Because cattle are reared on corn in beef factories.

You’ve read Michael Pollan and Eric Schlosser. You’ve seen “Food, Inc.” and the pictures in”CAFO.” Let’s take a brief tour of the beef industry, even if you’ve been on one before.

By “conventional beef,” I refer to an unconventional agricultural product. Against the 10,000 years humans have kept domesticated cattle, our present relationship with bovines is anomalous, a sliver of the swath. We used to live among our livestock and today, for the most part, we live away from them.

By conventional beef, I mean industrial beef. I mean the meat into which factory-farmed beef cattle are processed. I mean the new beef we now deem conventional because we know little else. There are other ways of rearing beef. These new methods are not conventional but exceptional.

Cheap beef begins with corn subsidies. Under the Farm Bill, the US government subsidizes corn more lucratively than any other crop. Between 1995 and 2006, corn growers received more than $50 billion in subsidies. Without these outside assets, corn would cost more to grow than it could command at market. This would spell ruin for processed foods, many of which consist of multiple corn-based ingredients.

Corn subsidies lower the price of conventional beef. Corn feed costs less than grass. With grass, farmers need to employ a livestock rotation system. Farmers also need ample pasture. Corn enables concentration. (The cornfields are elsewhere.) It also fattens cattle to slaughter weight in 14 to 16 months, which allows cattle to be processed more quickly.

Corn, however, doesn’t tell the whole story. The industrial model–large scale, high volume, and automated–curbs the cost of production to pennies. It costs more to pasture-rotate than feed cattle by machine. It costs more for a human to butcher a cow than a robot. The industrial model allows big beef to operate with efficiency. The corporate model affords the luxuries of lobbyists and revolving door friendships with government.

Perhaps most of all, conventional beef is easy to sell. Fast food and grocery store chains require high-volume shipments of beef. They turn to conventional beef, which industrial producers can supply in quantity for the lowest price. It’s hard for a niche market beef producers to find consistent buyers. For producers of conventional beef, the buyers are lined up.

Even within our anomalous sliver of the past 10,000 years, beef production has increased. In 1950, Americans ate 44 pounds of beef per capita. By 2007, we were eating 66 pounds per person. Such an increase speaks to the changed nature of our relationship to cattle. It takes consumer demand, industry, technology, corporation, and government to make a Big Mac cheaper than a salad.