Introduction to Hestevard Exagus

5th November 2020

Hestevard Exagus supports the normal gastric digestive of horses, particularly suitable for horses prone to gastric ulceration. It has a unique combination of 6 ingredients each of which contributes to the promotion of healing of the gastric mucosa. In line with the FEI Clean Sport Initiative Exagus does not contain any substances which are prohibited by the governing bodies of competitive sports within the UK. It can be used to reduce the incidence of recurrence of ulcers in horses where omeprazole or other pharmacological treatment has been successful.

THE INGREDIENTS

Threonine is an essential amino acid in horses, meaning it cannot be manufactured from other compounds and must be obtained from the diet. Threonine is required for mucus production; it has been shown in other species that low levels of threonine will limit the ability of the stomach to produce mucus, which provides a protective coating to the stomach lining, thereby reducing the potential for formation of gastric ulceration.

Glutamine has been shown to reduce gastric ulcer under experimental conditions. It appears to reduce levels of inflammation and associated damage in the stomach.

Short chain fructooligosaccharides (scFOS), a fermentable fibre-type carbohydrate, have recently been shown to act as a pre-biotic in horses. They promote the growth of beneficial bacteria within the gastrointestinal tract and appear to stabilise the ‘good’ bacterial population in the face of sudden dietary change. It has been demonstrated that dietary supplementation with scFOS can increase the gastric pH and that should reduce the risk of ulcer formation (Respondek et. al., 2008)

Laminaria hyperborea, (brown kelp) is highly palatable, and the majority of horses will happily eat Exagus. It is available in free 1kg trial packs allowing its palatability to be tested before purchase.

Calcium carbonate and magnesium hydroxide are antacids. Calcium carbonate has been shown to promote healing of non-glandular mucosa in vitro (in lab conditions rather than in the body). Magnesium hydroxide is thought to reduce pain associated with gastric ulcers and may reduce the recurrence following successful treatment.

IMPROVEMENTS IN GASTRIC ULCERATION SCORE

In the study carried out by Hatton et. al. (2007) 17 racehorses on one yard were scored for severity of gastric ulcers. 11 horses were treated with Exagus at the recommended daily dose of 33g three times daily for six weeks. The other 6 horses were the untreated control group. No other medications were given, and the horses all continued to follow the standard training and management routine on the yard. At repeat gastroscopy 73% of the treated horses had an improved gastric ulcer score, and the average ulcer score had decreased in the group treated with Exagus from 1.82 to 0.92. The average ulcer score in the untreated group had increased from 1.5 to 1.66, with 33% of horses showing a worsening of their gastric ulcers. This represents a statistically significant improvement in the treated group compared to the control group.

The recommendation to feed Exagus three times a day is based on the relatively short duration of action of the antacid’s calcium carbonate and magnesium hydroxide.

Lis Watson VetMB Ph.D Cert AVP (EIM) MRCVS


Equine Gastric Ulcer Syndrome – no acid no ulcer?

Equine gastric ulcer syndrome (EGUS) is a general term used to describe diseases that cause stomach ulcers in horses and is similar to the term peptic ulcer disease (PUD) in people. Unlike people however, the horse is unique in that the stomach lining (mucosa) is divided into a squamous and a glandular portion; and it is important to realise that there are differences between these two regions. Therefore, when referring to EGUS, you will often hear your veterinarian using the terms Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD) in order to clearly distinguish which part of the stomach is affected.

EGUS is common and it is an important disease in the equine industry. Performance horses are particularly susceptible, with studies showing that between 47-100% of Thoroughbred racehorses; 33-93% of endurance horses and 58-64% of show and sport horses may have stomach ulcers. Unfortunately, non-performance horses are also susceptible to EGUS, and studies have shown that between 11% to 67% of sedentary horses and horses that partake in less strenuous activities (e.g. pony club activities) may have ulcers.

There does not appear to be a clear relationship between the presence of ESGD and EGGD, and the fact that both conditions may occur together in the same horse does not indicate that they are associated. In the case of ESGD, the cause of the ulcers is well understood, with a variety of managemental risk factors (e.g. increase in exercise intensity, increased starch intake and reduced pasture turnout) contributing to an increase in the exposure of the squamous mucosa to acid. The squamous mucosa is not normally exposed to acid. As such it is inherently susceptible to acid injury, and with prolonged acid exposure, ulcers may develop.

