Gastric Ulceration: What the Research Says
Evidence from 32 peer-reviewed studies
What Professionals Should Know
- •Digestive support supplements alone may not be an effective intervention for managing cribbing behavior in horses, despite theoretical links between cribbing and GI dysfunction.
- •Cribbing cannot be reliably predicted or managed through standard GI markers (pH, cortisol, gastrin levels) or addressed via supplementation targeting these parameters.
- •Further research into the underlying mechanisms of cribbing and multifactorial management approaches is needed before recommending GI supplements as primary cribbing interventions.
- •Feeding pelleted dehydrated alfalfa as a 50% replacement for concentrates significantly improves glandular gastric health in horses with existing ulceration, with 83% improvement vs 0% in controls
- •High soluble sugar intake from concentrates alone does not protect against GGD—dietary composition and fiber type matter more than expected for gastric health
- •Consider alfalfa-based feed modifications as a practical dietary intervention for horses showing signs of gastric disease, particularly in high-training environments (≥5 days/week exercise)
- •Wheat straw of good hygienic quality can safely replace up to 50% of grass forage without increasing gastric ulcer risk, contrary to previous field study findings
- •Straw-based diets extend eating time and reduce caloric intake and insulin response—valuable for managing overweight horses or those prone to metabolic syndrome
- •Straw can be a cost-effective and practical roughage option for horses with lower energy requirements, provided forage quality is maintained
- •For horses with moderate-to-severe gastric ulcers, implementing appropriate dietary changes (restricted starch ration) appears essential for long-term improvement after stopping acid-suppressive medication
- •Omeprazole treatment alone is insufficient for sustained ulcer healing—dietary management must accompany or follow medication for lasting clinical benefit
- •Dietary modification is a practical, cost-effective management strategy that should be considered standard protocol alongside or after pharmaceutical treatment in exercising horses with ESGD
- •If NSAID therapy is necessary in horses, firocoxib causes less severe gastric and intestinal damage than phenylbutazone, suggesting it may be the safer choice for GI health
- •Both common NSAIDs cause GI injury even at standard dosages; consider gastric and intestinal protective strategies or alternatives when possible, particularly for prolonged treatment
- •Firocoxib shows faster GI recovery after treatment cessation (within 10 days), whereas phenylbutazone effects persist longer—factor this into treatment planning and monitoring protocols
- •The novel omeprazole paste (ULS) is pharmacodynamically equivalent to the registered reference product and can be used with confidence for managing gastric ulcers in horses
- •Both formulations effectively reduce gastric ulcer severity in clinically healthy horses with consistent pH elevation across a 6-day treatment period
- •Practitioners can choose between the two formulations based on availability, cost, or delivery preference without compromising therapeutic efficacy for gastric ulcer management
- •Omeprazole dosing in clinical gastric ulcer cases may be optimizable—lower doses may be effective, potentially reducing treatment costs
- •Understanding differential healing rates between squamous and glandular ulcers can inform treatment protocols and prognosis discussions with clients
- •Blinded, randomized design provides higher-quality evidence for evidence-based treatment recommendations compared to previous pharmacokinetic studies
- •Anesthesia in dorsal recumbency does not cause excessive gastric acidification—normal physiological pH is maintained during the procedure, reducing concern for perioperative gastric ulcer risk from this position alone
- •Post-operative gastric pH becomes alkaline rather than acidic, which is unexpected and suggests anesthesia may alter normal gastric acid secretion; monitor post-operative feed intake as normal acid environment needed for digestion may be transiently disrupted
- •Routine gastric protectant medications are not indicated based on gastric pH changes alone during routine inhalation anesthesia, though clinical decision-making should consider individual risk factors and concurrent medications
- •Feeding timing before transport affects oxidative balance in horses; feeding closer to departure (1 hour) may trigger different antioxidant responses than feeding 6-12 hours prior
- •Long-distance transport (12 hours) without food or water increases oxidative stress markers even though they remain within normal ranges, suggesting subclinical effects warrant further investigation
- •Gastric ulceration risk during transport cannot be reliably predicted by oxidative stress parameters alone; additional factors beyond oxidative stress likely contribute to EGUS development
- •While elevated DGGR-lipase (>2x URL) correlates with surgical disease and worse outcomes in colicky horses, it cannot be relied upon as a standalone diagnostic or screening tool due to poor sensitivity
- •DGGR-lipase may have some prognostic value when markedly elevated (>2x URL), suggesting consideration of more aggressive treatment approaches, but normal values do not rule out serious disease
- •This biomarker should complement, not replace, clinical examination, imaging, and other diagnostic modalities in colic assessment
