Equine Gastric Ulcer Syndrome: Diagnosis, Treatment, and Recurrence Prevention
Equine Gastric Ulcer Syndrome (EGUS) is a common condition affecting horses across all disciplines, characterized by ulceration of the stomach lining. This article provides veterinarians and horse owners with evidence-based guidance on diagnosing EGUS, differentiating squamous from glandular disease, selecting medical treatments, and implementing long-term management strategies to prevent recurrence. The information is drawn from peer-reviewed veterinary literature and official veterinary resources, including the American Association of Equine Practitioners (AAEP), Merck Veterinary Manual, and American College of Veterinary Internal Medicine (ACVIM).
At a Glance
| Aspect | Key Information | Clinical Relevance |
|---|---|---|
| Definition | Ulceration of the equine stomach lining, divided into Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD) | Different regions require different treatment approaches |
| Primary Causes | Management factors: intermittent feeding, high-concentrate diets, stress, NSAID use, intense exercise | Modifiable risk factors are central to prevention |
| Diagnostic Gold Standard | Gastroscopy with sedation and 12-hour fast | Direct visualization allows grading and region-specific diagnosis |
| Medical Therapy | Proton pump inhibitors (omeprazole) for ESGD, mucosal protectants (sucralfate) for EGGD | Treatment duration typically 28 days, recurrence is common without management changes |
| Recurrence Prevention | Continuous pasture turnout, free-choice forage, reduced concentrate meals, stress reduction | Long-term dietary and environmental modifications are essential |
Understanding Equine Gastric Ulcer Syndrome
Equine Gastric Ulcer Syndrome encompasses two distinct disease entities affecting different regions of the equine stomach. The squamous mucosa, located in the upper portion of the stomach, is susceptible to acid damage when exposed to low pH for prolonged periods. The glandular mucosa, in the lower portion, has protective mechanisms but can still develop ulcers, particularly under stress or with NSAID use. The Merck Veterinary Manual provides foundational information on equine digestive health and ulcer pathophysiology.
The distinction between ESGD and EGGD is clinically important because treatment responses differ. ESGD typically responds well to acid suppression therapy, while EGGD may require additional mucosal protectants and longer treatment courses. A review published in the Veterinary Journal (London, England: 1997) in 2022 discusses the syndrome in adult horses, emphasizing the need for region-specific diagnosis and management.
Clinical Signs and Risk Factors
Common Clinical Signs
Horses with EGUS may present with a range of clinical signs, though some affected horses show no outward abnormalities. Common signs include poor appetite, weight loss, dull coat, mild colic after eating, teeth grinding (bruxism), excessive salivation, and poor performance. Performance horses, particularly racehorses, may show decreased stamina, reluctance to work, or behavioral changes such as irritability. A 2022 study in Frontiers in Veterinary Science found that EGUS affects fitness parameters in poorly performing Standardbred racehorses, linking ulcer severity to measurable performance deficits.
Risk Factors
Several management and environmental factors increase EGUS risk. Intermittent feeding schedules that leave the stomach empty for extended periods allow acid to accumulate and damage the squamous mucosa. High-concentrate diets, especially those rich in grain, increase volatile fatty acid production that can irritate the stomach lining. Intense exercise, particularly in racehorses and sport horses, increases abdominal pressure and splashes acid onto the squamous region. Non-steroidal anti-inflammatory drug (NSAID) use, especially with prolonged administration, inhibits protective prostaglandin synthesis in the glandular mucosa. Stress from transport, training, competition, or social changes also contributes to ulcer development.
Diagnostic Approach
Gastroscopy: The Gold Standard
Gastroscopy is the only definitive method for diagnosing EGUS. The procedure requires sedation and a 12-hour fast to ensure the stomach is empty for visualization. A flexible endoscope is passed through the esophagus into the stomach, allowing direct examination of the squamous and glandular mucosa. The American College of Veterinary Internal Medicine (ACVIM) provides resources on diagnostic standards for equine gastrointestinal disease.
During gastroscopy, the veterinarian grades ulcer severity using established scoring systems. The squamous mucosa is typically graded from 0 (normal) to 4 (severe, widespread ulceration). The glandular mucosa is assessed separately, with attention to lesion appearance, location, and depth. This region-specific assessment guides treatment decisions.
Limitations of Gastroscopy
Gastroscopy requires specialized equipment and sedation, which may not be available in all practice settings. The procedure is generally well-tolerated but carries minimal risks associated with sedation and endoscope passage. False negatives can occur if the stomach is not adequately emptied or if lesions are located in areas difficult to visualize. Repeat gastroscopy is recommended after treatment to confirm healing, as clinical improvement does not always correlate with endoscopic resolution.
Alternative Diagnostic Considerations
No reliable blood test or fecal test currently exists for diagnosing EGUS. Sucrose permeability tests and other biomarkers have been investigated but are not widely validated for clinical use. Response to empirical treatment is sometimes used as a diagnostic tool, but this approach risks misdiagnosis and inappropriate therapy. The Merck Veterinary Manual advises that gastroscopy remains the standard for definitive diagnosis.
