Dr. Maurice Eastridge, Extension Dairy Specialist, Department of Animal Sciences, The Ohio State University
Johne’s Disease continues to be a considerable health issue in the dairy industry. The USDA’s DAIRY 2014: Dairy Management Practices in the United States study provided some insights on the current management practices to prevent Johne’s Disease in the US. The Dairy 2014 study was conducted in 17 of the US major dairy states and refers to estimates for the calendar year of 2013. Data collected for the study represented 76.7% of U.S. dairy operations and 80.3% of US dairy cows at the time of the study.
Of the 28.6% of the operations that brought cattle onto their operation during 2013, 11.4% of the small herds (30 to 99 cows), 12.9% of the medium herds, and 20.1% of the large herds required information on Johne’s Disease status of the herd of origin for the purchased cattle. Of operations that tested new animal additions, 74.6, 41.8, and 50.1% of the small, medium, and large herds, respectively, tested new additions for Johne’s disease. Cows that test positive for Mycobacterium avium subspecies paratuberculosis—the causative agent of Johne’s disease—are likely to shed the bacteria in feces or in colostrum around the time of calving. Test-positive cows about to calve should be managed in a separate area away from test-negative cows. There was no difference by herd size in the percentage of operations that tested for Johne’s disease; overall, 74.4% of the farms tested for Johne’s disease and 7.3% allowed test-positive cows in the calving area.
A Johne’s Disease Risk Assessment Practicum has been developed that is sponsored by the National Milk Producers Federation, the Johne’s Disease Integrated Program, and the American Association of Mycobacterial Diseases. This program is an online application designed to help evaluate a farm for management practices that may increase the risk of introducing Johne’s Disease into a herd and/or spread the disease to uninfected animals. It provides an introduction to farm risk assessments and the development of management plans. The resource is located at http://jdrap.info. You are encouraged to review this resource and work with your local veterinarian to develop specific herd management practices for your farm to minimize the risk of acquiring or spreading Johne’s Disease.