Ulcers in Horses: Signs & Treatment

Gastric and colonic ulcers are common health problems in horses, affecting performance, behavior, and overall well-being. Whether your horse is a competitive athlete, pleasure horse, or pasture pet, understanding ulcers in horses is essential for early detection and effective treatment. This article provides a comprehensive overview of equine ulcers, including how to recognize the signs, what causes them, and the treatment options available to get your horse back to health.

Ulcers develop when the protective lining of the stomach or colon breaks down, creating painful sores. In horses, gastric ulcer syndrome (EGUS) and equine colonic ulcer syndrome (ECUS) are the two primary types. These conditions are far more prevalent than many horse owners realize—studies suggest that up to 90% of racehorses and 60% of sport horses experience gastric ulcers at some point. Early recognition and veterinary intervention can prevent complications and reduce pain.

This guide is not a substitute for veterinary diagnosis or treatment. If you suspect your horse has ulcers, consult an equine veterinarian promptly. For acute symptoms such as severe colic, refusal to eat, or signs of shock, call your veterinarian immediately.

Understanding Equine Ulcers

Equine ulcers are erosions in the mucous membrane lining the stomach or colon. Unlike humans, horses cannot vomit, making them particularly vulnerable to gastric ulcer development. The equine stomach produces acid continuously throughout the day, and the protective mucus layer can break down under stress, poor diet, or other risk factors.

Gastric ulcers typically occur in the squamous (non-glandular) portion of the stomach, which lacks the same acid-resistant coating as the glandular portion. Colonic ulcers, while less common, are often more severe and can be harder to treat. Both types cause significant pain and can lead to behavioral changes, reduced performance, and digestive complications if left untreated.

Signs and Symptoms of Ulcers in Horses

Recognizing the signs of equine ulcers is critical for early intervention. Symptoms can range from subtle to severe and may vary depending on the location and severity of the ulcers.

Digestive and Behavioral Signs

• Poor appetite or picky eating habits
• Weight loss despite adequate feed intake
• Dull coat and lack of shine
• Chronic diarrhea or loose stools
• Mild to moderate abdominal discomfort or colic episodes
• Excessive salivation
• Reluctance to drink water

Performance and Behavioral Changes

• Decreased performance, speed, or endurance
• Bucking, rearing, or resistance under saddle
• Behavioral changes such as irritability or aggression
• Inability to maintain consistent training progress
• Reluctance to move forward
• Changes in temperament or attitude

Physical Indicators

• Rough or dull coat quality
• Sensitivity to girth or cinch tightening
• Teeth grinding (bruxism)
• Persistent back soreness
• Lying down more frequently than normal

It’s important to note that some horses with ulcers show only subtle signs, while others display multiple symptoms. The severity of symptoms does not always correlate with the severity of ulceration. A horse with severe ulcers may appear relatively normal, while another with mild ulcers might show pronounced behavioral issues.

Causes and Risk Factors

Understanding what causes ulcers helps with prevention. While stress is often blamed, the reality is more complex, involving diet, management, and individual susceptibility.

Dietary Risk Factors

• High-grain diets with insufficient forage
• Infrequent feeding (more than 4-6 hours without food)
• Rapid diet changes without a gradual transition period
• Poor-quality hay or moldy feed
• Insufficient water intake
• High-protein commercial feeds without adequate buffering

Management and Lifestyle Risk Factors

• High-intensity training or competition
• Stall confinement with limited pasture turnout
• Transportation and travel stress
• Weaning in young horses
• Social stress or herd changes
• Inadequate rest periods between intense workouts

Medical and Individual Factors

• Use of non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone (Bute) or firocoxib
• Pre-existing gastrointestinal conditions
• Breed or individual predisposition
• Age—young horses and older horses may be more susceptible
• Bacterial overgrowth (e.g., Helicobacter spp.)

Diagnosis of Equine Ulcers

A definitive diagnosis requires gastroscopy, a procedure where a veterinarian passes an endoscope through the horse’s nose into the stomach to visualize ulceration directly. This is the gold standard for diagnosing gastric ulcers.

