Grass-Fed vs. Grain-Fed Beef – What’s the Difference?

Written by Kris Gunnars, BSc on December 4, 2019
Republished from

The way cows are fed can have a major effect on the nutrient composition of their beef.

Whereas cattle today are often fed grains, the animals people ate throughout evolution roamed free and ate grass.

Many studies have shown that the nutrients in beef can vary depending on what cows eat.

Where beef is mass-produced, such as in the United States, cattle are usually fed grain. However, grass-fed beef is common in many other countries, such as Australia.

You may wonder whether the way cows are fed makes any difference to your health.

This article looks at the evidence to determine the differences between grass-and grain-fed beef.

The Difference Between Grass-Fed and Grain-Fed Cattle

In the United States, most cows start living similar lives.

The calves are born in the early spring, drink milk from their mothers, and are then allowed to roam free and eat grass or other edible plants they find in their environment.

This continues for about 7-9 months. After that, most conventionally raised cows are moved to feedlots.

Large feedlots are called concentrated animal feeding operations (CAFOs). There, the cows are kept in confined stalls, often with limited space.

They are rapidly fattened with grain-based feeds that are usually made from a base of soy or corn. Typically, their diet is also supplemented with small amounts of dried grass.

Of course, it’s not that simple. The different feeding practices are complicated and varied.

For example, grass-fed beef in Australia may not be directly comparable to US products, and grass-fed beef isn’t necessarily pasture-raised. Not all grass-fed cows can graze outdoors.

In fact, the term grass-fed isn’t clearly defined.

That said, grass-fed cows eat (mostly) grass, while grain-fed cows eat (mostly) an unnatural diet based on corn and soy during the latter part of their lives.

To maximize growth, the cows are often given drugs, such as antibiotics and growth hormones.

As of January 1st, 2017, the Food and Drug Administration (FDA) passed new legislation known as the Veterinary Feed Directive. According to this legislation, antibiotics that are considered important in human medicine need to be administered under the oversight of a licensed veterinarian and cannot be used for growth promotion (1″).

Most cows start on a pasture, drinking milk and eating grass. However, conventionally raised cows are later moved to feedlots and fed mainly grain-based feeds.

Differences in Fatty Acid Composition

“You are what you eat” applies to cows, too.

What a cow eats can significantly affect the nutrient composition of its beef. This is particularly evident when it comes to fatty acid composition.

  • Monounsaturated fat. Grass-fed beef contains much less• Monounsaturated fat. Grass-fed beef contains much lessmonounsaturated fat than grain-fed beef (2).
  • Omega-6 polyunsaturated fats. Grass-and grain-fed beef contain very similar amounts of omega-6 fatty acids.
  • Omega-3s. This is where grass-fed makes a major difference,containing up to five times as much omega-3 (3).
  • Conjugated linoleic acid (CLA). Grass-fed beef contains about twice as much CLA as grain-fed beef. This fatty acid is associated with afew health benefits (4, 5).

In short, there are some significant differences in the composition and amount of fat in grass-and grain-fed beef.

Moreover, the breed and cut of meat considerably affect the fat composition of beef (2).

Grass-fed beef may contain less total fat than grain-fed beef, but a lot more omega-3 fatty acids and CLA, which are both linked to health benefits.

Both grain- and grass-fed beef are highly concentrated sources of nutrients.

Beef is loaded with vitamin B12, B3, and B6. It’s also rich in highly bioavailable iron, selenium, and zinc. In fact, meat contains almost every nutrient that you need to survive (6).

It also contains high quality protein and various lesser-known nutrients, such as creatine and carnosine, which are very important for your muscles and brain.

But even though the difference isn’t great, grass-fed beef generally contains higher amounts of certain nutrients. Compared with grain-fed beef, grass-fed is much higher in the following vitamins:

  • Vitamin A. Grass-fed beef contains carotenoid precursors to vitamin A, such as beta carotene.
  • Vitamin E. This antioxidant sits in your cell membranes and protects them from oxidation (4).

Grass-fed beef also tends to be richer in other antioxidants (7, 8).

Conventional grain-fed beef is highly nutritious, but grass-fed beef contains more carotenoids, vitamin E, and other antioxidants.