Cow magnet is a kind of veterinary medical equipment used to treat or prevent hardware diseases of cattle. Hardware disease is a common term used for traumatic gastritis and traumatic reticulitis. From 55 to 75 percent of the cattle slaughtered in the eastern United States have been found to have hardware in the reticulum. However, no damage or perforations of the reticulum was evident.
Traditionally, cow magnets are strong Alnico magnets, in the shape of a smooth rod, about 1 cm by 8 cm (0.4 by 3.1 inches). However, today they are more commonly several ring-shaped ferrite magnets attached to a stainless-steel or plastic core.
The cow magnet works by attracting any metal objects and prevents them from travelling further through the body. Once swallowed, it remains in the cow’s stomach and collects magnetic foreign bodies rendering them harmless.