Medical Treatment Options
Omeprazole for Squamous Disease
Omeprazole, a proton pump inhibitor, is the primary medical treatment for ESGD. It works by irreversibly blocking the proton pump in gastric parietal cells, reducing acid secretion. Omeprazole is administered as a paste or oral suspension, typically once daily. A 2017 review in The Veterinary Clinics of North America. Equine Practice discusses therapeutics for EGUS, including omeprazole efficacy and dosing considerations.
Treatment duration is typically 28 days, after which repeat gastroscopy is recommended to assess healing. Some horses may require longer treatment courses, particularly those with severe or chronic ulcers. Omeprazole is most effective when given on an empty stomach, ideally 30-60 minutes before feeding.
Sucralfate for Glandular Disease
Sucralfate is a mucosal protectant that forms a barrier over ulcerated glandular mucosa, promoting healing. It is often used in combination with omeprazole for EGGD or for horses with both squamous and glandular involvement. Sucralfate is administered as a slurry via oral syringe, typically two to four times daily. It should be given at least one hour apart from other medications to avoid interference with absorption.
Other Medical Options
Histamine-2 receptor antagonists (e.g., ranitidine, cimetidine) have been used historically but are less effective than omeprazole for acid suppression. Antacids provide rapid but short-lived acid neutralization and are not suitable as sole therapy. Misoprostol, a synthetic prostaglandin analog, may be considered for NSAID-induced glandular ulcers but carries risks of diarrhea and abortion in pregnant mares. A 2003 review in The Veterinary Clinics of North America. Equine Practice discusses treatment and prevention strategies, including these alternative options.
Treatment Monitoring
Clinical improvement is often observed within 7-14 days of starting appropriate therapy. However, endoscopic healing may take longer. Repeat gastroscopy at 28 days is recommended to confirm ulcer resolution. If ulcers persist, the veterinarian may extend treatment, adjust medication, or investigate underlying management factors. A 2023 update in Animals: an open access journal from MDPI provides current knowledge on EGUS management, emphasizing the importance of follow-up endoscopy.
Dietary Management
Forage-First Approach
Continuous access to forage is the cornerstone of EGUS prevention and management. Horses are natural grazers, evolved to consume small amounts of forage throughout the day. Free-choice hay or pasture turnout maintains a constant food supply in the stomach, buffering acid and reducing squamous exposure. Alfalfa hay, with its higher calcium and protein content, provides additional buffering capacity compared to grass hay.
Concentrate Feeding Modifications
High-concentrate meals should be minimized or eliminated during treatment. If concentrates are necessary, they should be fed in multiple small meals instead of one or two large meals. Adding oil to the diet can increase caloric density without increasing starch content. Soaking hay or using haylage may reduce dust and improve palatability for horses with oral discomfort.
Feeding Schedule
Horses should never go more than 6-8 hours without access to forage. For stalled horses, hay nets or slow feeders can extend eating time and prevent long periods of an empty stomach. Turnout on pasture is ideal, as grazing provides continuous forage intake and reduces stress.
Environmental and Management Modifications
Stress Reduction
Stress is a significant contributor to EGUS, particularly in performance horses. Management changes that reduce stress include consistent daily routines, adequate turnout time, social contact with other horses, and minimizing transport and competition frequency. For horses in training, adjusting work schedules to allow for rest days and reducing intensity during treatment can support healing.
Exercise Considerations
Intense exercise increases abdominal pressure and acid splashing onto the squamous mucosa. Horses should not be worked on an empty stomach, as this exacerbates acid exposure. Providing hay or a small meal before exercise can help buffer stomach contents. After exercise, horses should have access to forage to replenish stomach contents and neutralize residual acid.
NSAID Use
NSAIDs should be used judiciously in horses with EGUS. If NSAID therapy is necessary, the lowest effective dose for the shortest duration should be used. Concurrent administration of omeprazole or sucralfate may provide some mucosal protection. The World Organisation for Animal Health (WOAH) provides guidelines on animal health and welfare, including responsible medication use.
Recurrence Prevention Strategies
Long-Term Dietary Management
Preventing EGUS recurrence requires sustained dietary modifications. Continuous access to forage, preferably pasture turnout, is the most effective strategy. If pasture is unavailable, free-choice hay should be provided. Concentrate meals should be limited to no more than 0.5% of body weight per meal, and total daily concentrate should not exceed 1% of body weight unless required for performance.
Environmental Enrichment
Horses benefit from environmental enrichment that reduces stress and promotes natural behaviors. Turnout with compatible companions, access to shelter, and opportunities for movement all contribute to gastric health. Stalled horses should have visual and auditory contact with other horses and access to hay at all times.
Monitoring and Early Intervention
Owners should monitor horses for early signs of EGUS recurrence, such as subtle changes in appetite, behavior, or performance. Horses with a history of EGUS may benefit from periodic gastroscopy, particularly before and after periods of increased stress or training intensity. Early detection allows for prompt treatment and minimizes the impact on health and performance.
