Bronchopneumonia and polyarthritis due to Mycoplasma bovis in a calf

This case report describes gross lesions and histopathological findings in a 3-months-old calf originating from a feedlot with approximately 400 cattle. In this animal and additional 14 cattle of similar age, which were kept together in the same stable, swollen joints had occurred suddenly. The examination of this calf showed that a severe polyarthritis induced by haematogenous spread of Mycoplasma bovis following bronchopenumonia was present, which was characterised by necrotising lesions of the joint capsules and severe cartilage erosions.