Turns out that the most valuable parts of cows are the ones that can be sold to medical companies. They're using pituitary glands, bones, heart muscles and hides to make things such as bone screws and artificial skin. Weird.
Tough times in the commodity beef market in 1975 forced Prather Ranch to scale back its herd. No new animals have been introduced since. In a lucky coincidence, closing the herd turned out to be great for business. Combined with the cattle's long-time strict vegetarian diet, the closure ensures that cattle have never been exposed to bovine spongiform encephalopathy, or mad-cow disease, which first emerged in the 1980s.
The Rickerts' unique situation brought them to the attention of a company looking for a safe supply of cowhides to turn into collagen, often used for lip injections. After constructing a custom abattoir, or slaughterhouse, in 1995, they began to attract attention from other medical and pharmaceutical companies.