What do we really know about equine gastric ulcers? For horse caretakers and their veterinarians, gastric ulcers are all too familiar, yet not very well understood.
What are Gastric Ulcers…really?
Gastric ulcers are simply lesions (damaged areas) on the inside surface of the stomach
Technically speaking this condition is more accurately described are "Equine Gastric Ulcer Syndrome" or EGUS. The key word is "syndrome"- is the case, a set of health issues that cause stomach lesions. Put another way, ulcers themselves are really a symptom of an underlying pathology. It's underlying disease that remains more of a mystery.
The Horse's Stomach
The horse’s stomach is divided into two regions. The lower two-thirds is known as the “glandular” region (after the glands that exist there to secrete acid and enzymes for digestion). The glandular region of the stomach is coated with a thick layer of mucus that protects it from stomach acid. The upper one-third, called the “squamous” region, is less protected. The two sections of the stomach are divided by a visible line called the margo plicatus, and it’s here that ulcers are often found.
What is the Cause?
Any horse, no matter their breed, age, sex or level of exercise, can have ulcers, performance animals are particularly prone. This is because stress of any type - due to transport, changes to routine, stall confinement. Studies even show that stress from strenuous exercise itself not only increases the production of stomach acid but movement causes the aid to splash up into the vulnerable upper stomach.
Twice-a-day feeding, limited grazing and high carbohydrate rations can also exacerbate the possibility of ulcer development.
Horses are designed to eat fibrous plants, not grains full of sugar and starches. Grain-based feeds increase production of a hormone called gastrin that stimulates the stomach to produce acid. Combined with a the fact that these feeds are quickly consumed, means less acid neutralizing saliva to protect the stomach.
According to the most up-to-date consensus statement on gastric ulcers, the development of ulcers appears to be most frequently reported in performance horses that are actively training or competing.
That study reported the following statistics:
Only 37% of untrained Thoroughbreds have ulcers, but that rate increases to 80-100% within 2-3 months of training;
About 44% of untrained Standardbred racehorses have ulcers, which increases to 87% during training/racing;
Only 48% of endurance horses have ulcers during the off-season; however, 66-93% develop ulcers during the competitive period;
Up to 58% of show/sport and pleasure horses have ulcers; and
Horses kept at home and that rarely compete only have a prevalence of 11%.
Therefore, despite the availability of FDA-approved omeprazole products for horses, gastric ulcers continue to plague the delicate lining of the equine stomach.
Ulcer Prevention and Non-Medical Management
While the only FDA-approved medication for the resolution of ulcers is omeprazole, there are ways to help manage the condition through diet.
Allow horses to live as natural a life as possible. Offer access to forage 24-7 to mimic a horse's natural feeding pattern. Reduce or eliminate grains and concentrates. If you must feed grain, feed four or more small meals a day. Ensure the stomach has some forage in it before exercise to help absorb stomach acid. Switching to a forage cube offers less volume and digest easier and quicker.
While gastric ulcers are a common and recognized condition in horses, it seems the more we learn about them, the more our beliefs are challenged. Much remains to be studied before we truly understand this issue. In the meantime, taking steps to mitigate the risks of ulcers may be the best you can do to protect your horse.