A Comparison of Cow and Human Digestive Tract Anatomy 

The digestive differences between cows and humans

Ruminant animals, like cows, have a digestive system uniquely designed to eat large quantities of plant matter, effectively break down the fiber, and absorb the nutrients in plants. Let’s compare how cows and humans digest food.

Sink Your Teeth Into This

While you don’t have fangs like lions, tigers, and bears, you also don’t have teeth like a cow. Fangs are also unnecessary when you can craft sharp cutting tools from obsidian or other stones.

Cows have no front teeth on their upper jaw and only have molars. Cows have a large, hard dental pad at the front of their mouth, which they use to grasp vegetation. A cow’s bottom jaw has incisors in the front to tear and rip vegetation, followed by more molars for chewing and grinding.

On the other hand, your teeth are designed to bite and tear into food. Run your tongue along the back of your front teeth. Notice the slight angle? These are called ‘shearing crests’ and function the same way the edge of a knife blade does. Your front teeth cut through your food when you take a bite. 

Digestion Starts in the Mouth

When cows eat grass or other plant matter, they don’t chew it first. Instead, they swallow the mouthful whole and continue until they’ve filled their rumen (more on that soon!).

Properly chewing your food doesn’t just prevent choking. Chewing breaks down your food into smaller bits, and stimulates digestive enzymes in your saliva. These enzymes start breaking down your food before it even hits your stomach. Humans take a bite of food and chew it before swallowing, and cows do not. 

Size Matters

A cow’s stomach can hold about 25 gallons of food, while humans can hold approximately one quart. A cow needs to eat many plants to get enough protein and nutrients.

Cows also need a larger stomach because it can take 24 to 72 hours for a cow to digest its food completely. Your stomach, however, usually takes 40 to 120 minutes to digest food, depending on what you eat. Fats and protein take more time to digest than carbohydrates, which is one of the reasons why you feel fuller for longer when you eat fatty meats.

Cow Stomach: Form and Function

A cow is a ruminant herbivore. This means cows have a four-chambered stomach designed to eat and digest plant matter.

Rumen

The rumen is the biggest of the four stomach chambers. When a cow swallows plant matter, it first goes into the rumen. The rumen is a storage tank that can hold up to 25 gallons of food. The rumen has no stomach acid. Instead, bacteria in the rumen go to work breaking down the cellulose (fiber) found in plants. 

Reticulum

When some of the plant matter in the rumen is broken down, it passes to the reticulum. Like the rumen section, the reticulum doesn’t have digestive acid, only bacteria. 

The reticulum allows the cow to regurgitate the partially digested plant matter back into its mouth, where the cow will then chew this wad of food. 

This is where the phrase ‘chewing the cud’ comes from. Chewing the cud further breaks down the plant matter before the cow swallows it again. Cows spend 35-40% of their day chewing cud.

Omasum

Once the cow swallows the ‘cud,’ it enters the omasum, where water and some nutrients are absorbed.

Abomasum 

Food moves from the omasum to the abomasum. This final compartment of the cow’s stomach contains acid to break down the plant matter further and absorb more nutrients before passing it to the cow’s intestines.

As you can see, it takes a lot of time and work for a cow to digest the plants it eats and obtain all the nutrients it needs. 

Human Stomach: A One-Way Street

Unlike the cow, your stomach has one chamber. Your stomach uses mechanical and chemical processes to digest your food. 

The inside of your stomach is ‘rippled’ with muscles that churn and mix your food with digestive enzymes, acids, and bile to break down your food in an efficient manner appropriate for your body. Once your food is broken down into a liquid, it moves to the small intestines, where nutrients are absorbed. 

Human digestion is a very efficient and effective system. It allows you to eat your food and get on with your life. You don’t have to spend most of your day chewing your food to unlock those necessary nutrients.

Your stomach also produces hydrochloric acid, with an extremely acidic pH of 1.5-2.0. The only other animals that have this are predators and scavengers, both dedicated meat-eaters.

The Difference Is Clear

When you compare the digestive system of a cow to that of a human, it’s clear that humans are not herbivores. Ruminant animals, like cows, can take in large quantities of plant matter, break down plant fiber, and absorb the nutrients locked within. Humans can not. 

From the structure of your teeth to the digestive enzymes in your mouth and down to your single-chamber stomach, your body is designed to obtain the nutrients and complete proteins from a low-carb diet that includes meat.