- •Feeding mares before 12-hour transport may help reduce ulceration risk by promoting gastric emptying, contrary to traditional fasting practices
- •Transportation itself, not simply confinement or fasting, is the primary risk factor for acute gastric ulceration in mares
- •Consider gastric protection protocols (e.g., omeprazole) specifically for transported horses, as pH elevation during transport creates a different mucosal injury mechanism than simple acid exposure
- •Transport horses rear-facing and in wider bays when possible to reduce balance-related stress and associated gastric ulcer risk
- •Monitor behaviour during transport and physiological signs post-transport (heart rate, temperature, behaviour observation) as reliable indicators of transport stress; standard blood work may not detect problems
- •Poor balance during transport is a red flag for gastric ulceration and muscle damage—transport conditions should be optimised to minimise balance loss
- •Automated fractioned feeders delivering grain in multiple small meals throughout the day effectively reduce gastric ulcer development in exercised young horses compared to traditional twice-daily feeding
- •Minimizing fasting periods is a critical management strategy for gastric ulcer prevention in training Quarter Horses—consider automated feeders as a practical tool for high-risk populations
- •Fractioned feeding maintains body condition and weight equally well as traditional feeding, making it a viable alternative without nutritional compromise
- •Hay grid feeders effectively reduce hay consumption without requiring horses to change their eating duration, making them useful for managing obesity while maintaining natural feeding behavior
- •Using a hay grid feeder does not compromise gastric pH control compared to ground feeding, so it can be safely used in horses at risk for ulceration without additional protective measures
- •Since hay grid feeders maintain eating time while reducing intake, they may help balance the competing goals of preventing both obesity and gastric ulceration in stabled horses
- •Gastric ulcers are highly prevalent in racehorses in active training—endoscopy should be considered as a diagnostic tool rather than relying on clinical signs or history alone
- •Horses undergoing intensive training and racing are at elevated risk; management strategies during preparatory and active racing phases warrant investigation
- •Age, sex, performance level, behaviour, and feeding regimens alone cannot reliably predict which individual horses will have gastric ulcers, so screening protocols should not exclude horses based on these factors
- •Nearly half of colicky horses have concurrent gastric ulceration—consider gastroscopic examination and ulcer treatment alongside addressing the primary abdominal condition
- •Medical colic cases show higher ulceration rates than surgical cases, suggesting gastric ulceration may be associated with less severe primary lesions or represents a secondary complication of painful states
- •Duodenitis-proximal jejunitis shows a concerning association with gastric ulceration; monitor these cases closely for ulcer development and consider prophylactic or therapeutic ulcer management
- •A practical serum-based screening test for ESGD does not yet exist, but these protein markers represent promising candidates for future diagnostic development
- •Given the high prevalence of ESGD (43%), improved non-invasive screening tools would be valuable for identifying affected horses without gastroscopy
- •Until antibody-based confirmation studies are completed, gastroscopy remains the gold standard for ESGD diagnosis in clinical practice
- •Gastric ulceration should be considered as a potential health concern in donkey populations, particularly working donkeys in resource-limited settings
- •Further research is needed on donkeys outside the UK to understand the prevalence and risk factors for gastric disease in diverse geographic and management contexts
- •Endurance horse owners should implement gastric ulcer prevention and screening protocols, as two-thirds of competition horses show ulceration despite lower severity than racehorses
- •Active bleeding from glandular mucosa is a significant finding in endurance horses requiring investigation—monitor for clinical signs of gastric disease and consider prophylactic management during training
- •Blood biochemistry markers (albumin, creatinine, glucose) may help identify horses at lower risk for gastric ulceration and should be incorporated into pre-competition health assessments
- •Nearly half of eventing horses experience musculoskeletal problems; focus preventive strategies on the foot and joint structures as priority areas for your population
- •Injury prevention strategies should differ by context: educate riders about competition-related hoof/tendon injuries and training-related ligament/stifle injuries
- •Recovery time varies dramatically by injury type (2 weeks to >12 months); set realistic owner expectations and tailor rehabilitation protocols accordingly
- •Horses receiving omeprazole during ulcer-inducing stress show measurable changes in heart rate variability that reflect reduced sympathetic nervous system activation, suggesting the drug mitigates stress responses associated with gastric ulcers
- •Heart rate variability assessment via electrocardiography could potentially serve as a non-invasive, field-applicable welfare monitoring tool for horses at risk of exercise-induced gastric ulceration
- •Athletic training protocols that include feed withholding appear to reliably induce gastric ulcers in horses; consider management strategies to prevent this common welfare concern in working equines
