Evaluation of long-acting oxytetracycline and a commercial monovalent vaccine for the control ofsubsp.infection in beef bulls.

Abstract

A blinded randomized controlled trial was used to evaluate a multi-modal therapeutic regime for treatment of beef bulls infected withsubsp.. Treatment included 2 doses of a commercially available monovalent vaccine and long-acting oxytetracycline applied twice at a 2-week interval with treatment completed 2 weeks before post-treatment observation. Fifteen confirmedinfected bulls were randomly allocated to control (= 8) or treatment groups (= 7). Preputial scrapings were collected each week from before infection to 11 weeks following the last treatment. When the polymerase chain reaction (PCR) results for both culture and preputial scrapings were interpreted in parallel, there were no significant differences between treated and untreated bulls. Regardless of the type of diagnostic testing considered, treatment with 2 label doses of this regime did not stop shedding ofin all treated bulls and is, therefore, not recommended as an effective management strategy.