In order to determine the prevalence and risk factors associated to paratuberculosis in ovine livestock production units in Guanajuato, Mexico; a cross-sectional epidemiological study was carried out for one year long. Serum samples(n = 1387) were analyzed with an agar gel immunodiffusion test. Bacteriological culture and IS900 nested PCR were done from the fecal samples (n=640). For epidemiological data, two questionnaires (individual animal and LPU) were filled out, statistical analysis was done with STATA 7 ® software. Ovine paratuberculosis prevalence in the studied population was to 4.54%, ovine older than 11 to 24 months age had a 3.52%; females with more than three parturitions showed a 6.5%., in the livestock production units that carried mucking out and elimination of feces only once a month the prevalence was to 50%. Odds-ratio analysis (OR) showed that the presence of thin females after parturition had an OR of 3, while females with more than 3 parturitions had an OR of 4.74., while livestock production units that mucked out and eliminated feces once a month the OR was to 1.41. Results in this study showed the degree of spread of paratuberculosis among sheep throughout various zones in the State of Guanajuato. Comprehensive ovine paratuberculosis epidemiological studies shall be a tangible asset that will allow the design of appropriate control programs for the elimination of the disease in livestock production units.

Keywords: Ovines, Paratuberculosis, Risk Factors, Prevalence, Epidemiology