Risk Factors associated with Gastric Ulcers

Pasture Turnout

In general, grazing horses appear to have a reduced prevalence of EGUS. Horses that are allowed to be horses will trickle feed and freely exhibit their natural feeding behaviour, therefore chewing frequently allowing for the copious production of saliva to buffer the continual acid production in the stomach.

Forage Feeding

ECEIM (European College of Equine Internal Medicine) identified that having more than 6 hours between forage meals increases the risk of ESGD by 4 times. When fed hay and pasture, horses produced 400 - 480 grams of saliva per 100 grams of dry matter consumed, whereas when a concentrate feed was fed, horses produced half as much saliva, therefore significantly reducing the buffering capacity.

Starch Intake

Cereal and starch intake has been associated with an increased risk of EGUS in horses. Exceeding 2g/Kg body weight (BW) of starch intake per day was associated with a two-fold increase in the likelihood of EGUS and feeding more than 1g/Kg BW of starch per meal was associated with a 2.6 fold increase in the likelihood of EGUS.

Fasting

Horses evolved to trickle feed and therefore almost continuously eat and chew and produce continual but varying amounts of gastric acid. Chewing produces saliva, an important buffer of stomach acid. Withholding feed, even if for a short time, causes a rapid drop in gastric pH as horses produce gastric acid continually over 12-24 hours.

Gastric ulceration can be induced by alternating 24-hour periods of feed deprivation and adlibitum access to hay for a total of 96 hours of feed deprivation. Feed deprivation reduces the amount of saliva production and feed ‘matting’ to protect the squamous mucosa.

Exercise

Workload has been suggested to be one of the important risk factors for EGUS, as horses with less than 2 days of rest a week are at increased risk of ulcers. Contraction of the stomach during exercise allows acid to splash onto the non-glandular region of the stomach resulting in acid injury to this relatively unprotected mucosal lining. Less marked injury has been seen in horses that have been fed fibre prior to exercise.

AGE, BREED, GENDER

Gastric disease is multifactorial and EGUS can affect any horse of age, breed or gender.

Water Deprivation

Intermittent access to water increases the risk of EGUS as it has been shown that horses without access to water in their paddock are more than 2.5 times more likely to have EGUS than horses with constant access to water. Ensuring clean water containers, multiple water sources and constant access to water is important. Strategies to maintain water intake when travelling or away at shows must be implemented and may involve the use of flavours or mashes such as RE-COVERY MASH.

OTHER RISK FACTORS

Electrolyte administration, administration of NSAIDs, bacterial contamination of ulcer beds.