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Equine Gastric Ulcers; 60-90% of horses affected


The competition season is nearly upon us once again and if the price of diesel doesn’t put you off its likely that you and your horse will be spending more time travelling to practise, train or compete.

What is worth considering during this busy and thrilling time is that the very event that is so enjoyable to us and hopefully for the horse is also very likely to cause a bout of equine gastric ulcer syndrome. It is estimated that between 60 and 90% of horses are affected by gastric lesions including the colon (hind gut ulcers) and it is thought that the majority of ulcers are due to modern management methods of travelling, training, feeding and stabling.

Luckily Equine Gastric Ulcer Syndrome is entirely manageable and with a few strategic changes to diet and routine you can ensure that your horse remains healthy in the busy months ahead.

The horse is a trickle feeder, it likes to eat little and often and has a stomach that constantly produces gastric acid at an extraordinary rate of 1.5 litres an hour in order to break down and digest a frequent supply of many small meals before passing everything into the hind gut where a slower and more holding digestion takes place. The stomach is divided into two clearly distinct parts. Most of the damage appears in the top part of the stomach as it is largely unprotected and relies upon the saliva produced by the frequent eating of forage which takes a lot of chewing to provide a buffering agent against gastric acid.

If the horse is on a maintenance type of feeding regime i.e. two feeds and two hay nets per day it is likely that the stomach will be empty for a too long and it is likely that an ulcer will develop. Any horse that is without food for more than four hours will have a low ph. in the stomach (greater acidity) which is damaging to the walls of the top (non- glandular) portion of the stomach, whilst horses with a constant supply of feed have a much higher (better) ph. and less chance of suffering from EGUS. The type of food fed also has an effect, for instance feeding alfalfa and oat straw significantly raises the ph. level, whilst feeding high grain diets produces volatile fatty acids and lactic acid, both easily damage the upper portion of the stomach causing pain and inflammation.

Many veterinarians quote stress as being a significant factor to the cause of ulcers, which would include travelling, confinement in a box for long periods and illness (laminitis, lameness, infections) all these events cause the body to release stress hormones and chemicals which ultimately lower the ph. of the stomach and damage the lining of the stomach.

Another major cause of ulcers in horses is the use of NSAID’s given as pain relievers and anti-arthritics, the most commonly prescribed one being bute. NSAID’s prevent the production of prostaglandin, which is a key ingredient in the protection of the stomach. Long term use of any NSAID’s in the horse is considered to be detrimental to gut and liver health but balance is the key and if a horse is so lame it is unable to walk around the box then most owners would agree that the primary concern is to make it comfortable as quickly as possible and consider ulcer medication alongside. Nsaids are also thought to be responsible for ulcers in the hind gut.

Nsaid’s claiming to have low ulcerogenic properties are called Coxhibs, but it is always worth asking the supplier or the vet for advice on research as sometimes claims from manufacturers can be misleading and inaccurate and it is important to understand what side effects or changes are likely to happen in long term use.

Signs of Ulcers

The first signs of ulcers can be nothing more than subtle changes in attitude or behaviour of the horse, i.e. sluggish movement, lacking in energy or becoming more nervous and spooky and resentment at having the girth tightened.

Other signs include, a change in the amount of food usually eaten, chewing wood in the stable or fencing (not trees) and the onset of windsucking, a sudden change in temperament especially of the grouchy or bad tempered type. Mild colic like symptoms turning round to look at his flanks, lying down and urinating excessively, sudden loss of coat condition maybe not as sleek and shiny as usual, coat looks slightly raised and flat coloured.


If ulcers are suspected the vet may want to examine the stomach with a gastroscope which takes about 15 to 20 minutes, the scope is passed up through the nostrils, into the pharynx and then into the oesophagus. The horse can be given a tranquilizer as although it isn’t a painful procedure most horses resent the sensation

Typical findings include scar tissue, erosions, thinning and bleeding of the stomach wall. The ulcers will be graded from 0 normal to 5 being severe, bleeding and about to perforate.

Following a full course of Gastrogard or other generic omeprazole it is usual for the horse to be given a half dose as a preventative, given that Gastrogard can retail at £30 per day this can be a significant cost to the owner and the other down side to long term use of omeprazole is that it use will produce a greater amount of gastrin which affects the population of gut microbial flora in the gastrointestinal tract.

Alternative treatments

The main downside of giving H2 antagonists Ranitine and Cimetidine as alternatives are that they must be given in frequent doses throughout the day as the effect isn’t as complete or as long lasting as omeprazole. Cimetidine should be given 4-6 times daily and Ranitidine 2-3 times daily for 10-21 days to be effective at 8.8 mg/kg. Lower doses are effective and relieving symptoms such as pain and temperament changes but have are ineffective at healing the ulcers.

Sucralfate acts as a local mucosal-adherent. In an acidic environment, sucralfate forms a sticky viscose-gel that adheres to an ulcer crater lasting about six hours. It improves the gastric ph. by absorbing pepsin and acts as a buffer by increasing bicarbonate secretion. It is also used on horses with hind gut ulcers.

For those that prefer a natural approach then the Brazilian plant Maytenus Ilicifolia has proton pump inhibitors and will bring relief to symptoms. It has low toxicity, and has does not alter gut microbial flora even in long term use. The advantages of using anti ulcerogenic plants instead of a synthetic drug are that plants have many synergistic chemicals and are generally able to provide analgesic and anti-inflammatory actions and contain anti-oxidants to aid healing.

By far the best and the cheapest method of treatment for an ulcer is to turn the horse out for two weeks holiday and once the ulcers are considered healed the next thing is to consider a strategy for keeping them from reappearing

Strategies for a Healthy Gut- Feed little and often!

The best way of keeping ulcers away are to promote a healthy gastrointestinal tract and this can be as easy as making a few of changes to the daily routine such as turning the horse out as often as possible and giving more feed portions per day. Avoid large grain meals only feed the recommended amount of 0.5kgs per 100kg body weight.

Give half a pint of corn oil twice daily instead of grain for the added anti-inflammatory protection of omega 3 and 6 and make sure the horse has access to some sort of forage throughout the day. The other most important action to take during times of stress, travel and restrictions to grazing is to provide protection and buffering to the vulnerable top part of the stomach by feeding an antacid such as bicarbonate of soda or calcium carbonate. These can be effective but short lived with the effects said to last for maybe only an hour, therefore it may be better to buy the antacid in syringe form and give it whilst travelling rather than make it a permanent addition to the feed. More long lasting antacids are dihydroxy-aluminium sodium carbonate, aluminium phosphate and magnesium carbonate, these both neutralize gastric acid and protect and coat the mucosal lining of the stomach.

Some products may also contain threonine and glutamine which are compounds known to increase the integrity and quality of the stomach wall and help produce mucus which is the body’s natural buffer against the effects of hydrochloric acid.

Many products that are antacids also contain probiotics such as yeassac and prebiotics which are food for the friendly microbial populations that live in the hind gut rather than the stomach. Seaweed extracts are becoming an increasingly popular addition to gut soothing products reportedly able to lower gastric acid production but more likely to be beneficial to the health of the hindgut and for its nutritional benefits especially the b vitamins.

Remember EGUS is manageable and by far the best and cheapest option is to turn the horse out as much as possible and stick to the golden rule of feeding little and often.

Great thanks goes to Dr Carol Michael for this superb insight!


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