Category Archives: grass-fed

The Myth of the Grass-Fed Pig

Previously in this series: Food, Inc. Part I: No Bones in the Supermarket and Food, Inc. Part II: Is the food more dangerous?

Pigs at High Farms in South Carolina, which are rotated between the field and forest and probably do eat some grass. Pigs can be grass-fed in the same way that humans can be spinach-fed. Greens can make up a small percentage of our total caloric intake, but if we tried to survive on them alone, we'd starve.

When Pigs Fly Eat Grass 

From his profile on the School of Social Work, click for page 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.

From an ad for Honeywell by The Q Group, click for full adRuminants 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).Vegetarians have been all up in Al Gore's business for not becoming a radical vegan. Fairlie, who I discuss below, challenges the oft-cited 18% stat on animal-produced greenhouse gasses, see his book for more. Image from, click for more

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.

Don't be sad, lil guy, it's not your fault they hate you. Image from, click for URL 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.

Food, Inc. Part II: Is the food more dangerous? Aiming for the heart instead of the head

I know the print is small, so fyi: the source of the "more than terrific--important" plug is Entertainment Weekly.

Part I of this series is here.

The Claim: “The food has become much more dangerous”

When NPR’s Steve Inskeep interviewed Robert Kenner and Michael Pollan about Food, Inc. he noted that the entire film can basically be summed up by one sentence spoken by an unattributed voiceover close to the beginning of the film:

Now our food is coming from enormous assembly lines where the animals and the workers are being abused, and the food has become much more dangerous in ways that are being deliberately hidden from us.

There are parts of that claim that I don’t dispute at all. A lot of the food—not just in this country but around the world—is mass-produced using assembly-line production. Many of the animals raised in industrial-scale agriculture are subjected to enormous pain and discomfort and conditions that require vast quantities of synthetic hormones and antibiotics to make them get big enough and live long enough to be profitable (even Pollan chose to feed the steer he bought during his research for Omnivore’s Dilemma corn and horomones instead of grass). Food processing plants are often dangerous places to work—according to the government, “In 2007, rates of work-related injury or illness for full-time food manufacturing workers were higher than the rates for all of manufacturing and for the private sector as a whole,” with especially high rates in the seafood and dairy industries. And the jobs pay very little. In the last few decades, the meatpacking industry in particular has come to  depend heavily on undocumented immigrant workers who are far less likely to seek compensation for job-related illness and injury or unionize to bargain for better conditions and wages out of fear that the employer will report them to immigration enforcement officials (and some companies have been accused of knowingly hiring undocumented workers who they can pay less than minimum wage). So please, don’t mistake me for a defender of the industrial animal agriculture system. It sucks for most of the animals and people involved.

Except for the consumers. I think that’s why Kenner and Pollan have to make the argument that the food is less “safe” even though they don’t have any real evidence to back up that claim. Animal rights and exploited immigrant workers might elicit a little sympathy from some people, but most of the people whose eating habits are actually going to be changed by those things alone have probably already been converted. Kenner and Pollan make a big deal about how it’s so hard to get this information, but I think they underestimate the average consumer. Just because there are happy-looking cows on the packages, that doesn’t mean most Americans are really duped into believing their meat and dairy come from halcyon farms, just like a million smiling suns on food packages don’t really convince anyone that the sun has a mouth. People know the meat production system is ugly—that’s the entire thrust of the cliché about not wanting to see how sausage is made. But if you really want people to stop eating industrially-produced meat, you have to convince them that it’s bad for them and/or their kids.

2006 edition with a forward by Eric Schlosser: grisly butchered cow staring at you with a sad, accusing eye 1980s cover apparently designed by someone who actually read the book and perhaps thought students being forced to read it deserved fair warning: an old painting of people who look poor and sad. 2006 edition with a forward by Eric Schlosser: grisly butchered cow staring at you with a sad, accusing eye

Upton Sinclair discovered the same thing over a century ago. The Jungle—as I was surprised to discover when I taught it a few years ago—is a novel about the exploitation of the mostly-immigrant workforce that powered the industrial revolution, not a piece of journalistic muckraking about the meatpacking industry. And it’s not subtle. It’s about the most heavy-handed treatment of the subject you could possibly imagine. Sinclair doesn’t leave any room for confusion about his agenda, which is not reform of the food system. But, of course, that is its legacy. Over 400 pages of leaden prose and cheap melodrama designed to reveal the crushing poverty, the lack of social support and legal protections, the punishing nature of the work, and the impediments to social mobility, and instead, people got their panties in a bunch over the idea that the meatpacking industry was insufficiently sanitary. As he famously put it:

I aimed at the public’s heart, and by accident I hit it in the stomach.

To abuse his metaphor a little bit, I don’t think Sinclair’s problem was his aim, but his weapon. He was so focused on trying to bludgeon the public in the heart with his softball-sized hunk of purple prose about worker’s rights that he didn’t even realize he’d shot a perfect, bullet-sized piece of rat shit-tainted sausage at its stomach.

Food, Inc. aims for the heart,too, with perhaps the most lethal form of sentimental appeal: be afraid for your children. I kept waiting for the film to offer some kind of real evidence for the “more dangerous” claim—or at least specify what ideal past moment the comparison was based on (pre-pasteurization and refrigeration, perhaps?). Instead, the “dangerous” part of the argument is carried almost entirely by the story about Barbara Kowalcyk, whose son Kevin died from eating hamburger that was contaminated with E. coli. The contaminated meat was recalled, but not in time to save her son. And that is tragic. You’d have to be a monster not to feel for a mother crying over the loss of her son and trying to find a way to make sure that never happens to any other family.

