Q. In an attempt to reduce my horse’s risk of developing gastric ulcers, I feed a supplement that is a stomach buffer twice a day with meals and before I ride. Is there any risk to my horse of doing this every day?

A. Horses are at risk of developing gastric ulcers in part because they constantly secrete stomach acid. This is different than you and I, who secrete acid in response to meals. The horse’s continuous acid secretion results from horses evolving to eat almost constantly around the clock. In their natural setting where they are consuming lots of fibrous, mostly low-nutritional-value forage, horses need to eat most of the day and night to consume enough calories to maintain condition.

As horses eat, they secrete saliva in addition to stomach acid. Their saliva contains sodium bicarbonate, which acts as a buffer, helping reduce stomach acidity. In a natural setting or when horses are allowed to consume unlimited forage, this system works very well. The constant chewing results in constant release of buffered saliva to balance the acidity of the constantly secreted stomach acid. The forage itself can also act as a buffer, helping raise pH.

When horses receive diets low in forage or don’t eat constantly but instead are meal-fed, periods pass when the constantly secreted stomach acid is not being as well-buffered. This can result in the stomach becoming increasingly acidic and increases the risk of gastric tissue ulceration.

What Is a Stomach Acid Buffer?

Buffers are substances able to resist pH changes by absorbing both acid and alkaline ions. A buffer can resist pH change and maintain the solution’s pH but is consumed in doing so, meaning it doesn’t last forever. As long as the buffer is not completely reacted, the pH will not change dramatically. As the buffer is depleted, the pH may go up or down more rapidly.

The product you are giving your horse is helping maintain a less acidic environment for as long as it’s not depleted. It is not stopping acid production; rather, it’s helping neutralize the acid being produced. The market offers a good number of buffering type supplements, and some are more effective and longer lasting than others. Research has shown that alfalfa hay has buffering capacity and might help horses at risk of ulcers. More recently, seaweed-derived calcium has been shown to be an effective buffer.

Take-Home Message

Because buffers aren’t effective for more than a few hours at most, the best use for them is to help short-term buffering around feed times when diets containing starch might make the stomach more acidic, as well as prior to riding, especially if several hours have passed since the horse last ate. Because their action is relatively short-lived and most are made from fairly common feed ingredients, there shouldn’t be any negative consequence of using them long-term. After all, when chewing on unlimited forage the horse is almost constantly buffering his own stomach acid.