Vicky Bond
The feed animals eat on factory farms—made from crops like corn and soybeans—is far removed from their natural diets. And it's linked to environmental destruction around the world.
In some parts of the continental United States, you might experience the strange phenomenon of driving for hours through a nearly unchanging landscape. Stretching for miles and miles, vast swaths of soil are dedicated to growing crops—the corn, grains, fruits, and vegetables that make up the foundation of the US food system. The process seems highly efficient, producing enormous quantities of food every year. But only a small percentage of these crops will go to feeding humans—just 27%, to be precise. So what happens to the rest?
Some are used for ethanol and other biofuels. And the rest—more than 67% of crops grown in the US—are used for animal feed.
Rather than feeding people, these crops will feed the billions of chickens, cows, pigs, and other animals who are currently being raised for food on factory farms. That means that all this food won’t feed humans directly; it will feed animals, who will then be raised and slaughtered for human consumption. And that’s a problem.
The issue is that feeding humans in this indirect way—essentially, making animals the caloric middlemen—is an extremely inefficient use of food. It takes about 100 calories of grain to produce about three calories of beef, or 100 calories of grain to produce 12 calories of chicken. In fact, researchers have found that if we grew crops exclusively for humans to consume directly, we could feed an additional four billion people.
Farming has always loomed large in American politics, history, and identity. But the idyllic farming we imagine—rich piles of compost, seedlings poking through soil, and flourishing gardens of diverse fruits and vegetables—has transformed into factory farming, a system far removed from earth and soil. So let’s take a closer look at animal feed, the massive industry that makes factory farming possible—supplying the cattle feedlots, broiler chicken sheds, and egg factories that increasingly make up the foundation of our food system.
If we grew food exclusively for humans to consume directly, we could feed an additional four billion people.
What is farm animal feed made of?
Take a moment to picture a farm animal enjoying her dinner. Are you imagining a cow grazing on grass, or perhaps a chicken pecking at the ground, foraging for seeds and insects? In today’s factory farming system, the “feed” these animals eat today is far removed from their natural diets. Rather than munching on grass or insects, the vast majority of animals on factory farms eat some type of animal feed—a cost-effective mixture of grains, proteins, and antibiotics designed to make them grow as quickly as possible.
The ingredients in animal feed don’t just matter to the animals’ health. They impact human health, too—especially since the average American consumes 25 land animals every year. Researchers have noted that animal feed ingredients are “fundamentally important” with regard to human health impacts. As author and journalist Michael Pollan puts it: “We are what we eat, it is often said, but of course that's only part of the story. We are what what we eat eats too.”
So what are the main ingredients used in animal feed today?
Corn and other grains
In 2019, farmers planted 91.7 million acres of corn in the US. That comes out to about 69 million football fields’ worth. How is it possible that so much land can be devoted to a single crop—especially something many people only eat on occasion?
The answer is that corn is in almost everything Americans eat today. It’s just there indirectly—in the form of animal feed, corn-based sweeteners, or starches. The US is the largest producer, consumer, and exporter of corn in the entire world. And a large percentage of all that corn is used for animal feed, supplying factory farms across the country.
While “cereal grains”—grains such as barley, sorghum, and oats—are also used for animal feed, corn is by far the number one feed grain used in the US, accounting for more than 95% of total feed grain production. Corn supplies the carbohydrates in animal feed, offering a rich source of energy to increase animals’ growth.
Unfortunately, what this system offers in efficiency, it lacks in resilience. Numerous researchers have expressed concern about the vulnerability of a food supply so reliant on a single crop. “Under these conditions, a single disaster, disease, pest or economic downturn could cause a major disturbance in the corn system,” notes Jonathan Foley, PhD, executive director of Project Drawdown. “The monolithic nature of corn production presents a systemic risk to America’s agriculture.”
Soybeans
When you think about soybeans, you might imagine plant-based foods like tofu and tempeh. But the vast majority of soybeans are used for—you guessed it—animal feed. Animal agriculture uses a whopping 97% of all soybean meal produced in the US.
While corn is rich in carbohydrates, soybeans are the world’s largest source of animal feed protein. Similar to corn, Americans might not eat a lot of soybeans in the form of tofu, tempeh, and soy milk—but they do consume soy indirectly through animal products like meat and dairy.
