Fly Eat Grass
The organizers of the free showing of Food, Inc. I attended last spring invited a few speakers to lead a discussion after the film over a vegetarian dinner. One of them was Dr. Brett Seabury, an Emeritus Professor of Social Work who has decided to spend his retirement raising cows, pigs, sheep, and chickens “naturally.” He showed us some pictures of his animals, and seemed especially eager to impress upon us how grass-dependent his whole operation is. His cows and sheep eat grass (unsurprising). His chickens eat grass, although that can’t be all they eat. Chickens can only get 30-35% of their calories from grass and other forage like clover and alfalfa, according to multiple sources including food movement demi-god Joel Salatin. If Seabury isn’t feeding his chickens grain or table scraps, they must be surviving primarily on insects, grubs, and seeds.
But his pigs, Seabury seemed ashamed to admit, still survive primarily on grain-based feed. They eat grass, too, he promised, and he said he was trying to increase the amount of grass in their diets. However, he admitted that he wasn’t nearly as “advanced” as a friend of his who raises a “special” breed of pigs entirely on grass. And if there were such a thing—a pig who could eat only grass—that would be pretty special. As I mentioned in passing in the last recipe I posted, pigs are extraordinarily efficient at producing meat in terms of speed and pounds of meat produced/pounds of feed consumed. According to Marvin Harris’s “The Abominable Pig”:
Of all domesticated mammals, pigs possess the greatest potential for swiftly and efficiently changing plants into flesh. Over its lifetime, a pig can convert 35 percent of the energy in its feed to meat compared with 13 percent for sheep and a mere 6.5 percent for cattle. A piglet can gain a pound for every three to five pounds it eats while a calf needs to eat ten pounds to gain one. A cow needs nine months to drop a single calf, and under modern conditions a calf needs another four months to reach four hundred pounds. But less than four months after insemination, a single sow can give birth to eight or more piglets, each of which after another six months can weigh over four hundred pounds.
However, as he notes later, there’s a crucial difference between the feed-to-meat alchemy performed by the pig and the kind performed by its barnyard pals:
Cattle, sheep, and goats thrive on items like grass, straw, hay, stubble, bushes, and leaves—feeds whose high cellulose content renders them unfit for human consumption even after vigorous boiling. Rather than compete with humans for food, the ruminants further enhanced agricultural productivity by providing dung for fertilizer and traction for pulling plows. And they were also a source of fiber and felt for clothing, and of leather for shoes and harnesses…. Feed [pigs] on wheat, maize, potatoes, soybeans, or anything else low in cellulose, and pigs will perform veritable miracles of transubstantiation; feed them on grass, stubble, leaves, or anything high in cellulose, and they will lose weight.
Ruminants can turn inedible vegetation into food thanks to their constant chewing (or ruminating) and their multiple stomachs, which are like a series of fermentation vats full of bacteria that help break down all those fibers and starches. Pigs just turn food into slightly-more-delicious food. And they do it at the cost of 65% of the feed’s initial caloric value, which is used to keep the pig warm and power all of its piggy activities like wallowing and rooting. To make matters worse, pigs aren’t really good for anything but producing meat. They aren’t suited for milking or shearing or pulling plows, and they don’t lay eggs. Even if it were slightly less efficient, a pig that could perform a grass-to-meat transformation would be the porcine equivalent of The Philosopher’s Stone. Or a bacon-producing version of the legendary golden egg-laying goose.
The Ecological Argument for Vegetarianism
The pig equation (Pork calories = .35 x Pig feed calories) is essentially the basis for one of the main arguments in favor of vegetarianism. It was the reason I stopped eating meat as a teenager after absorbing the basics of High School Biology, and although I’ve never actually read Frances Moore Lappé’s classic Diet for a Small Planet, my understanding is that it’s also the basis for her argument, which has inspired countless environmentally-concerned omnivores to eliminate or at least reduce the amount of meat in their diets. In terms of sheer caloric efficiency, meat sucks.
When Lappé started doing the research for Diet at the library at UC Berkeley, she discovered that it takes 21.4 pounds of feed protein to produce 1 pound of beef protein, 8 pounds of feed to produce 1 pound of pork, 5.5: 1 for chicken, and 4.4: 1 for milk (paraphrased by Warren Belasco in his brilliant Meals to Come: The History of the Future of Food). And even if those numbers can be nudged in the right direction by more efficient production systems (like battery-cage egg-laying operations, which require less feed per egg than free range or pastured system), they’re never going to get even close to 1:1 because animals will always have to use a significant portion of the calories they eat to keep themselves alive. This was what the units on photosynthesis and respiration taught me: plants are machines for making energy and cows are machines for burning it. Eating meat seemed wasteful, short-sighted, and maybe even outright ethically wrong in light of global hunger & food shortages.
