Lesions found at routine meat inspection on finishing pigs are associated with production system

Both conventional free-range and organic free-range production systems were associated with increased population averaged odd ratios (ORPA) for several lesions compared with conventional indoor systems. Pigs raised in conventional free-range and organic free-range production systems had higher odds for white liver-spots (ORPA, 5-7), tail lesions (ORPA, 3-4), arthritis (ORPA, 3), skin lesions (ORPA, 3), bone fractures (ORPA, 2), septicaemia (ORPA, 1.1-1.5) and abscesses (ORPA, 1.1-1.3) at slaughter. Pairwise comparisons of the two free-range production systems did not reveal statistically significant differences (P > 0.05). In all three production systems, airway infection was the most prevalent disease complex. In contrast to previous studies, this study did not find any association between airway infection and type of production (P > 0.05). Three lesions (leg swellings (ORPA, 0.4-0.5), hernia (ORPA, 0.7-0.8) and hoof abscess (ORPA, 0.7-0.9)) had lower ORs in conventional free-range and organic free-range production compared with conventional indoor production. There was a marked herd effect (intraclass correlation coefficients 21-35%) on the occurrence of white liver-spots, tail lesions, skin lesions and airway infections. These results suggest possibilities for herd-level management interventions of the problems studied.