Minnesota herds reduce risk of new infection
Use of recommended Johne’s disease control measures do work. But implementing the management changes must become a part of the daily routine and followed year after year.
An analysis of eight Minnesota dairy herds that were enrolled in the state’s Johne’s disease control program show they have significantly reduced the risk of new infections over 10 years.
The eight herds had about 6,000 cows enrolled in the project. Cows were tested for Johne’s at each lactation, using both bacterial culture and serum ELISA tests. Cows born one or two years prior to the implementation of Johne’s control measures were tested and then compared to cows born after implementation.
The hazard ratio of serum ELISA positivity of cows born the year management changes were implemented was 0.70 compared to 0.99 for cows born before changes were made. The hazard ratios for each succeeding year were 0.55, 0.35, 0.23, 0.17 and 0.05, reports Luis Espejo, a veterinarian and graduate student at the University of Minnesota’s College of Veterinary Medicine. "Similar results were obtained for bacterial culture of feces," he adds.
Also important, the more Johne’s control recommendations that were implemented by a farm, the lower the risk of new infections, Espejo says.
Johne’s disease control recommendations include:
- Calve in clean, well-bedded, individual pens. Separate newborn calves shortly after birth; do not allow them to nurse.
- Thoroughly clean the udder and teats before collection of the colostrum to avoid manure contamination.
- Use colostrum from Johne’s negative dams, and do not pool colostrum. Pasteurize colostrum and waste milk fed to calves, or feed milk replacer.
- Do not use the same equipment to handle feed and move manure.
- Avoid manure contamination of water sources.
- Identify and cull heavy fecal shedding cows.
- If purchasing herd additions, buy from low-risk herds. Look for herds enrolled in Johne’s control programs to help identify herds as low-risk.
- December 2011