Prophylactic Medication
In some cases, prophylactic omeprazole may be considered during periods of high risk, such as during intense training, transport, or competition. A 2012 study in the Journal of Veterinary Medical Science evaluated the efficacy of omeprazole paste in preventing gastric ulcers in 2-year-old Thoroughbreds, supporting its use in high-risk populations. However, long-term prophylactic use should be balanced against cost and potential side effects, and management modifications should always be the primary prevention strategy.
Records and Measurements
Diagnostic Records
Veterinarians should maintain detailed records of gastroscopy findings, including ulcer grade, location (squamous vs. glandular), and photographic documentation. This allows for accurate comparison on follow-up examinations and informs treatment decisions. Records should also note the horse's signalment, presenting signs, and relevant history.
Treatment Records
Owners should keep a treatment log documenting medication administration, including drug name, dose, frequency, route, and duration. Any adverse effects or lack of response should be noted. This information is valuable for the veterinarian when adjusting therapy or investigating treatment failure.
Management Records
A management diary can help identify factors contributing to EGUS. Records should include feeding schedules, forage type and amount, concentrate type and amount, turnout hours, exercise intensity and duration, transport events, and any stressful incidents. Patterns may emerge that point to specific triggers for ulcer development or recurrence.
Monitoring Records
Owners should track clinical signs using a simple scoring system, noting appetite, attitude, performance, and any gastrointestinal signs. This provides objective data for assessing treatment response and detecting early recurrence. Regular body weight and body condition score measurements are also useful.
Common Failure Patterns
Incomplete Diagnostic Assessment
Failure to perform gastroscopy or to adequately visualize both squamous and glandular regions can lead to misdiagnosis and inappropriate treatment. Horses with EGGD may not respond to omeprazole alone, requiring addition of sucralfate or other therapies. Repeat gastroscopy after treatment is essential to confirm healing.
Inadequate Treatment Duration
Some horses require longer than 28 days of treatment, particularly those with severe or chronic ulcers. Premature discontinuation of therapy can lead to incomplete healing and rapid recurrence. The veterinarian should guide treatment duration based on endoscopic findings.
Persistent Management Factors
If underlying management factors are not addressed, ulcers are likely to recur even after successful treatment. Continuing intermittent feeding, high-concentrate diets, or intense exercise without modification will perpetuate the cycle of ulcer formation. Owners must be committed to long-term management changes.
NSAID Misuse
Continued or intermittent NSAID use during or after treatment can prevent healing or cause new ulcers. If NSAIDs are necessary, the veterinarian should prescribe the safest option and consider concurrent gastroprotectant therapy.
Stress Overload
Horses in high-stress environments, such as race training or frequent competition, may experience recurrent ulcers despite optimal management. In these cases, a combination of management modifications, environmental enrichment, and strategic prophylactic medication may be necessary.
Welfare and Safety Context
Animal Welfare Implications
EGUS causes pain and discomfort that negatively impacts equine welfare. Horses with ulcers may experience reduced appetite, weight loss, and behavioral changes. Performance horses may be pushed beyond their comfort zone, exacerbating stress and ulcer severity. The World Organisation for Animal Health (WOAH) emphasizes the importance of preventing disease and promoting welfare through appropriate management practices.
Safety Considerations for Handlers
Horses with EGUS may be irritable or unpredictable due to discomfort. Handlers should exercise caution when approaching, grooming, or tacking affected horses. Sudden changes in behavior, such as biting or kicking, may indicate pain. Veterinary evaluation is warranted if behavioral changes are observed.
Medication Safety
Omeprazole and sucralfate are generally safe when used as directed. However, omeprazole should not be used in horses with known hypersensitivity. Sucralfate can cause constipation in some horses. All medications should be used under veterinary supervision, and withdrawal times should be observed for horses intended for food production.
Professional Escalation Criteria
Veterinarians should refer to a specialist or equine internal medicine service if:
- Gastroscopy is not available in the practice
- Ulcers do not heal after two treatment courses
- Glandular disease is severe or refractory
- Concurrent gastrointestinal disease is suspected
- The horse has recurrent colic or weight loss despite treatment
- Diagnostic imaging or advanced procedures are needed
Practical Decision Framework for EGUS Management: The Four-Phase Treatment and Prevention Protocol
Managing Equine Gastric Ulcer Syndrome requires a structured approach that integrates diagnostic findings, treatment selection, dietary modification, and long-term prevention. Without a systematic framework, treatment failures and recurrence rates remain high. The following four-phase protocol provides veterinarians and horse owners with a clear decision pathway based on current evidence from the Merck Veterinary Manual and peer-reviewed literature.
Phase One: Diagnostic Confirmation and Risk Assessment
The first phase establishes the diagnosis and identifies contributing factors before treatment begins. Gastroscopy remains the only definitive diagnostic method, as confirmed by the American College of Veterinary Internal Medicine (ACVIM) guidelines. During this phase, the veterinarian performs a complete endoscopic examination of both the squamous and glandular mucosa, documenting ulcer grade, location, and lesion characteristics.
