Brucellosis control in an infected herd by serological testing, removal of reactors, vaccination with reduced dose of strain 19 and improved hygiene.

Brucellosis was diagnosed in a closed herd of approximately 200 Fresian cattle in February 1982. Diagnosis was based on positive serologic tests and abortions from which B. abortus was isolated. Initial efforts to control the disease were the isolation of all cows which were positive on the standard tube agglutination test. In addition all cows which calved or aborted were isolated. In August 1982 all cows which were negative to the standard tube agglutination test were vaccinated with a reduced dose of strain 19 vaccine (approximately 1 X 10(9) organisms). The herd was retested 60 days after vaccination and all animals which were positive on the rivanol supplemental test at a titer of 1:50 or greater were considered infected and removed from the herd. Subsequent to vaccination there were an additional 22 cows which aborted. These cows were removed from the herd. A calfhood vaccination programme utilizing the standard dose of strain 19 has been initiated in the herd. An increased effort was made to maintain all of the stables at a higher level of sanitation.