And on top of the caloric inefficiency, domesticated animals also require fresh water, another limited resource (pending affordable desalination methods), and their waste produces gasses that contribute to rising global temperatures. Large farm operations, which is where the vast majority of our meat and animal products come from, also use mechanized systems for feeding, lighting, sewage flushing, ventilation, heating and cooling, all of which generate even more carbon emissions. They also depend on fossil fuel-driven transport to move the feed, animals, and products around at various stages of growth and processing. And to add insult to injury, something like 70% of the rainforests in Latin America have been cleared to make way for pastures where animals or their feed can be raised. (Here’s typical example of this argument in Time magazine).
But as it turns out, it’s not quite that simple. (I know, shocker, right? The world isn’t as simple as I thought at 18! Who would have guessed?)
In Defense of the Pig
If the pig were really such a bad caloric bargain, it never would have made it as a domesticated animal. Pigs would have been prohibitively expensive to raise—and, indeed, in areas like the Middle East, they were. Not for all time—there’s evidence that pigs had been domesticated in the areas that are now Jordan, Israel, and Iraq sometime before the early Neolithic period. However, as the human population density increased, nomadic people settled down, forests were destroyed to make way for agriculture, and the grazing land proceeded to become desert, pigs became prohibitively expensive. Marvin Harris again:
The pig had been domesticated for one purpose only, namely to supply meat. As ecological conditions became unfavorable for pig raising, there was no alternative function which could redeem its existence. The creature became not only useless, but worse than useless—harmful, a curse to touch or merely to see—a pariah animal.
He contrasts this with the case of the cow in India, which was subject to some of the same ecological changes—deforestation, erosion, desertification—but which became more useful than ever for plowing and milk, and thus became a blessing to look at or touch, and actually too precious alive to eat. He also notes that Islam has always had a much harder time getting established anywhere the pig is a major part of the traditional diet.
The reason the pig is part of traditional diets in many other parts of the world is because in the right ecosystem, it turns out to be pretty useful as a garbage disposal and forest scavenger. Pigs were traditionally raised on “slops” (or human food that’s been rendered unfit for human consumption) and the nuts and roots they could forage in wooded areas. Thus, rather than competing with humans for food, pigs ate things that people might technically be able to eat, but probably weren’t going to—fruit and vegetable peelings, table scraps, windfall produce, acorns, beechnuts, and truffles (which humans certainly like but have a difficult time finding on their own. Truffle-hunters still use hogs to help sniff them out and routinely lose fingers trying to snatch them away from under their noses).
The argument about the ecological wastefulness of meat is based on the idea that animals are eating food that humans could and would otherwise eat, but that’s a relatively recent development. This is essentially the argument Simon Fairlie makes in his recent book Meat: A Benign Extravagance, as paraphrased by George Monbiot:
Instead of citing a simple conversion rate of feed into meat, we should be comparing the amount of land required to grow meat with the land needed to grow plant products of the same nutritional value to humans. The results are radically different.
If pigs are fed on residues and waste, and cattle on straw, stovers and grass from fallows and rangelands – food for which humans don't compete – meat becomes a very efficient means of food production. Even though it is tilted by the profligate use of grain in rich countries, the global average conversion ratio of useful plant food to useful meat is not the 5:1 or 10:1 cited by almost everyone, but less than 2:1. If we stopped feeding edible grain to animals, we could still produce around half the current global meat supply with no loss to human nutrition: in fact it's a significant net gain.
Fairlie’s no fan of industrial agriculture, and he doesn’t think that it’s sustainable for people to continue eating as much meat as they do now, on average, in wealthy countries. Instead, he supports what he calls “permaculture” meat, or meat produced from biomass that is basically “free” in a system dedicated to the production of of vegetable food. Grass-fed ruminants are major part of that, but as he suggests, grass is not the only essentially-free source of animal feed. The key to sustainable pig production is to let them eat garbage. Marketing folks, get to work on this: how do you make “Garbage-fed Pork” as appealing as “Grass-fed Beef”?
This entry got a little long so I’m splitting it in two…more soon on why people like Professor Seabury get it wrong and the growing epidemic of Cornphobia.