Horse Digestive Problems: How to Spot the Signs and Protect Gut Health

Published on: April 24, 2025

By: Miles HenryFact Checked

As a long-time horse owner, I’ve seen how subtle digestive issues can snowball—from a little weight loss to serious problems like colic or ulcers. One gelding in my barn looked perfectly healthy… until he wasn’t. That moment taught me just how critical gut health is to every part of a horse’s life: their performance, behavior, and long-term well-being.

Horse digestive problems can be tough to detect, but they can quickly disrupt your horse’s health, energy, and appetite. In this guide, I’ll break down the most common equine digestive issues, how to spot the early signs, and what you can do to prevent them with confidence.

Why Horse Gut Health Matters (and How It Affects Everything)

The equine digestive system is a marvel of biological engineering, designed to extract nutrients from forage using a process humans don’t share—hindgut fermentation. This microbial process is essential for energy production, but it also makes the digestive tract highly sensitive to imbalances.

Even slight disruptions in the gut can lead to:

• Colic (a leading cause of equine death)
• Weight loss despite a good appetite
• Behavioral changes like irritability or “girthiness”
• Reduced performance
• Nutrient absorption issues

Colic is not just common—it’s one of the most frequent and severe medical emergencies in horses. Studies show recurrence rates can reach up to 10%, depending on the cause and management approach (Coenen et al., 2014).

👉 Learn more about what to do when your horse colics. Proactively supporting your horse’s gut health can help prevent these issues and significantly improve their overall well-being and longevity.

So, how exactly does a horse’s gut work—and why does it go off track so easily? Let’s break it down in simple terms.

How a Horse’s Digestive System Works: Foregut to Hindgut

To prevent common digestive problems like colic and ulcers, it’s important to understand how your horse’s gastrointestinal (GI) system works—from start to finish.

🔷 The Foregut (Stomach + Small Intestine)

The foregut includes the stomach and small intestine, where enzymatic digestion begins.

• Stomach: Breaks down food with acid and enzymes. Because it’s relatively small, food remains here for just 15–30 minutes. This is why horses are better suited to frequent, small meals rather than large, infrequent ones.
• Small Intestine: Absorbs proteins, fats, sugars, and most vitamins. Enzymatic digestion continues here before the food reaches the hindgut.

👉 This division of roles reflects the horse’s evolutionary adaptation to grazing—consuming low-starch, high-fiber forage throughout the day
(Goff, 2015 – Dukes’ Physiology of Domestic Animals; Hoffman, 2003).

🔷 The Hindgut (Cecum + Colon)

The hindgut is where fermentation takes place—an essential process that allows horses to extract energy from fibrous forage.

• Cecum: Acts as a fermentation chamber, where beneficial microbes break down structural carbohydrates (fiber). This process produces volatile fatty acids (VFAs), which are a major energy source.
• Colon: Continues fermentation and absorbs water and electrolytes. This is also where most of the moisture in manure is regulated.

Because horses rely so heavily on microbial fermentation in the hindgut, this part of the digestive system is especially sensitive to change.

⚠️ Why It’s So Sensitive

Horses evolved to graze continuously, relying on a finely balanced gut microbiome. Disrupting that balance—even slightly—can lead to digestive issues. Here’s why:

• Horses are not designed to eat large, infrequent meals. For a deeper understanding of appropriate hay quantities and feeding schedules, refer to our guide on how much hay a horse needs per day.
• The microbial population in the hindgut is extremely sensitive to abrupt feed changes and high-starch diets.
• Sudden shifts in routine, stress, or diet can lead to imbalances, fermentation problems, and serious issues like colic, ulcers, or hindgut acidosis.

“This foregut–hindgut division, along with the horse’s need for near-constant forage intake, is what makes equine digestion so unique—and so delicate to manage properly.”

When this system is thrown off, whether by feed, stress, or illness, it can result in colic, poor nutrient absorption, or behavioral changes.
Next, let’s delve into the details of the most common horse digestive problems, including what to watch for in the early stages.

Common Digestive Problems in Horses (and What to Watch For)

Horses are highly sensitive to disruptions in their digestive system, and the problems that arise often look mild at first, then escalate quickly. From colic to ulcers, the most common digestive issues often share overlapping symptoms; however, each requires different strategies to manage or prevent.

Below, we break down the most common horse digestive problems, what causes them, and how to recognize the signs early.

Click each to expand

Colic (Gas, Impaction, Displacement)

Gas Colic: Caused by fermentation buildup and trapped gas.

Impaction Colic: Blockage from dry, coarse feed or poor hydration.

Displacement/Torsion: Intestines move or twist—often a surgical emergency..

Signs: Restlessness, flank-watching, pawing, rolling, sweating, or reduced manure output.

