Blackleg (Clostridium chauvoei infection) in beef calves

Abstract

Blackleg (Clostridium chauvoei infection) has long been recognized as a cause of death in calves grazing summer pastures. Clinical signs are not often observed in affected calves due to the peracute nature of the disease, but may include fever, lameness, and swelling and crepitation over large muscle groups, followed by collapse and death. Typical gross and histopathologic lesions in these muscle groups are well-described and include gelatinous, gassy subcutaneous changes, along with well-defined muscle necrosis. Areas of necrosis can also be present in myocardium, diaphragm, and tongue, among other sites. Primary gross lesions consisted of pleuritis and pericarditis in animals examined in this report. More typical blackleg lesions were found in some but not all calves, including necrosis in thigh and abdominal muscles, dark discoloration of diaphragm muscle, and histologic evidence of necrotic myocarditis. Practitioners finding these lesions in animals found dead on pasture should consider C. chauvoei infection as the diagnosis regardless of whether muscle necrosis lesions are present.