Stress and Gastrointestinal Ulcers
Horses are emotional creatures, maybe that’s why we connect to them so strongly. They let us escape our personal life challenges by demanding our undivided attention. We in turn sometimes need to become psychiatrists on their behalf. The adage that “it’s not what life throws at you but how you handle it that counts” is true when talking about stress in humans and horses.
Biological stress is the body’s reaction to external (environmental) and internal (psychological) conditions. Stressful conditions affect us in positive and negative ways, from the adaptive stress of training to the debilitating stress of constant anxiety. Stressors can be anything that upsets mental or physical homeostasis. When balance is disrupted the body responds with immediate activation of the autonomic nervous system. The two main components of the ANS, the sympathetic (fight or flight) and the parasympathetic (rest and digest) mechanisms work in concert to appropriately react to the stress and then re-establish balance. Since life continually presents stimuli that knock us off kilter, the stress response is a primary biological coping mechanism for staying alive.
In horses there is a well established link between stress and gastrointestinal ulcers. Studies suggest that 50% to 90% of horses in sport may have stomach ulcers, but GI ulcers can affect any age or any breed. The stress response kicks into gear complicated reactions that include nervous, endocrine and immune processes within the body. All of these vital functions affect the GI tract in different ways, from increased acid production to decreased wound healing. Anatomy of the equine GI tract may also contribute to development of ulcers. For example, the horse was designed to eat small amounts of food throughout the day so its stomach is relatively small and sees a constant secretion of acid. Modern husbandry practices often leave the horse’s stomach empty for long periods with no feed or saliva to buffer the 24/7 flow of acid. High carbohydrate feeds produce volatile fatty acids that also contribute to ulcer formation. Exercise itself increases gastric acid secretion and especially on an empty stomach, may cause a “splash effect” where fluid contacts upper segments of the stomach not designed to withstand exposure to strong acid. An external factor that also increases the risk of developing gastric ulcers is treatment with NSAIDs (non steroidal anti inflammatory drugs) such as phenylbutazone (bute) or flunixin meglumine (banamine).
Psychological stress factors are high on the list of contributing causes of ulcer formation in all animals. Sometimes stressors are obvious and often they are not. Obviously, performance horses experience more disruption to their daily schedules than horses that stay home. Training itself requires fine tuning to produce enough good stress to improve performance but not enough to cause distress. Not so obviously, every horse responds differently to the pressures of life and their personality may significantly impact their body’s response to stress. Keeping in mind the emotional nature of our horses, it’s incredibly important to know your animal and pay careful attention to their moods and responses to daily living. It’s often a change in the usual attitude, reactions and performance of an individual, rather than their baseline personality, that signals a problem with GI ulceration.
Clinical signs of ulcers in horses range from seemingly normal, to subtle behavioral changes, mild signs of discomfort, to intermittent colic. A definitive diagnosis of gastric ulceration can only be obtained by gastroscopy, the insertion of a flexible fiberoptic gastroscope through the nose and into the stomach where tissue damage can be directly visualized. Gastroscopy is a relatively straightforward procedure that we perform at 3H Veterinary Hospital providing valuable information for effective treatment and subsequent management of GI ulcers.
With such a high incidence of this disease, it’s likely that your performance horse (or any horse) will experience GI ulcers sometime in their life, so how can we help them? We can start with feeding and nutritional management; giving small meals at frequent intervals or free choice grass hay, minimizing high carbohydrate diets, feeding alfalfa hay prior to work (its high levels of calcium increases buffering capacity and decreases the “splash” effect of acid in an empty stomach). Keeping a training journal can be helpful to chronicle changes in attitude and performance that may signal more than just a bad mood or estrous cycle. It’s impossible to eliminate stress from our lives, but we can manage its consequences to some degree. The drug omeprazole which stops gastric acid secretion has proven efficacy for the treatment of ulcers in horses and also as a prophylactic to decrease their formation. Omeprazole is available as a paste in formulations geared to treatment (Gastroguard) and to prevention (Ulcerguard) of ulcers. While the drug is relatively expensive, be aware that other brands and formulations that sell at cheaper prices have been shown to have less efficacy.
Remember that stress linked disease IS manageable. One of these days we will be back in the show ring with our horses, so take advantage of this extra time to contact 3H Equine Hospital (919) 363-1686 and discuss possibilities for diagnosis, prevention and treatment of gastric ulcers in your horse.