Gastric ulcers are a very common condition in horses (with an estimated prevalence between 50 and 90%), especially in performance horses or those subjected to frequent stress (Young, 2019). The specific anatomy of the equine stomach, combined with dietary, behavioral, and environmental factors, makes these animals vulnerable to developing this disease. Fortunately, in recent years, particular attention has been paid to prevention and early diagnosis, as well as the use of alternative remedies for the treatment of peptic ulcers.
In this article, we will provide an overview of gastric ulcers in horses, focusing on the use of aloe vera as a therapeutic and preventative aid.
Horse Stomach Anatomy and Development of Peptic Ulcers:
The horse's stomach, a relatively small organ, is lined internally by two mucosal layers: the glandular mucosa and the non-glandular mucosa, separated by a transitional band called the margo plicatus. The non-glandular mucosa, which lines the upper part of the stomach, is particularly vulnerable to gastric acid, as it is not protected by mucus and bicarbonate secretion as the glandular mucosa (Ellis, 2020). Gastric ulcers in horses are primarily caused by acid hypersecretion, most often caused by inadequate exercise and dietary management, stress, and/or uncontrolled use of non-steroidal anti-inflammatory drugs (NSAIDs). The condition is prevalent in athletic horses, which are subjected to high levels of physical and psychological stress.
Gastric ulcers most frequently form in the non-glandular mucosa and are generally classified into four grades of severity based on anatomical location and extent. Grade I is characterized by hyperkeratotic changes in the mucosa, but without erosion; grade II presents with small, single or multiple ulcerations along the mucosa; grade III, on the other hand, is characterized by large ulcers, which may be single, multiple, or even extend across a large portion of the mucosa. Finally, when ulcers are deep and/or bleeding, they are defined as grade 4 (Sykes et al, 2015).
Diagnosis
The gold standard for diagnosing gastric ulcers in horses is gastroscopy, which allows direct observation of the lesions in the mucosa. However, there are some warning signs of ulceration, some more or less nonspecific. Although associated clinical signs are not always present (they are closely related to the degree of ulceration and the individual's sensitivity), we know that the most common are:
- Reduction of appetite
- Occasional or recurrent colic
- Nervousness and restlessness (e.g., owner reports aggressive behavior when tightening girth)
- Weight loss despite adequate nutrition (Young, 2019).
If one or more of these signs are present, it's best to contact your veterinarian, who will evaluate your horse's physical condition. Early diagnosis is essential to prevent ulcers from developing into more serious conditions, which can cause pain and compromise the animal's health and athletic performance.
Treatment and prevention
Treatment and prevention of gastric ulcers in horses is based on:
· Suppression/management of any stressors
- Pharmacological treatments
- Nutritional management
- Reduction of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
1 - Management of the individual and stressors
It is crucial to assess whether there are any particular stressors in the animal's daily management (e.g., the presence of other dominant animals in the same living space as the individual or, conversely, a complete lack of others with which to interact; excessive working hours; frequent transport; little or no access to fresh air, etc.). Equally important is avoiding working the animal on an empty stomach: to prevent gastric juices from damaging the non-glandular mucosa during work due to the upward movement, it is strongly recommended to feed good-quality forage beforehand (NOT concentrated feed, which, on the contrary, increases acid secretion). The frequency with which hay is fed is also crucial, as, ideally, it should be available to the animal 24/7.
2 - Drugs
Proton pump inhibitors (PPIs), such as omeprazole, are the gold standard for treating gastric ulcers in horses. These drugs reduce gastric acid secretion by inhibiting the H+/K+ ATPase enzyme, promoting healing of the damaged mucosa.
- Antacids (Sodium Bicarbonate, Aluminum Hydroxide, Magnesium Hydroxide, Sodium Alginate) which act on acid secretion with a “buffer” effect;
- H2 receptor antagonists (such as ranitidine and cimetidine) prevent histamine from binding to its receptors in the stomach, thus inhibiting the production of gastric acid;
- Mucosal protectors (Sucralfate): act mechanically by creating a protective film on the damaged mucosa, protecting it from gastric acids.
