Idiopathic headshaking is a perplexing syndrome that manifests itself, sometimes suddenly,
sometimes gradually to which apparently, there is no definitive diagnosis or cure.
As a syndrome the symptoms are varied and few horses have the exact same patterns of
behaviour, however many may horses exhibit several of the following:
- Involuntary ticcing or jerking of the head as if a bee has stung it on the nose.
- Snorting continually.
- Throwing of the head either up & down or from side to side.
- Ear twitching/shaking.
- Rubbing the nose along the ground.
- Rubbing the sides of the mouth or face.
- Sensitivity of the ears or poll.
- Reluctance to accept the contact from the riders hands.
- Reluctance to go forward
- Idiopathic hind leg lameness.
- Irrational behaviour/spooking.
- Skin sensitivity to flies.
Symptoms may arise seasonally or be year round.
|Idiopathic Headshaking & Its Relationship with Chronic Equine Gastric
Ulceration Syndrome Caused by Acute or Chronic stress
There are many theories as to why horses start to headshake.
The western veterinary approach is to isolate the head pain by blocking the trigeminal nerve pathways that errupt in
the branches of the ocular, mandibular & nasal areas of the face. Drugs are used to lessen nerve impulses, steroids
administered to reduce 'inflammation'. Surgery has been attempted but results are unreliable.
Other theories blame the horses natural food - grass, and advocate the feeding of hay only, on areas devoid of all
green food & adding copious amounts of salt. This apparently balances the electrolytes that govern nerve impulses.
However there is no explanation as to why all horses are not affected in the same way, which clearly they are not as
millions of horses worldwide consume grass 24/7 with no ill effects.
The real reason for this problem is a lot simpler & when addressed can show dramatic changes in both
headshaking & the 'behavioural' issues that accompany this syndrome.
The endemic problem of equine gastric ulceration has been explained in depth (EGUS). Looking at the symptoms of
EGUS we can see many like for like symptoms with headshaking syndrome, however not all horses with ulcers
headshake, whereas I believe all headshakers have ulcers, & in particular hind gut ulceration which is mostly ignored
due to preoccupation with the horses head.
From a western perspective this connection is complex & many would say tenuous, but if we look at the Oriental
Channel System in relation to the Trigeminal nerve system in the face this relationship becomes very obvious.
|The Equine Trigeminothalmic Pathway conveys
nerve impulses for most somatic sensations (tactile,
thermal, pain, and proprioceptive) from the face, nasal
cavity, oral cavity & teeth to the cerebral cortex. It has 3
main branches which are the opthalmic, maxillary &
If we compare these branches to the equine Oriental
Channel System for the digestive tract & organs the
connection becomes very clear.
The Large Intestine Channel begins on the distal
foreleg at a point proximal to the craniomedial aspect of
the coronary band. The channel travels proximally up
the medial pastern & metacarpus and along the cranial
aspect of the carpus. At the carpus, it moves laterally
and continues proximally along the craniolateral foreleg
up to the ventral neck. It continues along the larynx and
mandible and ends at a point lateral to the ventral
border of the nares.
It is important to note that the point LI-4, (which lies on
the medial side of the fore leg at the upper third of the
distance between the carpus & the fetlock, in a
depression between the splint bone & the cannon
bone) is empirical for all face & mouth pain.
(The internal pathway of this channel diverts to the
organ itself as it passes the shoulder.)
The Stomach Channel begins on the head just below
the midpoint of the eye. It descends to curve around
the edge of the lips, then returns along the angle of the
jaw in front of the ear to the TMJ. It then courses along
the lower aspect of the neck & chest running parallel to
the ventral midline, again diverting off to reach the
stomach organ. After reaching the groin, it runs towards
the lateral patella down the cranial lateral surface of the
hind leg & ends on the coronary band.
The Small Intestine Channel begins on the lateral
aspect of the coronary band & travels craniolaterally up
the foreleg. After passing the triceps and scapula it
diverts to the organ before moving up the neck, dorsal
to the cervical vertebrae. It ends on the lateral side of
the ear base.
From a western perspective absorption and secretion of electrolytes are controlled by the digestive system. In
human ulcerative colitis there are drastic changes in the colonic mucosa and profound metabolic disturbances due
to deficiency of electrolytes may also occur Lubran and McAllen (1951) and Smiddy et al (1960).
These profound disturbances may also affect sodium/potassium balances of the action potential of the nerves all
around the body, causing 'misfires', potentially in the trigeminal pathways.