Awareness of a disease that has mostly affected dairy herds is growing amongst all cattle producers, says a Weyburn veterinarian who recently spoke about it at the Livestock Update Forum held in Weyburn.

Dr. Leanne Varley spoke about Johne's disease, which is an intestinal infection that occurs in ruminants, including cows, elk, deer, sheep and goats. It is caused by bacteria, and there is no known cure or vaccine against it.

The reason the disease is untreatable is that it is related to tuberculosis in humans, said Dr. Varley; humans have to be treated for several years with expensive drugs, but for animals there isn't any equivalent treatment available.

She brought the topic to the Livestock Update, which was hosted on Dec. 13 by the Weyburn office of Sask. Ag and Food, as the cattle industry is considering bringing in a testing or control program to ensure animals can be tested for whether they have been exposed to the disease or not.

Many other countries have such a program in place already, such as the U.S., the Netherlands and Australia, and Canada would be in a better position to export cattle or milk products abroad if the buyers could be assured there has been no exposure to Johne's disease, said Dr. Varley.

Asked how prevalent the disease is in southeast Saskatchewan, Dr. Varley said there aren't any studies specific to this area, but notes figures for the prairie region indicate between 20 and up to 50 per cent of dairy herds are exposed to Johne's disease, with beef herds at a much lower rate.

"Every year we diagnose a couple cases in beef herds, so it's here, but it's not a huge problem," she said.

As far as humans are concerned, there is no medical evidence to suggest any connection between animals with Johne's and the human equivalent, Crohn's disease, but research is ongoing. Dr. Varley notes that the medical community has been speculating since the 1920s about a possible link, but to date no evidence of any link has been found.

Animals are exposed via the fecal oral route and it's picked up by other ruminants; of top concern to producers and vets are baby calves, who seem to be the most susceptible to pick it up.

The bacteria can be passed on if a cow's udders aren't clean, or if the cow herself is contaminated, it can be passed through the milk to the calf, said Dr. Varley. If a calf does become infected, the bacteria has an extremely long incubation period before the animal comes down with it. Typically vets deal with mature animals which are five to seven years old when they come down with the disease.

She noted most ruminants become immune to the disease as they get older, but some animals can be carriers of the disease without becoming infected with it themselves.

Dairy producers are more aware of Johne's disease, because if one cow is infected, chances are very good all of the baby calves in the herd may be exposed to it.