An attempt to induce clinical infectious keratoconjunctivitis in calves with naturally occurring Moraxella bovis infection
Barber, D.M.; Jones, G.E.
Veterinary Record 122(9): 210
1988
ISSN/ISBN: 0042-4900 PMID: 3381465 Document Number: 306329
Swabs were taken each week from the eyes of 31 Friesian bull calves introduced on to a farm in February, when they were one week old. No isolations of M. bovis were made from the first 3 weekly samples. Non-haemolytic, non-fimbriated M. bovis were isolated from 28 calves in week 4, 23 in week 5 and 29 in week 6. From mid March, calves were divided into groups, and attempts were made to change non-haemolytic M. bovis to haemolytic M. bovis and to produce clinical infectious keratoconjunctivitis. Temporary mild conjunctivitis was produced in calves treated with U.V. light (wavelength 280-350 nm for 15 minutes daily), but no changes were seen even immediately after treatment in calves treated with sterilized sand (introduced into the conjunctiva 3 times daily) or when 1 ml betamethasone was injected into the conjunctiva once daily. No haemolytic M. bovis were isolated, and the proportion of calves infected with non-haemolytic M. bovis gradually reduced until they were all negative in September.