10/17/2022
TRY THIS EXPERIMENT....
I want you to try an experiment.
Put about 200-500 ml of water in a container. Then add a sq**rt of liquid detergent into the water. Get a spoon or whisk and gently stir the solution. Slow and steady like you were stroking a cat on your lap. Notice if any foam is formed by your gentle stirring. If there is no foam, gradually increase the energy of your stirring. Incrementally increase the energy and the agitation of the whisk/spoon until you start to see bubbles forming. Note the difference in the amount of energy you used when you first started to gently stir the water solution to the energy required to create foam.
In the horse world, in particular, the dressage world, when foam appears from the horse’s mouth it is considered a good thing. It is believed to be a sign of a soft, relaxed, mobile jaw. It is sometimes called a “happy mouth” and a positive sign of a horse “seeking” the bit or “accepting” the bit. Tension can often result in a locked and tense jaw in a horse, so if the jaw is not locked or super tight it is very often assumed the horse is relaxed or at least more relaxed.
There can be disease factors that lead to the production of foam in the mouth (eg, rabies), but for the purposes of this essay I’ll stick to the role of training and riding.
However, before I go on, let’s look at the causes of foaming from a horse’s mouth.
Foam around the lips or dripping from the mouth is the result of two things occurring simultaneously.
Foam is simply saliva with bubbles in it. Creating the bubbles requires the saliva to be mixed with air. In fact, it takes a lot of air because foam is approximately air and only a small fraction is saliva. So the first factor necessary to create foam is a mechanism to mix air into the saliva.
The second factor is swallowing. Creating foam requires a pool of saliva in the mouth. But when a horse swallows, the mouth is emptied of saliva. When a horse swallows all that is left is a coating of saliva over the tongue, teeth, palate, epiglottis, gums, inner lips surface, etc to prevent dryness in the mouth. But there is no pool of saliva until more is secreted into the mouth, which in turn is whisked away when the horse next swallows.
The formation of foam requires a pool of saliva to be mixed with air. So foam from the mouth requires the swallowing reflex to be inhibited enough to allow a pool of saliva to build up. That pool of saliva is then mixed with air by the action of the tongue rolling around, much like the spoon or whisk in our experiment.
If we look a little more closely at the claim that foam created in a horse’s mouth is a positive sign of relaxation, how does that gel with the logic?
Our experiment indicates that a gentle and relaxed swirling of the solution does not create foam. Instead, it takes some vigorous agitation to mix enough air into the solution to cause bubbles to form. If your horse was swirling its tongue with the same energy you had to swirl the whisk in the container of water/detergent to create some foam, would you consider that a relaxed tongue?
I am puzzled how a tongue rolling around with enough energy to create bubbles in a horse’s mouth is a sign of relaxation and acceptance of the bit or rein contact. In fact, when I have seen horses exhibit that response there are always plenty of other indicators to tell me the horse carries considerable anxiety and resistance.
Secondly, how can an inhibition of the swallow reflex be an indication of an emotionally comfortable horse? I don’t know of any circumstance where relaxation turns off the swallow reflex. For that to happen, the production of saliva would also need to be inhibited. But we know that in the case of foam build up in a horse’s mouth, saliva is present and being released into the mouth.
So the question begs, what is the logic that the inhibition of the swallowing reflex and a busy tongue are indicators of a horse’s quiet emotions and relaxed jaw? I have never seen foam in the mouth of a horse with a quiet mind and a relaxed mouth while being worked.
When I see a horse being worked with foam around the lips or dripping from the mouth I see a horse in trouble.