Gastroscopy Procedure

Gastroscopy typically takes 20-30 minutes and is performed with the horse sedated. The procedure is minimally invasive and allows the veterinarian to assess the number, size, location, and severity of ulcers using a grading scale (usually Grade 0 to Grade 4, with Grade 4 being the most severe). The exam may also reveal secondary conditions such as bleeding or secondary bacterial infection.

Ultrasound and Other Diagnostics

Abdominal ultrasound can help assess colonic ulcers or secondary complications such as thickened intestinal walls, but endoscopy remains the standard for gastric diagnosis. Blood work may reveal anemia (low red blood cell count) if bleeding ulcers are present.

Clinical Diagnosis Limitations

While clinical signs can suggest ulcers, they are not definitive. Many conditions mimic ulcer symptoms, including dental disease, back pain, or behavioral issues unrelated to gastric disease. This is why veterinary evaluation is essential.

Treatment Options for Equine Ulcers

Treatment depends on the type and severity of ulcers and typically combines medication and management changes. Most horses respond well to appropriate therapy within 4-8 weeks.

Gastric Acid Suppressants

These are the cornerstone of ulcer treatment, reducing stomach acid to allow healing.

• Omeprazole (Gastrogard, GastroGard paste): A proton pump inhibitor that blocks acid production. The standard dose is 4 mg/kg once daily, and it is highly effective for healing gastric ulcers. Treatment typically lasts 28 days but may extend longer for severe cases. Cost ranges from $200-$600 for a 28-day course.
• Famotidine (H2-receptor antagonist): Reduces acid production and is sometimes used as an alternative or adjunct. Less commonly used than omeprazole due to shorter duration of action, requiring multiple daily doses.
• Injectable acid suppressants: Veterinarians may use injectable options for horses with severe disease or feeding difficulties.

Gastric Protectants

• Sucralfate: Forms a protective barrier over ulcerated tissue. Dosing is typically 20 mg/kg three to four times daily. Often used alongside omeprazole. Cost is approximately $100-$200 for a multi-week course.
• Misoprostol: A synthetic prostaglandin that enhances mucus production and blood flow. Used less frequently due to cost and the availability of more effective omeprazole-based protocols.

Antacids

Products containing aluminum hydroxide or magnesium hydroxide can provide temporary acid relief but are generally less effective as primary treatment compared to omeprazole.

Nutraceuticals and Supplements

While not substitutes for medication, certain supplements may support healing:

• L-glutamine to support intestinal lining integrity
• Zinc carnosine for mucosal protection
• Licorice root or other herbal support (used cautiously and under veterinary guidance)
• Probiotics to maintain healthy gut flora

Always consult your veterinarian before adding supplements, as some may interact with medications or have limited evidence for efficacy.

Treatment Duration and Monitoring

Standard treatment protocols typically run 28-56 days, though severe cases may require longer courses. Your veterinarian may recommend a follow-up gastroscopy to confirm healing before stopping medication. Some horses require maintenance therapy to prevent recurrence, especially if management factors cannot be fully controlled.

Management and Prevention Strategies

Medication alone is insufficient—management changes are essential for healing and preventing recurrence. In fact, many horses treated with medication alone without management improvements may develop ulcers again once treatment stops.

Feeding and Nutrition

• Increase forage intake: Horses should consume at least 1.5-2% of their body weight in forage daily. Frequent, small meals are superior to large meals. Aim for feeding every 3-4 hours if possible.
• Reduce grain and concentrate: High-carbohydrate feeds increase acid production. Gradually reduce grain or switch to low-starch, high-fat alternatives if performance demands feed supplementation.
• Provide quality hay: Good-quality, dust-free hay or pasture is ideal. Avoid moldy or poor-quality hay.
• Use alfalfa products strategically: Alfalfa is naturally more buffering than grass hay due to higher calcium and protein content. A portion of the daily forage ration can include alfalfa pellets or hay, though excessive alfalfa may not be appropriate for all horses.
• Ensure constant water access: Fresh water should be available at all times. Some horses drink more from automatic waterers than from buckets.

