Assessment of the injuries sustained by pregnant sows housed in groups using electronic feeders.

The incidence of injuries to pregnant sows kept in dynamic groups in a commercial herd was recorded over a period of 18 months. The sows were maintained in a solid-floored building with a straw-bedded lying area allowing 1.7 m2 per sow and fed by means of electronic feeders. Injuries on 12 possible areas of the body were assessed every week, and graded on the scale of 0 to 3 (maximum body score 36). The lesion scores sustained by the sows were very low, with a maximum of 19 and a median of 4. Lesions of the greatest severity constituted only 0.16 per cent of all the recorded injuries. The injuries were not distributed uniformly over the body, most being on the shoulders, flanks and hindquarters, with very few on the head or in the vulval region. The total injury score was related to parity, with sows in parities one, two and three sustaining more injuries than sows in later parities, and it was also related negatively to bodyweight. More agonistic interactions were observed between sows in the lying area and in the vicinity of the feeders than in the dunging area.