The effect of two different surface preparation procedures on motion in the equine hoof and metacarpophalangeal joint

There are at present no set standards or guidelines advising surface type or maintenance necessary to maintain optimum health and wellbeing of the horses (Weishaupt, 2010) however it is clear that preparation and maintenance procedures will affect surface characteristics. The aim of this work was to investigate the effect surface preparation (rolled or harrowed) had on hoof and limb movement using infra-red cameras and retro-reflective markers at walk, trot and canter in nine horses. There were no differences in hoof rotations and hoof displacements but there were some differences between fetlock and limb posture on the rolled and harrowed surface. Small changes in the surface cushions (i.e. light rolling or harrowing a surface), influenced the stride characteristics.

Rationale

Research of the horse and ground interaction has until recently focused on the racing industry (Peterson and McIlwraith, 2008). The idea of catering the surface type to discipline is however fast becoming the consensus (Murray et al., 2010; van Weeren, 2010) meaning specific research into surface substrate and maintenance is needed. Mechanical surface properties affect the limb loading rates, shock attenuation and supporting structure loads, as well as the accelerations and decelerations of the limb and hoof (Hobbs et al., 2010).  Incorrect rotation of the foot on the surface during the stance phase of the gait has been suggested as a possible cause of injury to the distal limb joints (Chateau et al., 2001). The relationship between surface maintenance and hoof and limb kinematics is therefore an area of interest and relevant to orthopaedic health of the horse.

Objectives

The objective of the work was to measure and compare distal limb and hoof movement on two preparations of one sand and fibre surface and identify the relationship between the hoof and limb kinematics and the mechanical properties of the surface.

Methods

Infrared cameras and retro-reflective markers (Qualisys Oqus) were used to capture the left forelimb through a calibrated volume at walk, trot and canter on two surface preparations (rolled and harrowed) in a cross-over design. Hoof rotation and displacement, metacarpophalangeal joint (MCPJ) extension and third metacarpal (McIII) inclination (roll, pitch and yaw) were assessed. Surface hardness (Clegg Impact hammer) and traction (adapted torque apparatus, modified with a horseshoe stud) were used to assess different in surface mechanical properties. A General Linear Model was used to analyse the data.

Results

There were no differences in hoof rotations or hoof displacements between the rolled and harrowed surfaces. There was however, significantly greater MCPJ extension at mid-stance and significantly greater McIII adduction at impact when gait (walk, trot and canter) was grouped. There was no statistical difference between hardness and traction between the two surfaces.

Conclusion

Despite no evidence of differences between hardness and traction when the same surface is rolled or harrowed, there was evidence of subtle differences in fetlock (MCPJ) extension and limb posture. These findings suggest that light rolling or harrowing of a surface influences horse limb kinematics. Only one surface was investigated here so this may not be representative of all surfaces.