Hot feet, cold feet

While I was giving the workshop at Writtle University College recently someone asked a very good question about whether hooves should be warm or cold. 

Its an interesting question because when you have a shod horse you are normally taught that feet should feel cold and that warm feet can be a sign of a problem - for example laminitis.

However I noticed when I started taking shoes off horses that in fact their feet change temperature - and usually warm up - when shoes come off. Horses who are barefoot will normally have feet which feel warm-ish, with a higher temperature on a hot day, naturally, and a lower temperature on a cold day. 

There are a few theories for the difference in temperature between shod and bare hooves but for me the most compelling - and the most obvious - answer came from a farrier who gave me this.

Its a heat sink and its designed to be extremely efficient at conducting heat to or from an object (like a computer). The farrier gave me this because its a brilliantly simple explanation of why shod feet will always be a different temperature from bare feet.

The heat sink is a very efficient conductor and so is a horseshoe. Both are made of metal and have long thin spikes to increase conductivity. The heat sink is made of aluminium, most shoes are made of steel but the effect is the same.

Shoes will always conduct heat. In a cold climate this will normally make hooves colder than they would otherwise be as they will take heat from the hoof; in a very hot climate in theory they could make hooves warmer.

Of course, there are no studies as to what effect this has on the horse's heath, either immediately (does it affect circulation?) or over the longer term (do hooves grow at a different rate or heal slower if they are cooler than they would otherwise be?). A nice subject for someone's PhD, perhaps?