Influence of tooth resection in piglets on welfare and performance.

In six commercial pig farms, we compared the effects of two methods of tooth resection (tooth clipping with pliers and tooth grinding with a rotating grindstone) on teeth themselves, on skin lesions of piglets and of sow udders as well as on litter growth and survival. An intact group was included for control. Treatments were balanced within herds with sows assigned to one of the three experimental treatments. Observations were from 107 sows and their litters (n = 35 or 36 litters/group) at farrowing (day 0) and approximately 8, 15 and 27 days later. Tooth resection was done within 24 h of birth after cross-fostering. Data concerning sows' lesions were analyzed on a farm basis and those concerning piglets' mortality, growth and skin lesions were analyzed on a litter basis. Frequency and severity of udder lesions differed between treatments at farrowing and on day 8; differences depended on the location of the teats (front, median or rear). Litter size and liveweight of piglets on day 0 (11.9+/-0.1 pigs, 1.51+/-0.03 kg) and on day 27 (10.8+/-0.1 pigs, 8.08+/-0.10 kg) were similar in the three groups (mean+/-S.E.M., n = 107). Skin lesions on piglets were more frequent and/or severe in intact than in clipped piglets on days 8 and 27, whereas ground piglets had intermediate results. Because the length of the teeth was similar after clipping and grinding (P > 0.1), tooth shortening itself does not explain the differences between treatments. Overall, tooth resection had very little effect on sow mammary injuries and litter performance. It might reduce skin damage to piglets (especially, when it is performed by clipping) but teeth are severely injured.