Effects of ‘navicular’ shoeing on equine distal forelimb kinematics on different track surface.

The research investigates the effects of different types of horseshoes and varying track surfaces on the movement and pressure of the horse’s lower front limb. The study specifically examines normal shoes, eggbar shoes, and shoes with heel wedges across asphalt, a fiber/sand mix and pure sand track surfaces.

Methodology

• The study was conducted using eleven healthy Dutch Warmblood horses. These horses were made to walk and trot across three various track surfaces: an asphalt track, a fiber/sand mix track (Agterberg) and a pure sand track.
• Three different types of shoes were used for each track – a normal shoe, an eggbar shoe, and a shoe with heel wedges.
• The researchers recorded the rotation of the horse’s hoof and the maximal extension of the fetlock joint (the joint that connects the horse’s leg and hoof) during the midstance period – the moment when the hoof is bearing the most weight.
• An infrared light-based gait analysis system (ProReflex) was used to measure these factors.

Results

• The outcomes showed a significant impact of track and shoe type on hoof rotation and fetlock extension, as well as an interaction between shoe and track type.
• On softer track surfaces, the balance of the lower front limb led to a forward rotation of the hoof, between 1.5 and 4 degrees, when wearing either the normal or eggbar shoes. This forward rotation was greatest on the sand track.
• Shoes with heel wedges always created a significantly greater hoof rotation, similar to the rotation observed on hard track surfaces, resulting in a 5 degrees forward rotation of the hoof.
• The maximal extension of the fetlock joint was found to be less on soft surfaces, specifically on the sand track. This decrease was notable when the horses were shod with heel wedges and less pronounced with normal shoes.

Conclusion

• The research concluded that sand tracks particularly allow for a forward rotation of the hoof, thereby relieving pressure in the navicular area (a region in the horse’s hoof often affected by navicular disease) and lowering maximal fetlock extension. Hence, the joint is essentially unloaded.
• The additional forward rotation caused by wearing heel wedges on hard tracks is nearly the same on soft track surfaces.
• Eggbar shoes, as well as the fiber/sand mix tracks, yielded intermediate effects in unloading pressure from the lower front limb.