Osteokondros hos tjur
Several bulls in Sweden are culled because of lameness. Studies of beef bulls have shown that osteochondrosis is an important underlying cause of hind limb problems (Persson, 2003; Dutra, 1998). Osteochondrosis in horses, dogs, swine, poultry and man are well documentated in the literature, but there are few studies in cattle. The prevalence of osteochondrosis in dairy bulls in Sweden is unknown. The aim of this study was to investigate the presence and localisation of osteochondrosis in the hindlimbs of dairy bulls.
This study consists of 48 one-year-old bulls divided into four groups related to which farm they came from. The main group A, consisted of 25 bulls of the SRB (18) and SLB (7) breeds, kept in boxes with ?strawbedding?. Group B consisted of fattening bulls of SRB (4) and SLB (2) breeds, also kept on a ?strawbedding?. Group C consisted of 9 SLB bulls, kept on a slatted floor. Group D consisted of 7 charolais bulls and one SLB, which had been tied up during their growth. The group of beef bulls was used as a reference to the groups of dairy bulls. The animals were healthy at the time of slaughter and the stifle- and tarsal joint of the right hindlimb were examined post mortem regarding the presence of osteochondrosis and other joint lesions.
In total 41 (85.4%) of 48 bulls had joint lesions in at least one joint. Lesions classified as osteochondrosis were present in 35 (72.9%) bulls. In group A 21 (84.0%) bulls had joint lesions and 15 (60.0%) of these were classified as osteochondrosis. The number of bulls with joint lesions in the other three groups were the equal to the number of bulls with osteochondrosis, 5 (83.3%), in group B, 7 (77.8%) in group C and 8 (100%) in group D. Osteochondritis dissecans was the most common lesion followed by ulcers of the articular cartilage. The most frequent localisation of the lesions was in talus of the tarsal joint.
The results indicate that dairy bulls have a high frequency of osteochondrosis. The prevalence of osteochondrosis was lower in group A, but at comparison the prevalence of all joint lesions was as high as in any other group. All the lesions were mild and none of the bulls had clinical signs. Remarkably there were more lesions in the tarsal joint than in the stifle joint, which contradictes previous studies. The cause of the concentrated localisation in the tarsal joint is uncertain. Finally it can be stated that osteochondrosis is present in dairy bulls and further studies are needed to evaluate the clinical importance.