All businesses and industries have mantras and mental models that are used to motivate and inspire. A common motivator and rallying cry for those of us in agriculture is that we “feed the world.” You’ve no doubt seen bumper stickers on the back of a pickup truck proclaiming, “If you eat, thank a farmer.”
That message (“we need to feed the world”) is a good motivator inside the industry, although in the past I’ve argued it might not always be selling point to people outside the industry. The message is not entirely inaccurate, but it’s not entirely accurate either. There are other ways to think about what agriculture is “doing” that might also be productive and enlightening.
Another way to think about agriculture is as a means to harness and store energy and nutrients. Or, as a producer of biomass, some of which later gets turned into food. An apt analogy is think of corn (and many other staple crops) as living solar panels. The plants capture energy from the sun and store the energy in many tiny batteries (i.e., seeds) that are easily storeable and transportable.
So, how much of agriculture is about “food” vs. other things? A while back, I showed trends in farm acreage over the last century in the United States. As those data reveal, just four crops account for about 95% of all planted farmland: corn, soybeans, wheat, and cotton. Cotton (at about 5.6% of the total) is, of course, a fiber with a few minor food uses (oil and hulls/seeds fed to livestock). The two biggest crops, corn and soy, with roughly the same acreage planted to each, together account for about 70% of planted crop acres in the U.S. What happens to all that corn and soy?
Here’s a graph I a created about a year ago, showing the supply and use of corn in the U.S. (data are from the USDA). Of the total corn supplied to the U.S. market in the 2016/17 marketing year (454 million metric tons, MMT), more than 40% went to a category the USDA calls “food, alcohol, and industrial use,” which is mainly alcohol for fuel or ethanol. Some of this indirectly ends up as animal feed in the form of "spent” or “distillers” grain left over after fermentation (livestock as food waste preventers is a vastly underappreciated aspect of our food supply chain). More than 30% of corn supply goes directly to animal feed. The rest is exported, stored, or is seed for next year.
Here is a similar figure for soy. About 44% is exported and then 41.5% is crushed for meal and oil. Most of the meal is used for livestock feed, and a little less than one-third of the oil goes to producing bio-diesel.
In these two figures, we see that our two main commodity crops grown in the U.S. are primarily used to produce fuel, alcohol, and to feed animals.
There are of course many critics of agriculture who look at these facts and bemoan the amount of acreage devoted to feeding livestock and producing fuel. But, this get’s back to my original point. The criticism is premised on the notion that the purpose of agriculture is to grow food, but what if we instead re-imagined the purpose of agriculture is something different: to produce energy and nutrients? I’ve written a lot about whether it is proper to view corn and soy fed to livestock as an inefficiency or waste, so I won’t delve into that whole bit again in this post; the point for now is that this only looks inefficient if one views the entire point of agriculture as a means to produce calories that end up on our plate. (BTW, see this tweetstorm for a humorous and eye opening look at the ubiquity of corn in our food and daily lives. My favorite quote in all of it: “Corn is not a food. Corn is a platform.”).
If corn is a solar panel and seeds are batteries, then livestock and poultry are machines that are “hooked up” to the batteries, which power the animals to produce useful outputs, some of which are food and some of which are not.
When we take a closer look at animal production, we see that a big portion (maybe most?) doesn’t go to human food. A simple way to look at this is to consider the dressing percentage of cattle, hogs, and broilers. The dressing percent is the weight of the carcass (which contains most of the edible meat plus bones) divided by the live weight of the animal just prior to harvest multiplied by 100. For hogs, a typical dressing percent might be around 70%, so for a 250 lb live hog, one only has 175 lb of carcass, and much of that is bone. Or, for cattle, a 1,200 lb steer equates to only a ~750 lbs carcass. (I should note that some of the weight removed from the carcass is “food” - hearts, kidneys, etc., - that is infrequently eaten in this country unless we’re talking about our pets). From the carcass, one might end up with 400 to 500 lbs of edible meat, depending on how it is cut and the amount of fat. So, only about 30 to 40% of the live weight of a finished steer ends up in form of what we typically think of as “food.”
One might be temped to think: that’s really wasteful. But, it isn’t as if the other 60 to 70% of the animal is just thrown away! There are interesting stories of the late 19th century meat mogul Gustavus Swift trudging out in his dark suit and top hat to inspect the sewer pipes that flowed out of his Chicago packing plants to look for trace amounts of fat or hair in the river, because anything that escaped was lost revenue. Where do all the modern animal byproducts go? Check out this interesting video - cows end up in everything from lipstick to jet fuel.