What lies beneath - Katy delves into gastric ulcers at a scoping day

By Katy Islip

YH Blogs

14 August 2012 15:22

YH writer Katy's been learning about various parts of the equine anatomy recently - find out how she got on when she attended a scoping day set up to raise awareness of equine gastric ulcer syndrome (EGUS).

Every day’s a school day when it comes to horses, and recently I’ve been learning about everything from the internal structure of the equine foot to the workings of the respiratory system, with a dose of gastric ulcers thrown in for good measure.

I learned about the latter at a special scoping clinic set up by animal healthcare firm Merial, which produces ulcer treatment GastroGard, and held at Rase Veterinary Equine Unit in Market Rasen, Lincolnshire. Over the course of the day, I saw vet Rachael Conwell, of Tadcaster’s Castle Vets, examine five horses using an endoscope, which allowed her to look out for the tell-tale signs of gastric ulcers. “It’s estimated up to 63% of performance horses have gastric ulcers but many don’t show clinical signs,” says Rachael. “Travelling, competing and training all increase the risk.”

During the scoping day, she explained to owners how the equine stomach has two types of lining –non-glandular at the top and glandular in the lower half – acid is produced here to help digest food, but this area is also self-protecting, producing mucus and bicarbonates to prevent damage.

The glandular and non-glandular parts of a horse’s stomach are divided by a line called the margo plicatus, and it’s here Rachael’s looking for signs of ulceration in the form of ‘splash lesions’, caused by stomach acid splashing up onto the non-glandular area, which has no in-built protection. Unlike humans who only produce acid when eating, horses continuously produce stomach acid as they are designed to be trickle feeders, constantly grazing, but the way many horses are managed today means they are more vulnerable to problems as they aren’t constantly eating, which gives the stomach acid something to work on and helps stop it sloshing around.

Rachael tells us most research into gastric ulcers has been done on Thoroughbreds or Standardbred horses, and has shown increased training activity results in increased ulcer severity because it leads to a lower stomach pH (meaning it’s more acidic) and compression of the stomach – this sits right behind the diaphragm and during work it gets squashed by the intestines. It’s also been shown feeding lots of concentrates can up the risk, as these foment in the stomach, don’t have to be chewed as much and pass through the stomach quite quickly, so feeding roughage alongside them can help slow everything down.

Stress is also an important consideration in the diagnosis and management of gastric ulcers – this can result from all sorts of things from training to transport and bereavement. Racheal says: “Although it’s difficult to measure stress, we can measure cortisol, a stress hormone in the blood – it’s tricky to do but very stressy type horses are more likely to develop ulcers.” Non-steroidal anti-inflammatory drugs (or NSAIDS) like bute are also a contributory factor in the development of stomach ulcers, but only if they are given in high doses or in combination with other drugs. Rachael says: “At the correct dosages bute is probably a minimal risk factor, but like painkillers like paracetamol in people they can affect the blood supply to the stomach and therefore the ability of the stomach to repair itself normally.”

In terms of the horses affected, we learn all ages and breeds have been found to have ulcers, with performance horses more at risk – research has shown up to 100% of thoroughbreds in training are affected, as well as 67% of endurance horses, 58% of show ponies, 75% of eventers and 70% of broodmares – the latter are thought to be affected because of the stressful nature of pregnancy, the growing foal taking up lots of room and compressing the mare’s stomach, and also the ups and downs of herd life.

Signs of ulcers include mild colic, poor body condition, poor coat, being a picky eater, poor performance, altered temperament and crib biting or wind sucking. Ulcers have been shown to be performance-limiting in racehorses, who usually have more severe ulcers and tend to show signs more obviously, but the signs are often more subtle in competition and pleasure horses who have been observed to be irritable at feed time, and can resent having the girth area and/or their legs groomed. Detection of ulcers takes two forms – one a fecal blood test carried out on droppings, called the SUCCEED test, which indicates if ulcers are present but doesn’t have any way of indicating the site of ulcers or their severity, and a gastroscopy, where a flexible tube carrying a tiny camera is passed down the horse’s throat into the stomach, allowing vets to make an assessment on the number, location and severity of the ulcers.

Rachael tells us treatment of ulcers has a two-fold aim – to promote the healing of the existing ulcers by decreasing acid production to encourage healing, and preventing their recurrence. Full healing usually takes three to four weeks for severe cases, and for milder cases just two weeks can show an improvement. Treatments like GastroGard contain omeprozol, a protein pump inhibitor which basically stops acid production, allowing the ulcers to heal. Some severe cases will also require antibiotics to help the healing process along. Without treatment, it is possible for ulcers to improve and resolve if the horse is taken out of training (removing the acid splash), but this doesn’t happen in every case. Turn out can also help, providing constant food intake and hopefully a more relaxed atmosphere for the horse, however Rachael warns some horses kept out will still suffer recurrent ulcers.

In terms of preventing ulcers, Rachael explains roughage is vital because it requires properly chewing, stimulating the production of saliva and helping form a ‘fibre mat’ of food, which helps prevent the acid splash occurring. Turn-out can also help, as can replacing carbohydrates with fibre in the diet, and feeding for extra calories. Feeding a handful of alfalfa or a double handful of an antacid before exercise can also help as these will soak up the stomach acid and stimulate the production of more bicarbonate which will limit the pain and discomfort of acid splash.

Of the five horses scoped, signs of ulcers were found in four, with varying degrees of severity - although upset their horses were in discomfort, the owners were relieved to discover the cause of their horse’s symptoms, and hopefully with treatment all are now feeling comfortable and well. It was a fascinating day and as you can probably tell, I learned a lot! To find out more about GastroGard and Merial visit http://uk.merial.com/equine/index.asp