Frequently (and not so frequently) Asked Questions
BRIEF: What could cause these horses to drool?
A woman I know has a pasture that is very dry and weedy. The horses have used this pasture for 7 years without noticed problems, but this year they drool when they are on this pasture. She brings them in to another pasture with grass and clover, and they quit drooling. Puts them back out and they start drooling within 24 hours. Could you give me an insight on the cause of this?
This is a common problem in drought-stricken pastures. Clovers (red and white) which harbor an endophyte fungus (Rhizoctonia) produce a alkaloid (slaframine) which causes the slobbers. This was really a hassle in the the days of draft horses in which workers started every day drenched in drool from putting on all those bridles. If the clover in the other pasture is not affected, then by all means use it. It is possible when that new pasture gets munched down low enough that the horses are eating a lot of clover, then you may see drooling there, too. I see more of this in dry years than wet, oddly enough, maybe because the grass overstory gets eaten away.