Animal Health-Johne’s Disease (JDIP): Johne’s Disease

The National Johne’s Demonstration Herd Project (NJDDHP) in the United States was initiated to evaluate the long-term feasibility and effectiveness of management-related practices designed to control Johne’s disease on dairy and beef cattle operations. The NJDDHP began in 2003 and includes 62 dairy herds and 20 beef herds in 17 states. All herds began with culture-confirmed Mycobacterium avium subspecies paratuberculosis (MAP) on the operation, and all herd owners agreed to make efforts to control Johne’s disease on the operation. Risk assessments, management plans, and testing of herds were completed on an annual basis. Results to date indicate that, for both beef and dairy herds, prevalence of Mycobacterium avium subspecies paratuberculosis (MAP) in the third, fourth, and fifth years of participation was significantly lower than prevalence during the first year of participation. An analysis using Poisson regression was undertaken to identify areas from the risk assessment most important with regard to MAP prevalence. Among the main areas from the risk assessment (which included calving area, preweaned heifers, postweaned heifers, bred heifers, cows and bulls, and additions/replacements), preliminary results indicate that for dairy and beef herds, the calving and preweaned heifer areas appeared to be most important with regard to risk of cattle being MAP-positive. Specific factors related to the calving and preweaned heifer areas will be further assessed to identify practices associated with a greater risk for cattle to be MAP-positive. For dairy herds, preliminary results indicate that making sure udders and legs of cows in the calving area are clean, using individual animal calving areas (or allowing fewer animals in the calving area), and preventing Johne’s disease clinical or suspect animals from entering the calving area were most important with regard to control of Johne’s disease on dairy operations.