Why do some farmers make their cows swallow magnets?
Cattle can get what is called “hardware” disease. Cattle will eat any bit of small metal they find. The magnet collects all the pieces of magnetic metal (wouldn’t help with aluminum) into one area of their rumen (stomach). This prevents the metal from traveling through their digestive system, and punching holes here and there. The magnets are about the size of a man’s thumb, and rounded on both ends. One problem….you have to make sure you get only ONE magnet into the cow. Otherwise two magnets may end up in separate compartments of the rumen, and then find each other, and stick together through the tissue of the rumen. This would eventually wear a hole in the cows rumen. A magnet does not completely stop problems with hardware disease. If the pasture is too dirty, with too much metal, the cow will still have too much metal in their system, and something will eventually break free, and start poking holes. Here’s a link on hardware disease, if you’d like: nz.answers.yahoo.com/question/index?qid=20080523061809AAqk4jP