Equine gastric ulcer syndrome (EGUS) is a major equine health problem worldwide. Some studies have reported an incidence of ulcers in performance horses in excess of 90% of horses training. A more recent study conducted in Western Australia found 53% of horses had ulcers.
Ulcers negatively and sometimes severely affect a horse’s ability to perform. They cause pain and discomfort, reduce a horse’s appetite which in turn limits its capacity to maintain bodyweight 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 seemingly wasn’t much progress made in preventing them in performance horses. New research conducted in Australia and the USA is however starting to shine some light on how ulcers can be avoided.
What are Gastric Ulcers
Gastric ulcers are lesions that are found in the stomach of horses. The horses stomach is made up of 2 major regions, the upper ‘squamous’ area and the lower ‘glandular’ area. The majority of ulcers in adult performance horses occur either in the squamous area or at the junction of the squamaous and glandular regions.
It is thought that the lack of buffering and protection from gastric acids in the upper squamous area of the stomach is what makes it more prone to ulceration when compared to the lower glandular area which secretes mucous to protect itself from the gastric acids that are continuously secreted into the stomach.
Why do gastric ulcers occur
Gastric ulcers are a ‘mulit-factorial’ disease, meaning they are caused by many things. The following factors have been identified as possible causes of gastric ulcers:
Training – horses in training are known to have a higher incidence and also more severe gastric ulceration than horses not in work. In a recent study it was reported that the risk of developing moderate to severe gastric ulceration increase 1.7 times for every week that a horses was in training (Lester et al. 2008).
Training location – in thoroughbreds, horses that were exercised on a track on the property where they lived had 3.3 times less chance of having gastric ulcers (Lester et al. 2008).
Turnout/paddock time – horses that were given access to some turnout time were less likely to develop ulcers (Lester et al. 2008).
Turnout time with paddock mates – horses turned out with other horses are even less likely to develop ulcers than horses turned out alone (Lester et al. 2008).
Stress/nervousness – talkback radio playing in stables was found to increase the likelihood of thoroughbred horses developing ulcers, suggesting stress is a risk factor for ulcers (Lester et al. 2008).
Exercise on an empty stomach – as a horse exercises the pressure inside the stomach increases which forces the highly acidic gastric contents from the glandular area up into the unprotected squamous area (Lorenzo-Figueras et al. 2002). Exercising horses on a close to empty stomach (as would be the case in horses exercised after an overnight fast) makes it is easy for the acidic contents of the stomach to be pushed up into the squamous upper region of the stomach where it can cause ulceration.
Forage type – lucerne hay appears to have a protective effect on the equine stomach and appears to reduce the incidence of gastric ulcers in horses (Nadeau et al. 2000; Lybbert 2007).
Feeding Frequency – feed deprivation such as might occur during transport and long periods between meals lowers the pH in the equine stomach and increases the risk of gastric ulceration (Murray 1994).
Non-Steroidal Anti-inflammatory Drugs (NSAID) – drugs like phenylbutazone have been shown to 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 and hoping it works. You need to assess your horse management systems and make changes wherever your horses are exposed to one of the above risk factors. Some feeding management practices that 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 hay prior to exercise will:
Help to stop the acidic contents from the glandular region of the stomach splashing up into the squamous region where it can cause ulcers;
Provide a buffering effect by causing the horse to produce saliva while it is chewing the hay and through the buffering effect of lucerne hay.
Provide a small meal of lucerne hay immediately following exercise – the Western Australian study which found horses trained off site had a higher incidence of gastric ulcers suggests that the time taken to return home following training and thus time between the completion of training and breakfast and perhaps the stress associated with travelling is increasing the incidence of ulcers. Providing a meal of lucerne following training will again help buffer the horse’s stomach and protect it from gastric ulceration.
Provide turnout time (with paddock mates where possible) as often as possible – paddock turnout will help to reduce a horses stress level and if pasture is available will provide the horse with an opportunity to graze, and thus continuously produce saliva to help buffer the stomach.
Provide regular small meals and constant access to hay – allowing the horse to feed continuously during the day and night will help to reduce the likelihood of gastric ulcers developing. Divide the horses daily concentrate ration into as many meals as you can to be fed during the day and evening and provide hay (preferably not all as lucerne hay, some grass hay will provide variety in the diet and keep the horses protein intake in check).
If you are travelling long distances with your horse take regular breaks to provide small meals during the trip. Providing hay in a hay net will also provide the horse with an opportunity to continue eating during transport (if the hay is dusty dampen it down).
If you are concerned about the horse’s gutfill leading into a competition, reduce the amount of hay you are feeding for 2 days leading up to an event. However be careful not to reduce total forage intake to less than 1% bodyweight per day.
Using these feeding management strategies in combination with strategies to reduce stress and the impact of NSAID drugs will help to reduce a horse’s risk of developing gastric ulcers.
If your horse already has ulcers you must treat them
While one study has shown that feeding lucerne hay has been shown to reduce the severity of ulcers already present in horses and long periods of pasture turnout will sometimes allow a horse to resolve gastric ulcer issues, if your horse already has ulcers you must treat them with a registered ulcer treatment. Talk to your vet about the best treatment regime for your horses.
Dr Nerida Richards