As many farriers are well aware, there are times when a horse drools excessively. While many believe that clover is the culprit, they are partially correct.
A specific fungus, Rhizoctonia leguminicola, affects many varieties of red clover. This fungus produces an alkaloid called slaframine. Also called black patch disease, the fungal infection is visible on leaves as small dark blotches. Usually, the undersides of leaves are affected first, and then the fungus spreads to other parts of the plant. The fungus thrives in moist, humid environments. Experiencing a rainy summer? Be on the lookout for diseased red clover.
The most widespread sign of slaframine ingestion in horses is hypersalivation.
“As long as horses have access to a clean water source, there will likely be no other notable side effects of slaframine intake,” says Kathleen Crandell, PhD, a nutritionist with Kentucky Equine Research. “If, on the other hand, a horse does not have access to water, dehydration might sneak up on a horse that is producing and spilling excessive saliva, especially in hot, humid climates.”