title: Vaccination of cattle against brucellosis using either a reduced dose of strain 19 or one or two doses of 45/20 vaccine.
abstract: Three groups, each of 14 mature Jersey heifers, were vaccinated. They were mated about 2 months later and those that became pregnant were challenged at about 6.5 months of pregnancy by the conjunctival application of virulent Brucella abortus. Group 1 heifers received 2 doses of B. abortus 45/20 vaccine 2 months apart. Only 5 of the 14 heifers became pregnant, and of these 5 only one resisted challenge. Group 2 heifers received only one dose of 45/20 vaccine, 5 of the 10 challenged resisted infection. Group 3 heifers received 3 x 10(8) cfu of strain 19. Six of the 10 heifers challenged resisted infection. All of 5 non-vaccinated control cattle became infected. It appeared advantageous to give only one dose of 45/20 rather than 2 as presently recommended. A single dose of 45/20 vaccine induced resistance to virulent B. abortus approximately equal to that given by the reduced dose of strain 19. One dose of 45/20 vaccine stimulated transient serological positivity in 2 of 28 heifers whereas the reduced dose of strain 19 gave rise to persistent titres in 2 of 14 vaccinated heifers.
mesh_terms: D000818:Animals; D002004:Brucella Vaccine / Q000008:administration & dosage* / Q000276:immunology; D002007:Brucellosis, Bovine / Q000517:prevention & control*; D002417:Cattle; D005260:Female; D011247:Pregnancy; D014611:Vaccination / Q000662:veterinary*
chemical_list: D002004:Brucella Vaccine