- Predisposition, diagnosis, and treatment
It is assumed that a large proportion of horses will suffer from gastric ulcers at some point in their lives. It is estimated that around 60% of trained horses and 90% of competition horses have gastric ulcers. Gastric ulcers are ulcerations in the horse’s stomach that negatively affect performance and quality of life. Predisposing factors include stress, insufficient forage, intense training and competition, long transport, and various life changes. It is helpful for owners to recognize early signs of ulcers and common risk factors.
Where do gastric ulcers occur in horses?
Horses have a relatively small stomach (about 10–15 liters), which works best when the horse can eat small amounts of forage throughout the day. The horse’s stomach consists of two regions: an upper region covered by squamous epithelium and a lower region covered by glandular tissue. The lower glandular region produces acidic gastric fluid and mucus.
“For treatment, it’s extremely important to know where the ulcers are—squamous, glandular, or both—because location affects the treatment approach,” said Jyme Nichols, PhD in equine nutritional sciences.
“And the only way to diagnose ulcers is to have a veterinarian examine the horse. That means using a gastroscope.”
How are gastric ulcers graded?
In 1999, researchers introduced the term Equine Gastric Ulcer Syndrome (EGUS) as an umbrella term for all equine gastric ulcers. Later, researchers found that ulcers in the glandular and squamous regions are quite different, and these two types should be described and treated separately.
Veterinarians use an established grading system for squamous ulcers in the upper stomach, describing ulcers based on severity. The scale ranges from 0 (healthy, no ulcers) to 4 (extensive damage, deep erosions).
Causes and risk factors for gastric ulcers in horses
Today, horses are kept in ways that differ from what evolution designed them for. Horses are also used for activities they were not originally designed for, such as competition and transport.
“Horses were designed to keep their heads down, graze in a herd—but we isolate them in stalls, transport them, and do things with them that matter to us. We feed them too infrequently and give too much grain, and not nearly all horses get to be outside all day,” says Nichols.
Key risk factors for developing EGUS include:
Long periods without forage. Six hours or more between hay (hay or pasture) increases risk. Extending feeding time (slow feeding) or offering free-choice hay reduces risk. However, free-choice hay does not suit all horses and may increase other risks.
Insufficient water. Water is an excellent buffer for gastric fluids, and horses that drink well and always have access to water have fewer gastric ulcers. In contrast, horses with restricted water access have more than double the risk of ulcers.
High-starch meals. Feeding starch-rich meals exceeding 2 g per kg of body weight doubles a horse’s risk of ulcers.
Medications. Non-steroidal anti-inflammatory drugs (NSAIDs, e.g. phenylbutazone and flunixin meglumine) increase the risk of glandular disease in particular by damaging the stomach’s protective lining.
Clinical signs of gastric ulcers
“Signs of ulcers can be very subtle, so it’s important for the owner to know what is normal for their horse in order to recognize what is abnormal,” Nichols notes.
Small behavioral changes—such as changes in facial expressions during saddling (ear, eye, and mouth position and movement)—can indicate ulcers. Other EGUS signs may include general irritability and crankiness (e.g. the horse may try to nip or swish its tail) and changes in performance.
Other signs include loss of topline, a dull coat, and colic-like symptoms.
Diagnosis and treatment of gastric ulcers
Always ask your veterinarian to perform gastroscopy if you suspect your horse may have gastric ulcers.
“It’s important to note that there is no relationship between glandular and squamous disease,” says Nichols. “In addition, there is no relationship between outward signs and the severity of ulcers.”
Treatment focuses primarily on reducing stomach acidity and protecting the stomach lining. The most commonly prescribed medications include omeprazole, ranitidine, and sucralfate.
It is also important to evaluate what factors contributed to ulcer development in the first place and to plan and adjust the horse’s daily routine and management so that risk factors are minimized.
Message to the stable:
Most horses are at risk of developing gastric ulcers at some point, so it’s worth paying close attention to behavioral changes. Plan feeding and diet, aim to minimize stress, and contact a veterinarian if your horse shows signs consistent with gastric ulcers.
Source:
The Horse.com, Stacey Oke, DVM, MSc
Jyme Nichols, PhD: 2024 virtual EquiSummit, held Dec. 3–4.