Turnout and Exercise

• Maximize pasture time: At least 4-6 hours of daily pasture grazing is recommended. Continuous turnout is ideal.
• Avoid stall confinement: Horses confined to stalls for extended periods are at higher risk. If stall confinement is necessary, provide good ventilation, bedding, and frequent turnout breaks.
• Moderate training intensity: High-intensity training increases ulcer risk. Ensure adequate recovery periods between intense workouts.
• Avoid feeding grain before or after intense exercise: Wait at least 1-2 hours after intense work before feeding grain or concentrates.

Stress Reduction

• Maintain stable herd groupings and avoid frequent social disruptions
• Minimize transportation stress when possible
• Provide consistent routines and handling practices
• Address dental disease or other painful conditions that may contribute to stress

Medication Management

• Use NSAIDs only when necessary and at the lowest effective dose
• Consider alternative pain management strategies (joint injections, physical therapy, etc.) when appropriate
• If NSAIDs are necessary for ongoing use, discuss gastric protection protocols with your veterinarian

Prognosis and Recovery Timeline

The prognosis for equine ulcers is generally good with appropriate treatment. Most horses show improvement in clinical signs within 7-14 days of starting omeprazole, though complete mucosal healing typically requires 4-8 weeks. Grade 1-2 ulcers may heal in 4 weeks, while Grade 3-4 ulcers often require 8 weeks or longer.

Behavioral and performance improvements often lag behind histological healing. A horse may show behavioral changes for several weeks even after ulcers have healed, as desensitization to the pain takes time. Conversely, some horses show rapid improvement in attitude and willingness within days of starting treatment.

Recurrence is common—approximately 80-90% of horses that had ulcers may develop them again if management is not maintained. This underscores the importance of long-term dietary and management modifications.

Frequently Asked Questions

How much does gastroscopy cost?

A diagnostic gastroscopy typically costs $500-$1,500 depending on the facility, location, and any additional diagnostics performed. Some veterinary teaching hospitals or equine clinics may offer discounted rates. When combined with treatment, total costs for diagnosis and initial therapy may range from $1,000-$3,000 or more.

Can horses with ulcers compete?

Most competition organizations do not prohibit horses with ulcers from competing, though the horse’s welfare should be the primary concern. A horse in pain or discomfort should not compete. After appropriate treatment and resolution of clinical signs, most horses can return to normal work. Check specific competition rules, as some events may have restrictions related to medication use (such as omeprazole during competition).

Is omeprazole safe for long-term use?

Short-term omeprazole (4-8 weeks) is very safe with minimal side effects. Long-term use beyond 12 weeks is less well-studied, though it appears generally safe. Some sources suggest that extended high-dose omeprazole may interfere with mineral absorption, though this is not well-established in equine medicine. Discuss long-term use with your veterinarian.

Can I treat ulcers at home without a veterinarian?

A definitive diagnosis requires veterinary evaluation, ideally with gastroscopy. Without a diagnosis, treatment is speculative and may be ineffective or inappropriate. Additionally, many conditions mimic ulcer symptoms, and treating the wrong condition wastes time and money. A veterinarian is essential for diagnosis, prescription medication, and monitoring.

How long after treatment can I resume intense exercise?

Most veterinarians recommend limiting intense exercise during the active treatment phase (first 4 weeks). Light work, walking, and turnout are usually acceptable. After clinical signs resolve and the full treatment course is complete, gradual return to work over 2-4 weeks is prudent. If a follow-up gastroscopy confirms complete healing, full return to sport may be warranted.

Key Takeaways

• Equine ulcers are common in sport and performance horses, causing pain, poor performance, and behavioral changes. Early recognition and veterinary intervention improve outcomes.
• Symptoms include poor appetite, weight loss, behavioral changes, reduced performance, and colic. Not all ulcers cause obvious signs, so veterinary evaluation is necessary for diagnosis.
• Gastroscopy is the gold standard for diagnosis and allows veterinarians to grade ulcer severity and direct treatment.
• Omeprazole is the most effective medication, with typical treatment lasting 4-8 weeks. Sucralfate and other protectants are often used as adjuncts.
• Management changes—including increased forage, reduced grain, more turnout, and stress reduction—are as important as medication for healing and preventing recurrence.
• Most horses respond well to appropriate treatment, but recurrence is common without ongoing management modifications.
• Consult an equine veterinarian for diagnosis, treatment planning, and monitoring. This article is not a substitute for veterinary care.