Antibiotic serum activities against bacterial isolations from cases of bovine pneumonic pasteurellosis in feedlot calves.

: The serum bactericidal activity test was carried out in two groups of 7 calves each suspected to be suffering from pneumonic pasteurellosis. The diagnosis was based on clinical signs, endoscopic examination and bacteriological investigations. The first group of seven calves received oxytetracycline at a dosage rate of 10 mg kg-1 once a day. A second similar group received penicillin at 30,000 IU kg-1 once a day. Results showed that the correlation between antibiograms, serum bactericidal activity and clinical response may be good for oxytetracyclines and poor for penicillin. The serum bactericidal activity test may be a good method to establish effective dosages for certain antibiotics in the treatment of pneumonic pasteurellosis.