It’s Slobber Season for Horses! - Kentucky Equine Research (2024)

September 16, 2014January 11, 2018By Kentucky Equine Research Staff

As you walk out into the pasture to catch your horse, you notice that the clover in the field is really growing well. You know that horses love clover, and it’s clear that there is plenty of the trefoil-leaved plant for Blaze to nibble.

You snap the lead shank on his halter, and Blaze reaches for the treat you always bring him. He opens his mouth and suddenly your carrot-bearing hand is drenched with what seems like an ocean of equine saliva. Blaze crunches happily away on his carrot as you lead him toward the barn, still wiping strings of drool off your hand and wrist. What’s going on?

In spring and summer, pastured horses frequently get what’s known as “a case of the slobbers.” Owners might notice the unpleasant phenomenon as they feed treats or ask the horse to open its mouth to accept the bit. This excessive salivation usually results from horses eating clover infected with Rhizoctonia leguminicola fungus. The fungus produces slaframine, an irritant that makes horses salivate heavily. Unless it’s excessive, this overproduction of saliva isn’t harmful, and will disappear as the clover becomes dormant. Property managers can mow clover fields often to diminish the problem, as clover plants tend to harbor lower levels of the fungus as they regrow.

While slaframine ingestion is the most common culprit when horses get slobbers, it’s not the only reason for excessive salivation. Owners of drooling horses should check to be sure that there is no foreign substance (weed seeds, feed particles, tree bark, twigs) lodged around or between the horse’s teeth. Injuries to the tongue or gums could also cause some salivation. These situations usually won’t produce the same impressive flood of slobber as slaframine, but they can be very uncomfortable for the horse and should be resolved.