I had to laugh when I passed this display at the Farmers' Union today (on the way to the cat food and the agricultural lime):
For those of you who didn't grow up in the country, you feed a heavy magnet to a cow so that when the cow eats nails, staples, etc. (and it will), they'll stick to the magnet in the cow's first stomach instead of tearing up the intestine. Mmmmmmm. Cow magnets. The ones pictured are plastic-coated, which seemed kind of yucky until I figured that if a cow is eating nails, a little bit of plastic doesn't sound so bad after all.