Equine gastric disease in foals (2023)
Emily F. Floyd
BVSc, DipACVIM, MRCVS
RCVS Recognised Specialist in Equine Medicine (Internal Medicine)
Diplomate of the American College of Veterinary Internal Medicine
The presence, or possible presence, of Equine Gastric Disease EGD in foals remains a major concern for horse owners and vets. What is the best way to treat EGD in foals? What is the true prevalence, and can we prevent development of the condition? In this blog we will try to help answer these key questions.
Background and risk factors
The gastric physiology in young foals is different to older foals and adults. Newborn foals naturally have a slightly higher pH, which decreases to adult levels over the first few days of life. Regular milk ingestion is important to buffer gastric acid and to maintain a normal gastric environment. The ability to produce acid is important and in young foals there is some evidence that having an alkaline gastric pH is associated with reduced survival. In these young foals, the main risk factors for EGD are poor gastrointestinal perfusion, more severe systemic disease, lack of enteral milk feeding and gastrointestinal inflammation.
In older foals, gastric physiology is similar to adults. Risk factors for EGD include stress, anorexia and dietary abnormalities. Weaning is a high-risk time for foals due to a combination of these factors. Other risk factors include use of non-steroidal anti-inflammatory drugs (NSAIDs) and presence of diarrhea or other gastrointestinal problems.
How common in EGD in foals?
The prevalence of EGD in foals is pretty high. The reports in the literature range from 20-50% of foals between 1-6 months of age. The presence of diarrhea is a major risk factor, and EGD is generally more common in older foals.
How do you recognise EGD in foals?
The classically reported clinical signs of EGD in foals include colic, bruxism and hypersalivation. However, clinical signs are often much less specific and usually include general ill-thrift, mild anorexia and decreased weight gain. Foals which have significant duodenal disease usually have much more profound clinical signs. These usually include severe hypersalivation and bruxism, weight loss, anorexia, persistent colic and gastric reflux. Unfortunately, some foals with EGD do not demonstrate any clinical signs and are only identified after a gastric rupture has occurred.
Accurate diagnosis requires gastroscopy. Other useful tools include abdominal ultrasound and bloodwork analysis. Contrast radiography can be useful to diagnose delayed gastric emptying in foals with duodenal disease and delayed gastric emptying.
How to treat EGD in foals?
In young foals the main focus of treatment should be to try to optimize perfusion and control systemic inflammation. Milk ingestion should be encouraged for its beneficial effects on the gastric mucosa. There is no evidence that suppressing acid production in very young foals is beneficial. In critically ill human neonates there is some evidence that the use of acid suppressive medication can increase the risk of bacterial colonisation of the intestinal tract with subsequent sepsis from bacterial translocation. This has not been shown in neonatal foals but use of anti-ulcer medication has been suggested to increase the risk of diarrhea in hospitalised foals. Sucralfate is a medication which is often used for its barrier action. Sucralfate is a complex of aluminium hydroxide and sulphated sucrose which binds to mucosa, forming a protective layer and encouraging local bicarbonate production, blood flow and tissue repair. There is little evidence to support the beneficial effects of sucralfate but the medication has minimal systemic absorption and appears safe.
In older foals (7 days+) the use of a proton pump inhibitors is more logical and omeprazole is generally considered the first line treatment for EGD in foals. The drug is well absorbed when given orally and causes prolonged and effective acid suppression. Injectable omeprazole has anecdotally been used in foals with good clinical effect but no studies have evaluated its use and this medication is not licensed in foals. Intravenous proton pump inhibitors such as esomeprazole or pantoprazole can also be used in sick neonates.
Historically, histamine receptor antagonists have been used for acid suppression in foals. However, these drugs are generally less reliable and are becoming less readily available.
Misoprostol is now considered a first line treatment for glandular disease in adult horses. No studies have evaluated its use in foals but anecdotally the drug can be used at the adult dose without adverse effects. Misoprostol is a prostaglandin analogue which promotes mucosal blood flow, minimizes neutrophilic inflammation and causes some acid suppression. More evidence is needed to understand the role of misoprostol in treating and preventing EGD in foals, but the drug is widely used due to these theoretical benefits. This drug may have a particular role when managing foals with diarrhea, or other gastrointestinal disease.
In general, use of NSAIDs should be minimised. This is especially important in young foals and in foals with perfusion abnormalities (such as foals with diarrhea). However, when NSAIDs are needed, the duration of use should be kept as short as possible and misoprostol can be considered as an adjunctive therapy. More COX-2 selective drugs such as meloxicam may be better than flunixin or phenylbutazone which have both been shown to induce EGD.
Treatment of foals with duodenal disease or delayed gastric emptying is more challenging. Medical treatment with intravenous fluids, nutritional support, pro-kinetics and general nursing care is often needed. In some foals once the inflammation has subsided gastric emptying improves and clinical recovery can occur. If the disease causes more severe structural changes with stenosis of the pylorus or duodenal stricture then surgical treatment may be necessary. Gastrojejunostomy can be used to bypass the diseased gastric outflow.
Prevention of EGD
There is a great deal of pressure to try to prevent EGD. This is mainly driven by the occasional loss of a foal due to a gastric perforation. However, there is little evidence in the literature that prophylaxis is very effective. Based on the evidence that the risk of EGD is higher in certain groups of foals, treatment is probably warranted in certain groups. The groups which may benefit from treatment include foals with diarrhea or other gastrointestinal disease, foals receiving treatment with NSAIDs and foals experiencing greater than normal amounts of stress. Older foals in general are more likely to have EGD. Oral omeprazole is probably the most logical choice for prophylaxis in foals experiencing high levels of stress. In foals with gastrointestinal inflammation due to diarrhea or other problems, misoprostol may be a logical choice.
Management factors to reduce risk factors are essential. In older foals ensuring access to good quality turnout and forage is essential. Concentrate feed should be fed in small amounts and should be low in rapidly digestible carbohydrates. It is also important to try to minimise stress. This can be difficult, but consideration should be given to ensuring stable social groups, maximising turnout and minimising stabling. Additional efforts should be made at weaning to try to make this as stress free as possible.
Medications that can be used for the treatment of EGD in foals. The author takes no responsibility for the doses provided here. All medications should be used in line with the Veterinary Medicines Regulation.
| Medication | Type of drug | Dose | Route of administration | Dosing interval (hours) |
| Sucralfate | Complex aluminium hydroxide salt | 20mg/kg | PO | 6 – 12 |
| Omeprazole | Proton pump inhibitor | 4mg/kg | PO | 24 |
| IM | 5 – 7 days | |||
| Esomeprazole | Proton pump inhibitor | 0.5mg/kg | IV | 24 |
| Misoprostol | Prostaglandin analogue | 5ug/kg | PO | 12 |
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