Diagnosis and epidemiology of Brucella ovis infection in rams

Abstract

The relationship between clinical, serological and bacteriological diagnostic criteria have been determined in Brucella ovis culture-positive and Brucella free control rams and also in 110 field rams belonging to 13 different flocks, in which an epidemiological survey was conducted. In control rams, a direct relationship was found among the existence of positive bacteriological results and the presence of a positive serological response in the gel diffusion (GD) and complement fixation (CF) tests for B. ovis. In field rams, the presence of macroscopic testicular alterations (MTA) caused by B. ovis was correlated with bacteriological and serological results. The percentage of reactors and the percentage of rams showing MTA was not related to the size of flocks nor to the ratios of ram/ewes. The prevalence of B. ovis infection was significantly higher in rams from imported breeds than in those from local ones. Moreover, the younger and the oldest rams showed the lowest prevalence of B. ovis infection, but the age of rams did not influence the prevalence of MTA not caused by B. ovis.