- •When presented with a girthy horse, prioritize gastric ulcer investigation via gastroscopy as it was the most common finding in this population
- •Perform systematic clinical examination including orthopedic evaluation, saddle fit assessment, and investigation of less obvious conditions (abdominal/systemic disease) as girthiness has multiple potential causes
- •Do not assume behavioral problems or training issues are the cause—girthiness warrants thorough diagnostic workup as 92% of endoscoped horses had gastric ulceration
- •Do not assume glandular gastric disease has the same cause or responds to the same treatment as squamous disease—inflammatory pathology requires different management strategies focused on stress reduction
- •Acid suppression alone (omeprazole) is insufficient for glandular disease; healing is slower and requires multimodal treatment approaches
- •Consider reduced gastric blood flow and possible inflammatory bowel disease as underlying causes when diagnosing glandular lesions, rather than assuming acid-related pathology
- •Implement consistent management practices including adequate forage, frequent feeding, and reduced starch to help prevent gastric ulceration in competition horses
- •Monitor stress levels during training and competition periods, as these are critical risk factors for gastric disease development
- •Consider prophylactic interventions before problems develop, as prevention is more economical and effective than post-ulceration treatment
- •When diagnosing gastric ulcers, determine whether lesions are in squamous or glandular mucosa—they require different treatment approaches and have different underlying causes
- •Always document the anatomical location of gastric lesions (cardia, fundus, antrum, or pylorus) in your records to enable meaningful comparison of cases and treatment outcomes
- •If you diagnose secondary ESGD, investigate the cause of delayed gastric outflow rather than treating the ulceration in isolation
- •Recognize that glandular gastric ulcers are a distinct condition requiring different diagnostic and treatment approaches than squamous ulcers
- •Understand specific risk factors for EGGUS to implement targeted prevention strategies in your management protocols
- •Apply evidence-based treatment recommendations specific to glandular ulceration rather than using generic gastric ulcer protocols
- •Recognize that squamous and glandular gastric ulcers are distinct conditions requiring different diagnostic and management approaches
- •Apply ESGUS-specific risk factor assessment and prevention strategies rather than treating all gastric ulcers uniformly
- •Tailor treatment protocols based on the location of ulceration (squamous vs. glandular) for improved clinical outcomes
- •Evaluate and modify multiple risk factors simultaneously (work intensity, feeding practices, medication use, housing) rather than addressing EGUS with single-intervention treatments
- •Prevention through appropriate management and environmental modifications is as important as medical treatment; consider the horse's anatomophysiological constraints when designing management systems
- •Current standard therapies may be cost-prohibitive; advocate for research into affordable treatment options and collaborate with veterinarians on individualized prevention protocols for your yard
- •Veterinarians should be aware that while gross lesion scoring exists for equine gastric ulceration, microscopic findings lack standardised classification, limiting disease understanding and research comparison
- •Implementation of a standardised histological scoring protocol would improve diagnosis of underlying causes of gastric disease and support evidence-based treatment protocols
- •Given high prevalence in racehorses, adoption of consistent scoring systems across practices and studies would enhance detection of emerging gastric pathologies and aetiologies
- •Understanding the histopathological basis of gastric lesions helps veterinarians better interpret gross gastroscopic findings and improve diagnostic accuracy in performance horses
- •Lesion characteristics vary by anatomical region of the stomach, suggesting different pathogenic mechanisms may be involved in different areas
- •Knowledge of normal versus pathological gastric histology is essential for early detection and management of gastric disease in high-performance horses
- •A simple blood test measuring serum sucrose levels could screen for gastric ulcers in performance horses without the technical difficulties of urine collection
- •Peak sucrose concentration at 45 minutes post-dosing correlates strongly with ulcer severity, enabling assessment of ulcer burden in racing and high-performance horses
- •This noninvasive method could facilitate regular monitoring of gastric health in horses undergoing intense training without requiring gastroscopy
- •Not all generic omeprazole preparations are equally effective—GastroGard and specifically formulated high-pH compounded versions work best; verify your compounded omeprazole has vehicle pH >8.0
- •For horses in intensive training, administer omeprazole 4-8 hours before training sessions rather than at arbitrary times to optimize gastric acid suppression during work
- •A single daily dose of 4 mg/kg omeprazole provides adequate gastric protection for at least 12 hours, making once-daily dosing practical for field management
Key Research Findings
A digestive support supplement showed no significant differences in fecal and gastric pH between cribbing and non-cribbing horses.
