RESUMO
Black leg has been reported in a variety of animals, but is of the most importance in cattle and sheep. A 20 days old Holstein dairy calf was examined because of anorexia and lameness from 2 days ago. The calf was depressed, tachypneic, tachycardic, and had a body temperature of 38.5°C. Both hind limbs proximal to the tarsal joint were markedly swollen, firm and painful. No crepitation was noted on palpation. The calf had bruxism, stiffness of gait and unwillingness to move. At necropsy, massive necrosis of thigh muscles which caused dark discolorated tissue with metallic sheen, large amount of thin sanguineous exuda and abundant gas bubbles were evident in the underlying tissues. Histopathologic examination revealed extensive degeneration and coagulative necrosis of muscle fibers and supported a diagnosis of black leg. No vaccination against Clostridium chauvoei was applied in the herd and the calf did not receive notable maternal antibody. Providing sufficient maternal antibody or early vaccination of the susceptible newborn calves should be considered in the endemic regions