Breeding for welfare in outdoor pig production: A simulation study

Despite the societal and market attention, to our knowledge, there is no breeding program for outdoor pig production in which improvement in animal welfare is emphasized. In this study, a dam-line selected for an outdoor production system was simulated. The purpose was to investigate the opportunities for improving welfare through traditional selection methods. The genetic gain from simulated breeding programs was compared for three alternative scenarios: 1) a conventional scheme that improves production and reproduction traits (litter size, piglet mortality (PM), mean piglet weight at weaning, weaning-to-mating interval (WMI), average daily gain (ADG) from birth to 20 kg, ADG from 20 to 100 kg, and lean content); 2) extension of the first scenario with welfare considerations including leg condition of sows after first lactation (LEGw) and additional non-market values on PM and WMI; and 3) a breeding program for welfare in which genetic progress of traits important for welfare (mothering ability and sow longevity) was obtained by increasing the non-market values of LEGw, PM and WMI. The simulation showed that, compared with weights found in the literature, greater weights on LEGw, PM and WMI (approximately 3, 2 and 7 times higher, respectively) were required to avoid deterioration of these traits. The improvement of traits important to welfare was realized with a reduction in the genetic gain of production traits. Thus, the implementation of a breeding program for welfare in outdoor production requires other prerequisites than the market value of the genetic progress only.