The most important step in prevention is to keep wire and metal objects out of feed. Feed-delivery systems should have magnets on conveyer belts to capture metal. And feed conveyers should be checked frequently to make sure their magnets are clear and able to operate.

In addition, work to keep hayfields as “clean” as possible. And, be careful when swathing or baling along a fence that might have broken wires out in the field that a swather or baler might chop up. 

Niehaus recommends giving cattle magnets. “In a cow-calf operation where cattle aren’t being fed a total-mixed ration, it’s less likely you’ll have problems, unless there’s wire chopped up in baled hay.”

But if a cow seems a bit “off” and you suspect she might have ingested foreign material, a magnet is a good idea. This might help keep a piece of metal from penetrating through the stomach wall, Niehaus says.

“Some farmers and ranchers routinely give magnets as a preventive, or put one into any cow that starts showing signs akin to hardware disease,” Miesner says. Inexpensive magnets are available for as little as $2, but it’s a preventive step rather than a treatment, he says.

Miesner says the traditional wisdom held that any cattle with magnets should be identified to avoid inadvertent administration of a second magnet. The thinking was that two magnets in the reticulum might line up and cancel each other out, he says.

“We hear this a lot, but I’ve put them side by side on my desk and they still attract and collect metal pieces. But if you want to check cattle for magnets, use a compass.”

If a metal object is just starting to poke into the stomach wall, a magnet may pull it back and hold it. “Once it goes through the wall, however, there’s no way to get it to come back. But as the stomach contents churn around, the magnet may attach onto metal and keep bringing it back away from the wall,” he says.