[Isolation of Haemophilus somnus from cattle].

Studied were a total of 220 samples of material taken from the respiratory tract of calves and from fetuses of cows that miscarried for the presence of Haemophilus bacteria. Haemophilus somnus was isolated for the first time in this country from the respiratory tract of calves (10.1 per cent) and from fetuses of cows with abortions (6.2 per cent). Haemophilus somnus was found in calves that had contracted respiratory diseases in 13 per cent of the cases, and in clinically normal calves--in 3.5 per cent of the cases. It was isolated both in pure culture and in mixed culture with P. multocida, M. bovirhinis, M. arginini, V. fetus, and C. pyogenes. As many as 21 strains of Haemophilus somnus were isolated, having the same morphologic, cultural, and biochemical properties characteristic of the species.