Influenced by changes in societal opinions and in technology developments
...
. Especially in the developed countries, societal concerns call for an improvement of health and welfare of sows and finishers. Therefore, pig breeding companies (e.g. Topigs Norsvin) extend the selection and breeding goal traits with longevity traits of sows and robustness traits of piglets. Longevity of sows is negatively influenced by the incidence of leg injuries and lameness and the incidence of uterine prolapses. These are heritable traits, e.g. the heritability for the incidence of uterine prolapses is 0.20-0.30. Robustness traits of finishers will be improved by selection for survival of piglets and finishers. Variation in daily feed intake is used as an indicator of robustness and expresses the resilience of an animal (less variation in daily feed intake = more robust and more resilience). Natural selection against the Porcine Reproductive and Respiratory Syndrome (PPRS) is under development and gene-editing is in this respect in discussion. The technique is promising in this respect, but the societal opinion is at least in the European Union negative.
...