Unfortunately, soy production comes with its own downsides. It’s heavily linked to deforestation, driving the destruction of forests, savannahs, and grasslands as they’re converted to farmland. Critical habitats, like the Cerrado savannah in Brazil, are razed to clear space for soybean production, all to meet demand for animal feed. Tragically, over half of the Cerrado’s native landscape has already been lost, with livestock and soybean farming as a major contributor.
It’s a common misconception that plant-based soy alternatives, like tofu, are driving global deforestation. In fact, only 7% of soy is used directly for human consumption. To fight this tragic habitat destruction, it’s far more effective to replace meat with soy-based alternatives.
Animal protein and waste
Note: This section contains some confronting descriptions.
Disturbingly, it’s not just plants like corn and soybeans that go into animal feed. The factory farming industry has a long history of feeding animals the waste and proteins from other animals. In 2014, outrage ensued when an investigation by The Humane Society of the United States revealed pig farmers feeding animals the intestines of their own piglets. At a huge factory farm in Kentucky, workers were filmed eviscerating dead piglets and turning their intestines into a purée that was being fed back to mother pigs.
This wasn’t even an isolated atrocity. The executive director of the American Association of Swine Veterinarians commented that the practice was “legal and safe,” meant to immunize the mother pigs against a virus called porcine epidemic diarrhea. And pigs aren’t the only animals who are effectively turned into cannibals by the factory farming industry.
Farmers were only prohibited from feeding cow meat to other cows following concerns about bovine spongiform encephalopathy (BSE), more commonly known as mad cow disease. As the USDA notes on their website, BSE may have been caused by feeding cattle protein from other cows. The practice was banned in 1997—but only because of the risks to human health, not out of concern for the animals.
Antibiotics
So far we have carbohydrates, proteins, and fats. But another key ingredient in animal feed likely isn’t something that comes to mind when you think about animal nutrition. This secret ingredient is antibiotics—which are widespread in the food being given to animals across the country.
On factory farms, animals are confined in extremely crowded, filthy facilities—the perfect conditions for spreading illness and disease. Not only do antibiotics allow animals to survive the conditions in these facilities; they also encourage animals to grow unnaturally large, unnaturally fast. Drugs are administered through food and water and are given to prevent animals from getting sick, starting when they're just a few days old.
The problem? The meat industry’s excessive antibiotic use has been directly linked to antimicrobial resistance (AMR), a massive threat to human health. As bacteria are killed off and surviving bacteria remain, they gradually learn how to survive the attacks, becoming resistant to antibiotics over time.
AMR means that conditions that should be easy and affordable to treat—like ear infections—can become life-threatening. It’s “one of the biggest threats to global health, food security, and development today,” according to The World Health Organization, and is projected to kill four times as many people per year as COVID-19 did in 2020.
Additives and preservatives
Along with the mixture of corn, soybeans, and cocktail of antibiotics, animal feed may also contain a plethora of additives and preservatives. The Code of Federal Regulations provides a very long list of additives legally permitted in animals’ food and drinking water. These include “condensed animal protein hydrolysate” (produced from meat byproducts of cattle slaughtered for human consumption), formaldehyde, and petrolatum—just to name a few.
Animal feeding operations
Of course, we can’t talk about animal feed without talking about animal feeding operations.
Of all the animals in our food system today, 99% live on factory farms—enormous, vertically integrated operations designed to make as many profits as possible (at the expense of animals, people, and the environment). The transition to using animal feed has been closely intertwined with the transition to this type of large-scale factory farming.
What are concentrated animal feeding operations (CAFOs)?
The official term for a factory farm is a concentrated animal feeding operation, or CAFO. As the name implies, these operations are laser-focused on feeding large numbers of animals until they reach “slaughter weight,” when they will be killed and turned into products.
The faster an animal reaches slaughter weight, the more quickly the industry makes a profit. So factory farms have dialed in on the most efficient way to feed animals in the shortest amount of time. Rather than grazing on pasture, animals are confined in stationary cages or crowded sheds and given feed that will increase their growth rates—even while it hurts their health.
Take cows, for example. Along with sheep and other grazing animals, they are known as “ruminants”—because they have a rumen, an organ perfectly designed to transform grass into protein. But the industry feeds cows corn instead of grass, because it brings them to “slaughter weight” much faster than grazing does. Sadly, this high-starch diet can disturb a cow’s rumen, causing serious bloat, acidosis (or heartburn), and other types of stomach upset.
