title: Serologic and bacteriologic test results after adult vaccination with strain 19 in three dairy herds infected with brucellosis.
abstract: Milk culture data and serologic test results were evaluated after adult vaccination with Brucella abortus strain 19 in cattle of 3 large California dairy herds infected with brucellosis. Strain-19 organisms were isolated by culture of milk from 1.9% of the vaccinated cows. Isolation of field strain of B abortus varied directly with magnitude of complement-fixation (CF) and rivanol titers. At time of milk culture, 74% of cows from which field strain was isolated had CF titer greater than or equal to 160, compared with 58% of cows from which strain 19 was isolated. Cows with CF titer greater than or equal to 160 at 2 months or greater than or equal to 80 to 4 months after adult vaccination were more likely to be correctly classified as reactors (on the basis of subsequent milk culture results and/or persistently high serologic titer) than were cows with lower CF titer at these times. Cows from which B abortus strain 19 was isolated from milk were more likely to maintain persistent serologic titer than were cows from which neither strain of B abortus was isolated.
authors.affiliation: Animal Health Branch, California Department of Food and Agriculture, Sacramento 94271-0001.
authors.forename: R E
authors.initials: RE
authors.lastname: Breitmeyer
authors.forename: D W
authors.initials: DW
authors.lastname: Hird
authors.forename: T E
authors.initials: TE
authors.lastname: Carpenter
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D002004:Brucella Vaccine / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology* / Q000302:isolation & purification; D002007:Brucellosis, Bovine / Q000382:microbiology / Q000517:prevention & control*; D002417:Cattle; D003168:Complement Fixation Tests; D004975:Ethacridine; D005260:Female; D008892:Milk / Q000382:microbiology; D014611:Vaccination / Q000662:veterinary*
chemical_list: D000907:Antibodies, Bacterial; D002004:Brucella Vaccine; D004975:Ethacridine