Cortisol, behavioral responses, and injury scores of sows housed in gestation stalls

Objective: To assess welfare status of 25 pregnant sows housed in gestation stalls, in terms of cortisol concentrations, behavior responses, and injury scores. Materials and methods: Data were collected on gestation days 5, 56, and 108. Time-lapse video recording for 24-hour periods was used to observe behavior at each data point. Salivary cortisol concentrations were assessed using radioimmunoassay. Injuries were scored individually and added to provide a total injury score (TIS). Results: Cortisol concentrations were lower on gestation day 56 than on other days, and TIS was higher on day 108 than on days 5 and 56 (P < .05). Time spent lying was highest on day 108 (P < .05). Sows spent more time on exploration and active behavior on day 56 than on days 5 and 108 (P < .05). Time for the transition from sitting to lying was higher on day 108 than on day 56 (P < .05). Frequencies of overall postural change and of standing or sitting to lying and lying to sitting were highest on day 5 (P < .05). Frequency of lying to standing was higher on day 5 than on day 108 (P < .05). Body weight was negatively correlated with time spent on exploration and active behavior and standing, and positively correlated with time spent lying (P <.05). Implications: Welfare of sows in gestation stalls appears to be more compromised during early and late stages of gestation. Providing larger sows with larger stalls might improve welfare.