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It is probable that Equine Gastric Ulcer Syndrome (EGUS) has been a problem in horses for many years. It has only really come to light in recent years due to the development of an endoscope long enough to reach and view the horse’s stomach. What the vets saw, when they looked into the stomachs of many racehorses, wasn’t pretty and resulted in many epidemiological studies to determine just how many horses were affected.
Estimations are that nearly every racehorse will, at some point in its career, suffer with gastric ulcers and at any one time, up to 90% of horses in any racing yard could have ulcers. But this is not a problem exclusive to racehorses and many performance and leisure horses have been found to suffer too.
To understand why ulcers occur, it is necessary to be familiar with the simple anatomy of the stomach. It can be divided into two regions; the bottom half is referred to as the gastric region and the top half is the squamous region. The gastric region is where acids and enzymes are secreted to break down food and it has built-in protection systems to stop the acid from damaging the stomach lining.
The squamous region acts as a reservoir for food as it makes its way down to the bottom of the stomach and has no built-in protection system. Instead, it relies on the almost continuous supply of grass and other fibrous material trickling into the stomach to defend it against acid attack.
Fibre has two important functions; firstly it acts as a physical barrier mopping up the acid and literally stopping it from coming into contact with the stomach lining. Secondly, chewing produces saliva which contains bicarbonate that helps to neutralise the acid in the stomach. As a horse only produces saliva when it chews, the more a horse eats, the more saliva is produced so eating grass almost continuously would produce an almost constant supply of neutralising saliva.
What goes wrong?
Ulceration of the stomach lining can occur in both regions of the stomach but are due to very different causes. The long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) such as Bute, can break down the defence mechanism in the gastric region and result in ulcers forming in this area.
Ulceration to the squamous region was initially thought to be simply due to high starch, low fibre diets. A lack of fibre means that there is no defence against the acid and, as racehorses and performance horses typically receive less forage, it was no surprise that so many horses were affected. Subsequent studies and investigations have suggested that intense exercise regimes could also have a very important part to play in EGUS.
The Effects of Exercise
As the severity of ulcers seems to be greatest in horses that have been in training for a prolonged period of time, researchers began to look at the effects of exercise on the digestive system. It was found that there is increased pressure when a horse exercises at high intensity, leading to compression of the stomach, which pushes the acidic contents of the gastric region up into the squamous region. The longer the horse trains for, the increased time the squamous region is exposed to the acid, and the greater the potential for ulcers to occur. This clearly offers an explanation as to why the problem seems to be worse in horses that have been in training for longer periods.
Are all horses at risk?
The racehorse is clearly at greatest risk because they work at greater speeds and are typically fed very little fibre. The link between exercise and ulcers however, suggests that all horses that are worked regularly could be at risk so this would include dressage and event horses, as well as showjumpers.
How would I know if my horse has ulcers?
The only way to make a definitive diagnosis is via an endoscope examination. The symptoms that would lead you to request an examination include poor appetite, weight loss, grumpy behaviour, dull coat and possibly poor performance. Obviously many of these symptoms could be indicative of several other problems but, if they are all occurring together, then ulcers could be the culprit.
What can I do to avoid ulcers?
The simple answer is to try and keep things as they would be in the horse’s natural environment. Constant access to ad lib forage is the ideal and, if the horse can’t be trained or worked from the paddock, lengthy daily spells at grass are the next best thing. Concentrate feed then needs to be kept as low in starch as possible to help keep acidity levels in the digestive tract under control. The horse should also not be exercised on an empty stomach so it’s wise to ensure that some forage has been consumed, or perhaps a small feed containing alfalfa, which is known to have natural acid-buffering properties, is given before exercise.
All-Round Endurance Mix is a high fibre, high oil mix which delivers performance levels of slow release energy, vitamins and minerals but is relatively low in starch for a mix of this type. For those aiming to cut starch intake to an absolute minimum, Ease & Excel has been specifically developed as a low starch, high specification feed to support performance and maintain condition in horses working up to the highest levels. It contains additional ingredients, including a bespoke In-Feed formulation from Protexin, which help protect the stomach and intestinal linings and support digestive efficiency.
A combination of a balancer, like Lo-Cal or Performance Balancer, to provide essential nutrients, plus non-cereal calorie sources, like alfalfa, sugar beet and/or oil will also provide a low starch option as will Keep Calm, which is suited to horses in up to moderate work. Alfalfa Plus Oil has a Digestible Energy (DE) content similar to that of a competition or conditioning feed but, being much lighter, must be fed in considerable volumes to provide sufficient calories. Not all horses find this amount of alfalfa palatable and combinations of this plus Outshine high oil supplement and/or Speedi-Beet or Fibre-Beet, may prove more acceptable. Indeed, there is evidence that the pectin content of sugar beet, present in both Speedi- and Fibre-Beets, can have an action similar to mucous and help line the stomach and protect it against acid attack.
Alfalfa Plus Oil has a Digestible Energy (DE) content similar to that of a competition or conditioning feed but, being much lighter, must be fed in considerable volumes to provide sufficient calories. Not all horses find this amount of alfalfa palatable and combinations of this plus Outshine high oil supplement and or Speedi-Beet or Fibre-Beet, may prove more acceptable. Indeed, there is evidence that the pectin content of sugar beet, present in both Speedi- and Fibre-Beets, can have an action similar to mucous and help line the stomach and protect it against acid attack.
Treatment for Ulcers
There is currently only one licensed, and rather expensive, drug treatment for ulcers, but it is generally accepted that it is better to diagnose and treat any ulcers present, rather than simply to change a horse’s management and diet. Management and diet can then be instrumental in the prevention of recurrence although, in many instances, without the intervention of drugs, some recurrence is likely. There is a growing plethora of supplements on the market, designed to support a healthier stomach environment, yet very few have clinically proven effects. Combined with the management and dietary changes, however, they can prove helpful.