Feed Your Cow A Magnet

Feed Your Cows A Magnet

©Lauritzen 2020

            Veterinarian Dave Wenger* got a call from a farmer about a cow that was dying. The farmer said he’d already lost two cows. Dr. Wenger suspected hardware disease so he did field surgery to explore the cow’s stomachs.  After administering the anesthetic, the vet opened up the stomach and reached in and, ouch!, something poked his finger.  He pulled out the object and showed it to the farmer--a large screw.  It had penetrated the wall of the reticulum into the diaphragm and was poking at the cow’s heart.  Before sewing up the animal, Doc left a magnet inside the stomach. 

Where did that sharp object come from and how did it get into the cow’s stomach?  And why would the vet put a magnet in the cow’s stomach?

Hardware disease can be a problem for cows, especially ones fed chopped-up feed. The farmer in this story had a new hay shed and the builders had left a lot of nails and screws scattered everywhere. When the farmer scooped up the hay, he also picked up some dirt that had nails and screws in it.  Feed, dirt and metal all went into the mixer and then into the feed bunks where the cows swallowed it. Cows gulp mouthfuls of food and don’t chew it much before swallowing.

If there is a piece of metal in the food, it goes right into the cow’s first stomach. That’s right—cows have more than one stomach. The first stomach, the rumen, holds about 40 to 50 gallons. In this stomach, the food is churned around and ferments. Any metal such as a piece of wire, a part of a metal can, or a nail will move around and eventually either settle to the bottom of the rumen or move with the food into the next stomach, the reticulum. The reticulum is next to the cow’s diaphragm and just past the diaphragm is the tip of the heart. The metal pieces all end up in the reticulum because the third stomach is above the reticulum and the metal is too heavy to move up. If there is a sharp piece of metal, it can poke through the lining of the stomach into the cow’s diaphragm and interfere with breathing or into the heart and cause heart failure.

This is where a magnet can help. A cow magnet is a strong magnet about the size of a finger. It is stuck down the cow’s throat using a bolus gun to make sure the cow swallows it. The magnet will end up in the reticulum and metal in that stomach will stick to it. This keeps the metal pieces from hurting the cow. Even though the magnets cost about three dollars, they can be a good investment for a farmer trying to keep the herd healthy.

The happy ending to the story is that the farmer was grateful to Doc for saving his cow and for getting advice about how to prevent hardware disease in the rest of his herd.  Just feed the cows a magnet!

*Thanks to Dave Wenger, a terrific veterinarian, for the information and ideas that helped in the writing of this story.