Cow magnets

Domesticated cattle often ingest small bits of metal in their feed, called tramp iron, like staples, baling wire, or nails. These can cause damage to the digestive tract in a phenomenon known as Hardware Disease. The incidence and severity of this condition can be reduced by feeding the cow a device called a cow magnet. This gathers together all of the loose, dangerous bits of metal together and prevents them from moving around and causing damage. This magnet cannot be passed, and remains in the animal until death.