Recommended management practices for infected herds include:
Cattle producers should not let their guards down when it comes to Johne’s disease.
A prairie-wide disease surveillance program of more than 100 beef herds showed about 1.5 percent of herds tested positive for Johne’s, a slow moving, wasting bacterial disease.
“I am not sure we can say it is definitely getting higher but it does look like it might be trending that way,” said John Campbell of the Western College of Veterinary Medicine.
The school is running a five-year surveillance study looking for several diseases and conditions including:
- intestinal parasites
- neospora, a parasite that causes abortions
- trace mineral levels and deficiencies
- bovine leukosis, which can lead to cancer
- venereal diseases, such as trichomoniasis and campylobacter in bulls
The tests are not perfect for Johne’s and only indicate positive or negative results. They do not mean the cow is actually sick because the test measures antibodies in serum rather than the presence of disease. However, 1,800 cows in 93 herds were checked and 28 cows tested positive.
“Almost 24 percent of herds had at least one cow test positive for Johne’s disease,” Campbell said.
A production limiting disease survey across Canada in 2003-04 showed less than one percent tested positive.
All cattle are susceptible
The Beef Cattle Research Council reports about one to two percent of beef cows may be infected and two to nine percent of Canadian dairy cows may have it.
The disease is carried in manure and can be found on udders, feed or water supplies that are contaminated with feces from infected animals. Calves may also get it from colostrum and milk from infected cows.
It affects calves but they do not show signs of illness until they are between four and six years of age.
Infected cows may continue eating and look alert but as the infection works its way through the intestines, nutrients are not ab-sorbed and the cows get diarrhea.
They become very thin but in beef herds these cows are often culled before actual sickness is seen, said Campbell.
Johne’s is not a reportable disease, but there have been initiatives to track it and educate producers about the detrimental affects.
The Canadian Johne’s Disease Initiative works on education and eradication in a partnership between government, Dairy Farmers of Canada, Canadian Cattlemen’s Association and the Canadian Animal Health Coalition.
Biosecurity and assessment of risks are emphasized because the disease is hard to eradicate.
An infected cow can shed billions of organisms into the environment and pass on the infection to others through manure.
Besides keeping calving areas clean and dry, producers are reminded not to spread manure from a high-risk herd on pastures.
A closed herd is advised but if replacements come in, the history of the herd of origin should be known. Producers should try to pick cattle from herds with a health status equal to or better than their own.
For more about Johne’s Disease visit bit.ly/2mVOmX9.
- Cull animals exhibiting signs that suggest Johne’s disease. Have carcasses examined to confirm the diagnosis.
- Cull all offspring, dams and siblings of confirmed cases.
- Separate unthrifty animals from the herd.
- Clean and disinfect areas where infected animals have been kept. The bacteria are susceptible to 10 minutes exposure to five per cent formalin, 1:32 cresylic disinfectant, 1:40 phenol, 1:1000 mercury bichloride and 1:50 calcium hypochloride.
- Pasture calves on clean pasture and maintain in winter quarters separate from adults until the heifers enter the herd.
- Protect young animals from adult manure drainage.
- Ensure feed and water are not contaminated with manure. Drinking water should come from clean sources.