An interaction between supplementation and cribbing status was observed for squamous mucosa ulcer scores (P=0.003), suggesting differential response by phenotype.
No differences were found in serum cortisol, serum gastrin, or crib-bite count between cribbing and non-cribbing horses or between treatment groups.
The GI support supplement did not effectively address cribbing behavior or alter the gastrointestinal environment in either phenotype.
Horses with healthy glandular mucosa (scores 0-1) consumed significantly more soluble sugars from concentrates (77.5 g/kg BW) than those with ulceration (59.1 g/kg BW), contrary to expectations (P=0.01)
Starch intake did not differ between ulcerated and non-ulcerated horses (P=0.24)
Substituting 50% of concentrates with pelleted dehydrated alfalfa reduced severe GGD at 42 days in ulcerated horses (1/6 vs 6/6 remaining affected, P=0.02)
Clinical success was 47.7 times more likely with alfalfa supplementation compared to control diet (95% CI: 1.6-1422.8)
Replacing 50% of grass forage with wheat straw did not increase gastric ulcer scores (squamous or glandular) over 21 days
Straw diet extended feeding time (p < 0.05) and significantly reduced energy intake and plasma insulin concentrations compared to grass-only diet (p < 0.0001)
Plasma serotonin concentrations tended to be higher on straw diet (p = 0.05), suggesting potential behavioural or metabolic benefits
Good quality wheat straw can safely comprise up to 50% of forage-only rations and promotes a metabolic profile suited to overweight or easy-keeper horses
In severe ESGD (Grade ≥3/4), dietary change resulted in sustained improvement between weeks 4-10 (no significant worsening, P=0.32), whereas horses remaining on original diet showed significant worsening after omeprazole cessation (P=0.005)
For severe ESGD, dietary change produced significant improvement from baseline to week 10 (P=0.003) even after omeprazole discontinuation
Omeprazole alone without dietary change provided only temporary benefit in severe ESGD, with ulcer grades returning to baseline by week 10 (P=0.08)
Evidence Base
Investigating the gastrointestinal physiology of mature horses with and without a history of cribbing behavior in response to feeding a digestive support supplement.
Arias-Esquivel Ana M, Vasco Ana C Cerqueira de Melo, Lance Jill et al. (2024) — Journal of equine veterinary science
Effect of diet composition on glandular gastric disease in horses.
Julliand Samy, Buttet Marjorie, Hermange Tanguy et al. (2023) — Journal of veterinary internal medicine
Straw as an Alternative to Grass Forage in Horses-Effects on Post-Prandial Metabolic Profile, Energy Intake, Behaviour and Gastric Ulceration.
Jansson Anna, Harris Patricia, Davey Sara Larsdotter et al. (2021) — Animals : an open access journal from MDPI
Effect of Changing Diet on Gastric Ulceration in Exercising Horses and Ponies After Cessation of Omeprazole Treatment.
Luthersson Nanna, Bolger Coby, Fores Paloma et al. (2019) — Journal of equine veterinary science
Effect of selective versus nonselective cyclooxygenase inhibitors on gastric ulceration scores and intestinal inflammation in horses.
Richardson Lauren M, Whitfield-Cargile Canaan M, Cohen Noah D et al. (2018) — Veterinary surgery : VS
Pharmacokinetic and pharmacodynamic effects of two omeprazole formulations on stomach pH and gastric ulcer scores.
Raidal S L, Andrews F M, Nielsen S G et al. (2017) — Equine veterinary journal
A comparison of two doses of omeprazole in the treatment of equine gastric ulcer syndrome: a blinded, randomised, clinical trial.
Sykes B W, Sykes K M, Hallowell G D (2014) — Equine veterinary journal
Evaluation of Gastric pH and Gastrin Concentrations in Horses Subjected to General Inhalation Anesthesia in Dorsal Recumbency.
Guerrero Jesus Leonardo Suarez, Brito Pedro Henrique Salles, Ferreira Marília Alves et al. (2024) — Animals : an open access journal from MDPI
Effects of Transport and Feeding Strategies Before Transportation on Redox Homeostasis and Gastric Ulceration in Horses.
