Animal Welfare Science and Bioethics Center
Professor David J Mellor
Equine welfare during exercise: Do we have a problem?
 Horses domesticated ~6000 years ago
 Bitted bridle use began ~2500 BC for control and safety
 Control and safety achieved by pressure applied to different parts of the head, especially the
lips, interdental space, tongue, hard palate
Evidence of Bit induced pain
 Threat of pain and pain itself controls the horse
 All mouth parts are richly innervated
 Bit sits on the gums
 After long-term bitted uses:
o Mandibular spurs and erosion
o Tooth loss and erosion
o Periodontitis of empty tooth socket
o Compresses the gum between the bit and jaw bone
o Stimulates pain receptors between the gum and periosteum
 Pain induces:
o Mouth slightly or wildly open
o Teeth grinding
o Tongue protruding
o Profuse salivation
o Skittish movements
 Note pain induced mouth behaviors are absent when the mouth is closed
Benefits of closed mouth breathing
 The horse is obligate nasal breather
 For fully effected respiration it MUST breath through its nose
Jowl Angle
 Rein tension sets the jowl angle of ridden or driven horses
 The greater the rein tension the greater the bit-induced pain and usually the lower the jowl
angle.
 Lower jowl angle cases more nasal airflow to be obstructed
 The more exchange of respiratory gases is impeded in the lungs
Behavior problems and solutions
 Mouth slightly or wildly open = uses tightly applied nose band
 Tongue protruding = tongue ties
 Head tossing or shaking = martingales