Osteochondrosis of the elbow joint in finishing pigs from three herds: associations among different types of joint changes and between osteochondrosis and growth rate.

Osteochondrosis (OC) is a degenerative condition of the cartilage seen in growing animals. The objective of the study was to investigate (1) the prevalence of macroscopically visible OC in the elbow of finishing pigs, (2) the relationship between changes in the surface of the articular cartilage and changes in the underlying cartilage and bone and the synovial membrane, and (3) the association between growth rate and the occurrence of OC in the elbow. The study used 9696 finishing pigs from three herds. After slaughter, the left elbow joint of each pig was examined, and macroscopically visible lesions in the articular cartilage, subchondral bone and synovial membrane were recorded. The highest prevalences of OC lesions were found in the humeral condyle with thickening of the articular cartilage (53%), irregularity of the articular cartilage (32%), lesions in the subchondral bone (26%), fissures under the cartilage (21%) and osteochondrosis dissecans (OCD) (14%). Irregularity of the articular cartilage was strongly associated with fissures under the cartilage and lesions in the subchondral bone (OR 13.7 and 5.8, respectively). Irregularity of the articular cartilage and OCD were associated with villous proliferation of the synovial membrane. For each additional 100 g of average daily gain in the weaner period or in the finishing period, the risk of irregularity in the articular cartilage and OCD increased by approximately 20% (ORs ranging between 1.14 and 1.20 for both weaners and finishers).