Gastric ulcers are erosions of the stomach lining caused by gastric acid. It is estimated that 50 to 90 percent of domestic horses have ulcers. They can develop in as little as 24 hours and recur in 24 hours respectively. The pain is stressful which can further exacerbate ulcers. The most common causes of gastric ulcers are lack of forage and stress. Thankfully, as owners, we have some control over both causes.
Read on to learn how and why gastric acid causes ulcers - and what you can do to help prevent ulcers from occurring.
Understanding the Equine Stomach
The equine stomach is divided into two regions - 1) the lower (glandular) portion, and 2) the upper (non-glandular) portion. Ulcers can develop in either region.
The lower portion produces gastric acid - and mucus - which helps to buffer the acid. The upper portion has squamous epithelium – similar to our skin - which offers no protection, making it even more susceptible to damage by gastric acid.
Horses Produce Gastric Acid 24/7 - Saliva is Key to Buffering
Equines produce gastric acid 24/7 in preparation for constant food uptake. Why? Physically and mentally they are designed to have access to forage 24/7! Chewing activates saliva production (an alkaline substance), which buffers the gastric acid. It's a perfect balance if we follow nature's design.
In nature, horses will voluntarily take breaks to sleep and rest for periods of time, typically no longer than an hour. In domestication, involuntary periods of time without forage can be physically painful and mentally stressful. Mental and physical experiences are synonymous in that each has an influence on the other.
According to Martine Hausberger, PhD, director of the Laboratory of Animal and Human Ethology, a branch of the French national research center (CNRS) and the University of Rennes, “It is well-known that horses are trickle feeders that would naturally consume a semicontinuous supply of forage for 40-70% of each 24-hour period....It is also known that horses can experience gastrointestinal discomfort if deprived of food for a mere one to two hours.”
Gastric Acid Build Up - The Math
If we assume the stomach empties in 1 hour - with a 3 gallon capacity - the gastric acid can reach the upper half of the stomach (1 1/2 gallons) in a little over 2 hours.
In addition, the pH of the acid is not being reduced by saliva (rich in bicarbonate) because 1) the horse is without forage, and 2) without chewing, there is no saliva production. Due to this fact alone, equines were not designed to be deprived of forage long enough for the gastric acid to reach the unprotected upper portion of the stomach, if stationary.
Movement (without Adequate Fiber) Doubles the Equation
Movement can cause splashing of acid (learn more about why you need to be careful exercising your horse on an empty stomach), which effectively bathes the upper portion - unless it has fiber creating a protective mat of sorts combined with the reduction of pH from saliva . If the stomach lacks fiber, acid can splash the upper region regardless of how long it's been empty.
What Ulcers Look Like
How to Prevent Gastric Ulcers
Minimize stressful situations, which can include:
If you suspect your horse has ulcers, consult your veterinarian. Prevention is key. Unfortunately, ulcers have the potential to develop in just 24 hours.
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Monique Warren is the owner of Hay Pillow Inc.