Breeding Values, Accuracies, and Rank Changes Using Purebred and Combined Purebred and Crossbred Information in Swine

Abstract

A data set including 2,002 purebred litter records and 14,583 crossbred litter records from a swine production unit with a defined great-grandparent (GGP), grandparent, and parent stock genetic system structure was used to examine the gains in accuracy of breeding value estimation of the purebred GGP animals through inclusion of crossbred information with purebred information. Other objectives were to determine if a change in ranking of the purebred GGP animals occurred and to determine if this new information would cause a change in the selection decisions of the producer. The traits used in this evaluation were number of pigs born alive, adjusted litter weaning BW, and the interval from weaning to first service. Animals were ranked based on 2 indices, one calculated using only purebred information and the other calculated using combined purebred and crossbred information. Gains in mean accuracy ranged from 7.3 to 8.7% for the GGP sows. Spearman rank correlations were less than 0.85 for the GGP sows and less than 0.90 for the GGP sires. It was concluded that improvement was made in accuracy of breeding value estimation with the inclusion of crossbred information. There was a highly significant (P < 0.01) re-ranking of both the sows and sires in the GGP. Rankings based on the 2 indices also suggest that selection decisions may change based on the inclusion of the crossbred information.