Radiographic study of bit position within the horse’s mouth

Bits can differ in size, shape and mechanics. This study showed diffference in position within the mouth and the way it acts when pressure is applied. Individual differences like: oral anatomy, position of the lips, interdental space, width of the mandible, shape of the palate and size of the tongue have influence on the experienced comfort level of a bit. Non-fitting bits or improper usage can cause injuries such as mucosal ulcers, osteitis and sequestrum formation.

This study compared the following 6 bit types and made radiographs with and wihtout rein tension (image below).

• Jointed snaffle
• KK Ultra
• Boucher snaffle
• Myler low port comfort snaffle
• Myler ported barrel
• Myler correctional-ported barrel

With no rein tension, single-jointed bits sit further away from the teeth than the Myler bits, however they slide closer tot the teeth when pressure is applied. In contrast the Myler bits stayed more or less in the same position under pressure.The smooth surface of the KK avoid pressure of the palate and might explain why many horses go well in this bit. However under tension the change of the position of the entire bit toward the mandible is remarkeble. The Boucher bit was different to the other bits as the cannons were more elevated. The results suggest that horses which experience discomfort due to the bit, may learn to lean into the bit to relieve palate pressure instead of being unsensitive.

> J. Manfredi et al., Equine and Comparative Exercise Physiology, Volume 2, Issue 03, August 2005, pp 195-201. All rights reserverd to Cambridge University Press 2005 Click here for the full article