Antimicrobial therapy for rams with Brucella ovis infection of the urogenital tract

Rams shedding Brucella ovis in semen but without palpable abnormalities of the epididymides were treated with long-acting oxytetracycline for 15 days and dihydrostreptomycin for 7 days (n = 9) or conventional oxytetracycline and dihydrostreptomycin (n = 9) for 7 days. Nine rams were not treated. More treated rams were considered to have satisfactory breeding soundness examination results at posttreatment weeks 3, 7, 12, and 19. Nontreated rams continued to shed B ovis in semen. After treatment, B ovis was not recovered from 78% of rams given long-acting oxytetracycline and dihydrostreptomycin or from 89% of rams given conventional oxytetracycline and dihydrostreptomycin. At week 21, all rams were euthanatized, and specimens of the testes and epididymides were bacteriologically cultured for B ovis. Brucella ovis was not recovered from the testes of rams or from the epididymides from rams not shedding the organism in the semen. In one treated ram, B ovis was recovered from the semen but not from other tissues. All rams remained ELISA-positive, with the exception of 2 treated rams that ceased shedding B ovis in semen immediately after treatment was started; both these rams became ELISA-negative on the last examination at week 19.