Does the presence of shoulder ulcers affect the behaviour of sows?

Shoulder ulcers are common in lactating sows. This case-control study compared behaviour of sows with shoulder ulcers (U-sows; N = 19) versus controls (C-sows; N = 19) and involved multiparous LxY sows, 14.7 ± 0.3 days post partum, kept in farrowing crates in a Danish herd. U-sows had at least one shoulder ulcer. Behavioural data were based on video recordings during a 24h period. U-sows spent less time lying (P = 0.04), tended to perform more postural changes (P = 0.096), spent more time standing still (P = 0.02), showed increased shoulder rubbing (P = 0.03) and reduced nursing frequency (P = 0.03) compared to the controls. These results show that the behaviour of sows with shoulder ulcers differ from healthy sows, suggesting that U-sows experienced discomfort or pain, and indicating that maternal behaviour can be sensitive to the presence of shoulder ulcers. Further studies - focussing on temporal development of shoulder ulcers combined with behaviour of sows and piglets - are needed to clarify animal welfare impact.