All horses live under daily stressors.

Changes in routine, feeding schedules, weather, and environment place constant demands on the digestive system. Add to that the workload of training, hauling, competition, and time spent stalled, and the demands on the gut increase even further for working and performance horses.¹

When ulcers are discussed, most attention goes to the stomach. Hindgut ulcers are just as common, but they are harder to identify and often overlooked.²

Understanding hindgut ulcers starts with understanding how the hindgut works and why disruption there affects the entire horse.

What Are Hindgut Ulcers

Hindgut ulcers affect the cecum and large colon. This part of the digestive tract is responsible for fermenting fiber, absorbing water, and supporting a large portion of the horse’s microbiome.³

Think of it this way.
The hindgut is where forage is turned into usable energy. It depends on steady fermentation and a balanced microbial environment to keep the lining healthy and functioning the way it should.

Unlike the stomach, the hindgut does not have the same protective mechanisms. When fermentation becomes unstable or the microbial balance shifts, the lining is more vulnerable to irritation.⁴

Dr. Rob Franklin, DACVIM, explains it this way:

“The hindgut is where fiber fermentation happens. When that environment becomes unstable, the lining is more vulnerable to irritation, and the effects can extend well beyond digestion.”⁵

Because the hindgut plays an essential role in water absorption, immune signaling, and nutrient utilization, disruption in this region often presents as whole-horse issues rather than isolated digestive signs.⁶

Why Performance Horses Are at Higher Risk

Hindgut ulcers are closely tied to management and routine rather than a single cause.²

The hindgut functions best when daily patterns stay steady. When routines change or stressors stack up, the environment inside the gut has to adapt quickly, and that adjustment is not always smooth.³

Common stressors include:

• Diets higher in starch and sugar⁷
  

• Inconsistent forage intake
  
  Training and competition demands
  

• Hauling and environmental changes
  

• Stall confinement and reduced movement
  

• Use of non-steroidal anti-inflammatory drugs⁸
  

Stress on the hindgut often begins earlier than expected, particularly when horses transition into more intensive management systems.⁹

This is why hindgut support matters for horses at every stage, from young horses entering training to seasoned performance horses.

Signs Commonly Associated With Hindgut Ulcers

Hindgut ulcers cannot be seen with gastroscopy, which makes them harder to identify. Instead, they are often suspected based on patterns, symptoms, and veterinary evaluation.

Discomfort in the hindgut often shows up subtly rather than as an obvious digestive crisis.

Signs may include:

• Loose manure or intermittent diarrhea¹⁰
  

• Sensitivity through the flank or abdomen

• Changes in attitude or willingness to work
  

• Difficulty maintaining body condition
  

• Recurrent low-grade colic¹¹
  

Any horse showing these signs should be evaluated by a veterinarian to rule out other causes and guide appropriate management.

The Hindgut as a Foundation System

The hindgut houses trillions of microorganisms that influence digestion, immune activity, and inflammatory balance.

When fermentation stays steady and the microbiome remains balanced, the gut lining is better supported and water absorption stays efficient.

Disruption in hindgut function has been associated with changes in hydration status, inflammatory responses, and overall performance.⁶

This is why gut health is often described as a foundation system rather than an isolated concern.

Supporting Horses at Risk

Supporting hindgut health comes back to consistency and daily management.

Prioritize Forage Intake

Horses are designed to consume forage throughout the day. Long gaps without hay can disrupt fermentation patterns in the hindgut. ¹¹Free-choice forage or slow feeders help maintain consistency.

Make Diet Changes Gradually

Sudden changes in feed or forage can disrupt microbial balance. When changes are needed, gradual transitions give the hindgut time to adapt.

Support the Microbiome

Prebiotics, probiotics, and postbiotics each play a role in supporting fermentation and microbial balance.

Highly Recommended --> 6666 Complete Gut Protection is formulated to provide all three, helping support the entire gastrointestinal tract, including the hindgut, during normal stressors such as training, hauling, and seasonal changes.

Do Not Overlook Hydration

The hindgut absorbs a significant amount of water. Reduced water intake can place additional strain on fermentation and manure consistency. Clean water access and appropriate electrolyte use support hydration and digestive balance.¹²

Highly Recommended --> 6666 Electrolyte Powder and Paste is formulated to replenish electrolytes and minerals while promoting healthy hydration. 

Use NSAIDs Thoughtfully

Non-steroidal anti-inflammatory drugs can affect protective mechanisms in the digestive tract. When these medications are necessary, digestive support and veterinary oversight are important.

Why a Whole-System Approach Matters

Hindgut ulcers rarely occur in isolation. They are part of a broader interaction between digestion, hydration, immune signaling, and inflammation.⁶

Long-term support focuses on foundational systems working together rather than isolated interventions or short-term solutions.

Key Takeaway: 

Hindgut ulcers are common in performance horses but frequently missed. Understanding how routine stressors affect the hindgut allows owners to make informed management decisions before small disruptions become larger problems.

Consistent forage intake, hydration, microbiome support, and thoughtful management form the foundation for digestive health and whole-horse resilience.

Learn more about whole horse health:
Immune Health in Horses: How the Gut Sets the Pace
The 5 Most Common Hydration Myths
Gastric Ulcers vs. Hindgut Ulcers in Horses



References
1. Andrews, F. M., Reinemeyer, C. R., & McCracken, M. D. (2017).
2. Sykes, B. W., et al. (2015). Risk factors for equine gastric and intestinal ulceration. Equine Veterinary Journal.
3. Julliand, V., Grimm, P. (2017). The impact of diet on the hindgut microbiome of horses. Journal of Equine Veterinary Science.
4. Merritt, A. M. (2003). Normal equine gastrointestinal physiology. Equine Veterinary Education.
5. Franklin, R., DACVIM. Clinical commentary cited within educational content.
6. Van den Berg, M., et al. (2013). Inflammation and intestinal barrier function in horses. Equine Veterinary Journal.
7. Luthersson, N., et al. (2009). Dietary and management risk factors for gastric ulceration in horses. Equine Veterinary Journal.
8. McConnico, R. S., et al. (2008). Effects of phenylbutazone on the equine gastrointestinal tract. Journal of Veterinary Internal Medicine.
9. Murray, M. J., et al. (1996). Effects of training and stabling on gastric ulceration in horses. Equine Veterinary Journal.
10. Proudman, C. J., et al. (2002). Large intestinal disease and diarrhea in horses. Equine Veterinary Journal.
11. Archer, D. C., Proudman, C. J. (2006). Epidemiological factors associated with colic. Equine Veterinary Journal.
12. Lopes, M. A. F., et al. (2014). Water intake and digestive health in horses. Journal of Equine Veterinary Science.