Genetic determination of components of piglet survival in a two-generation crossbreeding selection experiment

摘要: Piglet mortality is of substantial animal welfare concern and of great economic importance, in particular under the circumstances where continuous genetic improvement of litter size is expected to result in higher mortality (Baxter et al. 2009; Su et al., 2008). As a consequence, genetic improvement of piglet survival will be one of the main challenges to be faced by pig breeding. The main cause of postnatal mortality is crushing of piglets by the mother. Crushing is expected to be mainly a maternal genetic effect but it may also be affected by the genetic potential of the piglet for eg vitality, alertness. Furthermore, crushing may be influenced differently under indoor than under outdoor conditions. Roehe et al.(2009, 2010) found for other piglet mortality traits higher direct and maternal heritabilities under outdoor conditions than under indoor conditions. Genetic correlations between survival by avoiding crushing and other survival traits or birth weight will give further insight into the genetic improvement of this trait, with the overall aim to improve sow productivity. Therefore, the objectives of this study were to estimate the direct and maternal genetic determination of survival by avoiding crushing, its genetic correlations with other survival traits and birth weight as well as its genetic response, from data of a two-generation selection experiment under outdoor conditions.