For horse owners, diagnosis of gastric ulcers is now as familiar as arthritis and colic, but what does this diagnosis mean for horses long-term? Do horses recover fully from gastric ulcers? What can be done to help prevent recurrence?
Prevalence of gastric ulcers is widespread across the domestic horse population, is not reserved to elite athletes. The term “Gastric Ulcers” is an umbrella for two different problems which can both occur in the stomach of the horse independently of each other, but is not uncommon to see both diseases together.
To be able to prevent a problem, we must first understand how it was caused, and what the risk factors are. Then, we must make changes to avoid these risk factors.
Squamous Ulcers
The cause of squamous ulcers is now well understood, it is the result of acid splash injury. Key risk factors for acid splash injury include high starch diets, low forage diets and intense exercise.
Why?
High starch: The stomach is home to its own microbial population. If starch present in the stomach is broken down by bacteria to make volatile fatty acids, lactate and acetic acid. These acids make the stomach acid more acidic. Traditionally it has been common to feed large volumes of high starch feeds to competition horses. A combination of large meal size, low fibre content and high starch content can result in the gastric juice close to the squamous region being very acidic, with no fibrous matt present to stop it splashing.
Low forage: Horses produce gastric juice 24 hours a day, rather than around meal times like humans. This is because they are designed to eat fibrous food for 16+ hours per day. Diets which are low in forage, or management regimes where access to forage is restricted increase the risk of squamous ulceration as there is less likely to be a fibrous matt in the stomach to stop acid splashing around, plus the pH of the stomach acid is likely to be lower.
Intense exercise: Exercise plays a significant role in the development of squamous ulcers, demonstrated by the incidence of squamous ulcers reducing by almost 50% when horses are taken out of training. Moving at trot and above can cause acid to splash up onto the squamous area. The effect of this can be minimized by ensuring fibre has been eaten (creating a fibrous matt) prior to exercise.
Preventing the recurrence of squamous ulcers
Without diet and management changes squamous ulcers will recur quickly after successful treatment. Dietary starch content should be reduced to as low a level as possible, and meals should be small but frequent where condition needs to be maintained. Allow free access to forage and water at all times. Modify training regimes to reduce hours spent without access- remember travelling and exercising are both times spent without free access. Ensuring fibre intake before exercise to create a fibrous matt in the stomach is important. This can be any form of fibre, the best would be hay or grass, but chaffs are also suitable. Supplementation with antacids can be beneficial at meal times and before intense exercise. Where antacids (Magnesium Hydroxide, Calcium Carbonate, Sodium Bicarbonate) are used in combination with complex polysaccharides (Pectin, Alginate) and Lecithin, it is possible for them to create a soothing, protective alkali gel barrier which coats the sensitive stomach lining. The antacid Magnesium Hydroxide is used in combination with Pectin and Lethicin as well as other ingredients in GastroKind.
Glandular Disease
The risk factors for glandular gastric disease are different from those for squamous ulcers, as is their response to medical treatment which is why it is so important to get an accurate diagnosis (only possible by performing gastroscopy) prior to commencing and then finishing treatment.
The glandular region of the stomach is designed to be in contact with acid 24/7. Therefore, acid is not the primary cause of this disease. It is believed that glandular disease is the result of a breakdown of the normal defence mechanisms that protects the stomach lining from the stomach acid. Frustratingly, the mechanism responsible for this breakdown has not yet been identified.
Although we do not completely understand why the defence mechanism fails, risk factors for the development of glandular disease have been identified.
Exercise: In contrast to squamous ulcers, which increase as the intensity of exercise increases, the prevalence of glandular disease is more variable, implying the risk factors for the disease are more complex than just training. This is supported by the fact that the prevalence of glandular disease decreases in some populations as their competition level increase.
Increased exercise frequency (days worked per week) rather than intensity (how hard the horse is working in a session) increases the risk of glandular disease. This could be because exercising reduces blood flow to the digestive tract, reducing mucus production and the repair of the lining. It is recommended to give horses at risk of glandular disease two consecutive days off training per week.
Experience: It has been found in both showjumpers and polo ponies that the more advanced the horse is, the less likely it will have glandular disease. There are a whole host of reasons which could contribute to this finding. Perhaps the more important point to acknowledge is that less experienced horses are at higher risk of glandular disease and therefore more effort should be made to reduce other risk factors.
Stress: Horses with glandular disease have an increased stress response compared to those without the disease. Whether the increased stress response is as a result of glandular disease, or if a heightened stress response causes the disease is still unknown. What is considered “stressful” will depend on the individual, the stage of their training and familiarity with their lifestyle.
Stress can be both mental and physiological (as a result of exercise). Stress hormones are higher after exercise, but also higher at competitions compared to at home. When considering how to reduce mental stress a sensible place to start for all horses would be the three F’s: Friends, Forage and Freedom.
Diet: The connection between diet and glandular disease is not as straight forward as for squamous ulcers. Increased pasture turnout seems to be associated with a reduced risk of disease, as does feeding less grain. Whether these feeding practices directly influence glandular gastric health, or if they are of benefit because of mental stress reduction still needs to be investigated.
Preventing recurrence of glandular disease
Implementing management changes aimed at reducing both physical and mental stress for the horse is sensible. To a degree this will be individual, based on lifestyle they are accustomed to. The role of diet is not straight forward, but adopting feeding practices advised for squamous ulcers are likely to be beneficial as they increase access to forage/ grazing and reduce dietary starch content.
Nutritional supplementation with protective gel barriers (described above) is also advised for glandular disease. In addition, there is evidence to show horses with glandular disease experience oxidative stress, therefore anti-oxidant support is sensible (Vitamin C, Vitamin E). Lastly, Sea Buckthorn Berry extract has been found to be beneficial for glandular ulcers. It’s benefits are likely to be attributable to antioxidant content and other bioactive substances including flavonoids. Ficus Glomerata is another fruit with exceptionally high levels of natural phenolics, flavonoids, phytosterols and terpenoids and have high antioxidant capacity. Vitamins C and E can be found alongside Ficus Glomerata, Magnesium Hydroxide, Pectin and Lecithin in GastroKind.
For more information on GastroKind and our equine supplement range, click here.
References:
1. Sykes, B.W. and Jokisalo, J.M. (2015), Equine squamous gastric ulcer syndrome (ESGUS). Equine Veterinary Education, 27: 264-268.
2. Tamzali, Y., Marguet, C., Priymenko, N. and Lyazrhi, F. (2011) Prevalence of gastric ulcer syndrome in high-level endurance horses. Equine Vet. J. 43, 141- 144.
3. Pedersen, S.K., Cribb, A.E., Windeyer, M.C., Read, E.K., French, D. and Banse, H.E. (2018), Risk factors for equine glandular and squamous gastric disease in show jumping Warmbloods. Equine Vet J, 50: 747-751.
4. Scheidegger, M. D., Gerber, V., Bruckmaier, R. M., van der Kolk, J. H., Burger, D., & Ramseyer, A. (2017). Increased adrenocortical response to adrenocorticotropic hormone (ACTH) in sport horses with equine glandular gastric disease (EGGD). Veterinary journal 228, 7–12.
5. Banse, H. E., & Andrews, F. M. (2019). Equine glandular gastric disease: prevalence, impact and management strategies. Veterinary medicine (Auckland, N.Z.), 10, 69–76.
6. Andrews, F.M., Larson, C. and Harris, P. (2017), Nutritional management of gastric ulceration. Equine Vet Educ, 29: 45-55.