Magnets can help prevent hardware disease in cattle herds
Cow Magnets | Stanford Magnets
Cow Magnet – Exploratorium
Amazon.com: Master Magnetics COW-RUM5CX3BX Cow Magnet, Ultimate Heavy Duty Ru-Master 5, Steel Ring and Ferrite, 0.75" Diameter, 3.375" Length, Black and Silver (Pack of 3) : Industrial & Scientific
For cows, a magnet one day can keep the surgeon away – A new I don't know thing for curious kids – 2 New Things