In livestock, mortality in general, and mortality of the young, is societal worries and is economically relevant for farm efficiency. Genetic change is cumulative; if it exists for survival of the young and genetic merit can be estimated with sufficient accuracy, it can help alleviate the pressure of mortality. Lack of survival is a moving target; livestock production is in continuous change and labor shortage is a given. There is now ample evidence of clear genetic variance and of models able to provide genomic predictions with enough accuracy for selection response. Underlying traits such as birth weight, uniformity in birth weight, gestation length, number of teats, and farrowing duration all show genetic variation and support selection for survival or, alternatively, be selected for on their own merit.
Keywords: farrowing; piglet survival; pre-weaning mortality; selection; teats.
Piglet survival is under genetic control and there are clear differences between individuals in their ability to live. Animals that do not survive their first weeks will obviously not reproduce as this is natural selection. Animals that survive still harbor relevant genetic differences. The genomic toolset, the use of genetic markers, makes it possible to link each animal to all others in the population, alive or dead, creating good opportunities for selection. Piglet survival depends on the genetic make-up of 1) the piglet itself, is it vital and heavy enough, 2) of the mother, are the piglets born at term, with low variation in birth weight, and 3) of the sow nursing the piglets, often the mother, does she allow the piglets to drink enough colostrum and milk of enough quality? This review explores the black box approach, complex statistical analysis of very large scale genomic recording of survival data, and it explores the biological approach, the influences of gestation length, birth weight, uniformity, number of teats, colostrum, etc., on birth weight. There is little doubt that genetic selection can increase survival of piglets. The challenge is to do this selection in balance with other production traits, such as litter size and body composition.
© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science.