Answer: Magnets

If you’re a young calf ready for your vaccinations and life outside the barn, you’ll not only get your vaccinations, a dose of vitamins, and a thorough examination, but you’ll also get fed a stainless steel rod holding together a series of high-strength magnets about the size of a small human finger. The magnet will stay with you for the rest of your life.

Why feed a cow a magnet? In the course of grazing and life on the farm, cows unintentionally ingest all manner of metal objects including bits of wire, staples, and other metallic detritus. This is due largely in part to the fact that cows don’t really discriminate between what they’re eating and they don’t completely chew their food before swallowing—quite a bit of what they swing their large mouths toward ends up in their stomachs.

These foreign objects travel through the cows multi-chambered stomachs and often end up in their intestinal tract where they can snag and remain there for the cow’s life. This accumulation of metallic objects in the intestinal tract can cause what is known as “hardware disease” and has symptoms ranging from localized inflammation to decreased milk production and even death.

The purpose of the large pill-shaped magnets fed to the young calves is to serve as an entrapment device for future ingested metal objects. The metal objects stick to the magnet and remain in the first primary chamber of the cow’s stomach where they can do significantly less harm than if they had traveled freely through the cow’s digestive tract.