How widespread is Johnes disease in Canadian domestic livestock?
Nobody knows for sure. In the U.S. a national survey estimated that 1.4% of the nation’s beef cattle and 2.6% of the country’s dairy cattle are infected with M. paratuberculosis. Some areas of the country report much higher infection rates. Those figures are for individual cattle. An American Johne’s disease research scientist (M. Collins DVM, PhD at U of Wisconsin) says that 41% of U.S. dairy herds have at least one cow that tests positive (but is not necessarily showing signs) for Johne’s disease. In Canada, we currently have no way of knowing the level of disease in the collective national cattle herd or in individual cattle herds. Likewise, there are no figures for sheep, goats or elk and deer. We can only make educated guesses using information from countries with similar agricultural systems.
