In recent years the equestrian world has become aware of the problem of ulcers in the gastro-intestinal tracts of their horses. Humans know how painful ulcers can be, can say so and can seek treatment. Horses also know, but “no they can’t!”. There are however several symptoms of gastric ulcers which should alert owners. Gastro-intestinal pain may make horses badly behaved, for example bucking when ridden; refusing to jump; dislike of girth pressure; sensitive flanks etc and lethargic. They often windsuck and/or crib-bite. This is to generate saliva which counteracts stomach acid, and distend the stomach with air, hopefully to reduce the level of acid away from the unprotected upper wall, and so reducing the pain from gastric ulcers. The region just above the protected lower region is a common site for gastric ulcers to occur.  Colic, both acute and mild (repetitive) can also be caused by ulcers. Poor appetite, scour and loose, poorly formed droppings (passed with fluid) are further symptoms of gastric and colonic ulcers.  Food digestion is impaired, hence the “poor doer” or “hard keeper”. Problems such as anaemia and tying-up have also been associated with gastric and colonic ulcers.

So what causes equine gastric ulcers? Horses are naturally trickle feeders – in the wild they will graze until their stomachs are full. Once empty, they start feeding again. Strong hydrochloric acid is continuously produced by glands in the lower part of the stomach (unlike humans – it is only produced when we eat). It serves two purposes: to kill harmful pathogens ingested with food; and initiate the digestion process. In the absence of food it can penetrate the protective mucus layer and attack the cells beneath, causing ulcers to form. In extremis these can breach blood vessels with serious consequences.  Chewing food generates saliva; this is alkaline and buffers the stomach acid. Fibre produces a mat, or crust, on top of the stomach contents, which will reduce or prevent splashing onto the unprotected upper stomach wall thereby causing gastric ulcers. Sport horses, especially those that race or jump, are particularly prone to ulcers caused in this way. Such horses are often fed high starch concentrated feeds. If long fibre is not mixed with the food, it is rapidly swallowed with little chewing and therefore negligible saliva to buffer the acid in the stomach. Starch can also be fermented to lactic acid, exacerbating stomach acidity. Many sport horses are continually stabled, with little or no turnout. This can cause stress and also reduces the fibre intake from grazing. Inadequate forage (e.g. overnight in the stable) can result in acid building up in an empty stomach. If the horse is lying down, the acid can reach the upper wall. A small feed of e.g. chopped alfalfa before exercise will provide protection from ulcers induced by jumping and running.

Non-steroidal anti-inflammatory drugs (NSAIDs) e.g. ‘Bute, inhibit prostaglandin  (which encourages gut mucus production.) thereby reducing the protective mucus coat lining the gut wall. This effect also occurs in the hind gut. If a horse is under stress, and/or eating insufficient fibre and/or on a high starch diet, hind gut acidosis can develop, permitting colonic ulcers to form and pre-disposing to colic or scour. Treatments which reduce stomach acid production, (e.g. omeprazole) or neutralize it (antacids – common in the cheaper treatments) will reduce stomach ulcers, but also impair digestion. Consequently relatively undigested food can reach the hind gut. A high starch content will enable microbial fermentation to lactic acid. The fibre – digesting bacteria are suppressed; the accumulation of undigested fibre can lead to colic or scour. Recent research indicates that the use of omeprazole and other gastric ulcer treatments has reduced the incidence of gastric ulcers, whilst those in the colon have increased significantly.

If an owner suspects gastro-intestinal ulcers in his or her horse, they should in the long term look to modify the horse’s life style and management to make it as natural as possible. In the short term the options for the owner are to consult a vet, or if confident of their own ability to diagnose, to carry out a short term treatment with a suitable product.

Probably the most effective is Gastroguard  (prescription only) which works by reducing acid production . Vets will advise a 10 – 14 day course costing £25 or so per day. I have received a report from Florida where a vet successfully treated a patient with a low dose of omeprazole (Gastroguard ingredient ) and bismuth salicylate; this was much less expensive.

Cheaper proprietary products are based on amino-acid formulations; antacids such as limestone, sodium bicarbonate; herbal blends such as licquorice root, slippery elm bark, etc etc. The efficacy of all these is variable. Costs vary from £1 to £7 per day.

August 2010

John Chapman M.A. (Cantab) Equine Nutritionist

Horseheath Nutrition

Gravenhorse Feeds

July 2011

Blends of herbs and other nutritional products for use in the treatment and control of gut ulcers are currently being researched. If you think your horse has ulcers and would like to participate in FREE trials then please e-mail via the Contact page or call on 0844 8844 850 or 07721384508

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