This is a question that more and more of us are asking our vets, and when studies reveal that up to 70% of the horse population are affected by gastric ulcers, it’s little wonder that ulcers are on everyone’s mind.

Firstly though, it’s important to break down the sometimes confusing terminology for gastric ulceration in the horse, which is correctly named under the umbrella term of EQUINE GASTRIC ULCER SYNDROME. However, the key thing to understand is that this umbrella covers two completely different conditions: EQUINE SQUAMOUS GASTRIC DISEASE and EQUINE GLANDULAR GASTRIC DISEASE and this difference is due to them affecting completely separate areas of the stomach. More on the specifics of these diseases in next month’s blog.

As an equine vet and horse owner I’m acutely aware of the many, many reasons, excuses, explanations, and factors we consider when trying to put our finger on the reason for “poor performance” in our horses. It is so often the case that there might be more than one thing going on too. All good equine vets will approach “poor performance” in the equine patient systematically, holistically, and in partnership with the owner, trainer, rider and at times physio, saddle fitter and farrier as everyone has a role to play. These cases can be some of the most frustrating we deal with but also the most satisfying when a collaborative approach results in a positive outcome for all.

Poor performance is in itself such a wide-reaching term, and what it means to a Grand Prix Dressage rider, vs Mounted Games Pony vs a Happy Hacker or Racehorse can be vastly different. But a recent expansive literature review on the subject of EGUS has highlighted that poor performance is quoted by owners as the most common clinical sign (symptom) in horses with EGUS (both ESGD and EGGD). It has been suggested that this decrease in performance across the disciplines could be associated with gastric pain, which can manifest itself as reduced stride length therefore reducing speed for racehorses and eventers but also leading to poorer marks in dressage. This gastric pain can also cause increased sensitivity of the skin around the chest and girth area in general, resulting in resentment to leg aids and girthing, which can be subtle, or marked, with bucking and napping in some cases.  As an owner, other observations you might make can include teeth grinding, a poor coat, recurrent mild colic often associated with feeding, and perhaps a little indelicate but annoying nonetheless, watery poos and farts - or as we like to term it in the business, “free fecal water.” With free fecal water, horses tend to pass normal formed manure followed by a jet of liquid poo at the end, usually spraying their freshly washed tails and white socks!

When your vet is investigating poor performance it can take time to systematically rule out issues. Is the resentment to girthing and you putting your leg on due to a nasty case of equine glandular gastric disease, or simply a poor fitting saddle and a nappy horse who hates leaving the yard? Has your poor mare got acid splash causing erosion of her stomach lining (Squamous disease) as you’ve upped her jumping or is she just grumpy and uncomfortable when she’s in season? Have you just bought this gelding and it turns out he isn’t exactly the bombproof schoolmaster he was sold to you as? Is your horse struggling with lateral work because it has a sore tummy or is it a subtle lameness which is making it particularly difficult to get them to move sideways? Or sometimes awkwardly, could it be a rider factor causing the change in performance? Or even more confusingly, could it be all of the above?! This can be a diagnostic conundrum so using an equine vet you trust and has experience in the area is an essential.

I recommend that all my clients keep a diary of their horse; it sounds basic but countless times when working up complex poor performance cases, we have looked back in the diary and noted the onset of an issue corresponding with a management change, and this can give us vital clues as where to start the process of the poor performance work-up - a classic example of a stitch in time saves nine!

So what’s my advice? Horses with EGUS can have all of the signs we have discussed here or none of the above, so how do we know?

The only definitive way to diagnose EGUS and the only way to differentiate EGUS into which specific disease type is for your vet to perform gastroscopy. This is where an endoscopic camera is passed into your horse’s empty stomach and the whole stomach is visualized. Horses we suspect of gastric ulcers may have glandular disease, squamous disease, or be particularly unlucky and have both or have neither! We really can’t tell until we look. Depending on the vet’s initial findings on physical examination and their clinical suspicion they might start the process of the poor performance work-up with a gastroscopy, or it might be the last thing on their list.

We don’t recommend treating based on the clinical signs (symptoms) alone as they can be so vague, subtle and non-specific. Without scoping we have no way of knowing which treatment to prescribe and treatment can be costly and may be unnecessary. Scoping allows us to follow cases up and ensure treatment has been successful.

In future blogs we’ll run through the differences between Equine Squamous Gastric Disease and Equine Glandular Gastric Disease, look at the commonly used treatments for both and look more closely at what to expect with the gastroscopy procedure itself. Until then, I hope you can get out on your horses and enjoy some of this late spring sunshine before the flies descend upon us and we all start complaining it’s too hot!

Jill Thomson MRCVS, Equine Vet

Sponsored by RelyneGI

References: Vokes, Lovett 7 Sykes (2023; Equine Gastric Ulcer Syndrome: An Update of Current Knowledge