The commonly-used snaffle bit exerts a downward force on the tongue, preventing swallowing when rein contact is being taken rather than pushing up into the roof of the mouth as is traditionally believed (see illustration). Obedient horses who can tolerate the tongue pressure will basically keep their heads in the correct “frame” or position for the sport you choose with only minor moves to swallow. Horses ridden with a loose rein will be able to swallow in any bit since there is no pressure on the tongue other than the weight of the bit. Most horses will try to escape the tongue pressure by either putting their noses up in the air or ducking “behind the bit” in order to swallow.
Bits with a port or curved mouthpiece can be much more comfortable and offer relief to the tongue.
The following links are to articles (pdf format) detailing research on bits and bitting done by Dr. Hilary Clayton:
Bitting: The Inside Story (pt 1)
The above articles include x-rays and stills from flouroscopy that show bit position in a horse’s mouth.
[ I am not speaking out against bits or bitting, but I feel there is good information here that anyone involved with horses should consider and might want to be aware of. I myself ride my horse in a very fat eggbutt snaffle and she is very soft-mouthed and has no issue with the bit. ]
Thrush in Your Horse’s Hoof - Thrush can develop right under our noses … literally! Fortunately, it’s usually easily treated and managed. The worst thing you can do is ignore it, as serious thrush infections can cause injury and lameness. But fear not! You can head it off … at the frog.
WHAT IS THRUSH?
Most of us recognize thrush as a smelly infection that eats away at the frog, especially down in the cracks called the sulci. When we sink our hoof picks into a thrush-infected crack, we drag out black, gooey, stinky crud. It can seem like there’s just no end to it! In some cases, the frog itself peels away, too.
Thrush predominantly occurs because of a nasty group of bacteria called anaerobes, and it can quickly appear on all four feet. Anaerobic bacteria grow in environments with little-to-no oxygen, like deep in the sulci, the crevices of the frog.
There can be dozens of different species of anaerobe involved in a thrush community, but predominantly we find a nasty little stinker named Fusobacterium necrophorum. In addition to bacteria, thrush has a fungal component. Fungi are hearty bugs that can be difficult to kill. They love environments that are moist with little air.