The overwhelming majority of “hardware” ingested by cattle consists of wires 2-5.5 in. long.

“Shorter pieces may pass through the stomachs without causing a problem. Cows can ingest fence staples, barn nails, bits of wire or any other objects that find their way into feed; that’s why fathers yell at their kids to pick up nails and staples,” says David Steffen, a DVM with the University of Nebraska’s Veterinary Diagnostic Center.

Cattle can chew the ends of baling wire used to fasten panels to fences, for instance. In addition, there may be nails, roofing tacks and other metal objects around a barnyard or junk pile where cattle graze. In feedlots, metal pieces come off feed-handling equipment and get mixed with feed.

 “Another name for hardware is tire wire disease,” adds Matt Miesner, Kansas State University assistant professor of agricultural practices. “A frequent problem in the 1990s was ingestion of wire from old tires used as feeders or for holding down tarps on silage or feed piles,” he says. Over time, tires decay and the rubber disintegrates, exposing wire reinforcement. Those small wires may break up and get into the feed.

Knives or cutting blades in a mixer can wear out and fall apart, with bits and shards breaking off and going into the feed. Strong, heavy magnets on feed conveyers usually catch those, but they must be checked frequently to make sure they’re capable of attracting and holding metal pieces.

In addition, cattle are sometimes put into situations that make them vulnerable to hardware. During a drought, for instance, cattle may graze vacant lots, or people cut and bale grass along a roadway or other areas that generally aren’t grazed or baled. There may be junk piles or litter, loose bits of wire or other discarded objects.

Sidebar: Metal’s not always the culprit

Occasionally, some other type of object – even a sharp rock – may penetrate the stomach lining and cause peritonitis or damage the heart.

One rancher tells of a cow that suddenly showed signs of acute hardware disease and heart failure in late winter. She was humped up, reluctant to move, trembling and staggering; she died quickly. Upon necropsy, the veterinarian found a small, flinty rock of the shape and sharpness of an arrowhead that had gone through the lining around the cow’s heart. 

The day before the cow died, the herd had been moved to a different field, traveling across a driveway where hay had been spilled along the edge of the road, on shale-type gravel. The cattle had gobbled up some hay, and apparently this cow ingested a piece of sharp gravel with a mouthful of hay. A magnet would not have helped in this situation. 

Heather Smith Thomas is a rancher and freelance writer based in Salmon, ID.