How Many Stomachs Does a Horse Have? (Equine Digestion Facts)

How many stomachs does a horse have?

As non-ruminant herbivores, horses have a unique digestive system.

It affects how they eat and what is safe for them to eat.

In this article, I will share facts about the horse digestive system, explain the difference between ruminants and non-ruminants, and answer some related questions about horse digestion.

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All About the Horse Digestive System

a sabino horse walking

Horses are non-ruminant herbivores, so they have plant-based and high-grain diets. Their digestive tract or digestive system has the mouth, esophagus, stomach, small intestine, and large intestine.

How Many Stomachs Does a Horse Have?

The horse only has one stomach with a single compartment or chamber. It is the smallest part of their digestive system, making up just 10% of the total volume.

The horse’s stomach only holds around 2 – 4 gallons of material, which is roughly the same as 8 cartons of milk. They have a very small stomach capacity in comparison to their body size.

Because the horse’s stomach is so small, it supports a slow rate of intake of forage several times a day.  Although the stomach only has a single chamber, this chamber has two distinct regions:

  • Glandular region – this region has all the cells that produce stomach secretions like hydrochloric acid and peptidases to break down proteins. It also makes mucus and bicarbonate to protect against the low pH of the acid 
  • Non-glandular region – this region does not have any of the protective features of the glandular region and is more prone to the formation of ulcers as a result

The functions of the stomach are mixing and churning to break down food, food storage, and the slow release of food into the small intestine.

Here is a video that explains more about the horse’s digestive system:

How Many Chambers Does a Horse’s Stomach Have?

As mentioned above, a horse has a single-chambered stomach. Because of this is that horses cannot store large amounts of food.

They need to be able to turn food into energy quickly to support their high activity level.

Parts of the Horse Digestive System

The horse digestive system consists of the mouth, esophagus, stomach, small intestine, and large intestine. This chart highlights each part and its function in horse digestion

Digestive System PartFunction
MouthIncludes the teeth, tongue, and salivary glands that release saliva to break down food. 
Esophagus The tube connecting the mouth to the stomach, once the food leaves the mouth it is squeezed down the esophagus to the stomach in a process called peristalsis
StomachMixes and stores food. It controls its release into the small intestine. It also secretes peptides to start protein digestion. Churned food moves from the stomach to the small intestine
Small intestine The small intestine is 70 ft long and makes up 30% of the digestive system. It absorbs nutrients and digests carbohydrates, protein, and fat.
Hindgut The hindgut is the last part of the digestive system and consists of the cecum, large colon, small colon, and rectum. Its main function is to digest the fiber that the horse gets through its diet

All of the parts of the digestive system work together to ensure that your horse gets proper nutrition.

When food cannot be properly digested, your horse will not have enough energy and be more prone to illnesses like impaction colic.

Interesting Facts About Horse Digestion

horses eating grasses

Now that you know about the stomach, here are some other cool facts about horse digestion that will get you thinking.

Fact 1: The Horse’s Esophagus Only Goes in One Direction

This means that food cannot come back up the esophagus and that horses cannot vomit. [1]

Since they cannot vomit, a horse choking could be a fatal accident. Have someone on your barn staff that knows how to help a choking horse.

Always seek a veterinarian’s help immediately for a horse with choke. It is an emergency that requires veterinary intervention.

I have been at the barn while a horse was choking, and although I did not witness the experience myself, I heard about it afterward and it is something I would not wish on any horse enthusiasts.

Fact 2: Horses Do Not Have Gallbladders

Because the horse’s digestive tract is designed a certain way to fit the structure of their body, they do not have room to fit a gall bladder. [2]

Ohio State University states that “The liver continually secretes bile to assist in fat digestion. Amazingly, horses can digest and absorb relatively high levels of fat in their diets despite not having a gallbladder.” [2]

READ MORE: Can a Horse Carry a 200 Pound Person?

Fact 3: The Microbes and Bacteria in the Horse’s Gut Adaptto the Food They Eat

When a horse’s diet is changed suddenly and changes are not introduced gradually, the microbes and bacteria cannot ferment the new food, which leads to colic. [3]

Horses must have all new food introduced a little bit at a time so that their body has enough time to prevent digestive disturbances and so they do not fall ill.

horse eating in a brown plastic bag

Fact 4: When a Horse’s Stomach is Empty, the Stomach Acid Can Break Down the Stomach Lining

This is also a cause or possible cause of gastric ulcers in horses and why horses need small meals several times a day so that the stomach is never empty. [4]

Jennifer MacNicol, a PhD candidate at the University of Guelph says – “If acid splashes up, or their stomach is empty, it can really damage a horse’s stomach,” [4]

This is why horse experts recommend that horses have constant access to roughage such as hay. It helps prevent an acidic stomach and gastric ulcers.

Fact 5: Horses Can Only Chew On One Side of Their Mouth At a Time 

They use a slanted outside to inside motion of their teeth to grind up the food, which only allows them to use one side of their mouth at a time.

The matching surfaces of the upper and lower cheek teeth work together to break down food so that it can pass through the esophagus.

