Effectiveness of various therapeutic regimens for bovine brucellosis.

Various chemotherapeutic regimens were evaluated in 48 culture-positive dairy cows. Cessation of shedding of Brucella abortus from udder secretions and absence in selected tissues at necropsy were criteria of success. A combination of a long-acting oxytetracycline and streptomycin eliminated Brucella in 10 of 14 (71.4%) cows. Two cows that were retreated with the same regimen also became culture-negative. Other treatment regimens, including the use of liposome-encapsulated antibiotics, were less successful. Serotests were a poor criterion of effectiveness.