Decision Point 1: Differentiate ESGD from EGGD
The distinction between Equine Squamous Gastric Disease and Equine Glandular Gastric Disease determines the initial treatment strategy. ESGD typically appears as linear or diffuse lesions in the squamous mucosa near the margo plicatus. EGGD presents as discrete erosions, hemorrhagic lesions, or thickened mucosa in the glandular region. A 2022 review in the Veterinary Journal (London, England: 1997) emphasizes that region-specific diagnosis is essential because treatment responses differ significantly between the two conditions.
Decision Point 2: Grade Ulcer Severity
Using established scoring systems, the veterinarian assigns a grade from 0 (normal) to 4 (severe, widespread ulceration) for squamous lesions. Glandular lesions are described by appearance, depth, and extent. This grading guides treatment duration and follow-up intervals. Horses with grade 3 or 4 squamous ulcers typically require longer treatment courses and more aggressive management modifications.
Decision Point 3: Identify Modifiable Risk Factors
During the initial consultation, the veterinarian conducts a thorough management history including:
- Feeding schedule and forage access patterns
- Concentrate type, amount, and feeding frequency
- Exercise intensity, duration, and frequency
- NSAID use history, including drug, dose, and duration
- Recent transport, competition, or social changes
- Housing conditions and turnout availability
This risk factor assessment identifies the specific management changes needed for Phase Three. Without addressing these factors, treatment success rates decline significantly.
Phase Two: Medical Therapy Selection and Administration
Phase two focuses on selecting the appropriate medical therapy based on the diagnostic findings from Phase One. Treatment duration, drug selection, and administration protocols follow evidence-based guidelines.
Decision Point 4: Select Primary Therapy for ESGD
For horses with squamous ulcers only, omeprazole is the first-line treatment. The proton pump inhibitor reduces gastric acid secretion by irreversibly blocking the proton pump in parietal cells. A 2017 review in The Veterinary Clinics of North America. Equine Practice discusses omeprazole efficacy and dosing considerations. The standard protocol involves once-daily administration on an empty stomach, ideally 30-60 minutes before the morning meal.
Decision Point 5: Add Sucralfate for Glandular Involvement
When gastroscopy reveals glandular ulcers, sucralfate is added to the treatment regimen. Sucralfate forms a protective barrier over ulcerated glandular mucosa, promoting healing. It is administered as a slurry two to four times daily, at least one hour apart from omeprazole to avoid interference with absorption. Horses with both squamous and glandular disease require combination therapy.
Decision Point 6: Determine Treatment Duration
The standard treatment course is 28 days, but this may vary based on ulcer severity and location. Horses with grade 1 or 2 squamous ulcers may heal within 14-21 days, while those with grade 3 or 4 lesions or glandular involvement often require 28-42 days. A 2023 update in Animals: an open access journal from MDPI emphasizes that follow-up endoscopy is necessary to confirm healing instead of relying on clinical improvement alone.
Decision Point 7: Monitor for Adverse Effects
Omeprazole is generally well-tolerated, but some horses may experience loose stools or reduced appetite. Sucralfate can cause constipation in some individuals. Owners should report any adverse effects to the veterinarian promptly. If adverse effects occur, the veterinarian may adjust dosing or consider alternative therapies.
Phase Three: Dietary and Environmental Modification
Phase three addresses the underlying management factors that contributed to ulcer development. This phase is critical for healing and essential for preventing recurrence.
Decision Point 8: Implement Continuous Forage Access
Horses should never go more than 6-8 hours without access to forage. For stalled horses, this means providing hay at all times using slow feeders or hay nets to extend eating time. Pasture turnout is ideal because grazing provides continuous forage intake and reduces stress. Alfalfa hay, with its higher calcium and protein content, provides additional buffering capacity compared to grass hay.
Decision Point 9: Modify Concentrate Feeding
High-concentrate meals should be minimized or eliminated during treatment. If concentrates are necessary for energy requirements, they should be fed in multiple small meals instead of one or two large meals. Total daily concentrate should not exceed 1% of body weight, and individual meals should be limited to 0.5% of body weight. Adding oil to the diet can increase caloric density without increasing starch content.
Decision Point 10: Adjust Exercise Protocol
Intense exercise increases abdominal pressure and acid splashing onto the squamous mucosa. During treatment, exercise intensity should be reduced. Horses should not be worked on an empty stomach. Providing hay or a small meal before exercise helps buffer stomach contents. After exercise, horses should have immediate access to forage to replenish stomach contents and neutralize residual acid.
Decision Point 11: Minimize NSAID Use
NSAIDs should be discontinued during treatment if possible. If NSAID therapy is necessary, the lowest effective dose for the shortest duration should be used. Concurrent administration of omeprazole or sucralfate may provide some mucosal protection. The World Organisation for Animal Health (WOAH) provides guidelines on responsible medication use in animals.
