External supporting research Colic, gastric emergencies & veterinary care EXT-S12

Gastric Dilatation & Rupture in Horses: Veterinary Reference

An expert-authored veterinary reference explaining how excessive gas, feed overload and intestinal obstruction can cause gastric dilatation in horses. It describes the clinical signs, emergency implications and potentially fatal progression to gastric rupture.

Original study title

Diseases Associated with Colic in Horses by Anatomic Location

Colic Gastric dilatation Gastric rupture Intestinal obstruction Gastric reflux Feed overload Gastrointestinal emergencies Equine digestive anatomy

Study at a glance

Study type Veterinary clinical reference and narrative overview

Publication Expert-authored veterinary clinical reference. Full review October 2021; last updated June 2025. Not an original peer-reviewed journal study.

EquiNectar tested? No

Peer reviewed No / not specified

Open access Yes

Relationship External supporting research

Research question

What did the researchers want to understand?

What gastrointestinal conditions can cause gastric dilatation and rupture in horses, and what clinical mechanisms, warning signs and prognostic implications should veterinarians consider?

Researchers

Study authors

James N. Moore

University of Georgia

Research organizations

Research institutions

University of Georgia

University
United States

Methodology

How the study was conducted

Study design

Expert-authored veterinary clinical reference published in the MSD Veterinary Manual.

The article is organized by anatomical location within the equine gastrointestinal tract, including the stomach, small intestine, cecum and large intestine.

It describes important causes of colic, associated clinical findings and relevant veterinary management considerations.

The section selected for this Science Center record focuses specifically on gastric dilatation and gastric rupture.

There was no prospective recruitment, experimental intervention, control group or original

What was measured

No original measurements were collected or reported for this reference article.

The author summarizes veterinary clinical knowledge concerning gastrointestinal anatomy, disease mechanisms, clinical signs, diagnosis, treatment considerations and prognosis for different causes of colic.

The gastric dilatation and rupture section focuses on mechanisms of stomach distension, associated gastrointestinal disorders and the clinical consequences of gastric rupture.

Study findings

Key results

This is a veterinary clinical reference, not an original results-based study.

Key clinical points include:

• Gastric dilatation in horses is commonly associated with excessive gas accumulation or intestinal obstruction.

• Overconsumption of fermentable feedstuffs may contribute to gastric dilatation in some cases.

• Small-intestinal obstruction can cause fluid to accumulate in the stomach, producing gastric distension and reflux.

• Certain large-colon displacements and proximal enteritis-jejunitis can also be associated with gastric dilatation.

• Severe abdominal pain, increased heart rate, retching and pale mucous membranes may accompany gastric dilatation.

• Gastric rupture is a fatal complication of progressive gastric distension.

• Apparent relief of severe pain followed by depression may occur after rupture and must not be mistaken for clinical recovery.

• Early veterinary assessment is essential because some causes of gastric dilatation may have a favorable prognosis when appropriately treated before rupture occurs.

Interpretation

What do the findings mean?

The MSD Veterinary Manual describes gastric dilatation as a serious consequence of excessive gastric gas or impaired passage of gastrointestinal contents.

The condition may arise from feed overload, small-intestinal obstruction, certain large-colon displacements or inflammatory disorders associated with gastric reflux.

Because horses have limited ability to release accumulated gastric contents through the esophagus, progressive distension can become dangerous.

Gastric rupture represents a catastrophic complication and is fatal.

The reference highlights the importance of distinguishing potentially manageable gastric dilatation from the irreversible consequences of rupture.

It also demonstrates why colic cannot be understood as a single digestive disorder. Different anatomical locations and disease processes can produce abdominal pain while requiring very different veterinary interventions.

This material supports veterinary education and responsible horse management but does not demonstrate the effectiveness of any specific feed supplement.

In practice

Why this research matters

Gastric dilatation is a potentially life-threatening condition in horses that requires urgent veterinary assessment.

The MSD Veterinary Manual identifies excessive gas and intestinal obstruction as major causes. Overconsumption of fermentable feedstuffs, including grains, lush grass and beet pulp, may also contribute in some circumstances.

The condition can develop when gas or fluid accumulates in the stomach and cannot pass normally through the digestive tract.

Clinical signs may include severe abdominal pain, increased heart rate, retching and pale mucous membranes.

A particularly important warning is that a horse may appear temporarily relieved after the stomach ruptures. This apparent improvement is not recovery and may instead indicate a catastrophic complication.

The reference reinforces the importance of prompt veterinary intervention when a horse develops signs of severe colic.

Appropriate feeding management is important for digestive health, but no feeding strategy or supplement can guarantee prevention of gastric dilatation or rupture.

Research transparency

Study limitations

This is an expert-authored veterinary reference rather than an original experimental, observational or clinical study.

It summarizes established clinical knowledge about multiple anatomical causes of colic and does not provide a newly recruited study population, controlled intervention or original dataset.

The section on gastric dilatation and rupture describes clinical mechanisms, associated conditions, signs and prognosis, but it does not systematically quantify the strength of evidence supporting each statement.

The reference discusses several possible causes of gastric dilatation, including feed overload, intestinal obstruction and impaired gastrointestinal movement. It does not establish that one cause accounts for all cases.

The discussion of fermentable feeds should not be interpreted as evidence that ordinary consumption of grains, grass or beet pulp necessarily causes gastric dilatation.

The reference does not evaluate nutritional supplements, digestive enzymes, microbiome interventions or EquiNectar.

Its primary value is as a clinical reference explaining disease mechanisms and emergency implications, not as evidence of the effectiveness of a particular preventive treatment.

EquiNectar context

How this research relates to EquiNectar

This veterinary reference did not test EquiNectar and provides no evidence that EquiNectar prevents or treats gastric dilatation, gastric rupture or colic.

Its relevance to the EquiNectar Science Center lies in explaining the wider clinical importance of equine digestive physiology, feeding management and gastrointestinal function.

The reference describes how excessive gas, overconsumption of fermentable feed and intestinal obstruction can contribute to gastric dilatation. It also explains that impaired passage of gastrointestinal contents may lead to fluid accumulation and dangerous pressure within the stomach.

These mechanisms provide background for understanding why feeding practices and gastrointestinal function matter to horse health.

However, gastric dilatation is not equivalent to hindgut acidosis, and the reference does not establish that changes in fecal pH, microbiome composition or digestive enzyme supplementation prevent gastric emergencies.

EquiNectar research separately investigates selected digestive and microbial outcomes. Those findings should not be presented as evidence of protection against gastric rupture.

Tharos / EquiNectar involvement

None. This veterinary reference was produced independently of Tharos Ltd and EquiNectar. It does not evaluate EquiNectar or report results from an EquiNectar intervention.

EquiNectar evaluated No

Source record

Publication details

Journal

MSD Veterinary Manual

Publisher

Merck & Co., Inc.

Species

Horse

View original source ↗ Read full text ↗

Recommended citation

Moore JN. Diseases Associated with Colic in Horses by Anatomic Location. MSD Veterinary Manual. Full review October 2021; updated June 2025. Accessed October 13, 2026. https://www.msdvetmanual.com/digestive-system/colic-in-horses/diseases-associated-with-colic-in-horses-by-anatomic-location

Gastric Dilatation & Rupture in Horses: Veterinary Reference

What did the researchers want to understand?

Study authors

James N. Moore

Research institutions

University of Georgia

How the study was conducted

Key results

What do the findings mean?

Why this research matters

Study limitations

How this research relates to EquiNectar

Publication details

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How to Help Prevent Colic in Horses: Feeding & Management