Prevalence of antibodies against Mycobacterium avium subsp paratuberculosis among beef cow-calf herds

Objective-To estimate the prevalence of Mycobacterium avium subsp paratuber culosis infection among cows on beef operations in the United States. Design-Cross-sectional seroprevalence study. Sample Population-A convenience sample of 380 herds in 21 states. Procedure s-Serum samples were obtained from 10,371 cows and tested for antibodies to M avium subsp paratuberculosis with a commercial ELISA. Producers were int erviewed to collect data on herd management practices. Results-30 (7.9%) herds had 1 or more animals for which results of the ELIS A were positive; 40 (0.4%) of the individual cow samples yielded positive r esults. None of the herd management practices studied were found to be asso ciated with whether any animals in the herd would be positive for antibodie s to M avium subsp paratuberculosis. Conclusions and Clinical Relevance-Results suggest that the prevalence of a ntibodies to M avium subsp paratuberculosis among beef cows in the United S tates is low. Herds with seropositive animals were widely distributed geogr aphically.