[Pasteurella haemolytica serotypes in cattle].

Eight-two bovine Pasteurella haemolytica strains were serotyped. The majority of the strains were isolated from calves which had died from fibrinous pneumonia and small numbers from cases of pleuritis, sepsis and abortion. A total of eight different serotypes were noticed. Serotype A1 was found to be the most prevalent 37.8 per cent, followed by serotype A2 with 20.7 per cent. Antibiotic resistance was found for sulfonamide, tetracycline and penicillin in about half of all strains. Conventional combination of biotype to serotype per strain was not confirmed by the results of arabinose and trehalose fermentation.