Emergency Situation: Esophageal Obstruction in Horses—Recognize, Treat, Prevent

Definition and Pathomechanism

Esophageal obstruction refers to the partial or complete blockage of the esophageal lumen (the interior of the esophagus), usually caused by food particles that have not been sufficiently moistened with saliva (DocCheck Flexikon, 2024).

Since horses do not have a pronounced gag reflex and vomiting is anatomically impossible, a feed bolus that becomes lodged cannot dislodge itself. The spastic contraction of the esophageal muscles triggered by the obstruction further hinders the bolus’s passage; swallowed saliva causes the bolus to swell further, so that the lumen becomes increasingly obstructed (DocCheck Flexikon, 2024). Since many horses continue to eat unhindered despite the onset of obstruction, the entire esophagus can become filled with feed.

There are three anatomically predisposed narrowings of the esophagus: the area where the pharynx transitions into the esophagus, the area of the thoracic inlet (the upper opening of the thoracic cavity that connects the trunk to the neck), and the transition into the stomach at the diaphragm (Merck Veterinary Manual, “Esophageal Obstruction in Large Animals,” 2024).

Causes and Primary versus Secondary Forms

The veterinary literature distinguishes between primary and secondary esophageal obstructions. Primary obstructions result from hasty swallowing of feed that has not been sufficiently moistened with saliva, particularly dry or insufficiently soaked beet pulp and pellets, but also from concentrate that has been ground too coarsely or apples and carrots that have not been chewed thoroughly. Ingestion of bedding material is also a possible trigger. Dental problems and hasty eating behavior further increase the risk (Hippo Magazine, “Esophageal Obstruction (Esophageal Obturation),” citing Gehlen 2017 and Fischer 2013).

Secondary esophageal obstructions, on the other hand, occur as a result of preexisting conditions, such as gastric distension or other esophageal disorders (Hippo Magazine, citing Fischer 2013).

According to a retrospective study by Feige and colleagues at the University of Zurich, these pre-existing conditions include structural changes in the esophagus. In their analysis of 34 cases of esophageal obstruction, 28 were attributable to feed impaction alone, while megaesophagus (pathological dilation of the esophagus) was identified as the underlying cause in four horses, a stricture (narrowing) in the upper third of the esophagus, and in one additional horse, an esophageal diverticulum (a sac-like protrusion from the esophageal wall) were identified as the underlying causes (Feige, Schwarzwald, Fürst, and Kaser-Hotz, “Esophageal Obstruction in Horses: A Retrospective Study of 34 Cases,” Canadian Veterinary Journal, 2000).

An analysis of 74 horses with esophageal disorders at the University of Leipzig’s Veterinary Clinic confirms this picture: Sixty of the animals examined had primary esophageal obstruction, while functional disorders and morphological changes such as diverticula were significantly less common but more challenging to treat (Breuer, Böttcher, Reischauer, Müller, Spallek, Recknagel, and Uhlig, “Retrospective Analysis of 74 Horses with Esophageal Diseases,” Pferdeheilkunde – Equine Medicine, 2011).

The UC Davis School of Veterinary Medicine also cites, in addition to eating too quickly, other triggers such as inadequate water intake, eating while under heavy sedation, and pre-existing conditions such as megaesophagus, abscesses, or cysts. It also notes an increased incidence of esophageal diseases, particularly megaesophagus, in Friesian horses (UC Davis School of Veterinary Medicine, “Esophageal Obstruction (Choke) in Horses,” 2025).

Clinical Presentation

The primary symptom of esophageal obstruction is what is known in medical terms as regurgitation: Food bolus and saliva flow back from the esophagus into the throat and larynx (pharynx and larynx) and escape through the nostrils (DocCheck Flexikon, 2024).

The Merck Veterinary Manual describes a classic sign as the discharge of regurgitated feed from the nostrils, often accompanied by a greenish secretion. Additional symptoms include coughing, increased salivation, teeth grinding, and anxious behavior with the neck extended or bent (Merck Veterinary Manual, “Disorders of the Esophagus in Horses,” 2024).

