Q: My horse is drooling heavily. He seems normal in every other way, but when he stands on cross ties, a puddle forms around his feet. It is disgusting! What is wrong?

A: It sounds like your horse is suffering from a condition commonly known as Slobbers. It is from eating clover that is infected with a fungus called blackpatch (Rhizoctonia leguminicola). Blackpatch produces a toxin called slaframine that causes excessive frothy salivation in horses. The slaframine toxin can be present in either pasture clover or stored hay. Because blackpatch infects all parts of the clover plant, mowing does not lessen the problem, and the fungus persists on infected fields from year to year. Fungal growth is heavier after cool rainy weather and is usually worse in late spring and early fall. Drooling begins within 1-3 hours of consumption of the toxin and will continue for 2-3 days after the contaminated forage is withdrawn. Slobbers is very messy to deal with, but is not a threat to your horse.

Slaframine toxicosis causes no other signs than drooling, so if your horse is off feed, fusses with the bit, has inflamed lips or gums, or shows any other abnormal symptom, your veterinarian should be called for an examination. It is something other than Slobbers.