Disentangling the behavioural and fibre influences of nesting enrichment for sows on piglet survival

Abstract

The pork industry is willing to adopt practices that improve the welfare of pigs, but these practices should be evaluated appropriately to ensure success for all stakeholders. Nest-building is a highly conserved, innate behaviour that, despite many years of domestication, still exists in commercial sows. The behaviour is inhibited because of confinement within a crate and the absence of appropriate materials. Allowing the sow to perform some aspects of nesting will enhance welfare, as well as offspring survival through improved farrowing ease, reduced risky posture changes, and increased maternal bonding and colostrum/milk access. The aim of this review was to summarise outcomes from nesting investigations that utlise different substrates on piglet survival. The most commonly studied nesting enrichment material is straw, and it can be argued that straw has the most consistent and positive influence on piglet survival. However, in addition to using it to build a nest, sows will consume large volumes of straw, which increases dietary fibre intake. Fibre improves gastrointestinal health, energy release and satiety, all of which have been shown to offer similar benefits to piglet survival as allowing the sow to nest. So, to argue that straw is the most appropriate nesting substrate when using piglet survival as a benchmark is flawed. There may be an opportunity to exploit nesting materials other than straw that are easier for the industry to adopt in combination with high fibre peri-parturient diets, and such strategies should be considered.