EPIDEMIOLOGIC-STUDY OF ON-FARM MANAGEMENT-PRACTICES ASSOCIATED WITH PREVALENCE OF MYCOBACTERIUM-PARATUBERCULOSIS INFECTIONS IN DAIRY-CATTLE

Objective-To use an on-farm recording form to quantify the effect of s pecific management practices on apparent prevalence of Mycobacterium p aratuberculosis in dairy cattle herds. Design-Epidemiologic survey. An imals-26 commercial Wisconsin dairy farms. Procedures-An instrument wa s developed on the basis of literature review and expert interviews to quantify on-farm management practices associated with increased appar ent prevalence of M paratuberculosis. On-farm visits were conducted to assess how specific management practices were conducted, Apparent pre valence of M paratuberculosis infection was measured for all animals > 20 months old on ail farms, using a commercial ELISA, Regression anal ysis was used to identify management variables that were significantly associated with apparent prevalence of M paratuberculosis. Results-Re gression analysis (R(2) = 0.90) identified that high scores for enviro nmental conditions, newborn calf care, grower calf care, bred heifer c are, and manure handling were significantly associated with M paratube rculosis apparent prevalence in Wisconsin dairy herds. Clinical Implic ations-Environmental conditions, newborn calf care, grower calf manage ment, bred heifer management, and manure handling factors may serve as a prioritized checklist for instructing owners and managers where to place emphasis in changing management practices to limit M paratubercu losis prevalence. likewise, the factors identified as having low assoc iation with apparent prevalence may be de-emphasized in control progra ms, allowing dairy managers to focus rime and finances on more effecti ve components of an M paratuberculosis control program.