Decision Point 12: Reduce Environmental Stress
Stress is a significant contributor to EGUS, particularly in performance horses. Management changes that reduce stress include consistent daily routines, adequate turnout time, social contact with other horses, and minimizing transport and competition frequency. For horses in training, adjusting work schedules to allow for rest days supports healing.
Phase Four: Recurrence Prevention and Long-Term Monitoring
Phase four begins after endoscopic confirmation of healing and focuses on maintaining gastric health through sustained management modifications.
Decision Point 13: Establish Long-Term Feeding Protocol
Continuous access to forage remains the cornerstone of prevention. Pasture turnout is ideal, but if unavailable, free-choice hay should be provided. Concentrate meals should be limited to no more than 0.5% of body weight per meal. Horses with a history of EGUS may benefit from alfalfa hay as part of their forage ration.
Decision Point 14: Implement Environmental Enrichment
Horses benefit from environmental enrichment that reduces stress and promotes natural behaviors. Turnout with compatible companions, access to shelter, and opportunities for movement all contribute to gastric health. Stalled horses should have visual and auditory contact with other horses and access to hay at all times.
Decision Point 15: Develop Monitoring Protocol
Owners should monitor horses for early signs of EGUS recurrence, such as subtle changes in appetite, behavior, or performance. A simple scoring system tracking appetite, attitude, performance, and gastrointestinal signs provides objective data. Regular body weight and body condition score measurements are also useful.
Decision Point 16: Consider Prophylactic Medication
In some cases, prophylactic omeprazole may be considered during periods of high risk, such as during intense training, transport, or competition. A 2012 study in the Journal of Veterinary Medical Science evaluated the efficacy of omeprazole paste in preventing gastric ulcers in 2-year-old Thoroughbreds, supporting its use in high-risk populations. However, long-term prophylactic use should be balanced against cost and potential side effects, and management modifications should always be the primary prevention strategy.
Record System for the Four-Phase Protocol
A structured record system supports consistent implementation of the four-phase protocol and facilitates communication between veterinarians and owners.
Diagnostic Record Template
| Date | Horse ID | Squamous Grade | Glandular Description | Risk Factors Identified | Veterinarian |
|---|---|---|---|---|---|
| 0-4 | Location, appearance, depth | Feeding, exercise, NSAIDs, stress |
Treatment Record Template
| Date | Drug | Dose | Frequency | Route | Duration | Adverse Effects | Prescribing Veterinarian |
|---|---|---|---|---|---|---|---|
| Omeprazole | Once daily | Oral paste | 28 days | ||||
| Sucralfate | 2-4 times daily | Oral slurry | 28 days |
Management Record Template
| Date | Forage Type | Forage Access Hours | Concentrate Type | Concentrate Amount | Exercise Type | Exercise Duration | NSAID Use | Stress Events |
|---|---|---|---|---|---|---|---|---|
Monitoring Record Template
| Date | Appetite Score (1-5) | Attitude Score (1-5) | Performance Score (1-5) | GI Signs | Body Weight | Body Condition Score |
|---|---|---|---|---|---|---|
Troubleshooting Common Protocol Failures
Failure Pattern 1: Incomplete Diagnostic Assessment
If a horse fails to respond to initial therapy, the first step is to review the diagnostic records. Was gastroscopy performed with adequate visualization of both squamous and glandular regions? Were lesions in the glandular mucosa missed? Repeat gastroscopy with careful examination of both regions is indicated.
Failure Pattern 2: Inadequate Treatment Duration
Some horses require longer than 28 days of treatment, particularly those with severe or chronic ulcers. If follow-up gastroscopy shows incomplete healing, the veterinarian should extend treatment for an additional 14-28 days. Premature discontinuation of therapy leads to rapid recurrence.
Failure Pattern 3: Persistent Management Factors
If underlying management factors are not addressed, ulcers are likely to recur even after successful treatment. Review the management record to identify any persistent risk factors. Common issues include continued intermittent feeding, high-concentrate diets, intense exercise without modification, or ongoing NSAID use.
Failure Pattern 4: NSAID Misuse
Continued or intermittent NSAID use during or after treatment can prevent healing or cause new ulcers. Review the treatment record for any NSAID administration. If NSAIDs are necessary, the veterinarian should prescribe the safest option and consider concurrent gastroprotectant therapy.
Failure Pattern 5: Stress Overload
Horses in high-stress environments may experience recurrent ulcers despite optimal management. In these cases, a combination of management modifications, environmental enrichment, and strategic prophylactic medication may be necessary. Consider referral to an equine internal medicine specialist for complex cases.
Professional Escalation Criteria
Veterinarians should refer to a specialist or equine internal medicine service if:
- Gastroscopy is not available in the practice
- Ulcers do not heal after two treatment courses
- Glandular disease is severe or refractory
- Concurrent gastrointestinal disease is suspected
- The horse has recurrent colic or weight loss despite treatment
- Diagnostic imaging or advanced procedures are needed
The four-phase protocol provides a structured approach to EGUS management that integrates diagnostic findings, treatment selection, dietary modification, and long-term prevention. By following this framework, veterinarians and horse owners can improve treatment outcomes, reduce recurrence rates, and support long-term equine gastric health.
