We've come to think of 'corn-fed' as some kind of old-fashioned virtue, which it may well be when you're referring to Midwestern children, but feeding large quantities of corn to cows for the greater part of their lives is a practice neither particularly old nor virtuous. Its chief advantage is that cows fed corn, a compact source of caloric energy, get fat quickly; their flesh also marbles well, giving it a taste and texture American consumers have come to like.Yet this corn-fed meat is demonstrably less healthy for us, since it contains more saturated fat and less omega-3 fatty acids than the meat of animals fed grass. A growing body of research suggests that many of the health problems associated with eating beef are really problems with corn-fed beef. (Modern-day hunter-gatherers who subsist on wild meat don't have our rates of heart disease.) In the same way ruminants are ill adapted to eating corn, humans in turn may be poorly adapted to eating ruminants that eat corn. Yet the USDA's grading system has been designed to reward marbling (a more appealing term than 'intramuscular fat,' which is what it is) and thus the feeding of corn to cattle. Indeed, corn has become so deeply ingrained in the whole system of producing beef in America that whenever I raised any questions about it among ranchers or feed-lot operators or animal scientists, people looked at me as if I'd just arrived from another planet. (Or perhaps from Argentina, where excellent steaks are produced on nothing but grass.) The economic logic behind corn is unassailable, and on a factory farm there is no other kind. Calories are calories, and corn is the cheapest, most convenient source of calories on the market. Of course, it was the same industrial logic—protein is protein—that made feeding rendered cow parts back to cows seem like a sensible thing to do, until scientists figured out that this practice was spreading bovine spongiform encephalopathy (BSE), more commonly known as mad cow disease. Rendered bovine meat and bonemeal represented the cheapest, most convenient way of satisfying a cow's protein requirement (never mind these animals were herbivores by evolution) and so appeared on the daily menus of Poky and most other feedyards until the Food and Drug Administration (FDA) banned the practice in 1997. We now understand that while at a reductive, molecular level protein may indeed be protein, at an ecological or species level, this isn't quite true. As cannibal tribes have discovered, eating the flesh of one's own species carries special risks of infection. Kuru, a disease bearing a striking resemblance to BSE, spread among New Guinea tribesmen who ritually ate the brains of their dead kin. Some evolutionary biologists believe that evolution selected against cannibalism as a way to avoid such infections; animals' aversion to their own feces, and the carcasses of their species, may represent a similar strategy. Through natural selection animals have developed a set of hygiene rules, functioning much like taboos. One of the most troubling things about factory farms is how cavalierly they flout these evolutionary rules, forcing animals to overcome deeply ingrained aversions. We make them trade their instincts for antibiotics. Though the industrial logic that made feeding cattle to cattle seem like a good idea has been thrown into doubt by mad cow disease, I was surprised to learn it hadn't been discarded. The FDA ban on feeding ruminant protein to ruminants makes an exception for blood products and fat; my steer will probably dine on beef tallow recycled from the very slaughterhouse he's heading to in June. ('Fat is fat,' the feedlot manager shrugged, when I raised an eyebrow.) Though Poky doesn't do it, the rules still permit feedlots to feed nonruminant animal protein to ruminants. Feather meal and chicken litter (that is, bedding, feces, and discarded bits of feed) are accepted cattle feeds, as are chicken, fish, and pig meal. Some public health experts worry that since the bovine meat and bonemeal that cows used to eat is now being fed to chickens, pigs, and fish, infectious prions could find their way back into cattle when they're fed the protein of the animals that have been eating them.
Michael Pollan, The Omnivore's Dilemma: A Natural History of Four Meals












