Consequences of selection for lean growth and prolificacy on piglet survival and sow attribute traits

Understanding consequences of selection

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 piglet survival and husbandry requirements of sows. For example, comparison of body composition and physiological state of piglets from boars born in 1977 versus 1998 showed that selection had resulted in lower maturity of piglets at birth Canario et al., 2007). Further, Ball et al. (2008) reviewed nutrient requirements of sows concluding that recommendations have not kept pace with the 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 and piglet 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 size, piglet birth weight, litter survival and litter weight gain as well as sow feed intake and weight and backfat of lactating sows.