Abstract
From February to September 1991 on a farm of Kumamoto Prefecture, 15 calves showed pneumonia with fever, cough and nasal discharge, and Mycoplasma bovis and Pasteurella multocida were isolated from the lung of one of 5 fatal cases. M. alkalescense, M. bovis, P. multocida and P. haemolytica were isolated from the nasal swabs of other calves showing pneumonia and M. alkalescense and M. bovis were isolated also from the nasal swabs of newly introduced animals after the outbreak of pneumonia. Eleven and 15 isolates of M. alkalescense and M. bovis, respectively, were sensitive to tiamulin, josamycin, lincomycin while resistant to erythromycin. Calves with pneumonia or those newly introduced showed low antibody titers to bovine herpesvirus type 1, parainfluenza virus type 3, bovine adenovirus type 7 and bovine respiratory syncytial virus.
