Equine Gastric Ulcer Syndrome

July 16, 2019

 

EGUS is commonly suspected as a cause of unsatisfactory performance in racehorses however, it is important to consider that horses of all ages including foals and all breeds have the potential to develop gastric ulcers.

Horses in training are undoubtedly living in unnatural conditions and it has long been postulated that these are a major factor contributing to EGUS. Horses are designed to continuously graze throughout the day so that their stomach is normally partially full but horses in training are normally fed two large concentrated, high energy feeds a day, confined to a stable as well as enduring the stresses of a rigorous training program.

Dietary changes, such as a higher forage/low grain diet, are often recommended to help manage EGUS alongside pharmaceuticals but strong evidence supporting some nutritional recommendations is lacking and conclusions from some research has been somewhat counterintuitive. However, alterations to the diet may help to maintain a healthy stomach in the long term when ulcer treatments have finished. Also, horses without access to water in their paddock are more than 2.5 times more likely to have moderate EGUS lesions than horses with constant access to water.

The stomach is divided into two regions; the squamous or non-glandular portion is the upper portion and the lower section is glandular region. Equine Squamous Gastric Disease occurs when this area of the stomach which is unaccustomed to acidity is overexposed to low pH gastric fluid. Less is known about Equine Glandular Gastric Disease but it is believed to be a result of normal protective mechanisms of the glandular stomach being overwhelmed. There is no relationship between the presence of ESGD and EGGD. Therefore, the presence or absence of one cannot be used as predictor for the presence or absence of the other.

Although NSAIDs (bute for example) have the potential to cause EGGD in individual animals they are unlikely to be an important factor in the development of the disease in the wider population.Clinical signs of EGUS can be vague and non-specific to this condition. These include a dull coat, lethargy, poor appetite and body condition, loose faeces, low grade colic and often a reluctance to train and poor performance in athletic horses. Owners tend to also report behavioural issues and discomfort during saddling. We can make a presumptive diagnosis based on these clinical signs but the only method of making a definitive diagnosis is by gastroscopy.

This involves inserting a video endoscope through the nasal passages which passes down the oesophagus and into the stomach. The images of the inside of the horse’s stomach are visible on a screen so owners can appreciate the extent of the EGUS lesions and the response to treatment. The horse is required to have feed withheld for twelve hours prior to the procedure and sedation is necessary. Follow up scopes are generally required to monitor progress. Racetrack Veterinary Services organises gastroscopes to be performed every three months for anyone who wishes to have their horses scoped on these days.

There are currently no reliable blood tests available to aid in diagnosis of gastric ulceration. Trial treatment is common where gastroscopy is not available. If a treatment trial is attempted and the horse fails to respond to treatment gastroscopy is still indicated to definitively rule out ulcers as the treatment may have been too short to fully resolve ulcers that may have been present.

The goal of treating EGUS is to raise the gastric pH above 4 so that lesions can heal without being bathed in acid. Omeprazole, which suppresses the production of stomach acid, has emerged as the drug of choice in treating EGUS. It is available as an oral paste in products like Ulcershield and Gastropell. It is absorbed into the bloodstream after being ingested where it can then act to impair acid secreting cells in the stomach. The severity and location of the lesions seen on gastroscopy determines what treatment protocol should be used for each individual horse.

Research does not support the use of aloe vera or other alternative therapies used to treat EGUS.

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