[The colonization of the upper respiratory tract and the bacteremic phases of enzootic pneumonia of calves].

Twenty calves, following their re-accommodation on a calf raising unit, were tested twelve days for presence of Pasteurellae and mycoplasms on the mucosa of the nasal pharynx and in blood. The same microorganisms were searched for in another 65 calves, yet, only at the beginning of pneumonia. Tests were applied to 19 calves for presence of chlamydia in the blood. The nasopharynx of all 20 calves was colonised by Pasteurellae, whereas mycoplasms were detected only in few cases. Neither Pasteurellae nor mycoplasms were isolated by blood culturing, though chlamydia were found in concomitance with pneumonia in three of 13 evaluable cases.