Bit & Bridle

Equine Glandular Gastric Disease (EGGD)

Other Names

  • EGGD
  • Equine gastric ulcer syndrome (EGUS) — broader category
  • Glandular gastric ulcers
  • Antral ulceration

What is Equine Glandular Gastric Disease (EGGD)?

Equine Glandular Gastric Disease (EGGD) is a condition characterised by lesions — ulcers, erosions, or chronic inflammation — affecting the glandular mucosa of the horse’s stomach. The horse’s stomach is divided into two main regions: the squamous (non-glandular) upper portion, lined with a stratified squamous epithelium similar to the oesophagus, and the glandular lower portion, which produces hydrochloric acid, pepsin, and bicarbonate for digestion. EGGD affects this glandular region specifically.

EGGD is differentiated from Equine Squamous Gastric Disease (ESGD), which affects the squamous region and has a better-understood pathophysiology (essentially an acid-splash injury from frequent exposure to gastric acid). EGGD is less well understood but is increasingly recognised as a distinct and important condition in sport horses, with a different set of causes, characteristics, and treatment requirements.

Prevalence studies suggest that EGGD affects between 17% and 65% of sport horses, depending on the population studied and the endoscopic criteria used. For a related condition affecting gastrointestinal health in younger horses, see our entry on Equine Scours in Foals.

Causes

The aetiology of EGGD is not fully understood, which makes it more challenging to manage than ESGD. Proposed contributing factors include:

  • Exercise and training stress — high-performance horses are significantly over-represented. The physiological and psychological stress of intensive training and competition appears to be a primary driver, though the exact mechanism is unclear.
  • NSAID use — non-steroidal anti-inflammatory drugs (particularly phenylbutazone) can compromise the protective mucosal barrier of the glandular stomach, increasing susceptibility to damage from acid and digestive enzymes
  • Altered gut motility — stress can affect gastric emptying and gut motility, changing the acid exposure pattern of the glandular mucosa
  • Disruption of the mucosal defence — the glandular mucosa is normally protected by mucus, bicarbonate, and prostaglandins. Any factor that disrupts this defence (including NSAID use, certain infections, or mucosal ischaemia from exercise-induced redistribution of blood flow) can permit acid damage.
  • Helicobacter-like organisms — while Helicobacter pylori has not been consistently identified in horses, Helicobacter-related organisms have been found in equine gastric mucosa. Their pathogenic role remains under investigation.
  • Diet — intermittent feeding, high-concentrate diets, and reduced forage availability alter the gastric environment unfavourably

Symptoms and Signs

EGGD can be subtle in presentation. Clinical signs include:

  • Poor appetite or selective feeding — the horse may eat slowly or leave feed
  • Unexplained weight loss or difficulty maintaining condition
  • Dull coat and reduced overall condition
  • Behavioural changes — increased irritability, girthiness, sensitivity to grooming or brushing over the flanks
  • Reluctance to work or reduced performance, particularly in collected movements
  • Mild, intermittent colic signs — pawing, box walking, looking at flanks
  • Grinding teeth (bruxism)
  • Changes in rideability — resistance to leg, back sensitivity, or refusal to engage the hindquarters

It is important to note that these signs are non-specific and can indicate many other conditions. EGGD cannot be reliably diagnosed from clinical signs alone — endoscopy is essential for confirmation.

Diagnosis

Gastroscopy (upper gastrointestinal endoscopy) is the definitive diagnostic tool for EGGD:

  • Gastroscopy — a three-metre endoscope is passed via the nostril into the stomach to directly visualise the mucosa. The horse should be fasted for at least 12 hours (hay) and six to eight hours (water) to ensure the stomach is sufficiently empty for visualisation. Grading of lesions uses the EGUS Council grading system (0–4) for both the squamous and glandular regions.
  • Biopsy — biopsies of the glandular mucosa can be obtained endoscopically to assess the nature and severity of lesions and rule out other pathology, though this is more commonly performed at referral centres
  • Pepsinogen assay — blood and urine pepsinogen levels may be elevated in horses with significant glandular disease, though sensitivity and specificity are variable

EGGD lesions are most commonly found in the antrum (pyloric region) and on the margo plicatus (the transition zone between squamous and glandular mucosa). The appearance can range from reddening and irregular mucosa to frank ulceration.

