Reciprocal Recurrent Selection in Swine: Postweaning Growth1

Publisher Website
Google Scholar
Abstract
Selection involving six cycles of reciprocal recurrent selection (RRS) was conducted over a period of 12 years, followed by a 4-year evaluation period. Selection in two unrelated selected strains (BS and LS) was based on an index of sow productivity for preweaning traits in the pure strains and on postweaning gain, carcass backfat thickness and yield of preferred cuts in their reciprocal cross-progeny (BSLS and LSBS). In addition, concurrent selection in two control strains (BC and LC) derived from the same base populations was based mainly on the dam's preweaning litter productivity. This study compared responses in postweaning growth traits in the BS and LS strains and in their cross-progeny with postweaning growth in the BC and LC strains. Standardized selection differentials among parents for growth traits were generally larger when based on performance of their crossprogeny rather than on their own performance and, as expected, were far short of potential maximum based on single-trait truncation selection. Responses to selection during the selection period were estimated by the regression on generations of deviations of performance of BS and LS strains and their cross-progeny from means for contemporary BC and LC strains. Results for postweaning gain showed a significant positive response to RRS among cross-progeny, but a significant negative response in the parental BS and LS strains. In the evaluation phase, comparisons of heterosis effects in the selected and control strains largely supported conclusions from the selection phase. A more definitive evaluation of the effectiveness of the selection practiced must await further planned studies. Copyright © 1982. American Society of Animal Science . Copyright 1982 by American Society of Animal Science

This publication has 0 references indexed in Scilit: