Effects of stage of gestation and breed on bovine responses to vaccination with Brucella abortus strain 19.
Eighty-eight cattle were injected SC with 2.5 x 10(8) viable cells of Brucella abortus strain 19. All but 1 heifer became seropositive on the basis of the results of 7 brucellosis tests, and the proportion positive decreased with time. The proportion of cattle that were seropositive during a 20- to 67-week period after vaccination was as follows, in decreasing order: hemolysis-in-gel, 59%; buffered-acid plate antigen, 39%; ELISA, 16%; card, 10%; rivanol, 8%; cold complement-fixation, 7%; and automated complement-fixation, 5%. Using the serologic classification in Uniform Methods and Rules for brucellosis eradication, 7 cattle tested brucellosis-positive (2 suspects and 5 reactors). None of the 27 nonpregnant heifers tested positive. Of 18 heifers that were 84 to 135 days in gestation when vaccinated, 6 (33%) tested positive for brucellosis, compared with 0 of 13 and 1 (3%) of 30 heifers that were 11 to 78 and 145 to 253 days in gestation at vaccination, respectively (X2 = 12.07; 2 df; P less than 0.01). Neither breed (Angus, Hereford, Jersey, and Brahman) nor calf survival was related to brucellosis-positive results. Postpartum milk samples from 61 heifers and 24 tissues from 2 reactor cattle were culture-negative for B abortus.
Crawford
R P
RP
Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station 77843.
Adams
L G
LG
Ficht
T A
TA
Williams
J D
JD
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000097:blood; D001947:Breeding; D002004:Brucella Vaccine / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology* / Q000302:isolation & purification; D002007:Brucellosis, Bovine / Q000517:prevention & control*; D002417:Cattle; D005260:Female; D008892:Milk / Q000382:microbiology; D010641:Phenotype; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary
D000907:Antibodies, Bacterial; D002004:Brucella Vaccine