Effects of periodic group housing opportunities on reproductive performance and welfare in sows

ObjectiveStall housing of pregnant sows raises welfare concerns, whereas conventional group housing systems often reduce space efficiency. This study evaluated the effects of periodic group housing (PG) on reproductive performance and welfare compared with continuous stall housing (CS). MethodsSows in the CS group (n = 15) were continuously housed in stalls. In the PG group (n = 15), sows were housed in groups of three and allocated 1 day of group housing and 6 days of stall housing per week over 10 weeks. During group housing sessions, the sows had access to a group housing area containing sawdust. Behavioral observations and salivary cortisol measurements were conducted on the first day of the stall housing session in weeks 1, 6, and 10. Behavioral indices were expressed as proportions based on 90 sampling points recorded at 1-min intervals. ResultsThe number of stillbirths was significantly lower in the PG group than in the CS group (0.63 vs. 1.49 piglets per litter). whereas other reproductive outcomes, including total litter size and average birth weight, did not differ. In older parity sows, the PG treatment markedly increased the proportion of time spent lying, suggesting reduced discomfort associated with restricted movement. Furthermore, the proportion of exploratory behavior decreased markedly, and drinking behavior showed a decreasing trend across parity levels in the PG group, suggesting partial satisfaction of motivations for environmental exploration and oral manipulation. The proportion of oral abnormal behavior showed a pronounced interaction between housing treatment and experimental week, increasing from week 1 to week 6 in the PG group. Salivary cortisol concentrations did not differ between the groups. ConclusionPG may improve reproductive performance and partially satisfy the behavioral motivations restricted under continuous stall housing. This system may represent a practical alternative for improving animal welfare while minimizing economic losses.