This is the fourth article in the "Fix It With Feed" series. Check back every Wednesday for more articles on nutrition and how it affects performance.
While the stress of riding and competing is often to blame for the development of ulcers in horses, feed programs are another factor behind Equine Gastric Ulcer Syndrome.
We try to tailor feed programs to provide our horses with everything they need, but maintaining a healthy gut requires more than the right nutrients. Feeding only a few times a day, while easier on us, has been proven to promote the growth of ulcers. One of the easiest ways to fix ulcers with feed is simply to feed more often.
“There are several factors that contribute to the development of gastric ulcers, but dietary management is key,” said Olivia Martin of Performance Feeding Inc. “Limiting fasting periods—keep hay in front of the horse throughout the day if possible, limited feeding of high soluble carbohydrate meals and the inclusion of alfalfa hay as all or part of the horse’s forage ration, along with pasture turnout can help reduce environmental stress and help prevent gastric ulcers.”
Why Are Horses So Ulcer Prone Anyway?
Horses are susceptible to ulcers for several reasons, but the guts of the problem lie in the horse’s stomach structure.
A horse’s stomach is very small compared to the rest of its digestive tract (about four gallons at maximum capacity), and it functions best with small, frequent meals, just as he would eat in the wild. The stomach also has two different sections, the glandular epithelium and the squamous epithelium. The glandular portion contains all the glands that produce the digestive enzymes and other factors that help protect the stomach, and the squamous portion serves as a place to contain food.
One way to think about the glandular epithelium is that it’s the protected section of the stomach. “It has a mucous coating that protects the tissue from acid that is secreted by cells that are also located in this protected region,” explained Tania Cubitt, Ph.D., a nutritionist with Performance Horse Nutrition LLC.
The squamous portion is the unprotected section. “These regions are divided by a line called the margo plicatus. Most gastric (stomach) ulcers are found directly above this line into the non-protected region of the stomach,” continued Cubitt. “Unlike dogs and cats, which secrete acid into their stomach based on a meal response, horses and grazing animals should be constantly nibbling on forages, which would therefore keep a constant supply of food and saliva in the stomach. Therefore, horses secrete acid constantly. If we do not supply forage constantly in the form of pasture or hay, then the acid will build up and splash onto the non-protected region and cause ulcers, or it will simply wear away at the protective coating and cause ulcers.”
Interestingly enough, EGUS is considered a “man-made” disease. Unlike human ulcers, which are associated with the Helicobacter pylori bacterium, EGUS has no correlation with the bacterium, and it has never been found in horses. Instead, ulcers in horses are linked to the way we have forced them to change their natural grazing instincts and disrupted the natural digestive process.
Other Ulcer Factors
- Infrequent, low-roughage/high-concentrate feeding
- Infrequent turnout
- Intensive training
- Increased stress levels
- Overuse of non-steroidal anti-inflammatory drugs. (NSAIDs interrupt the production of prostaglandins, which decreases blood flow to the stomach. NSAIDs can rapidly break down the mucous protective coating in the stomach and therefore leave it open to the acid and in turn ulceration.)
Factoring In Feed Problems
While we know that infrequent feeding is definitely a culprit, there’s also research that suggests a diet high in soluble carbohydrates may contribute to ulcers as well.
“Diets that contain large amounts of cereal grains and low fiber content have a few different detrimental effects,” said Martin. “High carbohydrate/low fiber diets are consumed rapidly, allowing for minimal saliva production and longer periods of time between meals. They also pass through the stomach quickly and leave the stomach environment without any buffer.
“Buffering capacity generally means the ability of a substance to resist changes in pH,” explained Martin. “An example in the horse would be: The pH of horses that have had feed withheld for several hours has been measured to be 2.0 or less. Because of the buffering capacity of hay, horses that received free choice timothy hay for 24 hours had gastric pH readings that were significantly higher than fasted horses.”
Another issue with high carbohydrate/low fiber feeds is that because they pass rapidly through the stomach, large amounts of soluble carbohydrate may reach the hindgut where rapid fermentation may cause colic or even laminitis.
So What Do I Feed?
Since creating a diet that is low in soluble carbohydrates and high in fiber is ideal for ulcer-prone horses, it’s important to decipher just what’s in the feed you’ve chosen. In general, sweet feed, corn, oats and barely top the list as the grains highest in soluble carbohydrates, whereas wheat bran, beet pulp, alfalfa and rice bran contain much lower percentages.
Nutrient Content Of Horse Feeds And Forages