Head and trunk movement adaptations in horses with experimentally induced fore- or hindlimb lameness.

This study examines how horses adapt their head and trunk movements when they experience either foreground or hindlimb lameness. The researchers observed that horses adjust their stride and elevation to compensate for lameness. Particularly, the trunk was kept higher during lame stance phases and the movement patterns of the head and withers varied depending on whether lameness was in the fore or hindlimb.

Research Method

• The study used the 3D locomotion analysis system CODA-3 to record the kinematics of 11 clinically non-lame Dutch Warmblood horses as they walked and trotted on a treadmill.
• A transient lameness model was applied to induce varying degrees of fore- and hindlimb lameness – achieved by evoking pressure-induced pain on the hoof sole.
• The peak vertical displacement, velocity, and acceleration of the head, withers, tuber sacrale (part of the pelvis), and both tuber coxae (hip joint) were recorded and analyzed at different phases of their stride.

Findings

• Similar sinusoidal patterns were observed in the vertical displacement, velocity, and acceleration of the head, withers, and tuber sacrale.
• The study found significant changes in movements during the lame stance phase. Notably, the vertical velocity of the trunk decreased at impact of the lame limb, resulting in the trunk being kept higher above the ground, reduced maximal acceleration, and reduced displacement amplitude compared to when the horse exhibited no noticeable lameness.
• The changes in head movements were seen to be more prominent than changes in withers movement during forelimb lameness but this observation was reversed during hindlimb lameness.
• Walking head movement patterns experienced similar changes as compared to trotting, with minimal observable changes in the withers and tuber sacrale patterns.
• Symmetry indices, which are quotients of the values during the lame and non-lame stance phase, exhibited changes due to increasing lameness. The maximum vertical acceleration of the head and the displacement amplitude of the tuber sacrale were found to be the best indicators of fore- and hindlimb lameness respectively.

Conclusion

• This research helps to understand how horses compensate for lameness by adjusting their stride and elevating their trunk higher during the lame stance phase.
• The research also indicates that the variations in the head’s movement patterns and the displacement amplitude of the tuber sacrale are significant indicators that can quantify fore- and hindlimb lameness in horses.