Equine gastric ulcer syndrome (EGUS) is a major equine health problemworldwide. Some studies have reported an incidence of ulcers in performance horses in excessof 90% of horses training. A more recent study conducted in Western Australia found 53% ofhorses had ulcers.

Ulcers negatively and sometimes severely affect a horse's ability to perform. They causepain and discomfort, reduce a horse's appetite which in turn limits its capacity to maintainbodyweight and lead to the development of vices including windsucking and crib biting.

While gastric ulcers have long been recognised as a major health concern there seeminglywasn't much progress made in preventing them in performance horses. New research conductedin Australia and the USA is however starting to shine some light on how ulcers can beavoided.

What Are Gastric Ulcers
Gastric ulcers are lesions that are found in the stomach of horses. The horse's stomach ismade up of 2 major regions, the upper 'squamous' area and the lower 'glandular' area. Themajority of ulcers in adult performance horses occur either in the squamous area or at thejunction of the squamaous and glandular regions.

It is thought that the lack of buffering and protection from gastric acids in the uppersquamous area of the stomach is what makes it more prone to ulceration when compared to thelower glandular area which secretes mucous to protect itself from the gastric acids that arecontinuously secreted into the stomach.

Why Do Gastric Ulcers Occur
Gastric ulcers are a 'mulit-factorial' disease, meaning they are caused by many things. Thefollowing factors have been identified as possible causes of gastric ulcers:
1. Training—horses in training are known to have a higher incidence and also more severegastric ulceration than horses not in work. In a recent study it was reported that the riskof developing moderate to severe gastric ulceration increased 1.7 times for every week thata horse was in training (Lester et al. 2008).
2. Training location—in thoroughbreds, horses that were exercised on a track on the propertywhere they lived had 3.3 times less chance of having gastric ulcers (Lester et al. 2008).
3. Turnout/paddock time—horses that were given access to some turnout time were less likelyto develop ulcers (Lester et al. 2008).
4. Turnout time with paddock mates—horses turned out with other horses are even less likelyto develop ulcers than horses turned out alone (Lester et al. 2008).
5. Stress/nervousness—talkback radio playing in stables was found to increase the likelihoodof thoroughbred horses developing ulcers, suggesting stress is a risk factor for ulcers(Lester et al. 2008).
6. Exercise on an empty stomach—as a horse exercises the pressure inside the stomachincreases which forces the highly acidic gastric contents from the glandular area up intothe unprotected squamous area (Lorenzo-Figueras et al. 2002). Exercising horses on a closeto empty stomach (as would be the case in horses exercised after an overnight fast) makes itis easy for the acidic contents of the stomach to be pushed up into the squamous upperregion of the stomach where it can cause ulceration.
7. Forage type—lucerne/alfalfa hay appears to have a protective effect on the equine stomachand appears to reduce the incidence of gastric ulcers in horses (Nadeau et al. 2000; Lybbert2007).
8. Feeding Frequency—feed deprivation such as might occur during transport and long periodsbetween meals lowers the pH in the equine stomach and increases the risk of gastriculceration (Murray 1994).
9. Non-Steroidal Anti-inflammatory Drugs (NSAID)—drugs like phenylbutazone have been shownto increase the risk of ulcers, particularly in the glandular region of the stomach.

How Can Feeding Management Reducing The Risk
Reducing the risk of gastric ulcers is not just a matter of changing one or two things andhoping it works. You need to assess your horse management systems and make changes whereveryour horses are exposed to one of the above risk factors. Some feeding management practicesthat may help reduce the incidence and severity of gastric ulcers are:
• Don't exercise horses on an empty stomach—providing a small meal of lucerne/alfalfa hayprior to exercise will:
1. Help to stop the acidic contents from the glandular region of the stomach splashing upinto the squamous region where it can cause ulcers;
2. Provide a buffering effect by causing the horse to produce saliva while it is chewing thehay and through the buffering effect of lucerne/alfalfa hay.
• Provide a small meal of lucerne/alfalfa hay immediately following exercise—the WesternAustralian study which found horses trained off site had a higher incidence of gastriculcers suggests that the time taken to return home following training and thus time betweenthe completion of training and breakfast and perhaps the stress associated with travellingis increasing the incidence of ulcers. Providing a small meal of lucerne/alfalfa followingtraining will again help buffer the horse's stomach and protect it from gastriculceration.
• Provide turnout time (with paddock mates where possible) as often as possible—paddockturnout will help to reduce a horse's stress level and if pasture is available will providethe horse with an opportunity to graze, and thus continuously produce saliva to help bufferthe stomach.
• Provide regular small meals and constant access to hay—allowing the horse to feedcontinuously during the day and night will help to reduce the likelihood of gastric ulcersdeveloping. Divide the horse's daily concentrate ration into as many meals as you can to befed during the day and evening and provide hay (preferably not all as lucerne/alfalfa hay,some grass hay will provide variety in the diet and keep the horses protein intake incheck).
If you are travelling long distances with your horse take regular breaks to provide smallmeals during the trip. Providing hay in a hay net will also provide the horse with anopportunity to continue eating during transport (if the hay is dusty dampen it down). If youare concerned about the horse's gutfill leading into a competition, reduce the amount of hayyou are feeding for 2 days leading up to an event. However be careful not to reduce totalforage intake to less than 1% bodyweight per day.
Using these feeding management strategies in combination with strategies to reduce stressand the impact of NSAID drugs will help to reduce a horse's risk of developing gastriculcers.

If Your Horse Already Has Ulcers You Must Treat Them
While one study has shown that feeding lucerne/alfalfa hay has been shown to reduce theseverity of ulcers already present in horses and long periods of pasture turnout willsometimes allow a horse to resolve gastric ulcer issues, if your horse already has ulcersyou must treat them with a registered ulcer treatment. Talk to your vet about the besttreatment regime for your horses.

Finally...
Gastric ulcers are a serious and common health problem in horses that will affect theiroverall wellbeing and performance. While researchers still don't have a full understandingof how and why they occur with such a high incidence, using the feeding and managementstrategies outlined above will help to reduce your horse's risk of developing gastriculceration.

Dr. Nerida Richards (PhD) is Australia's foremost expert in Horse Nutrition. This article iscourtesy of FeedXL DIY Diet Planner forHorses. If you would like be among the first to receive FeedXL newsletters thenplease consider subscribing to FeedXL.

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