A recent study detailed the barriers producers and veterinarians face in killing one of the most prevalent and costly diseases in dairy and beef herds – Johne's disease.

The scientific paper from the Council for Agricultural Science and Technology documents identified the following key issues that currently prevent eradication of the disease:

  • Diagnostic inadequacies: Improved diagnostic tests are needed because current diagnostic tests detect less than 50 percent of infected animals at any single point in time. Therefore, repeated testing is required.
  • Lack of vaccine: An efficacious vaccine is not available and would be an important tool in Johne’s control.
  • Regulatory deficiencies: Uniform interstate disease definitions and regulations are needed to decrease confusion and litigation associated with animal movement.
  • Crohn’s disease link: A number of researchers have proposed that the same organism as Johne’s disease in cattle and other ruminants may cause Crohn’s disease in humans. Milk and milk products that are raw or inadequately pasteurized could provide a source of the organism.

“Johne’s disease is complex and difficult to diagnose. Furthermore, it catches many cattle owners by surprise because affected animals may show the signs of chronic diarrhea and weight loss in a one-at-a-time fashion,” said CAST Johne’s Task Force Co chairs Robert D. Linnabary of the University of Tennessee College of Veterinary Medicine and Gavin L. Meerdink of the University of Illinois College of Veterinary Medicine. “Work must be done to answer key questions related to control of the disease in cattle and determine what impact it may have on human health.”

The paper reported that an estimated 22 percent of U.S. dairy herds and 8 percent of U.S. beef herds have the intestinal infection. A U.S. Department of Agriculture study estimates the disease causes $200 million to $250 million in economic losses to the U.S. dairy industry alone.

The complete paper, “Johne’s Disease in Cattle,” and other CAST reports are available at the CAST Web site at www.cast-science.org.