TONGUE- TIES, BITS, DEVICES and CROSSOVERS, NOSE BANDS.
My horse SWALLOWED HIS TONGUE and CHOKED on it. This statement is of course totally incorrect. Your horse can choose to withdraw its tongue , extend it, or move it sideways but it is incapable of swallowing it.
Obviously these three actions of extension, lateral movement and retraction are of great assistance in the process of eating. If extended the tongue can be used to coax grasses into the mouth to be incised (cut) and then chewed. Side or lateral movements deposit food between the molars (chewing teeth) and thus assist in mastication (crushing). Retraction assists in the passage of the food to the back of the mouth to be swallowed.
However eating is not something that the horse should be doing whilst racing so why and when does it move its tongue during a race???
1) A young horse may resent the device (bit) which does not naturally lay over its tongue. Thus bit playing and associated tongue movements in newly broken horses should be regarded as a reasonably normal response. If however this habit continues and occurs during gallops or racing then the situation should be reviewed.
2) A horse that hangs its tongue out whilst racing is not regarded as being normal. The horse may however race well. When a horses tongue is extended (hanging out) the base or back of the tongue is invariably flattened. Whilst flattened it is unlikely to push the soft palate up. When the soft palate rises the pharyngeal airway is constricted resulting in reduced air supply. This could then be a desirable trait, except that as the tongue is flattened it may loose contact with the underside of the soft palate and thus allow air into the oropharynx (back of the mouth). With air beneath the soft palate combined with negative inspiratory forces (suction during breathing in) within the nasopharynx above the soft palate the chance of DDSP (dorsal displacement of the soft palate-choke) occurring increases.
3) A horse may retract its tongue during a race, often as a result of being severely restrained. If the head is under flexed under tension it is normal for the constricted throat muscles to cause the base of the tongue to round up and thence push the mid and rostral soft palate further into the nasopharynx. This then results in reduced nasopharyngeal air supply and again increases the incidence of premature race fatigue and DDSP. Severe restraint is then not desirable which is a point most trainers are fully aware of.
4) The ease at which the tongue can be moved within the mouth is enhanced by at the same time holding the mouth open. If for what ever reason a horse wishes to acquire air via the oral (mouth) cavity whilst galloping, it is usually necessary for its mouth to be open a little to a lot. The acquisition of air in this manner should be viewed as abnormal as the horse should only breathe nasally (through its nose).
DEVICES
These have 3 purposes. To reduce the horses ability to 1) retract or 2) extend its tongue and to 3) reduce the incidence of mouth opening whilst working.
1)Tongue ties, tongue bits, devices............ are used to reduce the horses ability to move the tongue both backward and forward.
2) Crossovers, nose bands........are used to stop the horse opening its mouth whilst working.
IF THESE DEVICES ARE NOT HAVING THE REQUIRED EFFECT THEN THE HORSES NASOPHARYNX OR ANOTHER PART OF THE UPPER RESPIRATORY (BREATHING) TRACT MAY NOT BE FUNCTIONING PROPERLY. IT MAY THEN BE NECESSARY (WHERE POSSIBLE) TO EXAMINE THE UPPER AIRWAY WITH AN ENDOSCOPE WHILST STANDING OR PREFERABLY WHILST THE HORSE IS EXERCISING ON A HIGH SPEED TREADMILL.
NB:- OPP and TPP surgeries have on many occasions resulted in horses no longer opening their mouths whilst galloping . Also the majority of horses following surgery no longer require tongue ties.
FURTHER READING
Ahern T J :Acquired pharyngeal dysfunction (APD), J of Equine Vet Sci 1993 ; 13: 125-28.
Ahern T J: Oral palatopharyngoplasty .J of Equine Vet Sci 1993;13:185-188.
Ahern T J ; A review of the anatomical components, and the process of entrapment of the epiglottis in the horse, with a comparative synopsis of surgical treatments. J of Equine Vet Sci 1996;16: 408-414.
