How does a horse’s digestion work?

January 07, 2026
My Store Admin

Honestly, the horse’s digestive system is a bit of a puzzle. It’s long, sensitive, and honestly, not always easy to manage. But if you own or care for a horse, understanding how digestion in horses works is a must. It’s not just about feeding hay and hoping for the best. What (and how) you feed affects everything from their energy levels to their mood, and yes, even their manure.

So let’s break it all down in plain English. Whether you’re new to horses or just need a refresher, here’s your no-nonsense guide to the equine digestive system, how it works, what can go wrong, and how you can keep things running smoothly in the gut.

The Basics: How the Horse’s Digestive System Works

The horse’s digestive system is best described as a hybrid; it’s neither like ours, nor like cows’. Horses are non-ruminant herbivores, meaning they digest forage without a rumen. Instead, they rely heavily on microbial digestion in the hindgut.

Let’s walk through the path food takes, step by step:

1. It Starts in the Mouth (with a LOT of Chewing)

Digestion begins when the horse chews. Those strong molars grind feed into smaller particles to increase the surface area, making it easier to digest later. Chewing also stimulates saliva production, which helps buffer stomach acid.

Fun fact: Horses produce up to 10 gallons of saliva per day… but only when they chew! So, forage matters.

2. The Stomach: Small But Mighty

A horse’s stomach is… surprisingly small. It only holds about 8-15 liters, which means it fills up quickly and empties even if undigested. That’s why horses are built to eat small meals throughout the day, not two big ones like we humans do.

Inside, stomach acid is constantly secreted. Yes, even when the horse isn’t eating. This is part of the reason why feeding small amounts often is so important. Without that constant chewing and buffering, excess acid can cause problems like gastric ulcers.

3. The Small Intestine: Nutrient Absorption Zone

Next up, food passes into the horse’s small intestine, which is about 70 feet long (yes, you read that right). This is where starch, fat, and proteins are digested and nutrients are absorbed, including amino acids and fatty acids.

Important: Horses don’t have a gallbladder, so fats must be introduced slowly and in small quantities.

4. The Hindgut: The Fermentation Factory

This is where the real microbial magic happens. The hindgut includes:

The cecum
The large colon
The small colon
The rectum

The cecum is like a fermentation vat, where fiber from forage is broken down by microbes. The byproducts of this process (like volatile fatty acids) are used for energy. The large and small colon continue the absorption process and form manure.

If the microbial balance is off, horses can experience digestive disorders, like gas, diarrhea, or even colic.

Common Digestive Issues in Horses

Digestive upsets in horses are more common than many new horse owners think. Here are some issues you might run into:

Colic: A general term for abdominal pain. This is every owner’s nightmare. It can be caused by gas buildup, impaction, or changes in the gut environment.

Gastric Ulcers: Especially common in stabled horses, performance horses, or those under stress. The horse’s stomach is relatively small, and when it stays empty for too long, the acid gets to work on the stomach lining.

Impaction Colic: Usually seen in colder months when water intake drops and dry forage leads to poor gut movement.

Diarrhea or Loose Stools: Can signal everything from a digestive upset to parasites or feed changes.

What Causes Digestive Disturbances?

Horses are sensitive. Their gastrointestinal tract reacts quickly to:

Sudden changes in feed
Feeding large amounts of grain or starch
Not enough forage or roughage
Long periods without food
Inconsistent turnout or stress
Lack of water (especially in winter)
Dental issues (poor chewing = poor digestion)

Think of them as delicate machines. They function best when the fuel is steady, clean, and consistent.

How to Keep Your Horse’s Digestive System Happy

Here’s a friendly checklist for keeping digestion in horses smooth:

Feed Forage First: Forage (hay, pasture, roughage) should make up the majority of your horse’s diet. Horses evolved to graze. Feeding small amounts throughout the day mimics their natural pattern.

Monitor Water Intake: Dehydration = disaster. Especially in winter when buckets may freeze. Offer lukewarm water if possible, and check buckets regularly.

Be Smart with Concentrates: Too much grain = acid buildup, digestive upset, and risk of ulcers. Keep grain minimal unless your horse has a high workload and even then, introduce it gradually.

Feed Small, Feed Often: The horse’s digestive anatomy is designed for frequent small meals. Avoid long fasting periods, which can lead to excess stomach acid.

Maintain Dental Health: Chewing matters. Uneven teeth can prevent proper chewing and digestion, leading to larger particles reaching the hindgut and throwing things off.

Be Proactive with Turnout: Stress is a big contributor to digestive issues. Allow regular turnout, time with other horses, and a calm routine.

One of our favorites? EquiElite GC

Even with the best care, some horses need a little extra support, especially those prone to digestive upset, showing signs of stress, or going through dietary transitions.

Here’s what makes it special:

Contributes to a healthy acid-base balance in the stomach
Supports the intestinal flora for stable gut function
Includes pectin, which forms a gel to help protect the stomach lining
Contains yeast and chamomile, known for helping manage gas and digestive tension
Easy to use and safe for adult horses, ponies, and foals
We’ve seen it work especially well for horses that are stabled, in training, or going through feed changes.

Always consult your veterinarian or equine nutritionist if you're unsure what your horse may need.

Don’t Forget to Watch What Comes Out

Okay, yes, we’re talking about poop again.

Manure is a powerful indicator of how well your horse’s digestion is working. Healthy manure should be:

Moist, but not runny
Well-formed into fecal balls
Free of undigested feed particles
Any changes (too dry, too soft, too frequent) might be worth a closer look or a chat with your vet.

Digestion Matters More Than You Think

Your horse’s digestive system is delicate but manageable. When you understand how it works, what affects it, and how to support it, you unlock a huge part of horse care that impacts everything from behavior to performance.