The veterinary reports don’t lie: Colic is a leading killer of horses, and gastric ulcers are a pernicious problem in equines, too. Small wonder that you’ll find countless products to treat both. But as most veterinarians will tell you, the best treatment for digestive disorders isn’t treatment at all, but prevention. This is especially critical in the winter, when fluctuating temperatures and a lack of adequate nutrients in grass and hay can throw equine tummies into a tizzy. However, before you go investing in a new HVAC system for your barn, read the following. A proactive approach to gut health is easily achievable if you start with a basic understanding of nutrition and barnyard “best practices.” Feed quality forage, watch nutrient levels, and keep stomachs full. When it comes to the equine digestive system, nature really does know best. Horses are designed to graze nearly 24/7, and indeed, near-continuous chewing of forage helps promote gastric health. Why? Because a stomach that is seldom empty is less likely to develop gastric ulcers from the acids it’s constantly producing.

Just ask Mark Holman, DVM, of Boston Equine Associates in Rehoboth, MA. “Because plant material can be hard to break down and digest for nutrients, the food which is ingested must slowly flow through an elongated and complicated digestive tract in the horse,” he explains.

The digestive tract, he says, is like a nutrient-processing factory. It’s responsible for breaking down plant cells, changing their chemical composition, and reformulating them into energy.

“I believe that the most important feeding recommendation to prevent major digestive issues such as colic and gastric ulcers in the average horse is to provide a continuous supply of good quality roughage and forage at all times for the horse to slowly consume,” he continues. “I know this is a very broad statement, but essentially most of us feel that this is the missing link in today’s management practices—especially in competition horses.” The takeaway: Make forage the basis of your horse’s diet—whether in the form of cubes, hay or fresh grass—and ensure that he has as much access to it as possible. You might even consider adding a little alfalfa, which can help prevent gastric ulcers due to its higher level of calcium (a natural buffer) and protein. Keep in mind, however, that not all forage is created equal. Forage provides 50–90% of a horse’s total nutrients, but quality and nutrient levels in hay vary by cutting and decline with maturity. Examine the appearance and smell of your hay and avoid stemmy, less digestible cuttings, which contain less protein and other nutrients. Also, consider testing each hay lot to determine its protein, dietary fiber, and calorie content. Without knowing what’s in your forage, it can be difficult to know which concentrates or supplements your horse needs.

Spread out grain-based meals. Feedstuffs such as oats, corn, and pelleted grains have been fed to horses for ages, but they are not necessary in every equine diet. Some horses simply require a vitamin and mineral supplement to balance their forage. In addition, an overload of such concentrates can lead to the production of volatile fatty acids and lower gastric pH, which in turn damages the stomach lining. 

If a horse requires additional calories to maintain weight due to exercise or reproduction, look for quality commercial feeds that contain more calories from fat rather than from starches and sugar. The amount of protein in the commercial feed you select for your horse should commensurate with his lifestyle. In most cases, 8–12% crude protein is adequate for mature adult horses with a moderate workload. Also, be sure to check each bag for freshness, calculate your horse’s portions by weight rather than volume, and spread his ration into as many small meals as possible (three or more is best).

Exercise, exercise. Whether it’s maximizing your horse’s time in the paddock or pasture, or giving him adequate work in the arena, exercise helps reduce stress levels—especially in stall-bound horses—and keeps things moving along nicely in the gut. That said, truly intensive training can have the opposite effect and make a horse more prone to ulcers and/or colic. The trick is to stay vigilant while ramping up his routine and call your veterinarian at the first sign of a problem. Letting your horse socialize with friendly pasture pals is another way to help him stay relaxed and happy, which is good for his gut. However, make sure that horses that are turned out on pasture can’t ingest sand when grazing, as this can cause a type of colic. 

Stick to a routine. Horses are creatures of habit and any deviation from their established routine can cause stress, which, as we’ve noted, can trigger digestive upset or even colic. Feed and turn out around the same time every day, always provide plenty of fresh water, and be observant about the effects of extremes in weather. If a horse is clipped, for example, make sure that he is blanketed whenever the temperature drops. A sudden change in location or transporting can be stressful, too. So if he is not used to doing either regularly, try to prepare him for these events as gradually as possible. Administration of a probiotic paste (see below) is another way you can help head problems off at the pass. Probiotics, prebiotics, and watch the meds. Healthy gut flora—meaning a balanced population of microbes to aid proper digestion—is vital to your horse’s health. Unfortunately, stress and drugs like antibiotics can disrupt this balance, resulting in weight loss, diarrhea, or even colic. This is where supplements containing probiotics—live microorganisms that replenish and maintain healthy gut flora—can be useful. Many of these supplements also contain prebiotics to help feed beneficial bacteria and rid your horse’s system of pathogens. It’s especially helpful to give probiotics—which can be obtained in oral paste form—when administering antibiotics or preparing a horse for a stressful event, such as shipping. Speaking of medications, nonsteroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone can also have an adverse effect on your horse’s gastrointestinal tract. If given in large doses or over a long period of time, such as with older, arthritic horses, they can damage the stomach lining and increase the predisposition to ulcers. As with any change in your horse’s routine, you’ll need to keep an eye out for stomach discomfort and keep your veterinarian on speed dial. So, you see, a little common sense can go a long way toward keeping your horse’s tummy happy.