Thursday, 21 April 2011

Symmetry, twisted legs and strengthening hooves

As a follow on from yesterday, here are some photos of Oscar, who is a good example of a horse who arrived with beautifully shod hooves which were fairly symmetrical.  He had a noticeable twist in his left leg, it was difficult to get him to stand square and he was tending as a result to overload his hoof laterally.   
Below is a photo of Oscar today - its very easy to get him to stand square, he is loading his hooves more evenly and his limb looks straighter BUT his hooves are developing an asymmetry.  Ironically, I believe its this asymmetry at hoof level which is allowing his limb to be straighter.
Its counter-intuitive to many hoofcare professionals, whether farriers or trimmers.  We are taught that hooves are fairly static - that if they aren't symmetrical they will wear unevenly but in fact horses and their hooves are far cleverer.

Hooves are dynamic - they change and respond to load and wear continuously, adapting, supporting, strengthening or weakening in response to external stimuli and the function they are being asked to perform.
Generally, even in a well shod foot like Oscar's, the caudal hoof (the frog and heels externally and digital cushion and lateral cartilages internally) has less to do - here is his hoof straight out of shoes.  Much of the load is taken by the shoe and with a passive role on most surfaces there is less stimulus for the frog to be well developed.   
Once out of a shoe, the load of the limb is carried quite differently and there is every need for the frog to become as strong as possible.  It can change quickly under the right conditions - all these photos of Oscar were taken 8 weeks apart.
Compare the caudal hoof in these photos  - not only is it much bulkier and more robust after a few weeks out of shoes, but the development is more even.  In the top photo the overloaded lateral side is much bigger and the medial side looks distorted. 
 Even though Oscar's hooves appear, from a  dorsal view, to now be asymmetric, they are actually loading more evenly than they were in shoes.  Symmetry - for hooves - isn't a question of one half matching the other, its a question of even balance under load. 


jenj said...

Once again, wow. The before and after photos are just incredible. How I wish farriers would LOOK at these pictures and really understand (and accept!) what's going on.

Nic Barker said...

Jen, the photos make me smile too :-) I am getting some good feedback from the odd farrier, so its not all bad news...!

Andrea said...

The hind end is the real treat - how his hocks were practically knocking together in the first photo, and how much better his posture is in the second!

BruceA said...

Spot on Nic. Exactly what we had with Linkwood and his back right - leave the hoof alone and NEVER trim it and he is perfectly sound - take that medial deviation away and he is sore.

Why is this adaptive growth so hard for some folks to understand? The hoof grows to support what is above it and adapts to the forces on it. If it's growing funny, there's a reason for it that you probably won't be able to fix with the rasp! :-) let it grow funny!