For more in-depth statistics and research on colic in horses, the American Association of Equine Practitioners offers valuable resources.

Gastric Ulcers (Equine Gastric Ulcer Syndrome)
Learn more about horse ulcers

Causes: Stress, fasting, high-grain diets, NSAIDs, irregular feeding

Signs: Poor appetite, weight loss, dull coat, girthiness, irritability, teeth grinding

The Equine Science Society provides extensive research and information on equine gastric ulcer syndrome.

Hindgut Acidosis

Causes: High-starch or low-forage diets, sudden feed changes

Signs: Loose manure, undigested feed in manure, behavior changes, increased risk of laminitis
Probiotic support may help restore microbial balance, especially after feed disruptions.
Learn how equine probiotics can support gut health.

Diarrhea & Loose Manure

Causes: Sudden feed changes, stress, infections, parasites, or antibiotics

Signs: Watery or frequent stools, tail staining, dehydration, fever
If antibiotics are involved, supplementing with equine probiotics may help restore healthy gut flora and reduce recovery time.

Poor Nutrient Absorption

Causes: Parasites, inflammatory gut diseases, dental issues

This condition can be subtle at first, but it often results in chronic underperformance and difficulty maintaining weight, even with a quality diet.

Signs: Weight loss despite eating, dull coat, lethargy, underperformance

Choke & Feed Impaction

Choke Causes: Bolting feed, dry pellets, poor dentition

Feed Impaction Causes: Inadequate water intake, coarse forage, slow gut motility
Signs: Coughing, gagging, drooling, neck stretching, anxiety, mild colic, bloating

As you can see, digestive problems in horses can stem from a variety of causes—some subtle, others more severe. The good news? Many of these issues are preventable. In the next section, we’ll explore the most common causes of digestive upset in horses and how to reduce the risk through smart feeding, management, and care.

What Causes Digestive Problems in Horses?

Understanding what triggers horse digestive problems is key to prevention. Most issues arise from identifiable factors, often related to management practices that upset the gut’s delicate balance.

Here are the most common culprits:

🔹 Sudden Diet Changes

A horse’s hindgut relies on a stable population of microbes to ferment fiber. When feed is changed abruptly—especially hay types, grain blends, or pasture—those microbes can’t adjust quickly enough. The result? Fermentation issues, colic, or diarrhea.
➡️ Always transition feed over 7–10 days.

🔹 High-Starch, Low-Fiber Diets

Horses are built to graze on fiber-rich forage, not consume large quantities of starch or sugar. Diets heavy in grains can overload the foregut and spill undigested starch into the hindgut, disrupting pH and microbial balance. This raises the risk of ulcers, colic, and hindgut acidosis.
➡️ Here’s what you need to know about feeding hay correctly.

🔹 Stress (Travel, Performance, Herd Changes)

Stress doesn’t just affect behavior—it disrupts digestion too. Trailering, competing, isolation, or changes in herd dynamics can reduce gut motility and increase acid production, leading to ulcers or poor nutrient absorption.
➡️ Learn how performance-related stress affects your horse’s health and gut.

🔹 Parasites

Parasites like strongyles damage the intestinal lining and interfere with nutrient uptake. They can also cause colic or chronic digestive inflammation if unmanaged. Oklahoma State University has comprehensive information on internal parasites in horses.
➡️ Check out our complete guide to internal parasites in horses.

🔹 Dental Issues

Improper chewing leads to larger feed particles entering the stomach and hindgut, where they can ferment improperly or cause impactions. Uneven teeth, sharp points, or tooth pain are often silent contributors to digestive issues.
➡️ Does your horse need their teeth floated? Here’s how to tell.

🔹 Dehydration

Without enough water, feed becomes dry and difficult to move through the GI tract. This increases the chance of impaction colic. Horses may drink less in cold weather or when stressed, so water access and intake monitoring is key.
➡️ Know the signs of dehydration in horses and how to prevent it.

🔹 Moldy or Contaminated Feed

Mold in hay or grain can produce harmful mycotoxins that upset digestion, reduce appetite, and increase colic risk. Even small amounts of moldy hay can be dangerous. Information on mycotoxins in horse feed and their effects can be found on the website of the National Institute of Health.
➡️ Learn whether horses will eat moldy hay—and what to do about it.

Studies have linked mycotoxin ingestion to poor feed conversion and inflammatory GI responses, both of which can set the stage for chronic digestive problems (Blikslager et al., 2017).

🔹 Infrequent Feeding

Horses are trickle feeders by design. Long gaps between meals increase stomach acid levels and reduce gut motility. This can result in ulcers, colic, and stress behaviors. Feeding smaller meals more frequently supports healthier digestion.

Many of these causes leave subtle signs—changes in behavior, appetite, or manure quality—that are easy to miss. In the next section, we’ll cover the symptoms to watch for so you can catch problems early and keep your horse feeling their best.