Affected horses often try to continue eating or drinking despite the blockage, which exacerbates the symptoms (Merck Veterinary Manual, “Esophageal Obstruction in Large Animals,” 2024).

Diagnostics

In most cases, an obstruction of the pharynx can be diagnosed based on the clinical presentation and medical history. Regurgitation, nostrils soiled with food, and coughing are indicative of this condition. In cases of obstructions located closer to the head (cranially), the bolus can be palpated from the outside, whereas obstructions located deeper can be detected by the inability to advance a nasopharyngeal tube (DocCheck Flexikon, 2024). It was precisely this diagnostic approach—the inability to advance a nasopharyngeal tube—that also served as the decisive criterion for establishing the diagnosis in the Leipzig case series (Breuer et al., 2011). An endoscopic or radiographic examination is necessary only in exceptional cases, such as to rule out structural causes or a perforation (DocCheck Flexikon, 2024). The UC Davis College of Veterinary Medicine recommends further diagnostic testing using endoscopy, ultrasound, or X-rays, particularly in cases of complicated or recurrent disease (UC Davis School of Veterinary Medicine, 2025).

Therapy

The goal of veterinary treatment is to clear the obstruction while preventing aspiration pneumonia (DocCheck Flexikon, 2024)—that is, pneumonia caused by inhaling foreign objects that do not belong in the airways. If the obstruction does not resolve on its own within a short time, sedation with α2-agonists such as detomidine or xylazine is recommended, as these agents cause relaxation of the smooth and striated muscles of the throat, thereby facilitating the passage of the bolus (DocCheck Flexikon, 2024).

The Merck Veterinary Manual describes a similar procedure: Acute, uncomplicated obstructions often resolve within an hour after administration of a sedative or muscle relaxant. Careful placement of a nasopharyngeal tube can accelerate this process by gently advancing the bolus toward the stomach. If the obstruction persists after about an hour or lasts longer than two to three hours, deeper sedation with the horse’s head lowered is recommended to perform a careful esophageal lavage (Merck Veterinary Manual, “Other Common Emergencies in Horses,” 2025).

According to the DocCheck Flexikon, surgical treatment is indicated only in exceptional cases, as it is associated with a significant rate of postoperative complications such as wound infections or strictures (DocCheck Flexikon, 2024).

Complications and Prognosis

The main complication of pharyngeal obstruction is aspiration pneumonia, which is pneumonia caused by the inhalation of food bolus or saliva during persistent regurgitation (Merck Veterinary Manual, 2024).

In their analysis of 109 horses with esophageal obstruction that were presented at a North American university hospital between 1992 and 2009, Chiavaccini and Hassel were able to show that an elevated respiratory rate was associated with a significantly increased risk of pneumonia: A respiratory rate of more than 22 breaths per minute increased the risk of pneumonia nearly sixfold compared to horses with a respiratory rate of 12 or fewer breaths per minute. In addition, the extent of radiologically detectable contamination of the trachea (windpipe) was proportionally associated with the subsequent development of pneumonia (Chiavaccini and Hassel, “Clinical Features and Prognostic Variables in 109 Horses with Esophageal Obstruction (1992–2009),” Journal of Veterinary Internal Medicine, 2010).

According to the DocCheck Flexikon, if the obstruction persists for more than 24 hours, complications regularly occur: The sustained pressure caused by the food bolus leads to mucosal necrosis at the site of the obstruction, which can subsequently result in ruptures and scar-induced strictures (DocCheck Flexikon, 2024).

Esophageal strictures resulting from an untreated esophageal obstruction can, in turn—particularly in cases that are refractory to treatment—lead to megaesophagus and represent a serious complication due to the risk of aspiration (DocCheck Flexikon, “Esophageal Stricture (Horse),” 2024).

Overall, however, primary, uncomplicated esophageal obstruction caused by food accumulation is considered highly treatable: According to the Leipzig case series, primary esophageal obstructions—unlike morphological or functional changes in the esophagus—can generally be diagnosed easily and treated quickly (Breuer et al., 2011).

