Economic consequences of control programs for paratuberculosis in midsize dairy farms in the United States.

OBJECTIVE: To evaluate the epidemiologic efficacy and economic efficiency of current and potential future control programs for paratuberculosis (Johne's disease) on midsize dairy herds in the United States.
DESIGN: Stochastic dynamic computer simulation model. SAMPLE POPULATION: Data on prices and other input variables collected from various sources were used to represent a population of midsize US dairy herds infected with paratuberculosis. PROCEDURE: The simulation model was modified to reflect management and production characteristics of midsize dairy herds in the United States. The model was validated by use of field data and expert opinion. Various control strategies then were simulated and compared on an epidemiologic basis and on the basis of economic efficiency.
RESULTS: Test-and-cull strategies and vaccination against paratuberculosis were not able to decrease the mean prevalence of disease in the United States. Typically, only vaccination was economically attractive. Improved management strategies decreased the prevalence of paratuberculosis considerably and had high economic benefits. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of results of this study suggests that test-and-cull strategies alone do not reduce the prevalence of paratuberculosis in cattle and are costly for producers to pursue. Vaccination did not reduce the prevalence but was economically attractive. Finally, improved calf-hygiene strategies were found to be critically important in every paratuberculosis control program and most were economically attractive programs for midsize US dairy farms with the disease.