Practical Decision Framework for EGUS Management: The Four-Phase Treatment and Prevention Protocol
Managing Equine Gastric Ulcer Syndrome requires a structured approach that integrates diagnostic findings, treatment selection, dietary modification, and long-term prevention. Without a systematic framework, treatment failures and recurrence rates remain high. The following four-phase protocol provides veterinarians and horse owners with a clear decision pathway based on current evidence from the Merck Veterinary Manual and peer-reviewed literature.
Phase One: Diagnostic Confirmation and Risk Assessment
The first phase establishes the diagnosis and identifies contributing factors before treatment begins. Gastroscopy remains the only definitive diagnostic method, as confirmed by the American College of Veterinary Internal Medicine (ACVIM) guidelines. During this phase, the veterinarian performs a complete endoscopic examination of both the squamous and glandular mucosa, documenting ulcer grade, location, and lesion characteristics.
Decision Point 1: Differentiate ESGD from EGGD
The distinction between Equine Squamous Gastric Disease and Equine Glandular Gastric Disease determines the initial treatment strategy. ESGD typically appears as linear or diffuse lesions in the squamous mucosa near the margo plicatus. EGGD presents as discrete erosions, hemorrhagic lesions, or thickened mucosa in the glandular region. A 2022 review in the Veterinary Journal (London, England: 1997) emphasizes that region-specific diagnosis is essential because treatment responses differ significantly between the two conditions.
Decision Point 2: Grade Ulcer Severity
Using established scoring systems, the veterinarian assigns a grade from 0 (normal) to 4 (severe, widespread ulceration) for squamous lesions. Glandular lesions are described by appearance, depth, and extent. This grading guides treatment duration and follow-up intervals. Horses with grade 3 or 4 squamous ulcers typically require longer treatment courses and more aggressive management modifications.
Decision Point 3: Identify Modifiable Risk Factors
During the initial consultation, the veterinarian conducts a thorough management history including:
- Feeding schedule and forage access patterns
- Concentrate type, amount, and feeding frequency
- Exercise intensity, duration, and frequency
- NSAID use history, including drug, dose, and duration
- Recent transport, competition, or social changes
- Housing conditions and turnout availability
This risk factor assessment identifies the specific management changes needed for Phase Three. Without addressing these factors, treatment success rates decline significantly.
Phase Two: Medical Therapy Selection and Administration
Phase two focuses on selecting the appropriate medical therapy based on the diagnostic findings from Phase One. Treatment duration, drug selection, and administration protocols follow evidence-based guidelines.
Decision Point 4: Select Primary Therapy for ESGD
For horses with squamous ulcers only, omeprazole is the first-line treatment. The proton pump inhibitor reduces gastric acid secretion by irreversibly blocking the proton pump in parietal cells. A 2017 review in The Veterinary Clinics of North America. Equine Practice discusses omeprazole efficacy and dosing considerations. The standard protocol involves once-daily administration on an empty stomach, ideally 30-60 minutes before the morning meal.
Decision Point 5: Add Sucralfate for Glandular Involvement
When gastroscopy reveals glandular ulcers, sucralfate is added to the treatment regimen. Sucralfate forms a protective barrier over ulcerated glandular mucosa, promoting healing. It is administered as a slurry two to four times daily, at least one hour apart from omeprazole to avoid interference with absorption. Horses with both squamous and glandular disease require combination therapy.
Decision Point 6: Determine Treatment Duration
The standard treatment course is 28 days, but this may vary based on ulcer severity and location. Horses with grade 1 or 2 squamous ulcers may heal within 14-21 days, while those with grade 3 or 4 lesions or glandular involvement often require 28-42 days. A 2023 update in Animals: an open access journal from MDPI emphasizes that follow-up endoscopy is necessary to confirm healing instead of relying on clinical improvement alone.
Decision Point 7: Monitor for Adverse Effects
Omeprazole is generally well-tolerated, but some horses may experience loose stools or reduced appetite. Sucralfate can cause constipation in some individuals. Owners should report any adverse effects to the veterinarian promptly. If adverse effects occur, the veterinarian may adjust dosing or consider alternative therapies.
Phase Three: Dietary and Environmental Modification
Phase three addresses the underlying management factors that contributed to ulcer development. This phase is critical for healing and essential for preventing recurrence.
Decision Point 8: Implement Continuous Forage Access
Horses should never go more than 6-8 hours without access to forage. For stalled horses, this means providing hay at all times using slow feeders or hay nets to extend eating time. Pasture turnout is ideal because grazing provides continuous forage intake and reduces stress. Alfalfa hay, with its higher calcium and protein content, provides additional buffering capacity compared to grass hay.
