A comparison between lesions found during meat inspection of finishing pigs raised under organic/free-range conditions and conventional, indoor conditions

It is often argued that pigs raised under less intensive production conditions – such as organic or free-range – have a higher level of animal welfare compared with conventionally raised pigs. To look into this, an analysis of data from a large Danish abattoir slaughtering organic, free-range, and conventionally raised finishing pigs was undertaken. First, the requirements for each of the three types of production systems were investigated. Next, meat inspection data from a period of 1 year were collected. These covered 201,160 organic/free-range pigs and 1,173,213 conventionally raised pigs. The prevalence of each individual type of lesion was calculated, followed by a statistical comparison between the prevalences in organic/free-range and conventional pigs. Because of the large number of data, the P-value for significance was lowered to P = 0.001, and only biological associations reflecting Odds Ratios above 1.2 or below 0.8 were considered to be of significance. The majority of the lesion types were recorded infrequently (<4%). Only chronic pleuritis was a common finding. A total of 13 lesion types were more frequent among organic/free-range pigs than among conventional pigs - among others old fractures, tail lesions and osteomyelitis. Four lesion types were equally frequent in the two groups: chronic pneumonia, chronic pleuritis, fresh fracture, and abscess in head/ear. Four lesion types were recorded less frequently among organic/free-range pigs compared with conventionally raised pigs. These included abscess in leg/toe, hernia and scar/hock lesion. Possible associations between the individual lesion types and the production systems - including the requirements for each system - are discussed. The results emphasize the importance of using direct animal based parameters when evaluating animal welfare in different types of production systems. Moreover, individual solutions to the health problems observed in a herd should be found, e.g. in collaboration with the veterinary practitioner and other advisors.