Preventing Gastric Ulcers in Horses
Equine Gastric Ulcers: Feeding Management Strategies to Reduce the Risk for Your Horse
Equine gastric ulcer syndrome (EGUS) is a major equine health problem worldwide. Multiple studies have reported a 90% incidence rate of ulcers in performance horses.
Ulcers negatively and sometimes severely affect a horse’s ability to perform. They cause pain and discomfort. They may reduce your horse’s appetite which in turn limits their capacity to maintain bodyweight and ulcers can lead to the development of vices like windsucking and crib biting.
While gastric ulcers have long been recognised as a major health concern there is an evident lack of understanding in the horse owning community about what causes them and how they can be prevented.
Continue reading to find out a little bit more about what gastric ulcers are, how your horse’s stomach functions and a few little things you can do that will dramatically reduce the risk of your horse’s stomach developing this painful condition.
What are gastric ulcers?
Gastric ulcers are lesions or open wounds that occur in a horse’s stomach. Equine Gastric Ulcer Syndrome, or EGUS is an umbrella term used to describe ulcerative conditions of the horse’s stomach. EGUS is then divided into two main conditions, Equine Squamous Gastric Disease, or ESGD, which is the ulceration that occurs in the top part of the stomach.
AND Equine Glandular Gastric Disease, or EGGD, which is the ulceration that occurs in the lower section of your horse’s stomach.
The reason I am explaining this, is it matters a whole lot to understand that there is a difference between ulcers in the top of your horse’s stomach and ulcers in the bottom.
They are caused by different factors, their symptoms can be different and the type as well as length of treatment also usually varies.
This article is going to focus only on the squamous gastric ulcers, the ones up the top of the stomach. But please remember if your horse is diagnosed with ‘gastric ulcers’ it is critically important that you understand WHERE those ulcers are in your horse’s stomach so that, together with your vet, you can treat them properly and put the right measures in place to try and prevent them in future.
Image provided by RandLab (https://www.randlab.com.au)
Why do gastric ulcers occur in the upper section of the stomach?
The horse evolved as a grazing animal and when left to their own devices will eat for 17 hours or more per day. This means they are constantly chewing and salivating and their stomach is always full of fibre.
Because of this pattern of eating, their stomach never developed an on-off-switch for gastric acid production. So their stomach secretes gastric acid 24-hours a day, regardless of whether they are actually eating or not.
When you think about this from the perspective of our modern day horses it is not an ideal situation. Many horses are now stabled with limited access to free choice forage. Or they work, compete and travel, leaving them in situations where they go for extended periods of time without feed.
When a horse eats it produces saliva and one of saliva’s roles is to buffer or dilute the gastric acid in the stomach. When a horse isn’t eating, it isn’t salivating. BUT they are still secreting gastric acid. This results in a pool of undiluted (and therefore very acidic) gastric fluid accumulating in the lower section of the horse’s now empty stomach. The pH of the fluid in your horse’s stomach can get to as low as pH 1… this is like battery acid!
The lower part of the horse’s stomach was smart enough to protect itself from gastric acid, and, provided it is well nourished, is able to produce enough sticky mucous to protect itself from its own acid secretions.
BUT, the upper part of the stomach doesn’t have this same protection. In a grazing horse the stomach is always full of fibre and saliva, so the top of the stomach was never exposed to gastric acid simply because the forage a horse ate stopped the acid from ever splashing up there. And if a little bit did splash up there, it wasn’t acidic enough to burn holes in the stomach lining!
In our modern day, meal fed horses however, the stomach is often empty and the upper section of the stomach is left totally exposed to the highly acidic fluids that are allowed to accumulate in empty stomachs.
When a horse with an empty stomach trots, canters, gallops or even simply tenses up its abdominal muscles the gastric fluids are splashed or squeezed up onto the unprotected upper section of the stomach. The acid simply starts to burn holes and eat through the stomach wall lining. If you allow this to occur repeatedly the horse will eventually develop ulcers. This can happen in just a matter of days.
What factors influence the risk of gastric ulcers in horses?
Squamous gastric ulcers are a ‘multi-factorial’ disease, meaning they are caused by many things. The following situations have been identified as factors that can influence the risk of squamous gastric ulcers:
1. 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.