Treatment

Treatment of EGGD is more challenging than ESGD and requires a multimodal approach:

  • Omeprazole — the standard treatment for ESGD and commonly used in EGGD as well. Omeprazole reduces gastric acid production and allows mucosal healing. However, response rates in EGGD are generally lower than in ESGD, and some horses require higher doses or longer treatment courses.
  • Sucralfate — forms a protective barrier over ulcerated mucosal surfaces. Typically used in combination with omeprazole for EGGD as it provides mucosal cytoprotection independent of acid reduction.
  • Misoprostol — a prostaglandin E1 analogue that enhances mucosal defence mechanisms. Shows promise in refractory EGGD cases, particularly those with NSAID-associated lesions. Available on veterinary prescription.
  • Dietary management — small, frequent forage-based meals; reducing or eliminating grain feeding; ensuring ad libitum hay access where possible
  • Reducing exercise stress — where feasible, a period of reduced training intensity during treatment may improve healing rates

Treatment duration is typically four to eight weeks, with re-scoping at the end of the treatment course to assess healing. The British Equine Veterinary Association guidelines on EGUS provide a framework for treatment decisions: beva.org.uk.

Prevention

Given the association with exercise stress and diet, the following management practices reduce risk:

  • Provide access to forage at all times — even small amounts of hay prevent prolonged periods of acid exposure to an empty stomach
  • Feed small, frequent meals rather than large concentrate feeds twice daily
  • Maximise turnout time where possible
  • Minimise NSAID use and avoid prolonged courses without gastric protection
  • Allow a pre-competition dietary buffer — offering a small haynet before travelling or competing helps protect the glandular mucosa
  • Monitor for early behavioural signs of gastric discomfort and investigate promptly

Prognosis

The prognosis for EGGD is guarded compared to ESGD. Response rates to omeprazole alone are lower, and recurrence after cessation of treatment is common, particularly in horses returning to high-intensity work. Horses managed with appropriate dietary changes, reduced NSAID exposure, and multimodal medical treatment can show good improvement. However, some horses have persistent or recurrent EGGD despite treatment, and ongoing management may be necessary throughout their performance career.

When to Call the Vet

  • Your horse shows signs of poor appetite, weight loss, or condition loss without an obvious cause
  • There are behavioural changes such as girthiness, reluctance to engage, or general irritability under saddle
  • Mild colic signs occur repeatedly, particularly around feeding times
  • Your horse is on long-term NSAID treatment and you want to assess for gastric damage
  • You want to confirm a response to treatment with a repeat endoscopy after a treatment course

Frequently Asked Questions

What is the difference between EGGD and ESGD?

ESGD (Equine Squamous Gastric Disease) affects the upper, non-glandular portion of the stomach and is primarily an acid injury — gastric acid splashes onto the unprotected squamous mucosa, particularly when the stomach is empty or during exercise. EGGD affects the lower glandular region and results from failure of the mucosa’s own defence mechanisms. They have different causes, presentations, and treatment responses, though they can occur concurrently.

Does omeprazole treat EGGD?

Omeprazole reduces gastric acid production and is the first-line treatment for both squamous and glandular disease. However, it is less effective for EGGD than ESGD — response rates are lower, and some cases require additional mucosal protectants (sucralfate) or prostaglandin analogues (misoprostol) for adequate healing. Always confirm response with a follow-up gastroscopy rather than assuming treatment has worked.

How common is EGGD in sport horses?

Very common. Prevalence studies report rates ranging from 17% to over 60% in performance horses, depending on discipline and population. Racehorses, dressage horses, eventers, and endurance horses all show high rates. The condition is likely under-diagnosed as clinical signs can be subtle and gastroscopy is required for definitive diagnosis.

Can EGGD cause poor performance?

Yes — subclinical gastric pain is a recognised cause of unexplained poor performance in horses. A horse that is consistently below expectations, reluctant to work through transitions, or showing unexplained behavioural changes under saddle should have gastric disease ruled out as part of the workup. See our horse terminology guide for more on equine gastric anatomy and disease terminology.