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
|Feed||Protein (%)||Fat (%)||Crude Fiber (%)||Calculated Starch & Sugar||Estimated Digestible Energy (Mcal/lb)|
|Example Grain Pellet||12||6||8||8|
“The ideal diet is a pasture diet where the horse is eating small amounts of grass throughout the day, chewing the whole time and digesting slowly,” said Martin. “However, in the life of the modern performance horse, constant pasture turnout is not always possible. Free choice hay and limited fasting periods between meals—frequent concentrate meals if needed—are important.”
There is also strong evidence that feeding alfalfa hay, even as a part of the hay ration, will help avoid gastric ulcers. Alfalfa contains higher levels of protein and calcium, both of which buffer gastric acid. Also, the cell wall of alfalfa contains certain indigestible compounds such as lignin that gives it a greater buffering capacity than grasses.
Managing The Hot And Hard Keepers
While ulcer management seems fairly straightforward for your average horse, it becomes a little trickier for the high-anxiety horses or hard keepers . How do you provide the appropriate combination of calories without contributing to ulcer formation?
“Maximizing the fat content of the ration can offer cooler calories to the horse that has a lot of energy but also suffers from gastric ulcers,” said Martin. “Again, feed hay as frequently as possible and choose a concentrate that maximizes energy sources such as fat and fiber. There are many good quality beet pulp-based, high fat feeds available today that are ideal for the ‘hot’ horse that needs calories beyond just hay.”
Similarly, when you’re managing a hard keeper, it’s essential to maximize calories from fiber and fat. Adding fat is an easy way to boost calories in a horse’s concentrated ration, and ounce for ounce, fat provides more energy than grains.
“Switching to a high-fat feed or replacing part of the grain measure with a cup or two of vegetable oil will significantly increase energy intake,” said Martin. “One of the easiest and most palatable ways to introduce extra fat is by adding up to two pounds of rice bran to the grain ration. Rice bran products such can safely be fed to a wide range of horses, and feeding rice bran does not overload the digestive system with carbohydrates.”
Martin recommends a feed that has 8-12 percent fat and a beet pulp portion of 15-20 percent as a good choice to encourage weight gain without exacerbating ulcer conditions.
What About All Those Ulcer Medications?
Ulcer medications fall into four categories—proton pump inhibitors, H-2 blockers, sucralfate and antacids—and while all of them are effective, they are not necessarily a cure.
“There is definitely a place for ulcer medications, but long term use, particularly of acid pump inhibitors, is not recommended if we can avoid it and use feed and management,” said Cubitt. “Acid is produced in the stomach for a reason. It is the second (teeth are the first) line of breakdown of food so that it can pass through into the rest of the digestive tract and be digested further and absorbed accordingly. Ulcer medications block acid production, which is necessary in some cases in the short term so that we can heal the stomach lining, but long term I think they are interfering with the natural digestive process.”
A Universal Problem
While there are no particular breeds that are more susceptible to ulcers than others, any horse that has a nervous disposition or operates in a high-stress environment is prone to EGUS. Some researchers estimate that 93 percent of racehorses have ulcers, and 63 percent of non-racing performance horses develop ulcers during their careers.
“It is hard to rule out one feed ingredient that a horse with ulcers should never have,” said Martin. “Preventing and treating ulcers is a process of managing the different risk factors that a performance horse experiences while allowing them to maintain an active performance career.”