index comprising of body weightat 12 and 36 weeks of age and egg weight was almost as efficient as index I1.