Use of Individual Feed Records in a Selection Program for Egg Production Efficiency III. Relative Effectiveness of Two-Stage Selection

Abstract Two kinds of selection programs were compared. The first uses information on body weight (BW), egg mass output (EM), and individual bird feed consumption records (FC) to form a conventional single-stage selection index computed on all breeder candidates, T, in the flock from which S birds are selected as breeders. The second uses information only on BW and EM in Stage 1 from which t birds are chosen for testing in Stage 2 in which FC records are obtained. From these, the best S birds are chosen as breeders. The second program would be less costly because fewer birds, (T–t), are measured for individual FC records. Our results showed that when the net selection intensities in the two programs are equal with t/T = .5, the genetic gain in income over feed cost in the second would be about 3% less than in the first. Thus, there is a trade-off between the cost of testing and the expected genetic gains. The study was based on parameters estimated from two Leghorn populations for which individual feed records were taken.