An Environmental Article from

The Unnatural Diets of Factory Farmed Cattle

From Shay Schmida, FFAC Factory Farming Awareness Coalition
November 2023

The U.S. could feed 800 million people with the grain used to feed U.S. livestock. Beef cows are fed around 57% corn, and dairy cows around 39% corn, rather than forage as their main source of feed: these diets lead to a profusion of health issues.

cattle grazing

Those who are familiar with what goes on behind the scenes on factory farms probably know about greenwashing, where terms like ‘grass-fed’ and ‘cage-free’ are used without restriction, and usually don’t mean what the average consumer assumes (big pastures, endless fields of grass, acres and acres of land, as opposed to the realities of enclosed and crowded barns and muddy pens). If cattle in large-scale animal agriculture operations aren’t ‘grass-fed’, then what are they fed? As it turns out, there is a whole world being disrupted due to the unnatural diets designed to make the animals grow as quickly as possible--and that is the world of the gut. Ruminating livestock that are conventionally used for meat in the United States, such as cattle and sheep, have digestive systems designed for specific diets of grasses, clover, legumes, roots, weeds, and a wide variety of other plant materials, and the inner biome of these animals is drastically disrupted when they aren’t fed a natural diet.

The Natural Diets of Livestock

So what do cattle typically eat in a natural setting? Ruminants (such as cows, sheep, and goats) are hooved animals with unique digestive systems. They have four chambers to their stomachs: the rumen, the reticulum, the omasum, and the abomasum. These four stomach chambers allow ruminants to digest plant matter that monogastric (species with one stomach chamber, such as humans) cannot. One of the ways they do this is through chewing cud (also called ruminating). Chewing cud is when a bolus of semi-digested food is regurgitated and re-chewed, breaking it up into smaller pieces, where it is then re-swallowed.

This process makes it easier for the microbes of the gut to digest the plant matter. Ruminants such as cows and sheep fall into the bulk and roughage eaters category, meaning they are dependent on fibrous plants and grass, called roughage. These animals also forage, which provides protein from legumes, maximizes ruminating and cud-chewing (which leads to a healthier gut) and minimizes potential health issues such as acidosis and laminitis. Chewing cud is an indicator of a healthy animal, and foraging for roughage is necessary for the internal workings of ruminants to function properly, as phytochemically rich mixtures of grasses and plant-matter enhances health and requires less antibiotics. Unfortunately, this is not how 70.4% of cattle are raised in the U.S.

What Happens in Factory Farms

‘Grass-fed’ is a term that can be applied to cattle raised for meat when they are raised in pastures for the first few months or first year of their lives, but 96% are soon moved to feedlots to live in crowded pens with hundreds, or thousands, of other cattle. They are fed diets of corn and soy, which are highly fermentable and carbohydrate-rich, and often medicated with antibiotics, growth hormones, and buffers. Beef cows are fed around 57% corn, and dairy cows around 39% corn, rather than forage as their main source of feed.

With these diets follows a profusion of health issues. Digestive diseases are the second highest cause of death in feedlot cattle. Beef cows raised on grain diets are less likely to chew their cud, which can create displaced abomasums and twisted stomachs, as well as result in acidosis and laminitis. Ruminal acidosis is a bovine metabolic disease that occurs when cattle are fed a diet high in grains, and results in a high prevalence and accumulation of acids in the rumen, or a decrease in ruminal pH, and an imbalance between microbial production, microbial utilization, and ruminal absorption of volatile fatty acids. To put it more simply: these highly-digestible carbohydrate diets increase acid in the stomach and impact the microbial balances that keep the body healthy. Without the proper roughage diet, the inner system can’t function properly.

Acute ruminal acidosis is more common in feedlots, while subacute ruminal acidosis (SARA) is more common in dairy cows. Symptoms include liver abscesses, ulcers, dehydration and diarrhea, infections of the lung, heart, and/or kidneys, neurological issues, and laminitis. In extreme cases, it can lead to death. Laminitis is directly tied to acidosis, as it is caused by a rapid increase in grains. When the acidity in the rumen increases because of this, digestive organisms die off and release toxins into the bloodstream. This causes the blood vessels in the hooves to swell, causing pain and lameness. The science behind these diets is extensive, and it is evident that factory farmed cattle are greatly impacted by having no access to their natural diets. What factory farmed animals are fed also impacts human health, compared to truly pasture-raised. And while one might not think a cow’s diet impacts the environment–it does.

Environmental Impacts

How does the diet of an animal affect its environment? For cattle, it comes in the form of their feed. The U.S. is the largest producer, consumer, and exporter of corn, with 90 million acres planted yearly, of which 40% is used for animal feed, as well as 70% of soybeans grown in the U.S. Monocultures such as corn and soy require a greater usage of pesticides, herbicides, and fertilizers, all of which impact the environment through the contamination of soil and groundwater. Monocultures also contribute to soil degradation and fertility loss, as one crop grown over and over again in the same field quickly depletes the nutrients, requiring even further use of chemical fertilizers to combat infertile soil. There is also a significant amount of air pollution that happens as a result of corn farming, as well as water consumption, as grain-fed beef takes over 26,000 gallons of water to produce 2 pounds of food, much of that going towards raising the crops that are used to feed them.

So what would happen if all those millions of acres of corn and soy and other grains that are grown to feed animals, were instead used to grow produce that would go straight to the plate? It turns out, the U.S. could feed 800 million people with the grain used to feed livestock. The production of animal protein requires eight times as much fossil-fuel energy as plant protein, and even if pasture-raised, truly grass-fed livestock was our only source of meat, Americans would still get more than their daily allowance. If the estimated 26 million tons of grains grown to feed livestock on 30 million hectares in the U.S. were instead used to feed humans directly, there would be no need for industrialized animal agriculture, the environment would not be so greatly impacted, and meat would be produced more sustainably and would be healthier.


Corn, soy, and other grains are not the proper diets for ruminating animals, but natural diets such as fresh grass and roughage makes for happier and healthier livestock, environment, and people.

Shay Schmida is a teller of tales, dreamer of dreams, and writer of all things. She is a college advocate at FFAC, and is interested in illuminating the issues of our food system through her writing.

Return to Environment Articles
Read more at Meat and Dairy Articles