Farmers feed cows with a magnet to improve their growth and milk quality
Magnetic pill, also known as cow magnet, is a preventive veterinary medical device for cattle. A rancher or dairy farmer feeds a magnet which is usually in a form of pill or a ring to each calf at branding time; the magnet settles in the rumen or reticulum and remains there for the life of the animal thus preventing occurance of hardware disease.
Photo source: Flickr
The cow magnet attracts metallic objects and particles, preventing them from becoming lodged in the animal's tissue. While the resultant mass of iron remains in the cow's rumen as a sort of bezoar, it does not cause the severe problems of hardware disease.
Hardware disease is usually caused by ingestion of tramp iron in fodder or silage. Sharp metallic objects are ingested and settle in the reticulum, and can irritate or even perforate its lining. If the object perforates the reticulum and reaches the pericardium it causes a severe inflammation resulting in lower milk production (bad for dairy cattle) or lower weight gain (bad for feeder stock).