Nothing To Spit At: Saliva Is the Most Natural of Stomach Buffers in Horses

Saliva is a critical component of the equine digestive process. Unlike other species, its importance does not stem from any enzymatic mechanism. Rather, equine saliva has two prime functions, to act as a slickening agent for chewed feed as it passes through the esophagus, and to buffer the contents of the stomach.

Produced by three salivary glands, the largest of which is called the parotid and lies beneath the horse’s ear, saliva is estimated to be about 99% water, and it is relatively high in calcium and chloride when compared with saliva from other species.

Daily saliva output depends primarily on the size and composition of meals. Horses will produce more saliva to chew a mouthful of dry hay than a mouthful of moisture-rich grass. Mature horses may secrete 9 to 11 gallons (35 to 40 liters) of saliva each day. With this in mind, it is not difficult to see why horses must drink so much water for optimal health.

The beneficial effect of saliva on the pH of the stomach is well documented. Buffering the gastric contents keeps the stomach from becoming too acidic, which can create an environment ripe for ulcer formation. Gastric ulcers can negatively affect disposition and performance.

One way to maximize the effect of saliva as a natural buffering agent and sidestep gastric ulcers is to offer horses free-choice access to forage. Individual body condition and metabolism dictate the quality of the forage fed, though mature horses should consume 1 to 2% of their body weight in forage per day.

For lean hard keepers, access to high-quality forage rich in calories might be warranted to maintain weight or achieve an upswing in body condition. On the opposite end of the spectrum, roly-poly easy keepers should be limited to less nutritious forage. Regardless of body type and metabolic rate, the continual passage of saliva-coated forage through the stomach will help keep the stomach healthy.