No matter how much Zelda tries to convince me she’s not eating clover, the enormous amount of clover slobber running out of her mouth gives her away. The photo does not even come close to showing how much saliva has been pouring out her mouth. In fact, one of the more serious side effects of excessive salivation from clover is dehydration. A horse can generate 12-15 gallons of saliva daily. That’s one reason why it’s so important to provide horses that might be eating clover with sufficient water.
What causes slobbers?
Excessive salivation most often occurs because horses eat plants that are infected with the fungus Rhizoctonia leguminicola. This fungus grows on legumes of all kinds. The fungus produces slaframine, and it is this mycotoxin that provokes the drooling. The fungus flourishes in cool, wet, and humid conditions — just they type of weather that we’ve been having. A lot of rain and humidity and then bingo, puddles of drool.
The only way to treat slobbers is to remove the cause. Taking your horse off the pasture where the fungus is an issue will resolve the problem quickly. Curly and Zelda are only on pasture for about six hours a day; when they are on the dry lot paddock, they stop drooling. As mentioned above, it’s also important to provide sufficient, clean water. Especially when it’s hot. We also provide supplemental hay, so they never feel that eating the clover is a necessity. Moving your pasture to keep legumes short also helps.
Some horses seem more prone to it than others. Freedom is on the pasture right next to Curly and Zelda. I haven’t seen him drooling at all. Not this year or previous years. Curly drools a lot. This year Zelda is, too.