TDK conference 2017

We use horse shoes mainly to protect the hooves from excessive wear. The use of regular iron shoes, nailed to the hoof capsule is thought to decrease the movements of the hoof and consequently disturb the hoof mechanism and presumably also the blood circulation.

There are conflicting theories on how the hoof reacts during impact. The main theories are the Pressure theory, the Depression theory, and the Geometric theory.

We did an explorative study with the aim to develop a method to investigate heel expansion and potential blood pressure changes in equine cadaver limbs.

In vitro experiment was made using cadaver limbs and a pressure device with a high-pressure scale. We investigated the hoof mechanism on different surfaces and with different shoe-types while recording changes of blood pressure in both digital arteries and veins during impact. Parameters like widening of the heels and blood pressure changes in digital vessels were documented with alterations made to trimming, bearing surface, shoeing-type and frog support.

Two regularly shoed limbs were used and prepared by dissecting the medial and lateral digital artery and vein. The vessels were catheterized, rinsed and filled with physiological salt-solution before being connected to open syringes attached proximal to the setting. The limbs were exposed to a pressure of up to 650 kg each. Measurements of heel expansion were recorded along with changes of liquid-volume in the syringes. The experiment was repeated on both hard and soft ground, with and without side-clips and frog support.

One of the limbs showed an expansion of the heels during impact and the other showed the opposite, a decrease of heel width. Both limbs showed expansion when frog support was applied. Blood pressure changes could be mimicked.

We found that both expansion and contraction of the heels can occur during impact and that the presence of frog support caused widening independently of initial direction.