Selection for annual egg production in a pure line of domestic fowls based on part records of individual sibs and full records of their dams

1. An alternative to the selection on part record in egg laying chickens is suggested by incorporating the full record of selected dams into an index. 2. For various estimates of heritability of annual egg production (0–10 to 0.25) and part production (0–15 to 0–35) and genetic correlation (0.55 to 0–75) between them, the new index may be 6.9 to 29.3% and 19.5 to 48.8% more efficient for female and male respectively than selection on part record alone. 3. When 20% of the females are selected, because of correction for the effect of selection on dam’s information the accuracy of selection is lowered by about 0–2 to 1.4% and 0.5 to 2.0% for female and male respectively, compared with using uncorrected information.