Dr. Steve Hendrick is passionate about Johne’s disease in beef cattle. I have had the privilege in knowing this young scientist since the early stages of his career and what he has to say is important. It comes as no surprise that his research into Johne’s disease, based out of the Western College of Veterinary Medicine in Saskatoon, has led to a short list of best production practices for the prevention and control of this bovine nightmare.
You may have heard of Johne’s disease as the organism is the suspect culprit in Crohn’s disease, present in some human populations. In the beef herd, Johne’s disease often infects calves early in their life through the exposure to contaminated manure, but does not express itself until later on. After infection, the organism, Mycobacterium paratuberculosis, hides away within the immune cells of the animal and then between the ages of four and seven years, the bovine starts to express the disease through weight loss and diarrhea. In beef and dairy cows this has a huge effect on milk production as the cow is struggling to ingest enough feed to keep producing milk.
Diarrhea is the symptom of a host of problems or diseases, so Johne’s can often be missed or rather difficult to diagnose. Testing for Johne’s is expensive and it is hard to culture in the manure. Regular testing and then culling works, but is rather costly. So the best medicine, until we have a rapid and affordable test for Johne’s, may simply be a dose of prevention.
It makes common sense not to buy cattle from a suspect herd or to buy high-risk, stressed calves. Getting back into the farmyard, managing risk is in the containment of and access to the manure. If manure is the proven source of the disease, it needs to be controlled. Hendrick reminds cow-calf producers to give cows and baby calves lots of extra room and bedding or rotate them out of the system as pairs to a clean area. At calving some calves need a little help along the way and unfortunately, we could be killing them with commercial kindness. In herds where commercial colostrum milk replacer was used, the incidence of Johne’s increased by four times. Again, what is unknown is the reason why the incidence climbs when commercial replacer is used.
This was not a backyard study that led to the suggested best management practices. It involved 23 infected herds and 29 non-infected herds that were located in BC, Alberta, Manitoba and Saskatchewan. So, there was very fair representation on size, type, location, environment etc. Taking all into account, the research team looked at 35 different factors. And that lead to some very interesting findings outside of the farm gate. In the latest research conducted by Dr. Hendrick, it became clear that there was guilt by association, so to speak.
Beef herds that had some sort of interaction with wild deer were 14 times more likely to be infected with Johne’s disease, even if the study could not pinpoint “who infected whom.” Even in an environment where deer were not present, those cattle that were continuously grazed were five times more likely to be infected than those cattle on a grazing rotation. We know that rotational grazing has huge benefit to the plant and the animal and now it is supported from the perspective of disease prevention. It is an easy and inexpensive practice to implement.
Johne’s is a serious production disease in cattle and is considered a high-risk association as a zoonotic (a disease that can be transferred to or from humans). Therefore Johne’s is by default a public health issue and it needs to be addressed.
Although the best in research is available to us through Dr. Hendrick and his associates, there are still many unanswered questions. We need more research in this area and we need new and rapid tests developed for Johne’s that are not cost prohibitive, allow for early diagnosis and are user friendly.
More importantly, the industry and her partners in research, animal and public health have been motivated to plan ahead, based on the research of the day, on how we will handle outbreaks, zoonotic associations and related food safety issues that are associated with this production disease.
Brenda Schoepp is a market analyst and the owner and author of Beeflink, a national beef cattle market newsletter. A professional speaker and industry market and research consultant, she ranches near Rimbey, Alberta. Contact her at [email protected]