In contrast to ESGD, the cause of EGGD is poorly understood. The glandular mucosa is very different from the squamous mucosa in that it is exposed to a highly acidic environment under normal physiological conditions. As such, it is only when there is a breakdown of the normal defence mechanisms that protect the glandular mucosa from acidic gastric contents that EGGD occurs. While ulcers are most commonly seen with ESGD, horses with EGGD rarely present with ulcers. Rather, the lesions are more consistent with an inflammation of the stomach lining and can vary widely in their appearance. A number of scientific studies have identified that stress, both psychological (e.g. multiple riders or caretakers; confinement; stress associated with transport and competition) and physiological (e.g. increases in the total amount and frequency of exercise without adequate rest periods) may increase the risk of EGGD in horses. This may be due to a variety of mechanisms including suppression of the immune system and a reduction in the mucus coating and blood supply to the glandular mucosa; all of which compromise the ability of the stomach lining to resist acid injury.

Symptoms that may indicate that your horse has EGUS include:

  • Poor coat condition
  • Bruxism (teeth grinding)
  • Changes in temperament (including nervousness and aggression)
  • Acute or recurrent colic
  • Reduced appetite, altered eating patterns and unexplained weight loss
  • Poor performance and changes in rideability (including reduced willingness to work and reluctance to go forward)
  • Skin sensitivity (biting of the flanks or resentment of girthing, grooming, leg aids or rugging)

Gastroscopy is the only reliable method for definitive diagnosis of EGUS. Your veterinarian will usually ask you to withhold food from your horse for 16 hours and water for 6 hours prior to the procedure. Following completion of fasting, your horse will be sedated and a 3-m equine videoendoscope (camera) will be passed into the stomach via the nasal passages. This may require the use of a twitch in some cases. The stomach is then distended by air to enable your veterinarian to see the entire stomach. The procedure is painless, and most horses appear to tolerate it well.

If your horse has stomach ulcers, your veterinarian will assess where they are and how severe they are by assigning a score that represents the appearance of the stomach lining at the time of gastroscopy.

Treatment of EGUS will vary depending upon the severity and the location of the ulcers. In most cases treatment consists of management and dietary modification in conjunction with the use of drugs that reduce the acidity of the stomach contents. Oral omeprazole is the drug of choice and is currently the only licenced product for horses.

Nutraceuticals may offer some protective effects in horses at risk of developing EGUS, and there is some evidence to suggest that Hestevard Exagus may improve the rate of healing in horses with EGUS. This supplement contains alkaline buffers which help neutralise gastric acid. The product also contains sodium alginate which forms a gel on the surface of the gastric contents, thus acting in a very similar manner to the fibrous mat that normally protects the sensitive squamous epithelium from acid splash during exercise. In addition, amino acids like Threonine promote mucin synthesis, thereby improving the barrier function of the glandular epithelium and protecting it from acid injury.

Additional management and dietary adaptations which may help and can be implemented long term include:

  • Increased turnout where possible
  • Ad lib water
  • Reduction/avoidance of any social stressors
  • Provide regular rest days
  • Feed a handful of chaff 20 minutes prior to exercise to reduce acid splash during exercise
Dr Michael Hewetson BSc BVSc PhD DipECEIM CertEM(Int.med) FHEA


CASE STUDY

My 5* eventer had suffered with both squamous and pyloric ulcers for several years resulting in poor appetite, poor condition and tightness when ridden, despite continuing to perform well at top level. The ulcers always resolved to pharmaceutical treatment but, despite management changes, each time we discontinued treatment his appetite would slowly drop off again and repeat gastroscopy revealed return of the ulcers.

Not usually a supplement fan, I carefully searched for a gastric supplement with the correct balance of prebiotics, antacids and gastric protectants to try and help me prevent recurrence. I settled on Exagus and started using it in the build up to Badminton Horse Trials 2 years ago (alongside pharmaceutical treatment) to help treat his grade 3 ulcers which resolved incredibly rapidly, so we cautiously stopped medication and kept him on Exagus alone. It was amazing (and a great relief) to see him continue to gain condition and keep up his brilliant appetite and performance on the Exagus, repeat gastroscopy 3 months later confirmed no recurrence of ulceration despite a very busy eventing season and no further treatment.

For the last 18 months I have used Exagus consistently and have had no recurrence of any gastric ulceration; it's a great to have him feeling so well without having to resort to pharmaceutical medication – he has a great appetite, has needed less hard feed this year, is in the best condition ever and certainly feels amazing in his work.

I use the Exagus pellets on a daily basis throughout the eventing season and when we go to competitions I substitute the morning Exagus pellets for the Exagus paste to give us that bit extra protection (from the Slippery Elm) and to be sure he is covered as the excitement of an event often prevents him eating his morning feed!!
We are very much looking forward to Badminton 2021 and Exagus will be an essential part of his daily feed both at home and at competitions.

Katie Preston BVSc, MRCVS