Heel movement in horses: comparison between glued and nailed horse shoes at different speeds.
BACKGROUND
It has been suggested that the heel of the horse's hoof expands in the stance phase and this reduces the concussion at impact and helps pump blood into the hoof. Therefore, farriers usually leave a gap in the heel region when using the traditional nailed shoe. Recently glued shoes which are attached firmly to the heel have been developed and these could restrict heel movement.


OBJECTIVE
To compare the degree of mediolateral heel movement between glued and nailed shoes.


METHODS
Seven Thoroughbreds were used. Either their fore- or hind hooves were shod with plain aluminium shoes, attached first with glue and later with nails. Measurements were collected continuously with a displacement sensor fixed between the medial and lateral hoof walls at the heel. The horses ran on a treadmill at a walk (1.8 m/s), trot (3.5 m/s), canter (8 m/s) and gallop (12 m/s). The mediolateral heel movement in a nonweightbearing position was set at zero for each hoof and thus positive and negative numbers represented expansion and contraction, respectively. Average values of 10 consecutive strides at each speed were compared between the 2 shoeing methods by paired t test.


RESULTS
At all running speeds, the heels expanded in the first 70-80% of the stance phase and contracted at breakover. The total heel movement calculated as the sum of the maximum expansion and contraction value was less with glued shoeing than with nailed shoeing for walking (all limbs), trotting (all limbs), cantering (leading forelimb and both hindlimbs) and galloping (both hindlimbs).


CONCLUSIONS
Glueing restricted heel movement, suggesting possible interference with shock absorption and blood pumping in the hoof. Further study is needed to evaluate the influence of glued shoeing on hoof mechanics.
Equine Research Institute, Japan Racing Association, Tokami-cho, Utsunomiya, Tochigi, Japan. eirurich@gmail.com
E
E
Yoshihara
T
T
Takahashi
N
N
Otsuka
T
T
Isayama
T
T
Tomiyama
A
A
Hiraga
S
S
Wada
D000818:Animals; D001696:Biomechanical Phenomena; D005528:Foot / Q000502:physiology*; D005552:Forelimb; D006614:Hindlimb; D006724:Hoof and Claw; D006736:Horses / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D012775:Shoes