A KIRO Team 7 Investigation exposed the business of buying and selling unhealthy cattle.

We've showed you how "downer cows" get past USDA meat inspectors and into a local slaughterhouse. Our hidden-camera videotape also revealed some questionable treatment of some animals.

Now, we follow the money trail.

When sick or injured dairy cows no longer produce milk, farmers either call up the rendering plant or take the cow to one of just a handful of meat packing plants, which will turn the downer cows into human food.

VIDEO: Downer Cows Investigation: Part II

Consumers have made it clear to us: They don't want to eat meat from these kinds of cows. But money talks, so the downers industry thrives.

Rich Van Dam is a respected dairy farmer, taking care of 400 head of Holstein. Occasionally, one of his "mothers," as he calls them, ends up a "downer," unable to stand any longer.

Instead of paying a rendering plant $100 to kill and haul away the cow, he profits by selling it to a USDA-inspected slaughterhouse.

"The downer meat, there's nothing wrong with it to me. I have a real hard time letting that meat go to waste," Van Dam said.

Midway Meats in Chehalis turns Van Dam's used-up milk cows into boneless beef. The process gets far more secret from there on. That's because it's not good for business to let consumers know they are buying downer hamburger.

"Why would you take the risk?" asks Dr. Lester Friedlander.

Friedlander is a former USDA meat inspector. He says after what he's seen inside plants like this, consumers need to demand downer meat warning labels on their ground beef.

"It's federal money, your tax money in this program, so I think the consumer should have some say in how they want their meat processed," Friedlander said.

Animal rights groups like PETA say food safety issues aren't the only problem with downer meat. They say our videotape of a crippled cow being hanged by the neck, still kicking, should make all consumers stop and think.

"Every time we sit down to eat, we make a decision. Do we support animal cruelty or don't we? If we're eating these products, we're supporting that cruelty," said Bruce Friedrich, with PETA.

Farmers like Rich Van Dam say that's unrealistic. People want beef, without knowing all the details about how it gets to the plate.

"There's no slaughterhouse that'd be a pleasant site to watch. It's the end process for a cow. It's sad to watch, but that's the way the industry works," Van Dam said.

Our investigation is far from over. We discovered some major food chains promising customers they won't buy downer beef due to quality concerns. Is it finding its way into their meat aisles anyway? That will be the focus of a future report.