Gastric Ulcers

Written by Briony Witherow MSc, BSc, RNutr.

This month’s blog will focus on gastric ulcers; below we discuss what they are, who’s at risk, how to alter the diet to reduce risk and how supplements can help.

What are gastric ulcers?

Equine Gastric Ulcer Syndrome (EGUS) is an umbrella term for what we now understand to be two specific sub-categories of ulcers:  Equine Squamous Gastric Disease (ESGD) describing ulcers predominantly affecting the non-glandular ‘unprotected’ (top) region of the stomach; and Equine Glandular Gastric Disease (EGGD) for ulcers mainly affecting the glandular region (bottom) of the stomach. It is important to note that risk factors and therefore management vary between the two (and of the two, ESGD is thought to be more responsive to dietary management).

Who is at risk?

Equine Gastric ulcers are not just a problem affecting performance horses. In fact, ulcers are reported in all ages and breeds of horse, prevalence for leisure horses ranges from 37-59%for ESGD and over 50% for EGGD.

Factors which may increase the risk of ulcers

• Not enough fibre in the diet. Less than 1kg per 100kg bodyweight (5kg for a 500kg horse) of forage (hay/haylage/grass) in dry matter per day reduces your horse’s ability to employ his natural defences when it comes to ulcer protection; both saliva from chewing and the presence of fibre in the stomach act as a buffer to gastric acid and a physical barrier between this and the unprotected lining.
• Long periods without forage. More than 6 hours between forage feeds increases the risk of ESGD.
• Too much starch. More than 2g per kilogram bodyweight per day (>1kg for a 500kg horse) or feeding more than 1g per kilogram bodyweight per meal has been shown to double the risk of ulcers.
• Intense exercise. During exercise, ‘acid splash’ (contraction of the stomach causing acid to reflux onto the unprotected top region of the stomach) is thought to result in acid injury. The top region of the stomach has been shown to become significantly more acidic during exercise in gaits of trot and above.
• Other factors such as reduced water intake and very coarse fibre such as straw as the sole forage source may also increase acidity or aggravate existing irritation in the stomach.

Managing the Diet to Reduce Ulcer Risk

1. Provide plenty of fibre and maximise chew time.

Ensure a minimum of 1.5% bodyweight dry matter of long stem fibre (7.5kg for a 500kg horse which, when accounting for typical dry matter equates to 8.5kg of hay or 12.5kg of haylage). Employ slow feeders or change forage management to maximise chew time, particularly for those on restricted rations.

2. Keep any concentrate feeds low in starch and sugar and keep meal sizes small.
3. Provide a small fibre meal prior to exercise. This can mean offering hay or haylage while you groom/tack up and/or providing a Stubbs scoop of an appropriate fibre feed such as chaff.
4. Ensure access to fresh clean water and monitor intake.

Where do supplements come in?

While supplements should not be relied upon in the absence of veterinary treatment and management/lifestyle changes, they should not be discounted as part of prevention or long-term management strategy. Like all supplementation, their role should be viewed as ‘the cherry on top’ of good foundations.

Research supports the beneficial properties of supplements containing a combination of ingredients for the management of squamous gastric ulcers. Ingredients such as beta glucans, Sea Buckthorn Berries, pectins, liquorice, antacids, and gum arabic have been shown to provide benefits such as acid buffering, regulation of passage rate and protection of the stomach lining, but more research is required to determine the extent of their benefits.

Antacids such as Magnesium Hydroxide have been shown to help reduce acidity in the stomach, however, the effects of these are relatively short-lived. As such, when using antacid type supplements (like Gastro-Mag), effect can be optimised by feeding tactically based on when stomach acidity might be at its highest. For example, the product could be added to the small fibre meal prior to exercise.