Selection for egg production on part records : Part 2. Correlated response to selection.

Response in the selected and the correlated traits from five generations of index selection (I.D.S. method) for egg production to 40 weeks of age in four White Leghorn populations have been presented. The correlated traits measured included: Age at first egg, egg weight, body weight and also derived traits such as egg mass, survivors' rate of lay, efficiency index and ratio of egg weight to body weight. Response realized for the selected trait was significant in three out of the four selected lines. Predicted and realized genetic gains were comparable in magnitude for most of the traits studied. The significance of these findings in selection experiments is discussed.