3 - Nutritional modifications
A high-fiber diet, including frequent and abundant feedings of hay, is essential for protecting the gastric mucosa. Fiber stimulates saliva production, which neutralizes gastric acids and helps maintain a balanced pH. Equally important is not to feed excessive amounts of concentrates, especially if not preceded by hay.
3 - NSAID reduction
The most commonly used nonsteroidal anti-inflammatory drugs (NSAIDs) in horses are nonselective inhibitors of cyclooxygenase (COX 1 and 2), an enzyme involved in the synthesis of prostaglandins, molecules involved in numerous physiological processes, including the protection of the gastric mucosa. Inhibition of COX 1, therefore, inhibits the production of prostaglandins, exposing the stomach to irritation that can lead to the development of peptic ulcers. Restricting the use of NSAIDs to limited circumstances, therefore, is of fundamental importance (Van den Boom, 2022).
Use of Aloe Vera in treatment
and prevention of gastric ulcers
In recent years, there has been much discussion about the beneficial properties of Aloe vera. But what role does this much-maligned plant play in the horse's gastrointestinal tract?
Several components of aloe are beneficial for digestive health, including soluble polysaccharides, which are large, gel-like compounds composed of sugar molecules. The most studied polysaccharide for this mechanism is acemanno, a polysaccharide that has been shown in various studies to support wound healing by stimulating immune system cells to accelerate the healing process.
The role of acemannus, however, doesn't end there: its mechanism of protection against infections has also been studied, as it binds to macrophages (white blood cells), removing any pathogens. Furthermore, upon contact with the cells lining the digestive tract, acemannus can improve calcium absorption in cells, where calcium ions are important for activating stem cells, which are necessary to replace damaged tissue.
As previously mentioned, prostaglandins are known to play an important role in protecting and repairing the gastric mucosa. In fact, aloe vera, through acemannan, also affects prostaglandin E2, which is involved in this very repair mechanism. This mechanism of action is as follows: acemannan induces the expression of vascular endothelial growth factor (VEGF), which is important for maintaining blood vessels that supply nutrients to the affected area and remove waste products. This growth factor also increases the production of prostaglandin E2, which, as previously mentioned, promotes gastric ulcer healing.
Other beneficial effects of aloe vera not directly related to gastric ulcer (but which indirectly influence it) are provided by its antioxidant, antimicrobial and prebiotic activities (Darani, 2022).
Conclusions
Gastric ulcers are a significant problem for horses, but they can be effectively treated with a combination of medications, dietary modifications, and natural remedies such as aloe vera. The latter offers an attractive alternative for the complementary treatment of gastric ulcers, thanks to its healing and protective properties. It is essential, however, that treatment be supervised by an experienced veterinarian to ensure its safety and effectiveness.
By:
Anna De Leo Ratti • Veterinarian
BIBLIOGRAPHY:
Darani, P. (2022). Aloe vera for gastric ulcers in horses. Does it really work? https://madbarn.com/aloe-vera-for-horses-with-ulcers/?srsltid=AfmBOoo1zs1lrXSfOFbspVfNlq9SIuw2AYVoJC0VirWyBz4OhEwhVmvI
Ellis, C. (2020). Gastroscopy. Horse & Pony magazine.
Sykes, B. W., Hewetson, M., Hepburn, R. J., Luthersson, N., & Tamzali, Y. (2015). Equine Gastric Ulcer Syndrome in Adult Horses. Wiley. 10.1111/jvim.13578
Van Den Boom, R. (2022). Equine gastric ulcer syndrome in adult horses. The Veterinary Journal, 283-284 10.1016/j.tvjl.2022.105830
Young, A. (2019). Equine Gastric Ulcer Syndrome . https://ceh.vetmed.ucdavis.edu/health-topics/equine-gastric-ulcer-syndrome.
