Gastric ulcers are quite common in horses of any age, with most studies estimating that between 50 to 90 per cent of horses have gastric ulceration. The highest prevalence of gastric ulceration occurs in racehorses (80-90%), endurance horses (70%) and show horses (60%).
Signs of gastric ulcers range from subtle changes in attitude, trainability and performance, poor appetite, leaving food after a few mouthfuls, weight loss or a dull coat through to grinding of teeth, loose manure and colic. Gastric endoscopy is the only definitive means of diagnosis of gastric ulcers, and is required to distinguish between squamous and glandular ulcers, but will not detect disturbances of the hind gut caused by hind gut acidosis. It is important to identify where mucosal damage occurs as treatment protocols vary between squamous and glandular ulcers and for hind gut acidosis.
Since the horse’s stomach evolved to constantly digest low-quality roughage, it releases a constant flow of acidic digestive juices. In a natural environment, horses graze frequently, maintaining a steady flow of forage and saliva through the stomach which buffers the stomach acid.
In a modern, domesticated environment, horses are often meal-fed and can go many hours without access to food, allowing the acid concentration of the stomach to increase and burn the stomach lining, creating gastric ulcers in the glandular (lower) section of the stomach. In addition to this, acid splashing up onto the more sensitive lining of the upper section of the stomach (the squamous mucosa) during exercise can cause squamous ulcers.
Research demonstrates that equine gastric ulcers can form in an empty stomach during a period as short as four hours or in only a few hours of transport where stress is an exacerbating factor. For this reason, it is important to teach endurance horses to forage along the way.
Modern horse diets are often relatively high in starch-rich feeds such as cereal grains and by-products which can exacerbate stomach ulcer pain. Feeding large meals high in starch or uncooked cereal grains increases the risk of undigested starch passing through to the hind gut where it is microbially fermented, producing organic acids which cause hind-gut acidosis and pain.
Starch overload also creates a change in the microbial populations and if severe, can cause sudden death of the fibre-fermenting species which causes the release of endotoxins. This can create digestive upset and if severe, may trigger laminitis.
The final common contributor to development of gastric ulcers, particularly in the glandular (lower) section of the stomach is use of anti-inflammatory NSAID drugs such as phenylbutazone (Bute) which can slow the production of the protective mucus membrane of the stomach.
Management of diet and lifestyle in conjunction with veterinary care is necessary to overcome existing and prevent new ulcers developing. Severe ulcers need medical intervention using drugs to switch off the acid pumps in the stomach for a period of healing. It is important to correctly identify the site of ulceration as different medical protocols may be required to treat ulcers depending on their location.
Scientific trials have demonstrated the effectiveness of nutraceuticals rich in phospholipids and amino acids such as lecithin, pectin, fermented soy and aloe vera which can be fed alongside veterinary prescribed drugs such as omeprazole to facilitate healing. Good results are reported from continuing with the nutraceuticals as follow-up treatment for a month and later used at a reduced rate for maintenance of normal gut health.
We recommend Farmalogic ReLEAF, a low dose natural aid to managing horses prone to gastric ulcers. Made with scientifically supported ingredients, ReLEAF contains pure dried aloe vera inner leaf gel and a Lactobacillus fermentation product, providing prebiotics, amino acids, glucomannans, phospholipids and saponins to help maintain a healthy gastric mucosa, balanced gut microflora, and nutrients for cellular regeneration of gut lining.
Nutraceutical use is also advised during the use of NSAIDs such as phenylbutazone (Bute).
Lifestyle changes are also critical for successfully managing ulcer-prone horses in the long term. Horses left without access to roughage, exercised on an empty stomach and those with limited movement (e.g. stabled) are the ones most prone to development of ulcers.
Diets for ulcer-prone horses should consist of one to two per cent of the horse’s bodyweight in roughage (pasture, hay, chaff) topped up if necessary with an ulcer friendly energy (calorie) source such as legume grains (e.g. lupins), ‘super fibres’ (like beet pulp or soy or lupin hulls) or oils. These low GI feeds provided a better source of slow-releasing energy for endurance horses, and also aid with water retention along the GIT.
Research demonstrates that feeding lucerne hay reduces the risk of ulcers developing – so aim to feed around 1kg of lucerne hay for a pony and 2 – 4 kg of lucerne hay for a horse. Lucerne is rich in calcium which can buffer stomach acid, is high in pectins which help to protect the gastric lining and when fed just before a ride, will form a ball inside the stomach which soaks up acid, reducing the risk of splash during exercise.
Keeping horses in paddocks with grazing rather than small yards or stable, and allowing them the company of other horses and freedom to exercise are important lifestyle changes beneficial for reducing risk of gastric ulcers.
When horses need to be confined, providing hay nets in the stable or yard, during long float trips and when tied to the float are a practical means of ensuring that roughage is available for a longer period after a meal and minimizing the wastage that occurs when hay is fed on the ground.