Bovine mycoplasmal conjunctivitis: experimental reproduction and characterization of the disease

Epizootic conjunctivitis was studied in eight Iowa cattle herds. Mycoplasma bovoculi was isolated from the eyes of cattle in all affected herds and Ureaplasma sp. was isolated from the eyes of cattle in 3 of the herds. When either of these two organisms was experimentally inoculated into the conjunctival sac of healthy calves, conjunctivitis became apparent within 3 to 4 days after infection and persisted for more than 1 month. Calves inoculated with M. bovoculi responded with mild localized conjunctivitis and with serous lacrimation while calves inoculated with Ureaplasma sp. had diffuse conjunctivitis with watery lacrimation. With both microorganisms, the symptoms varied in intensity with peaks of recrudescence through the observation period. The microorganisms were recovered for periods of 1 to 2 months from the conjunctival mucosae of cattle undergoing natural or experimental infections.