Pathological and Radiological Investigations on Osteochondrosis in Pigs, Associated with Leg Weakness

Abstract

Summary Two‐hundred and seventy‐eight Danish Landrace boars were examined radiologically and pathologically for osteochondrosis and other joint lesions on the left legs at slaughter (95 kg). The joint changes were scored on a scale from 1 (normal) to 5 (very severe changes/osteochondritis dissecans). The correlations between radiological and pathological scores were highly significant in the humeral condyles (r = 0.66, P < 0.001), the distal ulna growth plate (r = 0.51, P < 0.001), the femoral condyles (r = 0.33, P < 0.001) and hock (distal tibia (r = 0.17, P < 0.01) and the medial trochlear ridge of the talus (r = 0.17, P < 0.01), indicating that radiographical examination is a useful method for diagnosing osteochondrosis in live pigs. Thickening of cartilage was strongly associated with subchondral lesions in the three predilection sites: the humeral condyle, the femoral condyles and the distal ulna growth plate. Osteochondritis dissecans (OCD) in the humeral condyles was significantly associated with subchondral lesions (&#x004f;&#x030a; = 1.86; P < 0.001), but not with cartilage thickness when analysed simultaneously. There were no associations between lesions in the distal ulna growth plate, the humeral condyles, the femoral condyles or the anconeal process. There was no significant correlation between OCD in the humeral condyles and the anconeal process. Osteochondrosis could therefore not be stated to be a generalized disorder. Regression coefficients between joint changes and leg weakness symptoms judged before slaughter were very small and showed no clear trends. OCD in the humeral condyles was, however, significantly associated with 'legs turned out on fore (&#x004f;&#x030a; = 2.48; P < 0.001) and hind (&#x004f;&#x030a; = 1.62; P < 0.05) legs', and OCD in the anconeal process with 'stiff movement in front' (&#x004f;&#x030a; = 2.01; P < 0.05). Osteochondrosis is thus comparable with a threshold trait, where the threshold is the development of an OCD in an osteochondrosis injured joint.

Heritabilities of osteochondral lesions and genetic correlations with production and exterior traits in station-tested pigs

“…In general, our results agree with results by Jørgensen (2000) and Jørgensen et al (1995). Those authors also found slight phenotypic associations between several leg weakness symptoms and pathological changes of bones and joints.…”

“…Those authors used a sub-data set of this study that included only test animals slaughtered in 2002 and 2003. Jørgensen et al (1995) observed a higher prevalence and variation of subchondral lesions at the medial humeral and femoral condyles in Danish Landrace boars. The prevalence at the lateral humeral condyles was similar to the present study and osteochondral lesions at the distal ulna growth plate showed the most phenotypic variation also.…”

Quantitative trait loci analysis of osteochondrosis traits in the elbow joint of pigs

“…Thus, it would be expected that depression of the edge of the radius and irregular sagittal groove were less closely associated with the other four lesions than these were with each other. With the exception of the studies by Jørgensen and co-authors (Jørgensen, 1995;Jørgensen et al, 1995;Jørgensen and Nielsen, 2005), other studies of osteochondrosis in the elbow generally do not describe the degree of the depression of the proximal edge of the radius or the degree of irregularity of the sagittal central groove. Consequently, the significance of these lesions in the osteochondrosis complex has been less well established.…”

“…The welfare consequences of osteochondrosis in pigs are not well understood. Only weak associations between the presence of osteochondrosis and clinical signs have been established (Grøndalen, 1974;Goedegebuure et al, 1988;Jørgensen et al, 1995). Severe cases of osteochondrosis in the elbow have been found to be associated with stiff gait and forelegs turned outwards Jørgensen, 2000).…”

“…Recordings of joint lesions After slaughter, each left elbow joint was examined for osteochondrosis by one of three scorers (veterinarians), according to Jørgensen et al (1995). As osteochondrosis lesions are usually bilaterally symmetrical (Reiland, 1978;Hill et al, 1984), it was decided to examine the left elbow joint only.…”