Tail biting in finishing pigs in Greek commercial farms: associations with welfare and behavioral indicators.

Tail biting remains a major challenge to pig welfare and the economic sustainability of pig farms, yet data from Southern European systems remain scarce. The aim of this study was to assess tail lesion prevalence, bursitis, skin lesion and behavioral risk factors for tail biting in finishing pigs, combining a slaughterhouse survey (5,765 pigs) with on-farm behavioral observation of 56 pigs. At slaughter, tail lesions were recorded in 29.4% of carcasses (27.9% mild, 1.5% severe). Intact and castrated males showed a higher severe-lesion prevalence than females, shorter tail stumps were associated with reduced severity, and lesions were more frequent in autumn, consistent with summer heat-stress exposure. Pigs with mild (28.7%) or severe (1.7%) tail lesions had a higher prevalence of hind-limb bursitis revealing a previously undescribed association (p = 0.007). To the best of the authors knowledge, for the first time it was documented that severe tail lesions nearly doubled (1.3%-2.2%) when posterior skin lesions were present (p < 0.001) suggesting that it could be used as a complementary welfare indicator at slaughterhouse. In the on-farm component, average daily gain (ADG) was a significant predictor of tail lesion severity: the odds of a higher tail lesion score rose by 73% for every 100 g/day increase in ADG (OR = 1.73, 95% CI [1.06, 2.82]). More active pigs were also more likely to direct biting behavior at penmates, and female showed more pen exploration and positive social interactions than castrated males, who spent proportionally more time in inactive states.