I have always wondered about this with dressage horses.
What is it that makes them foam at the mouth when doing advanced dressage?
I'm a western rider and I can't recall ever seeing any strenuous western discipline where the horse's mouth was foaming, even if the horse had foam somewhere else on their body from the hard work.
I would not think it was the rein contact, as the advanced dressage horses have self-carriage, but is there something else? Been watching US Dressage on RFDTV lately, and the recorded episode I watched today made me think of it, as the horse was foaming in his mouth.
I'm not sure it's the same as when horses foam up from sweat. My mare would get some foamy, drooly lips when we had a particularly good ride. Just the horse salivating. Not sure it specifically means something could, but with my mare, it came when she relaxed and "licked and chewed." Posted via Mobile Device
Foaming in the mouth is not due to strenuous anything, and even lower level horses will foam at the mouth.
There should not however be an excess of foam, we want it like lipstick. I'm going to steal Duffy's photo because it illustrates the kind of foam we want!
There can even be more and it is correct, as long as there is not foam flying everywhere!
Basically it shows that the horse has a relaxed jaw and is working into the contact. There should always be a pressure in the reins that is not from the rider pulling, but from the horse stretching into the bit to raise the base of his neck and round from the withers to the poll equally. This of course is caused by the motor behind propelling the horse into a soft contact. But the end result is having a soft jaw and a foamy mouth.
Dry mouths are the result of pulling, or a horse who is not suppled or working into a contact. Most horses ridden without contact will not foam. Horses on a contact that are not foaming are being ridden with hard hands and are hard in the mouth. They are being ridden front to back, with too much hand.
I hope that makes sense!!
The soft jaw allows for increased salivation and as the horse softly chews and moves the bit, air enters into the saliva and foams.
I'd heard that it was caused by digestive issues as well, although my instructor said the same thing as Anebel. Indie sometimes foams at the mouth, plus she tends to flap her lip.. although not as much lately. (we think the lip flapping was stress/nervousness)
Some of our reining horses tend to play with the bit and end up with foam. We find if we are standing waiting for our turn my horse gets bored and will play with his bit or try to grab a rein to keep himself amused.
It is a sign of relaxation.
My baby will foam up when he is working through properly, we have had it dripping down his front before now!
Its a lovely feeling when they relax, it is not so lovely a feeling when they give you a kiss complete with big green foamy slobber