Early Signs of Digestive Trouble in Horses

Recognizing early signs of digestive discomfort in horses is crucial for prompt intervention. Subtle behavioral changes can show up days or even weeks before a major issue occurs.

Here’s what to watch for:

• Behavioral changes: Girthiness (sensitivity or resistance when the girth is tightened), irritability, or increased lying down may indicate underlying issues. Notably, girthiness can be a subtle sign of gastric ulcers, as well as poor saddle fit or orthopedic problems. A study found that gastric ulceration accounted for 37% of cases of girthiness in horses. For more insights, refer to our guide on girthiness in horses.
• Appetite changes: Reduced interest in hay or grain—or becoming picky about meals—may signal discomfort or digestive upset.
• Weight loss: Losing weight despite eating well can point to poor nutrient absorption or other gastrointestinal issues.
• Dull coat: A dry, dull, or patchy coat often reflects nutritional deficiencies or poor absorption. For tips, check out our article on horse coat health.
• Abnormal manure: Watch for looseness, dryness, foul odor, undigested feed, or a noticeable reduction in output.
• Bloating or discomfort after eating: A swollen belly, restlessness, or reluctance to move after meals may indicate gas buildup or feed sensitivity.
• Teeth grinding, flank-watching, or pawing: These behaviors often reflect gut discomfort or abdominal pain.
• Excessive drooling or gagging: Persistent drooling may be caused by dental issues, irritants, or even toxic plants. “Slobbers,” for example, can occur when horses consume clover infected with Rhizoctonia leguminicola. Learn more about why your horse might be drooling.

Even small changes—like pawing after meals or resistance during grooming—can be early warning signs. These quiet cues often show up before more obvious symptoms do.

If you observe any of the signs above, it’s best to consult with your veterinarian to determine the root cause and take appropriate action early.

How to Prevent Digestive Issues in Horses: Daily Best Practices

Preventing digestive issues in horses primarily comes down to establishing the right routine, smart feeding habits, and proactive care.

🟢 Feeding & Management

• Use slow-feed hay nets to encourage grazing behavior and prevent bolting feed
• Feed on a consistent schedule—ideally small meals throughout the day
• Make all feed changes gradually over 7–10 days to avoid shocking the hindgut
• Provide high-quality forage as the foundation of the diet

👉 These practices mimic natural feeding behaviors and help maintain a stable gut environment.

🟢 Gut Support & Monitoring

• Monitor manure consistency and eating habits daily—changes are often the first warning sign
• Offer electrolyte support during hot weather, travel, or intense activity to help maintain hydration

👉 Staying consistent with hydration and gut support can help prevent both subtle and severe digestive issues.

🟢 Health Maintenance

• Schedule regular dental exams to ensure proper chewing and digestion.
• Follow a targeted deworming program based on fecal egg counts.
• Minimize environmental stress by offering consistent turnout, familiar herd mates, and low-disruption routines.
• Store all feed in a cool, dry place to prevent mold and mycotoxin exposure.

👉 Keeping up with routine care reduces preventable risks and supports your horse’s long-term digestive health.

When to Call the Vet for Horse Digestive Emergencies

Sometimes, despite your best prevention efforts, problems still arise—and acting fast can make all the difference. If you see any of the following red flags, don’t wait: call your vet immediately.

🚨 Red-flag signs that require urgent veterinary care:

• Violent colic symptoms, such as thrashing, rolling, excessive pawing, or sweating.
• No manure passed for 12 hours or more.
• Refusal to eat or drink, especially when combined with dullness or depression.
• Excessive bloating or a visibly distended abdomen.
• Signs of choke lasting longer than an hour (gagging, coughing, food-laced drool).
• Persistent diarrhea paired with lethargy, fever, or dehydration.

🩺 What your vet might do

To diagnose the issue and guide treatment, your veterinarian may perform the following:

FAQs: Horse Digestion, Colic, and Gut Health

Have questions about gut health in horses? Here are answers to some of the most common concerns horse owners ask.

Want to spot trouble early? This quick video highlights 5 warning signs that your horse may have poor gut health—a must-watch for proactive owners.

Final Thoughts on Preventing Digestive Problems in Horses

Digestive issues in horses aren’t always obvious, but being proactive can make all the difference. By understanding the signs, following smart feeding practices, and staying alert to changes, you can help your horse stay healthy from the inside out.

➡️ Related Reading: Feeding Guide for Underweight Horses

Your horse’s health starts in the gut. Stay observant. Stay consistent. And when in doubt, trust your instincts—and your veterinarian.

💬 Have you experienced digestive challenges with your horses? Share your insights and tips in the comments below to help fellow horse owners!
📩 Email me directly with any questions or leave a comment below.