[Haemophilus somnus as a cause of bronchopneumonia in calves].

A bacteriological examination of the pulmonary tissues of calves suffering from bronchopneumonia was complemented by a microaerophilic or anaerobic cultivation. Thirty-two strains (23.7%) of a microorganism hitherto not described in Czechoslovakia were isolated during the examination of 135 calves with disorders of the respiratory system. On the basis of the growth, morphological, biochemical and serological properties, the microorganism was identified as Haemophilus somnus. Chocolate agar supplemented with yeast extract, and blood agar were used for the cultivation. Incubation took place in a microaerophilic medium with 10% carbon dioxide or in an anaerobic medium. Serums against the collection strain of Haemophilus somnus were prepared in rabbits for the serological diagnosis. These antiserums reacted with all tested strains during test tube agglutination but did not enter cross reactions with other bacterial species. The coagglutination test, which was verified, did not provide reliable results.