Hardware in Cattle

by Heather Smith Thomas

Cattle occasionally swallow foreign material-- such as pieces of wire chopped up by a baler. Hardware disease occurs when a sharp object penetrates the gut lining and damages some other organ or creates peritonitis (infection within the abdomen).

Todd Tibbitts, DVM, veterinarian in Salmon, Idaho, says the problem is more common than we realize, since cattle often eat foreign material with their feed and only occasionally have sharp objects penetrate the stomach. "Up to 70 percent of slaughtered cull dairy cows have some form of hardware, without having shown clinical signs. This either means they have a magnet (which kept the object safely inside the stomach) or the object was not sharp enough to penetrate the stomach."

Sometimes the stomach takes care of the object. "At post- mortem I've retrieved rusty nails that were nearly dissolved by the forestomach fluid. I've also found many types of rocks and heavy objects. Roofing nails are the most common things in dairy cows, since people quit using baling wire," he says. In beef cattle the biggest problem is wire and junk that ends up in baled hay.

Feedlot cattle don't show signs of hardware as often as older animals that have longer to accumulate foreign material, but it can happen occasionally, since hardware is most common in animals being fed prepared feeds (rather than grazing at pasture). Wire that has passed through a feed chopper or forage harvester is one of the most common causes. In one study of 1400 necropsies, 59 percent of the lesions were caused by pieces of wire, 36 percent by nails and 6 percent miscellaneous objects.

Signs of Trouble
When the animal eats a sharp foreign object, the action of the stomach may push it through the stomach wall. The reticulum (second stomach, about the size of a volleyball, with honey-comb shaped compartments) is where the heavy material ends up. Once a nail or piece of wire (or sharp rock) goes through the stomach wall, it may puncture another organ or the heart cavity.

The most common signs of hardware disease are abdominal pain and discomfort. "The animal stands humped up with elbows out away from the body. Head and neck may be extended. The animal may be breathing hard, and grunt when it breathes. One way to check for hardware is to pinch the withers," says Tibbitts. When you pinch the withers of a healthy animal, it will reflexively lower its body to get away from the pinch. But an animal with hardware won't do this, because it hurts too much to move away from your touch.

"If a wire is just starting to migrate and the animal has peritonitis, fever will be 104 to 105. With a chronic case, it will be around 103 degrees. Respiratory rate is usually elevated and the animal is dull, reluctant to move, and off feed, sometimes grinding the teeth. Rumen contractions may be decreased."

At this stage, the problem might be mistaken for pneumonia. "Hardware can also be confused with an abomasal ulcer. These can show almost identical signs. With an abomasal ulcer, though, you usually see some blood in the stool--some dark, tarry stools. They don't always have a fever with an ulcer, however," says Tibbitts.

Early signs of hardware (the first day after penetration of the stomach wall), may be mistaken for indigestion or acute carbohydrate overload in a feedlot animal; he goes off feed suddenly and is very dull.

"If peritonitis is severe, the animal may die within a couple of days. But chronic peritonitis may go on for months. It may also cause liver damage. The animal may just be doing poorly, and you might mistake it for some other problem," he says.

Some animals will actually recover. The body walls off the foreign object. But this can lead to other problems. If the foreign body is walled off and creates an adhesion, the reticulum may adhere to the abdominal wall and then the rumen cannot function properly.

"Sometimes the animal becomes a chronic bloater, due to vagal indigestion, being unable to belch to chew the cud properly.

The stomach is adhered to the body wall and therefore cannot slide and move or contract as it should," he says. A chronic bloater may actually be a chronic hardware, in some cases.

The best prevention for hardware disease is a magnet. Many dairymen routinely put a magnet in each animal when cows are young.

The best prevention in feedlot animals is to have all processed feed pass over magnets. "If you use a feed wagon (putting chopped or processed feed into a feed bunk), you can install a magnet on the feed truck--to pick up metallic material before it gets to the feed bunk," he says. Use of baling twine instead of wire has resulted in a major decrease in hardware disease.

Treatment
Once the animal is showing signs, the only way to treat it, if the foreign object has migrated out of the stomach, is exploratory surgery. This can be frustrating, however, because sometimes you are too late, he says. If the damage and infection is too severe, the animal may die anyway.

"I go in on the left side to do the laparotomy (surgical incision through the flank), and sweep down around in there to see if I can find something in the abdominal cavity, and remove it.

The abdomen is then flushed out with sterile fluids, and treated with antibiotics to clear up the infection," says Tibbitts.

"If the animal is just starting to show signs, however, I may give it a magnet and some time, to see if the magnet will pull the nail or wire back into the stomach," he says. The perforation in the stomach wall will usually heal and the wire will stay safely in the stomach, adhering to the magnet. ©