Evaluating Housing Stress in Gestating Gilts Using Immunological Measures

Although gestation stalls have provided a reduction in building and labor costs to producers, they remain a controversial system of swine production in terms of animal welfare. Gestation stalls physically limit the sow to standing, sitting, and lying. Several studies have suggested that repetitive abnormal behaviors, termed stereotypic and considered an indicator of poor welfare, can be induced in animals by restrictive housing (Randrup et al., 1988). Due to the natural hierarchal social structure of swine, aggression often occurs in group settings. In addition, group housing can result in competition for resources. Although housing sows individually minimizes social conflict and competition, stalled sows may experience unresolved conflicts with adjacently housed animals. This may lead to frustrated states in sows. For these reasons, welfare evaluation in different housing systems remains necessary for the gestating sow.