Decision Point 9: Modify Concentrate Feeding
High-concentrate meals should be minimized or eliminated during treatment. If concentrates are necessary for energy requirements, they should be fed in multiple small meals instead of one or two large meals. Total daily concentrate should not exceed 1% of body weight, and individual meals should be limited to 0.5% of body weight. Adding oil to the diet can increase caloric density without increasing starch content.
Decision Point 10: Adjust Exercise Protocol
Intense exercise increases abdominal pressure and acid splashing onto the squamous mucosa. During treatment, exercise intensity should be reduced. Horses should not be worked on an empty stomach. Providing hay or a small meal before exercise helps buffer stomach contents. After exercise, horses should have immediate access to forage to replenish stomach contents and neutralize residual acid.
Decision Point 11: Minimize NSAID Use
NSAIDs should be discontinued during treatment if possible. If NSAID therapy is necessary, the lowest effective dose for the shortest duration should be used. Concurrent administration of omeprazole or sucralfate may provide some mucosal protection. The World Organisation for Animal Health (WOAH) provides guidelines on responsible medication use in animals.
Decision Point 12: Reduce Environmental Stress
Stress is a significant contributor to EGUS, particularly in performance horses. Management changes that reduce stress include consistent daily routines, adequate turnout time, social contact with other horses, and minimizing transport and competition frequency. For horses in training, adjusting work schedules to allow for rest days supports healing.
Phase Four: Recurrence Prevention and Long-Term Monitoring
Phase four begins after endoscopic confirmation of healing and focuses on maintaining gastric health through sustained management modifications.
Decision Point 13: Establish Long-Term Feeding Protocol
Continuous access to forage remains the cornerstone of prevention. Pasture turnout is ideal, but if unavailable, free-choice hay should be provided. Concentrate meals should be limited to no more than 0.5% of body weight per meal. Horses with a history of EGUS may benefit from alfalfa hay as part of their forage ration.
Decision Point 14: Implement Environmental Enrichment
Horses benefit from environmental enrichment that reduces stress and promotes natural behaviors. Turnout with compatible companions, access to shelter, and opportunities for movement all contribute to gastric health. Stalled horses should have visual and auditory contact with other horses and access to hay at all times.
Decision Point 15: Develop Monitoring Protocol
Owners should monitor horses for early signs of EGUS recurrence, such as subtle changes in appetite, behavior, or performance. A simple scoring system tracking appetite, attitude, performance, and gastrointestinal signs provides objective data. Regular body weight and body condition score measurements are also useful.
Decision Point 16: Consider Prophylactic Medication
In some cases, prophylactic omeprazole may be considered during periods of high risk, such as during intense training, transport, or competition. A 2012 study in the Journal of Veterinary Medical Science evaluated the efficacy of omeprazole paste in preventing gastric ulcers in 2-year-old Thoroughbreds, supporting its use in high-risk populations. However, long-term prophylactic use should be balanced against cost and potential side effects, and management modifications should always be the primary prevention strategy.
Record System for the Four-Phase Protocol
A structured record system supports consistent implementation of the four-phase protocol and facilitates communication between veterinarians and owners.
Diagnostic Record Template
| Date | Horse ID | Squamous Grade | Glandular Description | Risk Factors Identified | Veterinarian |
|---|---|---|---|---|---|
| 0-4 | Location, appearance, depth | Feeding, exercise, NSAIDs, stress |
Treatment Record Template
| Date | Drug | Dose | Frequency | Route | Duration | Adverse Effects | Prescribing Veterinarian |
|---|---|---|---|---|---|---|---|
| Omeprazole | Once daily | Oral paste | 28 days | ||||
| Sucralfate | 2-4 times daily | Oral slurry | 28 days |
Management Record Template
| Date | Forage Type | Forage Access Hours | Concentrate Type | Concentrate Amount | Exercise Type | Exercise Duration | NSAID Use | Stress Events |
|---|---|---|---|---|---|---|---|---|
Monitoring Record Template
| Date | Appetite Score (1-5) | Attitude Score (1-5) | Performance Score (1-5) | GI Signs | Body Weight | Body Condition Score |
|---|---|---|---|---|---|---|
Troubleshooting Common Protocol Failures
Failure Pattern 1: Incomplete Diagnostic Assessment
If a horse fails to respond to initial therapy, the first step is to review the diagnostic records. Was gastroscopy performed with adequate visualization of both squamous and glandular regions? Were lesions in the glandular mucosa missed? Repeat gastroscopy with careful examination of both regions is indicated.
Failure Pattern 2: Inadequate Treatment Duration
Some horses require longer than 28 days of treatment, particularly those with severe or chronic ulcers. If follow-up gastroscopy shows incomplete healing, the veterinarian should extend treatment for an additional 14-28 days. Premature discontinuation of therapy leads to rapid recurrence.
Failure Pattern 3: Persistent Management Factors
If underlying management factors are not addressed, ulcers are likely to recur even after successful treatment. Review the management record to identify any persistent risk factors. Common issues include continued intermittent feeding, high-concentrate diets, intense exercise without modification, or ongoing NSAID use.
