Nest-building behaviour in sows and consequences for pig husbandry

Patterns of maternal behaviour are strongly related to reproductive abilities in sows. Prepartal behaviour of sows is mainly characterised by nest-building activities, resulting in a nest that provides shelter for the piglets. In the course of domestication, sows have not lost their instinctive behaviour to nest-build, but perform at least elements of it when appropriate space and materials are available. The onset and performance of nest-building is both stimulated internally via hormones and externally via feedback from the environment. With this environmental influence, the possibilities to perform nest-building can be restricted to different extents in commercially farmed pigs. The aim of the present review is to point out the sow's need for nest-building performance as part of the natural behaviour pattern, although they are kept in different modern housing systems. With regard to increased demands for animal welfare and following changes in the legislation for pig husbandry, possible consequences for different housing systems are discussed. (C) 2009 Elsevier B.V. All rights reserved.