“The weight of the shoe seems to be what’s causing an effect on horses’ biomechanics above the fetlock, more than the design of the shoe,” said Joëlle Stutz, PhD candidate working under Antonio Cruz, PhD, of the Swiss Institute of Equine Medicine (ISME), at the University of Bern Veterinary School in Switzerland. Stutz presented her work at the 12th annual Swiss Equine Research Day, held April 6 in Avenches.
Stutz, along with Cruz’s research group, investigated the way horses moved when going barefoot or wearing three different kinds of shoes: an egg bar shoe, a rockered toe shoe, or a traditional shoe. They tested the shoes on 10 healthy Franches-Montagne stallions, which wore each kind of shoe (or no shoes) for four consecutive days. The horses worked on a treadmill and in a soft-surface arena while wearing eight inertial movement sensors on their limbs above the fetlocks, hocks, and knees (the researchers wanted to focus on how shoes affect a horse’s movement beyond his feet).
The “novel system” that Cruz’s group is helping develop allows researchers to simultaneously record spatial and temporal gait parameters such as stride duration, knee and hock joint range of motion, and certain angles during each stride, Cruz said.
The researchers also quantified changes in hoof morphology during the study, using calibrated digital photography and radiographs (X rays) to help determine any changes in shape.
They found no remarkable differences in biomechanical movement or morphology from one shoe to another, Stutz said. However, they did notice a significantly greater sagittal amplitude (front-to-back swing) of the limbs with any of the shoes when compared to no shoes.
“This appears to be an effect of the additional weight on the feet, exaggerating movement of the entire limb, as has been documented before,” Stutz said.
A previous study’s results suggested that horses can adjust to shoe weight over a one-year period, leading to fewer biomechanical changes in movement between shod and unshod horses. But not all scientists agree on the length of this adaptation period.
“We can say that horses do not experience movement changes in the upper extremity associated with the tested shoes, and the previously reported differences associated with these shoes seem to be limited to the foot level,” Cruz said.