Horses with digestive ulcers is an extremely common affliction. Ulcers are believed to affect about 60-90% of performance horses at some stage in their life.
What are ulcers?
There are two main types of ulcers that affect horses. These are hindgut ulcers and gastric ulcers.
Gastric ulcers are lesions that form in the stomach lining, due to over exposure to gastric acid in the stomach.
Hindgut ulcers are lesions that form in the horse’s large intestine. These are caused by excessive lactic acid and a bacterial imbalance.
In this article we’ll concentrate on gastric ulcers. You can find links to hindgut ulcer information at the bottom of this article.
The biology of gastric ulcers:
The stomach of a horse consists of two parts: the glandular and non-glandular portion. The glandular portion is the bottom part of the stomach and the non-glandular is the top part.
The glandular section of the stomach is responsible for acid secretion. It also contains protective coating that keeps the stomach lining form being damaged.
The non-glandular portion is the upper part of the stomach which functions as a mixer for stomach contents. It does not contain as much protective factors as the glandular part.
It is usually (but not always) the non-glandular section of the stomach that ulcers appear.
Types of gastric ulcers:
Horses with digestive ulcers fall into three main types of gastric ulceration. Glandular, Non-Glandular (also known as Squamous) and Pyloric ulcers.
Tricky, huh?
Non-Glandular or Squamous Ulcers in Horses
Non-Glandular or squamous ulcers are lesions that appear in the upper third of the horses’s stomach. Ulcers in this region are caused when the mucosal lining is damaged by bacteria, parasites or over-exposure to stomach acid.
The non-glandular section of the horse’s stomach does not have strong protective barriers against gastric acid, like the lower section does.
These are mostly caused by:
– An equine incompatible diet (low roughage, high grain)
– A stressful lifestyle (excessive stabling, travel, competitions etc)
Glandular Ulcers in Horses
Unlike the unprotected squamous section, the glandular section of a horse’s stomach is designed to cope with high levels of acidity.
The glandular mucosa is lined with mucous, protective proteins, electrolytes, lipids and antibodies. These all provide natural protection against stomach acid.
Glandular ulcers occur when this protective barrier is weakened. Usually by non-steroidal anti-inflammatories (known as NSAIDs) and bacterial agents.
Pyloric Ulcers in Horses
Pyloric ulcers occur in the pyloric region – which is where the stomach opens to the small intestine. Ulcers in this area can cause swelling and delayed gastric emptying which can cause colic.
If pyloric ulceration gets severe enough, cells can swell and cause delayed gastric emptying, a more acidic environment, and potentially colic. Delayed emptying of the stomach is a serious condition and difficult to treat. The causes of pyloric ulcers are the same as gastric ulcers. Namely NSAID over-use and bacterial agents.
Treating different types of gastric ulcers
Squamous or non-glandular ulcers:
Omeprazole is the best proven treamtent for squamous ulcers. Omeprazole works by suppressing acid production & giving the ulcers a chance to heal.
Glandular & Pyloric Ulcers:
Omeprazole alone is generally not enough to successfully treat these kind of ulcers.
However it is still essential in the treatment of these ulcers – but should be in conjunction with mucosal protectants like sucralfate and anti-biotics if bacterial involvement is suspected.
To find out more about hindgut ulcers and the appropriate treatment, check out this article.
