Prevalence of metatarsal growth plate lesions in Swiss fattening bulls

Abstract

The prevalence of osteochondral changes in the metatarsal growth plates of fattening bulls was investigated. Plantarodorsal radiographic views of the metatarsal region of 204 hind legs from 102 slaughtered fattening bulls were taken. Radiographic lesions in metatarsal growth plates were confirmed in selected cases using computed tomography (n=14) and histology (n=6). Radiographic criteria for growth plate lesions were axis deviations between the metatarsal bones and the digit, radiolucencies in the growth plate, increased bone density in the metaphysis, irregularities of the growth plate and marginal osteophytes («lipping»). The individual lesions were categorised as present/absent or 1 = slight, 2 = distinct, and 3 = severe. A weighted sum of these radiographic changes was generated for each growth plate and for each animal, and used for statistical analysis of the associations between husbandry factors and the occurrence of lesions. Almost all of the metatarsal bones had signs of osteochondral changes on the radiographs of the growth plates. The most common lesions were lipping (99,5 %), increased bone density in the metaphysis (66,6 %) and radiolucencies in the growth plates (64,1 %). Computed tomography and histology revealed hyperplasia of the margins of the epiphysis and metaphysis, focal increase in bone deposits accompanied by incomplete ossification and irregular and widened cartilage columns of the growth plate. There were statistically significant associations between the weighted radiographic changes and slaughter weight, average daily weight gain, husbandry practices and production label. The prevalence of radiographic lesions indicative for osteochondrosis of the metatarsal growth plates of fattening bulls slaughtered at a local abattoir was high. The extent to which the distinct and severe lesions are associated with reduced production and obvious clinical lameness requires further study.