Gharehaghajlou Yashar, Raidal Sharanne L, Freccero Francesca et al. (2023) — Journal of equine veterinary science
Diagnostic utility and validity of 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase activity in horses with colic.
Lanz S, Howard J, Gerber V et al. (2022) — Veterinary journal (London, England : 1997)
Effects of transportation on gastric pH and gastric ulceration in mares.
Padalino Barbara, Davis Georgina L, Raidal Sharanne L (2020) — Journal of veterinary internal medicine
Effects of Transport Conditions on Behavioural and Physiological Responses of Horses.
Padalino Barbara, Raidal Sharanne L (2020) — Animals : an open access journal from MDPI
Effects of Feeding Frequency Using a Commercial Automated Feeding Device on Gastric Ulceration in Exercised Quarter Horses.
Bass Luke, Swain Elsbeth, Santos Hugo et al. (2018) — Journal of equine veterinary science
The effect of a hay grid feeder on feed consumption and measurement of the gastric pH using an intragastric electrode device in horses: a preliminary report.
Aristizabal F, Nieto J, Yamout S et al. (2014) — Equine veterinary journal
Prevalence of gastric ulceration in Swedish Standardbreds in race training.
Jonsson H, Egenvall A (2006) — Equine veterinary journal
Prevalence of gastric squamous ulceration in horses with abdominal pain.
Dukti S A, Perkins S, Murphy J et al. (2006) — Equine veterinary journal
Searching for serum protein markers of equine squamous gastric disease using gel electrophoresis and mass spectrometry.
Tesena P, Yingchutrakul Y, Roytrakul S et al. (2019) — Equine veterinary journal
Pathology of gastric lesions in donkeys: A preliminary study.
Al-Mokaddem A K, Ahmed K A, Doghaim R E (2015) — Equine veterinary journal
Prevalence of gastric ulcers in endurance horses--a preliminary report.
Nieto Jorge E, Snyder Jack R, Beldomenico Pablo et al. (2004) — Veterinary journal (London, England : 1997)
Musculoskeletal Injury and Illness Patterns in British Eventing Horses: A Descriptive Study.
Tranquille Carolyne A, Chojnacka Kate, Murray Rachel C (2024) — Animals : an open access journal from MDPI
Show 12 more references
Changes in Heart Rate Variability with Induction of Gastric Ulcers in Adult Horses.
Louie Elizabeth Williams, Berryhill Emily H, Nieto Jorge et al. (2023) — Journal of equine veterinary science
Girthiness: Retrospective Study of 37 Horses (2004-2016).
Millares-Ramirez Esther M, Le Jeune Sarah S (2019) — Journal of equine veterinary science
Pathogenesis of equine squamous and glandular gastric disease
Hallowell Gayle (2018) — UK-Vet Equine
Maintaining gastric health in the competition horse
Hardy Emma (2017) — Equine Health
European College of Equine Internal Medicine Consensus Statement—Equine Gastric Ulcer Syndrome in Adult Horses
B. Sykes, M. Hewetson, R. Hepburn et al. (2015) — Journal of Veterinary Internal Medicine
Rethinking equine gastric ulcer syndrome: Part 3 – Equine glandular gastric ulcer syndrome (EGGUS)
Sykes B., Jokisalo J. M. (2015) — Equine Veterinary Education
Rethinking equine gastric ulcer syndrome: Part 2 – Equine squamous gastric ulcer syndrome ( <scp>ESGUS</scp> )
Sykes B. W., Jokisalo J. M. (2015) — Equine Veterinary Education
Equine gastric ulcer syndrome: risk factors and therapeutic aspects
José Ramón Martínez Aranzalez, G. Alves (2014) — Revista Colombiana de Ciencias Pecuarias
Pathology of gastritis and gastric ulceration in the horse. Part 2: a scoring system.
Martineau H, Thompson H, Taylor D (2009) — Equine veterinary journal
Pathology of gastritis and gastric ulceration in the horse. Part 1: range of lesions present in 21 mature individuals.
Martineau H, Thompson H, Taylor D (2009) — Equine veterinary journal
Sucrose concentration in blood: a new method for assessment of gastric permeability in horses with gastric ulceration.
Hewetson M, Cohen N D, Love S et al. (2006) — Journal of veterinary internal medicine
Effect of GastroGard and three compounded oral omeprazole preparations on 24 h intragastric pH in gastrically cannulated mature horses.
Merritt A M, Sanchez L C, Burrow J A et al. (2003) — Equine veterinary journal