2. Low Forage Diets – diets that are low in forage result in horses chewing and salivating less and also increase the periods of time a stomach is left empty. Less chewing, less saliva and longer periods of time where the stomach is empty dramatically increases the risk of squamous ulceration.
3. High Grain Diets - Research shows that excessive grain does increase the risk of squamous gastric ulcers and that reducing starch reduces the likelihood of ulceration reoccurring after treatment (Luthersson et al 2019).
4. Training – horses in training are known to have a higher incidence and also more severe gastric ulceration than horses not in work. In has been reported that the risk of developing moderate to severe gastric ulceration increased 1.7 times for every week that a horse was in training (Lester et al. 2008).
5. 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).
6. Turnout/paddock time – horses that were given access to some turnout time were less likely to develop ulcers (Lester et al. 2008).
7. 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).
8. Forage type – alfalfa (also known as 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).
9. Feeding Frequency – feed deprivation such as might occur during transport and long periods between meals lowers the pH in the equine stomach and allows the stomach to empty, both of which will increase the risk of gastric ulceration (Murray 1994).
How to reduce the risk of gastric ulcers in horses
To reduce the risk of gastric ulcers 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 alfalfa (lucerne) hay prior to exercise will:
1. Help to stop the acidic contents from the lower region of the stomach from splashing up onto the upper region where it can cause ulcers;
2. Provide a buffering effect by causing the horse to produce saliva while it is chewing the hay and through the buffering effect of alfalfa hay itself. If you don’t have alfalfa hay then your horse’s regular hay will also work well.
To learn more about what happens when you exercise a horse on an empty stomach, click here to read our post (and watch the video) on ‘Why You Should Never Ride Your Horse on an Empty Stomach’.
Provide a small meal of alfalfa (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 small meal of alfalfa following training will again help buffer the horse’s stomach and protect it from gastric ulceration. Again if you don’t have alfalfa hay your horse’s regular hay will help.
Provide turnout time (with paddock mates where possible) as often as possible
Paddock turnout will help to reduce a horse’s 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 and to keep their stomach full.
Feed as little grain as possible
Grain increases the risk of ulceration and the risk of reoccurrence after treatment. So it makes logical sense to carefully manage grain in your horse’s diet to reduce the risk or reoccurrence of ulceration.
You should feed as little grain as possible. Keeping grain low in the diet also helps you maximise forage intake which also reduces the risk of ulceration.
For the purposes of minimising ulcer risk, you should keep meals to 1 gram of starch per kg BW or less.
Which means if a grain-based feed is 20% starch, you can feed 2.5 kg of that feed per meal. If a feed is 50% starch, you should feed no more than 1 kg per meal.
And, regardless of starch content you shouldn’t exceed more than 1 kg of grain-based feed per day per 100 kg of bodyweight (e.g. a 500 kg horse should not be fed more than 5 kg of grain based feed per day)..
I also recommend feeding grain-based feeds together with lucerne chaff to help reduce the potential negative impact grain has in the stomach.
As high energy alternatives to grain, consider using fibres like sugarbeet pulp, lupin hulls and copra meal
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 horse’s daily concentrate ration into as many meals as you can to be fed during the day and evening and provide hay at all times (providing as much variety in hay as you can manage).
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. Just beware of dusty hay increasing the risk of travel-sickness and of course the risk of entanglement in the net. If you are traveling with your horse over long distances on a regular basis, consider using a gastric ulcer medication (omeprazole or ranitidine) just prior to and during travel to cut the acid production and reduce the risk of ulcers. Speak with your veterinarian about this.
If your horse already has ulcers you must treat them
While one study has shown that feeding alfalfa (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 horse.
Finally…
Gastric ulcers are a serious and common health problem in horses that will affect their overall wellbeing and performance. Squamous gastric ulcers are a human-made health problem for our horses and are cause by the way we feed and manage them.
Using the feeding and management strategies outlined above will help to reduce your horse’s risk of developing painful squamous gastric ulceration. If you remember nothing else, just remember this… Always feed hay befoe you ride your horse! That small change in feeding management alone will have a massive impact on reducing your horse’s risk of ulceration. AND it will make your horse comfortable and happy during rides, making your time together much more enjoyable for both of you!