Studies on repeated vaccination of cattle with Brucella abortus Strain 19. III. The response of vaccinated and revaccinated cattle to conjunctival exposure with a virulent strain of Br. abortus during the third gestation period
Berman, D.T.; Beach, B.A.; Irwin, M.R.
American Journal of Veterinary Research 13: 351-358
Three groups of Holstein-Friesian heifer calves were vaccinated with Br. abortus Strain 19 at 8 months of age. Two of these groups were re-vaccinated at 14 and 20 months of age. In the third pregnancy, the cows of these groups, along with unvaccinated controls, were exposed by the conjunctival route with 12 x 106organisms of Br. abortus Strain 2308. 15 of the 18 pregnant controls had abnormal parturitions with brucella infection demonstrable in 17.