What Does “Grass Fed” or “Corn Fed” Mean?

posted on

September 5, 2023

I recently wrote an article about Grass Fed beef vs Grain Fed beef. This article goes into more specifics on the main grain that is fed to cattle: corn.  The most widely used definitions of the terms are: 

  • Grass Fed, also known as GrassFed and Grass Finished or 100% Grass Fed Beef is beef that was born to a mother who eats only grass and has eaten nothing but mother’s milk and grass or other naturally growing pasture forage its entire life. 
  • Grain Fed beef is beef that has been born to a cow and probably raised on pasture for the first 6-8 months of its life.  It is then switched to a grain diet that may include corn, soybeans, brewers grains, wheat, oats, rye or any other grains.  The grains are very high in starches and are fed to the animals so that they grow very quickly and get fat very quickly. 
  • Corn Fed beef is beef that has been fed mostly corn grain and soybean grain for the fattening period of its life. The fattening period is the last 6 to 8 months of the animal’s life, done in a feedlot or factory farm. 

It will be helpful to you as a consumer to know what your food ate before it got to you and how that affects your health.  By the end of this article you will have much more information so you will be more able to make up your own mind. 

Why do we care about grass fed or corn fed anyway? Underlying all of this information are the facts about fatty acids in human cells.  Basic Omega 6 and Omega 3 are called essential fatty acids because their basic forms cannot be made by the human body. They must come from our diet.  If these essential fats and the fatty acids made from them are near the correct ratio (1:1)  our cell walls are more healthy.  If the ratios get out of whack, the cells get out of whack and people get sick

Corn is high in Omega 6 fatty acids and low in Omega 3 fatty acids. In fact the ratio is about 46:1 in favor of Omega 6. The animals that eat a lot of corn have high ratios of Omega 6 to Omega 3 fatty acids in their cells. 

The imbalance of fatty acids also affects the health of cattle fed this imbalance.  This is one of the reasons that the volume of antibiotics fed to farm animals is so high. Antibiotics in animal feed is another whole ‘thing’ and I will probably write about it also. 

There are long lists of diseases that a correct ratio of Omega 6 to Omega 3 fats helps prevent or helps the symptoms of.  A list of some of these diseases follows with links supporting the data. 

Ulcerative colitis, arthritis, asthma, cancer, chronic fatigue syndrome, diabetes, heart disese, kidney disease, stroke, osteoporosis, osteoarthritis, hay fever, allergies, gout, autoimmune disorders, thyroiditis, multiple sclerosis and a whole host of other body failings. 

Being able to understand how and why corn became a major feedstock for farm animals is valuable information in making good decisions about what you eat. 

Corn became a feedstock for cattle and other farm animals after WW II for several reasons.  Two of the main reasons are: 

  • Corn is a VERY productive plant for comparatively little work. A seed gets planted in the late spring and by the end of summer it produces an ear of corn with about 800 kernals.  An acre of ground produces between 100 and 150 bushels of corn.  For comparison a football field is about 1.3 acres.  A bushel is 9.3 gallons, so a bit less than 2 five gallon buckets. A little math shows that a football field could grow about 156 bushels or 1451 gallons of corn grain. 

Corn also carries a lot of calories.  

  • A Bushel of corn contains about 100,000 calories of energy. 
  • An average man needs about 2500 calories per day.  He needs a lot of other things as well but we will leave that out for right now. 
  • A bushel of corn would last that man 40 days if he ate nothing else and didn’t worry about his health too much.  
  • A football field of corn would last that man 4800 days or about 17 years.  Or 17 people for one year.   
  • Before WW II, large machinery and chemical fertilizers were almost non-existent. 

WWII brought about huge advances in mechanization and also chemical knowledge. Big tractors, chemical fertilizers and the use of pesticides made production much more efficient. Farm production rose. 

Given that productive capacity, there was a surplus of corn.  Farmers started feeding the corn to cattle and soon realized that there was a great increase in growth rates as well as the amount of fat on cattle carcasses at slaughter. 

Side-by-Side Comparison: Grass Fed vs. Corn Fed

It is true that ‘we are what we eat’.  By the same token, we are what WE eat eats.  An animal that has a simple diet of carbohydrates is not going to have nearly the complexity or variety of compounds in its body as a pasture raised animal that gets a wide variety of forages in its diet. 

This can make factory farmed cows prone to disease and low immune system function. This is one of the reasons that antibiotics are fed to factory farmed animals.  The subject of factory farms and the use of antibiotics is a whole subject in itself. 

Pasture raised, grass fed animals have a much cleaner and stress free environment than factory farmed animals.  Stress is a big cause of chronic illness in animals as well as humans. 

Here is a table that gives a side by side comparison between grass fed and corn fed beef. 

Grass Fed

Corn Fed

Feed: Grass and other forages. Free choice by the animal. 

Nutrients of feed: High in lignin, active chlorophyll, vitamins, minerals 

Nutrients of product: Higher concentration of Omega 3 fats, More vitamins, minerals and antioxidants. Less fat overall but this can vary widely. 

Time from birth to slaughter: 18-30 months. 

Stress level:  Low 

Cleanliness of environment: Usually high but there can be mud and dirt. 

Environmental impact: Under debate. 

Little waste pollution impact. 

Higher Methane output due to longer life span. 

Management intensive grazing has been proven to sequester carbon. 

Added Hormone Use:  Not used. 

Antibiotics: Usually no, unless an animal gets sick.  Pasture raised animals are much less prone to disease than factory farmed animals. 

Feed: Mostly corn and soy. Brewers grains from corn. Small amounts of hay and silage.

Nutrients of feed: High in carbohydrates, quickly digestible.  Many vitamins and minerals have evaporated or were never there in the first place. 

Nutrients of product:  Much higher concentration of Omeag 6 fats. More fat overall, less vitamins A, E, antioxidants. 

Time from birth to slaughter: 12-18 months. 

Stress Level: High due to crowding. 

Cleanliness of environment: Lower than a pasture. More fly pressure. 

Environmental impact:  High. 

High waste pollution impact. 

Methane output is less than GrassFed due to shorter life span. 

Very high carbon footprint due to current farming techniques used in grain farming. 

Added Hormone use: Yes, to increase growth rates. 

Antibiotics: Yes. Usually done to combat diseases because of high carbohydrate diet. 

So is grass fed meat better than corn-fed?

In summary: 

  • GrassFed beef is more healthy as food than corn fed.  It provides a better fat profile as well as more antioxidants and vitamins.  It cannot be said that grass fed beef will supply all the Omega 3 fats, antioxidants, vitamins and minerals needed for a healthy diet for all people but it is much better than its counterpart, corn fed beef.   
  • As far as the health of the animals themselves goes, grass feeding is by far better.  The animal lives a very low stress and healthy life from the moment of birth to the day of slaughter. 
  • Environmentally, grass fed appears to be better than grain fed, though parts of this are still under contention.  Mono cropping to produce grains pulls carbon out of the soil whereas if that land were used as pasture under management intensive grazing, carbon would be going back into the soil and there would be far less emissions from machinery. 

See How Grass Feeding Compares to Other Feeding Types

This article has been written to contrast corn fed beef with grass fed beef.  The main differences in the two comes back to two things: 

  1. You are what you eat and the food you eat is what it eats.  If you eat a diet high in Omega 6 fats and low in Omega 3 fats you are susceptible to many chronic diseases.  
  1. A grass fed animal leads a non-stressful life the way it was evolved to do.  A corn fed animal lives in a high stress environment eating foods it was not evolved to eat.  It gets sick much more easily and thus is fed antibiotics. 

I hope this helps in your search for good health. 


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