Effects of vaccination with a Moraxella bovis bacterin on the subsequent development of signs of corneal disease and infection with M bovis in calves under natural environmental conditions
Hughes, D.E.; Pugh, G.W.; Kohlmeier, R.H.; Booth, G.D.; Knapp, B.W.
American Journal of Veterinary Research 37(11): 1291-1295
1976
ISSN/ISBN: 0002-9645 PMID: 984561 Document Number: 103288
The cattle in the herd studied were allotted to 4 groups: 60 calves were vaccinated with an autogenous Moraxella bovis bacterin (group 1); 60 calves that were matched with group 1 calves were designated non-vaccinated matched controls (group 2); 99 calves were peer group non-vaccinated controls (group 3); and 219 cows, the dams of the calves, were non-vaccinated consorts (group 4). The infection rates in cattle groups 1, 2, 3 and 4 during the summer were 96.6, 98.3, 100 and 79%, respectively, and the keratoconjunctivitis rates were 90, 93, 85, and 20%. The infection and the disease rates were significantly different between calves and cows. The disease rate was also significantly different between older and younger cows. A larger percentage of the affected calves and cows had mild or moderate (61%) signs of keratoconjunctivitis rather than severe (39%) signs. The rate of body weight gain was reduced in calves with severe signs of keratoconjunctivitis. The results indicate that little would be gained by vaccinating cattle against keratoconjunctivitis under the conditions of the study.