Kevin’s law sounds like an entirely reasonable piece of legislation—it calls for the UDSA to do a survey of food-borne pathogens and develop a plan to reduce their presence in the food supply, and gives them the power to shut down plants that fail inspections and don’t take corrective action. I have not spent a lot of time with this law, and I’m not a law or policy expert—if you have or are, please let me know what you think. What I do know is that even if it’s a good law, it probably wouldn’t have saved her son—the meat that killed him wasn’t from a plant that had failed any inspections. Nor would she have been able to save him by feeding him only pastured beef, even if that were financially and logistically possible. As Food, Inc. also reminds us, many of the recalls in recent years have involved things besides meat, like spinach, jalapenos, and peanut butter. And don’t let the equally-falsely-pastoral marketing of Big Organic products or the Food, Inc. soundtrack choices fool you; if E. coli or salmonella gets into the water, “organic” food is just as vulnerable to contamination as conventional.

The Claim: Grass-Fed Beef Have Less of the E. coli O157:H7

The main reason the documentary gives for how industrial agriculture might be making the food supply more dangerous than pre-industrial or organic agriculture (or whatever else they’re comparing it to) is that feeding cows grain (mostly corn) instead of the grass they evolved to digest increases the prevalence of dangerous E. coli in their shit, which occasionally makes its way into our food. I actually thought that was well-established scientific fact, largely due to the 2006 NYTimes editorial about the source of the contamination in the spinach, “Leafy Green Sewage,” which said:

It’s [E. coli O157:H7] not found in the intestinal tracts of cattle raised on their natural diet of grass, hay and other fibrous forage. No, O157 thrives in a new — that is, recent in the history of animal diets — biological niche: the unnaturally acidic stomachs of beef and dairy cattle fed on grain, the typical ration on most industrial farms.

The editorial refers to a study in which, allegedly:

When cows were switched from a grain diet to hay for only five days, O157 declined 1,000-fold.

But that turns out to be not quite right. The review article in The Journal of Dairy Science they’re talking about mentions two studies in which generic E. coli declined in cows switched from a feedlot-type ration to hay, but neither of them measured E. coli 0157.H7. Most forms of E. coli are harmless. Additionally, the first study (Diez-Gonzalez 1998) only involved three cows and the second was never published, so it’s impossible to evaluate. Still, as a response to the NYTimes editorial noted, those findings did suggest that perhaps grain-feeding was more likely to cause the dangerous E. coli, too, assuming O157 works just like the generic forms. But subsequent research hasn’t supported that assumption: 

A substantial number of papers by researchers around the world have documented that cattle on pasture or rangeland (i.e., eating grass) have E. coli O157:H7 in their feces at prevalences roughly similar to those of confined, grain-fed cattle of a similar age (Sargeant et al, 2000; Fegan et al, 2004b; Renter et al, 2004; Laegreid et al, 1999). One study (Fegan et al, 2004a) found a higher prevalence among pastured cattle and, among positive cattle, similar concentrations of E. coli O157:H7 in feces.

Furthermore, if the problem was grain-feeding, then all O157 contamination would be caused by feedlot manure. Not so:

Several outbreaks and sporadic cases of human disease have resulted from pasture or water contamination with E. coli O157:H7 from grazing animals (Ogden et al, 2002; Locking et al, 2006) and several papers have documented environmental contamination with E. coli O157:H7 originating from cattle on pasture (Strachan et al, 2002; Ogden et al, 2005; Strachan et al, 2006; Looper et al, 2006). (Hancock and Besser 2006)

There are other reasons industrial animal agriculture might be “more dangerous”: 1) the close quarters in CAFOs may make E. coli contamination from fecal matter on hides harder to avoid during slaughter, 2) the speed of contemporary meat processing may make E. coli contamination harder to avoid, and 3) the health implications of hormones and agricultural antibiotics are still sort of unclear. But what’s the proof? Are more people getting sicker and dying because of industrial agriculture than without it?

It turns out there’s not a lot of long-term data, and even if there were, it would be difficult to evaluate because on the one hand, increases might reflect advances in the detection and tracking of pathogens, and on the other hand, a lot of cases of food poisoning still go undetected because they’re difficult to distinguish from other causes of GI distress. What little data is available suggests that infections from the most common forms of food-borne pathogens have decreased since 1996:

Vibrio is usually caused by eating raw oysters and shellfish. The CDC suggests that the higher relative rate in most years post-1998 may be due to inconsistent or insufficient refrigeration of shellfish consumed raw.

In 1999, the CDC estimated that food-borne pathogens caused approximately 76 million illnesses, 325,000 hospitalizations and 5,000 deaths in the United States every year. That’s more, per capita, than England or France (26,000 illnesses and 1.7 deaths per 100,000 Americans vs. 1,210 illnesses and .9 deaths per 100,000 French), so the people who claim that the U.S. has the “safest food in the history of the world” are wrong, too. It seems probable that a more centralized inspection system with better enforcement powers could improve our food safety, which is why reforms like Kevin’s law seem like a good idea.

But some people—including adorable children, who are especially vulnerable to the nasty death-causing complications of food-borne pathogens—are going to die no matter what we change about the food system. And depending on what we change, I worry that a lot of people, including adorable children, could starve. More on that later on in the series, when I get to the film’s list of what you can do.

It’s also worth noting that none of the above is being “deliberately hidden” from anyone. It’s available to anyone with an internet connection, probably because it’s not especially damning. I agree with Food, Inc. that there are hidden costs associated with industrialization—but it’s the animals and the workers who suffer the brunt of those costs, not the consumers. Maybe the people behind Food, Inc. had access to other evidence that does suggest the food supply really is more dangerous, but if so, why didn’t they include it in the documentary? There are only two options here: either the people behind Food, Inc. didn’t do their research, or they did, but opted not to show it in favor of manipulative sentimental appeals.