When it comes to feeding animals on factory farms, these are some key industry terms to know:
- Growth rates. This is the rate at which an animal grows, or how quickly the animal reaches “slaughter weight.” Sadly, most of the animals on factory farms are bred to grow so quickly that their health suffers. Chickens raised for meat frequently develop bone deformities, muscle diseases like white striping, and heart problems. Some chickens have difficulty walking, or even just standing, for the duration of their short lives.
- Feed conversion ratio. This is the ratio between the amount of feed an animal eats and the amount of body weight they gain. In other words, a feed conversion ratio is the industry’s effort to feed animals as little as possible, while making them grow as quickly as possible.
- Selective breeding. This is the practice of breeding two animals to produce offspring with a desired trait. For example, the poultry industry breeds birds who quickly develop outsized breast muscles. In the meat industry, selective breeding is generally used to optimize both feed conversion ratio and growth rates.
Animal feed industry impacts
On the whole, factory farming is incredibly resource-intensive and harmful to the environment. From agricultural runoff to water waste and pollution, CAFOs are responsible for some of the worst climate impacts humanity faces today. But the practice of growing crops for animal feed is one of the worst drivers of environmental destruction—leaving biodiversity loss, deforestation, and greenhouse gas emissions in its wake.
Deforestation
Growing the crops necessary to feed such huge numbers of animals ends up requiring vast amounts of land. And it’s resulting in deforestation on a massive scale. As you read this, forests around the world are being cleared and re-planted with mono-crops (such as the corn and soybeans mentioned earlier) to meet demand for animal products—and therefore, animal feed.
Brazil, for example, is one of the world’s biggest exporters of beef. In the Amazon rainforest, much of which is within the borders of Brazil, crops for animal feed are one of the primary drivers of deforestation—damaging an essential habitat for countless species. In the Amazon, deforestation rates have averaged two million hectares per year, or about seven football fields every minute.
Almost seven football fields of land are cleared or burned every minute to make space for animal agriculture
Biodiversity loss
Naturally, deforestation goes hand-in-hand with biodiversity loss—of which animal agriculture is also a key driver. A 2021 study found that land-use conversions (including deforestation) for animal agriculture are a primary driver of biodiversity loss. Tragically, researchers project that over 1,000 species will lose at least a quarter of their habitats by 2050 if meat consumption continues at the same rate.
At the UN Biodiversity Conference in late 2022, delegates warned that, if our land-intensive eating habits don’t change, more and more critical species will go extinct. As Michael Grunwald points out for The New York Times: “When we eat cows, chickens and other livestock, we might as well be eating macaws, jaguars and other endangered species.”
Water use
Along with vast amounts of land, growing crops for animal feed requires huge amounts of water. In the US alone, approximately 60% of freshwater is used to grow crops—the majority of which are used for animal feed. Corn, soybeans, and the other grains used in animal feed require about 43 times more water than grass or roughage, which animals could access if they were allowed to graze.
Soil degradation
The intensive farming practices required to grow huge amounts of crops—like corn and soybeans—even take a toll on the soil itself.
Healthy soil is full of millions of living organisms, which naturally replenish and recycle organic material and nutrients. Soil filters water, stores carbon, and allows for carbon, nitrogen, and phosphorus cycles that are critical for life on earth.
But intensive farming practices, like growing “monocultures” (huge amounts of one crop, like corn or soybeans), can degrade soil and deplete key nutrients. Not only do these farming practices prevent soil’s natural processes, but they can also reduce the amount of carbon stored in soil—a huge problem in the face of climate change. Intensive agriculture, closely intertwined with factory farming, is damaging our soil beyond repair.
How can I help?
The impacts of our animal-based food production system are far-reaching and complex. The intensive farming practices that supply animal feed for factory farms are destroying our water, air, and soil—and harming countless animals in food supply chains. But it’s not too late.
The movement to build a healthier food system is growing every day. Around the world, people are advocating for systemic change—from plant-based food options to better treatment of farmed animals. Together, we can hold corporations accountable for animal abuse and environmental degradation.
We created our Fast Action Network to give you quick, effective ways to take action for animals suffering on factory farms. Are you ready to build a better food system from the ground up?
