Assessment of Piglet Vitality by Farmers—Validation of A Scoring Scheme and Estimation of Associated Genetic Parameters

SIMPLE SUMMARY: The aim of animal breeding is to improve desirable traits in animals over generations by selecting those animals with the best performance for producing offspring. Sows have been bred for bearing and raising large litters. However, piglets in large litters are often underweight at birth and have a higher risk of dying before weaning. Therefore, breeding for large litters presents an animal welfare issue and focus should be put on new traits, such as piglet vitality. To select the best performing sows, breeders need a scheme to assess piglet vitality on a routine basis. In this study, 23 farmers used a four-point scoring scheme for piglet vitality (1 = low vitality to 4 = high vitality) to assess 3171 litters. To validate the new scoring scheme, i.e., to see if it assesses what it is supposed to assess, the vitality scores were compared to the piglet mortality rate of the respective litters. The results show that litters assessed with low vitality scores had the highest mortality rate and vice versa. Furthermore, genetic analysis showed that the trait is hereditary. Therefore, including piglet vitality into breeding programs may contribute to animal welfare improvement. ABSTRACT: Maternal breeds for sows have been bred for high prolificacy during recent decades. Although large litters may be beneficial for economic efficiency, pre-weaning mortality is increased. Thus, focus should instead be put on new traits such as piglet vitality (PV). Until now, no validated scoring scheme for piglet vitality exists, which is feasible to be applied for routine on-farm trait recording. The objective of this study was to validate a four-point vitality scoring scheme (1 = low vitality to 4 = high vitality) applied by farmers based on pre-weaning mortality and to estimate genetic parameters. A linear mixed model was fitted for piglet vitality for 3172 litters from Large White and Landrace sows on 23 farms and correlations were calculated for vitality score and piglet mortality. A subsample of 2900 records was used for genetic analysis. Pre-weaning mortality differed significantly between all vitality score categories except for 1 and 2, ranging between 7.98% (category 4) and 29.1% (category 1). PV was genetically negatively correlated to litter size (−0.68) and mortality rate (−0.65), whereas litter size was positively correlated with mortality rate (0.59). Including PV into breeding programs may, thus, improve animal welfare.