Effect of a square toe or perimeter fit horseshoe on quality of movement and gait kinematics of the western pleasure horse

Abstract Text:

Hoof care professionals often manipulate the thoracic hooves of the western pleasure horse by squaring the toe and moving the horseshoe caudally on the hoof capsule, which is thought to shorten the point of breakover, allowing for a flatter knee and more extension out of the shoulder during the swing phase. Manipulating the shape of the shoe in this way may compromise hoof capsule integrity and could contribute to chronic lameness. Our objective was to evaluate gait quality and kinematics of the western pleasure horse shod with a squared-toe aluminum shoe (ST) in comparison to a perimeter-fit aluminum shoe (PF) on the thoracic digit. Quarter horses (n=9; 5 geldings, 4 mares; 8.4±1.9 yr; 545.9±34.8 kg) trained in western pleasure were utilized in an 85 day repeated measures study and randomly selected on day 1 to be shod with either a ST or PF shoe for six weeks, then reshod with the opposing treatment on day 43. Horses were videoed being ridden at the walk, jog, extended jog, and lope for 3 repetitions over 50 m on days 15 and 57 wearing each treatment. EquineTec® software was used to evaluate humeroradial extension measured as the minimal elbow angle (extension out of the shoulder) at the end of the swing phase, metacarpal flexion measured as the minimal carpal angle (knee action) and metacarpalphalangeal flexion measured as the minimal fetlock angle (lower leg action) both at the beginning of the swing phase. Equine judges (n=11) assessed quality of movement by scoring each gait from -1.5 (extremely poor) to 1.5 (excellent) where 0 was considered average. The PF treatment improved quality of movement for some parameters, including humeroradial extension for all gaits (P < 0.034) and metacarpal flexion for all gaits (P < 0.0132) except the jog (P = 0.079). Metacarpalphalangeal flexion and judge evaluations were not different between treatments (P > 0.3). Kinematic evaluation revealed quality of movement advantages when the PF treatment was applied by allowing for more ideal western pleasure movement seen as decreased knee action and increased extension out of the shoulder, although professional judges did not score treatments differently. The PF treatment achieves equal or superior quality of movement compared to the ST, thus providing a more appropriate shoe for the western pleasure industry that may amplify the longevity of the western pleasure horse.

Keywords: horse, square-toe horseshoe, perimeter-fit horseshoe, western pleasure