Library Categories


Metal ingestion a risk for hardware disease

Austin Hinds, food-animal medicine and surgery specialist at the Caine Center, University of Idaho, says hardware problems are most common in dairy cattle and feedlot beef animals.

That’s because of mechanized feeding systems. “Metal pieces may break off the mixer wagon and end up in feed.”

Baled hay may contain chopped-up pieces of wire. Cattle may pick up small metal pieces or nails when grazing. “Hardware disease occurs when a cow eats something sharp that pokes through the wall of the reticulum — the forward-most stomach that catches heavier material,” Hinds says.

Key Points

• Processed feed can sometimes contain bits of wire or metal from equipment.

• Heart failure occurs if metal goes through reticulum and diaphragm into heart.

• Magnets are often given to dairy cows to prevent hardware disease.

If it goes partway into the wall, it may cause an abscess. If it goes completely through, bacteria from the stomach leak into the abdominal cavity. If a small area is contaminated, the animal may wall it off, but significant leakage causes peritonitis. Worst-case scenario is if it goes through the diaphragm and into the pericardium surrounding the heart,” says Hinds.

In that situation the cow becomes sick immediately. “Soon the infection squeezes the heart and it can’t pump blood adequately, and the cow goes into heart failure.”

Hardware disease may occur right after calving. “The sharp object may have been sitting harmlessly in the reticulum until the physical effort of labor — with the diaphragm pushing against the stomachs — pushes the wire or nail through the stomach wall and diaphragm,” says Hinds.

“A common source of hardwire fragments is a feed-mixing wagon. These often have a magnet affixed to the chute to grab any metal pieces and keep them from getting into the feed.”

Use of magnets

The best way to prevent hardware disease is with rumen magnets. “In a dairy, every replacement heifer should be given a magnet. These usually drop into the reticulum and sit in the bottom of it for the life of the cow. If she eats anything heavy it ends up down there and sticks to the magnet instead of being churned around in the stomach and pushed through the wall,” says Hinds.

Very few beef operations use magnets routinely. “Veterinarians and stockmen sometimes give an animal a magnet after the fact as treatment, but this rarely works because the magnet is not strong enough to pull something back out of the wall once it starts through. Having the magnet in there first is more helpful,” he says.

“When giving magnets, you need to know whether the cow already has one, or the two will line up side by side and decrease their magnetic field and effectiveness. We use a compass alongside the animal to detect whether she already has one, if the owner doesn’t have records on whether she was given a magnet earlier.”

Smith Thomas writes from Salmon, Idaho.

Watch for signs of disease

Signs of hardware disease include arched back, reluctance to move, distress and discomfort. “In a dairy situation you recognize it immediately because a cow drops off in milk production dramatically on the day it happens. In a beef herd, you might notice the cow standing off by herself,” says Austin Hinds, food animal medicine and surgery specialist at the Caine Center, University of Idaho.

She won’t have much fever. “Infection is often localized or walled off. Even severe peritonitis causes only mild fever such as 103.5 in cattle, compared with pneumonia in which temperature might be more than 105 degrees,” he says.

Sometimes you never know the cow ate hardware unless metal objects are found at slaughter, or old adhesions are discovered during surgery for something else.

“If the object punctures the pericardium, however, the animal goes into heart failure. Then we see bottle jaw [swelling/edema under the jaw] or brisket edema, or jugular distension. The milk vein will also be distended and firm when pressed, rather than soft,” says Hinds.

A warning: Austin Hines, food-animal medicine and surgery specialist at the Caine Center, University of Idaho, warns that cattle can ingest harmful items.


RUMEN MAGNET: This photo shows a new magnet (on left) and one that has collected foreign metal objects.


Sick to its stomachs: This dairy cow suffers from hardware disease.

This article published in the March, 2013 edition of WESTERN FARMER-STOCKMAN.

All rights reserved. Copyright Farm Progress Cos. 2013.