Equine Gastric Ulcer Syndrome (EGUS)

Equine Gastric Ulcer Syndrome (EGUS), describes a host of complex inflammatory and disruptive events that occur in the mucosa of the oesophagus, stomach and duodenum of both adult horses and foals. The prevalence of EGUS is estimated to range from 40-93% in performance horses and 25-51% of foals.

The anatomy of the horse is quite unique and this may explain why horses, especially exercising horses, are prone to gastric problems. The horse is a mono-gastric, meaning it has one stomach (unlike ruminants). The equine stomach is made up of two different regions, the region on the top is called the squamous region or non-glandular and the region on the bottom is the glandular region, which is more akin to the human stomach. The stomach is continuously secreting acid to digest food however, nowadays most performance horses are not continuously grazing and therefore their stomach may not contain enough feed at all times to neutralise this acid. The bottom part of the stomach is protected from the acid by glands but the upper part is more vulnerable. The area that divides these two regions is called the margo plicatus and this is where a lot of ulceration occurs due to acid splashing up on to the non-glandular region.

There are multiple risk factors for developing EGUS and unfortunately most of them are due to man-made interventions where we have taken the horse from its natural habitat as a trickle-feeder with continuous access to forage. These risk factors include confinement such as stabling, reduced pasture availability, reduced hay/roughage availability and increased grain feeding.

Physical stressors such as intensive exercise, behavioural and/or physical problems as well as NSAID (non-steroidal anti-inflammatory) use can also contribute to the high incidence of gastric ulceration.

Ulcers are associated with decreased acidity and reduced blood flow to the gut mucosa. This in turn can be damaging to the gut mucosa, creating an inflammatory environment. This hostile environment can then disrupt the gut microbiome, which can also create further inflammation and damage to the mucosa.

Clinical symptoms of EGUS involve reduced appetite, poor body condition, mild weight loss, poor performance, colic or more severe complications of duodenal structures. In the foal symptoms can include frequently lying on the back, reduced suckling, grinding of the teeth, excessive salvation and diarrhoea.

Treating the horse with ulcers can be difficult and involves eliminating clinical signs, promoting healing and preventing reoccurrence.

This process requires reducing fasting periods, increasing roughage availability and limiting or reducing the amount of grain fed. Taking measures to reduce the stress of the animal is also very important.

Medical treatments use pharmaceuticals to control gastric acids, provide mucosal protectant and improve blood flow to the mucosa. However, pharmaceutical treatment requires a prescription, is expensive and must be administered orally.

Thus, an alternative is to adjust the nutritional status of the horse by providing less expensive, natural alternatives that could be fed with daily rations for long-term use to prevent gastric ulcers from reoccurring and to reduce discomfort in the horse.

Several ingredients including fruit products, lecithin, sodium bicarbonate, calcium bicarbonate, omega fatty acids, natural anti-oxidants, and prebiotics or probiotics have been used in nutraceutical supplements. These nutrients have been shown to have many benefits both in the horse and other species, such as, supporting and protecting the stomach lining, supporting the normal digestive function, promoting a balanced gut microbiome, and protecting the stomach from the generation of damaging oxygen free radicals and inflammation of the mucosa.

Learn more about Digestion and Gastric supplements with comprehensive gut support for horses prone to gastric disturbances.

Some Other Tips to Reduce the Occurrence of Gastric Ulcers

• Have hay readily available at all times in the stable box
• Use a slow feeder
• Feed some chaff to the horse just prior to work so that the stomach is not empty
• Allow access to grazing every day