Consequences of Selection for Lean Growth and Prolificacy on Sow Attributes

Pig breeding programs focus on growth and carcase composition traits in the growing pig as well as higher reproductive performance of sows leading to considerable genetic gain in these traits. These changes in genetic potential have consequences for the husbandry requirements of sows, including dietary and housing needs as reviewed by Ball et at. (2008). They concluded that recommendations for nutrient requirements of sows have not kept pace with increases in animal performance. Lactating sow performance is a balance between meeting the demands of the litter and nutrients available from sow feed intake and the mobilization of body reserves. Understanding the consequences of selection on these components of sow performance is a first step towards optimizing both breeding programs that consider a wider range of traits, and management practices that continue to meet the changing needs of sow genotypes. It was the aim of this study to evaluate the effect of differences in estimated breeding values (EBVs) for traits that have been used as selection criteria on litter weight gain as well as sow feed intake, weight and backfat of lactating sows.