Salivary Cortisol Responses and Behavioural Reactivity of Lactating Sows During the Transition from Temporary Confinement to Free Movement in a Loose-Farrowing System

The placement of lactating sows in farrowing crates restricts movement and may limit the expression of species-specific behaviour. This study investigated physiological and behavioural responses of sows in loose-housed farrowing systems with temporary confinement. Seventy-one Landrace sows were temporarily confined in farrowing crates from entry into the farrowing unit until day 4 postpartum (p.p.), after which the crates were opened to allow greater freedom of movement. Saliva samples were collected twice daily on days 3, 5, 9, and 10 p.p. The Towel Test (TT) was performed on days 4 and 10 p.p. to assess behavioural responses to a novel stimulus. Cortisol concentrations differed significantly between sampling days, with higher concentrations on day 5 p.p. compared with days 3, 9, and 10 p.p. As this increase occurred after crate opening and declined thereafter, it suggests a transient physiological response to the change in housing conditions. Primiparous sows showed higher cortisol concentrations than multiparous sows. Behavioural responses in the TT were not significantly associated with cortisol concentrations, although higher TT scores were accompanied by numerically higher cortisol concentrations. These findings indicate that salivary cortisol is sensitive to short-term management-related changes, whereas behavioural responses provide additional information on individual variation. Combining physiological and behavioural indicators may improve welfare assessment in loose-farrowing systems.