Failure Pattern 4: NSAID Misuse
Continued or intermittent NSAID use during or after treatment can prevent healing or cause new ulcers. Review the treatment record for any NSAID administration. If NSAIDs are necessary, the veterinarian should prescribe the safest option and consider concurrent gastroprotectant therapy.
Failure Pattern 5: Stress Overload
Horses in high-stress environments may experience recurrent ulcers despite optimal management. In these cases, a combination of management modifications, environmental enrichment, and strategic prophylactic medication may be necessary. Consider referral to an equine internal medicine specialist for complex cases.
Professional Escalation Criteria
Veterinarians should refer to a specialist or equine internal medicine service if:
- Gastroscopy is not available in the practice
- Ulcers do not heal after two treatment courses
- Glandular disease is severe or refractory
- Concurrent gastrointestinal disease is suspected
- The horse has recurrent colic or weight loss despite treatment
- Diagnostic imaging or advanced procedures are needed
The four-phase protocol provides a structured approach to EGUS management that integrates diagnostic findings, treatment selection, dietary modification, and long-term prevention. By following this framework, veterinarians and horse owners can improve treatment outcomes, reduce recurrence rates, and support long-term equine gastric health.
Frequently Asked Questions
What is the difference between squamous and glandular gastric ulcers in horses?
Squamous ulcers occur in the upper, non-glandular portion of the stomach that is not protected from acid. Glandular ulcers occur in the lower portion that normally has protective mechanisms. The two types require different treatment approaches, with squamous ulcers responding better to acid suppression and glandular ulcers often needing mucosal protectants.
How is equine gastric ulcer syndrome diagnosed?
Gastroscopy is the only definitive diagnostic method. The horse is sedated and fasted for 12 hours, then an endoscope is passed through the esophagus into the stomach to directly visualize the mucosa. Ulcers are graded based on severity and location.
What is the standard treatment for equine gastric ulcers?
Omeprazole, a proton pump inhibitor, is the primary treatment for squamous ulcers. Sucralfate is often added for glandular ulcers. Treatment typically lasts 28 days, with repeat gastroscopy recommended to confirm healing. Dietary and management modifications are essential for long-term success.
Can equine gastric ulcers be prevented?
Yes, prevention focuses on continuous access to forage, minimizing concentrate meals, reducing stress, and avoiding unnecessary NSAID use. Pasture turnout is ideal. Horses at high risk may benefit from prophylactic omeprazole during periods of intense training or stress.
How long does it take for equine gastric ulcers to heal?
Clinical improvement is often seen within 7-14 days of starting treatment. Endoscopic healing typically requires 28 days of therapy. Severe or chronic ulcers may take longer. Repeat gastroscopy is recommended to confirm complete healing.
What are the signs of equine gastric ulcers in horses?
Signs include poor appetite, weight loss, dull coat, mild colic after eating, teeth grinding, excessive salivation, and poor performance. Some horses show no outward signs. Performance horses may exhibit decreased stamina, reluctance to work, or behavioral changes.
Can horses with gastric ulcers still be ridden?
Horses with active ulcers should have reduced exercise intensity during treatment. Light work may be acceptable, but intense training should be avoided until healing is confirmed. After treatment, gradual return to work is recommended, with continued management modifications to prevent recurrence.
Is gastroscopy necessary for follow-up after treatment?
Yes, repeat gastroscopy is recommended to confirm ulcer healing. Clinical improvement does not always correlate with endoscopic resolution. Without follow-up endoscopy, incomplete healing may go undetected, leading to rapid recurrence.
Related Veterinary Guides
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References and Further Reading
- aaep.org
- www.merckvetmanual.com
- www.acvim.org
- Merck Veterinary Manual. Merck Veterinary Manual.
- Animal Health and Welfare. World Organisation for Animal Health.
- Equine gastric ulcer syndrome in adult horses.. Veterinary journal (London, England : 1997), 2022.
- Equine Gastric Ulcer Syndrome: An Update on Current Knowledge.. Animals : an open access journal from MDPI, 2023.
- Therapeutics for Equine Gastric Ulcer Syndrome.. The Veterinary clinics of North America. Equine practice, 2017.
- Equine gastric ulcer syndrome in adult horses: a review.. New Zealand veterinary journal, 2007.
- Treatment and prevention of equine gastric ulcer syndrome.. The Veterinary clinics of North America. Equine practice, 2003.
- Equine Gastric Ulcer Syndrome affects fitness parameters in poorly performing Standardbred racehorses.. Frontiers in veterinary science, 2022.
- Advances in Diagnostics and Treatments in Horses and Foals with Gastric and Duodenal Ulcers. Veterinary Clinics of North America Equine Practice, 2018.
- Efficacy of omeprazole paste in the prevention of gastric ulcers in 2 years old Thoroughbreds. Journal of Veterinary Medical Science, 2012.
This article is educational and is not a substitute for veterinary diagnosis or treatment. Contact a veterinarian for advice about an individual animal.