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Johne’s disease: Cheap to buy, costly to live with

“Biosecurity” often conjures up images of poultry or hog operations with truckers-report-at-the-gate signs, shower-in-and-out rules and workers dressed in hazmat suits. The point of biosecurity practices is obviously to reduce the risk that disease-causing microbes will enter or spread within high-health status herds or flocks.

It is much harder to implement high levels of bio­security in beef operations. I’ve heard a cynic say that biosecurity only prevents diseases that are too big to fit between two strands of barbed wire. I stopped saying that when someone pointed out that most diseases aren’t coming through the fence. Most diseases are bought and paid for and come straight through an open gate along with the newly purchased cattle that are carrying them.

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Let’s use Johne’s disease as an example. It’s relatively uncommon in Canadian beef herds but well worth avoiding due to its significant economic costs, animal welfare concerns and impact on the operation’s reputation. Cows with active Johne’s disease can’t absorb nutrients well. This results in chronic diarrhea and loss of body weight and body condition score. As with underfed cows, Johne’s disease results in later rebreeding, lighter calf weaning weights, and losing or culling cows before they have recouped their production costs.

A producer can introduce and spread Johne’s disease to a well-run herd just by buying the wrong animal. Johne’s cannot be prevented by vaccination or effectively treated by antibiotics, and accurately identifying and culling infected animals is very difficult before they get visibly ill. Johne’s disease also can’t be prevented by high herd health, nutritional, grazing, or genetic management. Many beef producers may think they have closed herds, but realistically speaking hardly anyone does. Appropriate biosecurity is the best thing producers can do to help keep Johne’s from entering their herds.

Johne’s disease seems rare, but there are concerns that the risk of its spread is increasing. Drs. Cheryl Waldner and John Campbell led the Western Canadian Cow-Calf Surveillance Network (WCCCSN) under the 2013-18 Beef Science Cluster. Testing in participating herds indicated that fewer than six per cent of herds and two per cent of cows in Alberta, Saskatchewan and British Columbia were infected with Johne’s disease. These may look like small numbers, but further analysis showed that Johne’s disease may be 30 per cent more common in small herds than large herds. If large herds are growing by purchasing cows and heifers from herds that are downsizing or dispersing, they may be putting themselves at risk of introducing Johne’s disease. Statistics Canada confirms that Canada’s beef herd is consolidating. In 1996, Canada had 142,157 beef farms averaging 17 cows, with 11 per cent of all beef cows in herds larger than 273 head. By 2016, Canada’s 53,837 beef farms averaged 69 cows, with nearly 30 per cent of cows in herds with more than 273 head.

All these cows changing hands may be placing expanding operations at risk. A separate WCCCSN survey indicated that about a quarter of producers purchased foster calves from other farms. All the surveyed farms purchased bulls. Two-thirds purchased cows or heifers at auction marts. Purchasing cattle is essential to introduce new genetics, if you need to grow the herd faster than replacements can be raised, or if raising heifers doesn’t fit your skills and interests. There are some simple things that can be done to make buying breeding stock less risky, most of which involve asking questions about the health of the herd the cattle were coming from.

Only one-third of producers asked about the disease history of the animals they were purchasing, and only one-sixth asked about specific diseases. Johne’s disease was the specific disease asked about most often. This was especially true for producers who’d had recent experience with Johne’s disease.

Having learned how easy Johne’s disease can be to introduce to their herd, and how terribly challenging it can be to get rid of, these experienced producers tend to be a lot more careful next time.

Connecting with a seller to learn about their herd health practices and history before deciding whether to buy takes work, is uncomfortable and can cost more up front. But buying a load of anonymous cows at a bargain price can be even more expensive in the long run if you eventually learn that they came with an unwanted disease like Johne’s. There are a range of circumstances between those two extremes. Your veterinarian can guide you in what and how to ask and look for. The nature of the answers, production records and veterinary statements provided can also help figure out how much confidence to place in the answers and help assess your own biosecurity practices.

Would you feel more comfortable paying a bit extra for new electronics with a warranty and money-back guarantee, or buying partly wrapped electronics out of some guy’s trunk before Christmas? Fall cow sales will be starting before long. Ask questions and be careful what you buy. Ignoring biosecurity may buy you more than you bargained for.

More information about Johne’s disease and its management is available online.

The Beef Research Cluster is funded by the Canadian Beef Cattle Check-Off and Agriculture and Agri-Food Canada with additional contributions from provincial beef industry groups and governments to advance research and technology transfer supporting the Canadian beef industry’s vision to be recognized as a preferred supplier of healthy, high-quality beef, cattle and genetics.

— Dr. Reynold Bergen is the science director of the Beef Cattle Research Council.

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Dr. Reynold Bergen is the science director of the Beef Cattle Research Council.

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