Horses are fascinating creatures. Now that you know about the stomach and how the horse digestive system works, let’s explore the differences between ruminant and non-ruminant animals.

This video from Equine Veterinarian Dr. Ross Teitzel explains more about the horse’s digestive system.

Ruminants vs Non-Ruminants: What’s the Difference?

Animals are usually divided into two categories based on their stomach structure: ruminant and non-ruminant. In most cases, ruminant animals are herbivores while non-ruminant animals are omnivores and carnivores.

The following chart highlights the differences between ruminators and non-ruminators. [5]

RuminantsNon-Ruminants 
Animals that chew and spit out their food more than once and digest it in different stomachs each time Animals digest all of their food in one simple stomach.  Food does not ruminate because it does not have to be redigested
Usually herbivores Usually omnivores or carnivores 
Complex stomach with four digestive departments: the rumen, reticulum, omasum, and abomasumOne stomach with one compartment divided into glandular and non-glandular regions 
Long digestive process and systemShort digestive process and system
Do not produce peptides to digest proteinThe stomach makes peptides to digest protein
Have to blunt canines to break up plant materials Have two sharp canines to tear apart meat and other tough materials 
Premolars and molars move in a lateral directionPremolars and molars move in a vertical direction
Produce more saliva that has no enzymes to digest carbohydrates Produce less saliva that contains enzymes to digest carbohydrates. Participate in enzymatic digestion/
Regurgitate their food Do not regurgitate their food
Have a large liver Have a small liver 
Take a long time to digest plant materialHave a shorter digesting time compared to ruminant animals 
Digest all of the plant carbohydrates for energy, including cellulose Do not digest cellulose because they get carbohydrates from other sources 
Cattle, sheep, goats, buffalo, deerHumans, rabbits, dogs, pigs
Can have reverse peristalsis or esophagus motionCannot have reverse peristalsis
Need more fiber Need less fiber 

Ruminants and non-ruminants are so different from each other because they have unique dietary and energetic requirements that are necessary for them to survive

The only similarities between these two types of animals are:

  • They both have a complete digestive system consisting of the mouth, esophagus, stomach (or many stomachs), large intestine, and small intestine 
  • Both eat meals throughout the day and consume energy from the food they eat

At the end of the day, all animals can digest food because they need food to survive, some just do it differently from others.

FAQs

Do horses have small stomachs?

Horses have small stomachs relative to their size with a small stomach capacity. Their stomachs can only hold 2 – 4 gallons altogether. This is why do better with small quantities of food spread throughout the day. 

How many stomachs does a donkey have?

Donkeys have one stomach with a non-glandular and a glandular region. Donkeys are non-ruminants with a similar digestive tract to horses.

How many hearts does a horse have?

Horses have one heart because they are mammals.

Conclusion

How many stomachs does a horse have? Horses only have one stomach and they can only digest small portions of food at a time. If they eat too much, they can get colic.

Horses have a very interesting digestive process, and they cannot vomit up food so choking is a danger.

Horses are some of the only non-ruminant herbivorous animals, and ruminants and non-ruminants are very different from each other.

white large horse surrounded with fogs

How many stomachs does a horse have? Please share your opinion on this topic below!

References

1. “Maintaining a Healthy Equine Digestive Tract: Mouth and Esophagus.” Kentucky Equine Research, 31 Jan. 2012, ker.com/equinews/maintaining-healthy-equine-digestive-tract-mouth-and-esophagus/. Accessed 8 May 2022.

2. “The Gastrointestinal Tract of the Horse.” Ohioline.osu.edu, ohioline.osu.edu/factsheet/1022. Accessed 8 May 2022.

3. “Make Horse Feed Changes Gradually.” Kentucky Equine Research, 16 Sept. 2011, ker.com/equinews/make-horse-feed-changes-gradually/#:~:text=Start%20by%20mixing%20a%20small. Accessed 8 May 2022.

4. “Straight from the Horse’s Stomach | Ontario Agricultural College.” Www.uoguelph.ca, www.uoguelph.ca/oac/horses-stomach#:~:text=Like%20humans%2C%20horses. Accessed 8 May 2022.

5. “Discussion of Ruminants vs. Non-Ruminants.” Kb.wisc.edu, kb.wisc.edu/dairynutrient/414RN/page.php?id=55808.

Bryanna Tanase
Bryanna Tanase

Bryanna is a 23-year-old Florida-based Grade 1 Para-dressage rider based in Florida and she has been riding for 5 years. Horses are her passion and her ultimate goal is to be selected for the US Para-Equestrian Team and represent the US at the Paralympics. She rides at Quantum Leap Farm and Emerald M Therapeutic Riding Center and her equine partners are Shane, an American Paint Horse, and Cappy a Welsh x Thoroughbred. When she is not helping at the barn, riding, or training, she is learning about horses, writing articles about them, and using her social media platforms to raise awareness for therapeutic riding and para-equestrianism, shares her journey, and advocates for greater inclusion of para-equestrian in the media and equestrian sport at large.
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