University of Wisconsin researchers recently published the results of a six-year field trial investigating the control of Johne’s disease. The program focused on calf- and heifer-management practices and regular use of a low-cost blood test (ELISA) to identify and manage the most infectious cows.

The researchers required herds to implement the following changes:

  • Segregate maternity pens so only ELISA-negative cows calve in “clean” pens. Sick cows and ELISA-positive cows calved in another pen.
  • Remove calves from the maternity pen within two hours of birth or at least isolate them so they cannot be exposed to manure.
  • Bottle or tube-feed colostrum from a single ELISA-negative cow within six hours of birth (no pooled colostrum). Avoid manure contamination during colostrum harvest by cleaning the teats and using a clean collection container.
  • Feed milk replacer or pasteurized milk until weaning.
  • House calves away from cows to limit, if not completely prevent, exposure to manure from cows.
  • Cull cows with a strong-positive ELISA result before their next calving. Visibly identify cows with low to medium-level ELISA results.
  • Use ELISA-negative cows calving in the “clean” pen as colostrum donors and favor their calves for selection as herd replacements.

At the beginning of the study, each of the nine participating herds had 10 to 20 percent of the cows testing ELISA-positive. Across all herds, 11.6 percent of the cows were ELISA-positive. After six years, eight of the nine farms achieved a significant reduction in the level of infection within their herd and only 5.6 percent of all the cows tested ELISA-positive.

The results were published in the April issue of the Journal of Dairy Science.

Researchers noted there was no difference in Johne’s control success between herds feeding milk replacer or pasteurized milk. In addition, cleanliness of colostrum collection and storage was an area of concern for most herds in the study. A final observation was that maternity pen management seemed to be the most challenging aspect of the control program. While faster progress in controlling Johne’s could have been made with more effort and investment in management changes, use of a more sensitive diagnostic test, and more aggressive culling of positive cows and their daughters, the intent of the program studied was to provide a financially manageable strategy that produced measurable benefit.

Source:  Dairy Calf and Heifer Association