Prevention

Since hasty eating, as well as feed that has not been soaked sufficiently or is too coarse in texture, are among the major risk factors, prevention begins primarily with feeding management. Among other things, it is recommended to slow down chewing activity—and thus saliva production—by mixing chopped hay or straw into the feed in the feeder, and to generally feed concentrate only after roughage has been provided. In addition, a feed’s ability to swell can be tested in advance by soaking a defined amount in a measured quantity of water.

For horses prone to repeated esophageal blockages, it may be necessary to feed them exclusively with feed that has already been soaked and has swollen (Hippo Magazine, citing Gehlen 2017).

Regular dental checkups are also important, as insufficient grinding of feed due to dental disease increases the risk of primary pharyngeal obstruction (Hippo Magazine, citing Gehlen 2017).

Conclusion

Oesophageal obstruction is the most common esophageal disorder in horses and, in most cases, results from a buildup of feed that has not been sufficiently moistened by saliva at one of the three anatomical narrowings of the esophagus. Clinically, regurgitation is the primary symptom; for diagnosis, a medical history, clinical examination, and testing the patency of a nasopharyngeal probe are usually sufficient.

While uncomplicated primary cases can usually be treated quickly and without lasting consequences, an obstruction lasting longer than 24 hours requires prompt veterinary intervention due to the risk of mucosal necrosis, strictures, and, above all, aspiration pneumonia.

Sources

• Feige, K., Schwarzwald, C., Fürst, A., Kaser-Hotz, B. (2000): Esophageal obstruction in horses: a retrospective study of 34 cases. Canadian Veterinary Journal 41(3), 207–210. PubMed: https://pubmed.ncbi.nlm.nih.gov/10738598/


• Chiavaccini, L., Hassel, D. M. (2010): Clinical Features and Prognostic Variables in 109 Horses with Esophageal Obstruction (1992–2009). Journal of Veterinary Internal Medicine 24(5), 1147–1152. https://onlinelibrary.wiley.com/doi/10.1111/j.1939-1676.2010.0573.x


• Breuer, J., Böttcher, D., Reischauer, A., Müller, K., Spallek, A., Recknagel, S., Uhlig, A. (2011): Retrospective Analysis of 74 Horses with Esophageal Diseases. Equine Medicine, Faculty of Veterinary Medicine, University of Leipzig. https://www.researchgate.net/publication/298852124_Retrospective_analysis_of_74_horses_with_disorders_of_the_oesophagus


• DocCheck Flexikon: Esophageal Obstruction (Horse); Esophageal Stricture (Horse); Esophagitis (Horse). Retrieved in 2026:
  
  https://flexikon.doccheck.com/de/Schlundverstopfung_(Pferd)
  
  https://flexikon.doccheck.com/de/Ösophagusstriktur_(Pferd)
  
  https://flexikon.doccheck.com/de/Ösophagitis_(Pferd)


• Merck Veterinary Manual: Disorders of the Esophagus in Horses:
  
  https://www.merckvetmanual.com/horse-owners/digestive-disorders-of-horses/disorders-of-the-esophagus-in-horses
  
  https://www.merckvetmanual.com/digestive-system/disorders-of-the-esophagus-in-large-animals/esophageal-obstruction-in-large-animals
  
  https://www.merckvetmanual.com/emergency-medicine-and-critical-care/emergency-medicine-in-horses/other-common-emergencies-in-horses.


• UC Davis School of Veterinary Medicine, Center for Equine Health: Esophageal Obstruction (Choke) in Horses. https://ceh.vetmed.ucdavis.edu/health-topics/esophageal-obstruction-choke-horses.


• Hippo Magazine (Veterinary Education Platform): Esophageal Obstruction, citing Gehlen, H. (2017) and Fischer, K. (2013)
  
  https://www.hipposport.de/magazin/eevp/schlund/schlundverstopfung-oesophagusobturation/