Pasteurella infections in respiratory diseases of young cattle

Bacteriological examinations performed on 545 extracts of pneumonia-affected lungs and on nasal secretions collected from pneumopathy diseased young cattle led to the isolation of 176 (32.2%) Pasteurella (p.) multocida strains and of 125 (22.9%) P. haemolytica strains. P. multocida was isolated in 46.2% of the lung lesions and in 22.5% of the nasal secretions, P. haemolytica in 26.6% and 20.3%, respectively. Pathogenicity in mice was detected in 81.9% of the P. multocida strains and in 19% of the P. haemolytica strains. Pasteurella strains were very susceptible to chloramphenicol (82.3%), tetracycline (68%), penicillin (47%), and ampicillin and resistant to oxacillin, streptomycin and kanamycin. P. multocida and P. haemolytica strains in the respiratory tract and lung lesions of young cattle affected by pneumopathies represent the main ethiologic agent accounting for the clinical symptoms, anatomic lung lesions and finally for the death of the animal.