19/02/2026
Gastric Impaction in Horses
Brian S. Burks, DVM
Diplomate, ABVP
Board Certified in Equine Practice
Gastric impaction is one cause of colic in horses, with colic simply referring to intestinal pain, not a specific cause or disorder. An impaction is an obstruction of the gastrointestinal tract that can result in a variety of clinical signs. The obstruction most often is of food material, but may contain other foreign objects. It may be partial or complete.
Horses, being herbivores, are continuous grazing animals. Their GIT was equipped to have small amounts of food frequently. Horses may be kept in stalls, have limited turnout, and be fed meals twice daily, under some circumstances.
Causes
Impaction of the stomach has a variety of causes, or may be multi-factorial.
• Dehydration
• Coarse feed stuff that is poorly digestible
• Equine Gastric Ulcer syndrome
• Changes in exercise
• Anesthesia and surgery- post op ileus
• Parasitism- bot fly larvae
• Concentrates- especially high carbohydrate/fermentable food
• Neoplasia- squamous cell carcinoma
• Dentition
Clinical Signs
• Anorexia
• Lethargy
• Prolonged recumbency
• Dysphagia
• Dropping of feed
• Bruxism
• Salivation
• Insidious weight loss (if chronic)
• Spontaneous reflux with gastric contents visible at the nares (in severe cases)
In mild cases where signs resolve spontaneously or with analgesics, owners my continue to feed the horse, which only serves to worsen the impaction
Diagnosis of gastric impaction is by rule out of other diseases, gastric endoscopy, ultrasonography, and, sometimes, radiography. Other intestinal disease can be evaluated using re**al palpation and abdominocentesis, in addition to the testing listed above. Radiography is useful in foals or thin horses; it is mostly used to evaluate the ventral abdomen in adult horses, looking for sand or enteroliths (intestinal stones). Ultrasound used percutaneously can be used to assess intestinal or gastric distention, wall thickness, and intestinal motility. It can be used to image the stomach and other intestinal disorders, such as intussusceptions. Gastric endoscopy is the ‘gold standard’ as the impaction can be visualized directly. Most horses will completely empty the stomach in 18-24 hours; if the stomach is still full after fasting, this confirms the impaction.
Treatment of gastric impaction begins with correcting the primary problem. This is usually best done in an equine hospital setting where the horse can be closely monitored. Hydration should be assessed and IV fluids given as necessary. Feed should be withheld. The stomach can be lavaged with water and f***l softeners and electrolytes. Mineral oil should not be used in case of spontaneous reflux that could be aspirated into the lungs, causing a granulomatous reaction, resulting in lung death, and eventually death of the horse. Some horses will need to be kept comfortable using flunixin meglumine and/or sedation, along with other analgesic medication. Fortunately, most resolve within a few days. The stomach cannot be exteriorized in the adult horse during abdominal laparotomy, though in small foals it may be possible to reach the stomach for bypass surgery if the pyloric outlet is strictured.
Prevention
• Regular dental care
• Feed low carbohydrate feeds
• Secure storage of roughage and hard feeds
• Ensure free access to water at all times
• Regular exercise
• Feed small amounts frequently
• Have f***l egg counts done to assess the deworming program
Fox Run Equine Center
www.foxrunequine.com
(724) 727-3481
