Trimming the sole means you have no work to do. Yes, that’s right, we don’t trim the soles at all. Even when soles exfoliate, we leave them alone. The picture underneath where I wire-brushed the sole clean was just to show you true live sole, as opposed to dead sole.
Especially, we do not pare the soles to make it look like there is concavity. Concavity isn’t man made for us, it is the result of the correct trim, feeding and exercise coming together to give us a healthy hoof that has deep concavity.
The horse’s soles are his contact with the ground together with the frog, heels, bars and hoofwalls. The horse is meant to have ground contact on his soles and the hoof walls are not meant to hold the weight of the horse. When that happens, it is almost the same as putting shoes on the horse (from the peripheral loading perspective only) and we rob the horse of the much needed ground contact that is essential for the underneath of the foot.
Through the underneath of the foot, the weight of the horse landing (think landing after a jump for even bigger effect!) is distributed over a bigger area as opposed to the relatively small area of the (thin) hoof walls.
Consider that the soles are made of the exact same horn tubules (keratin) as the hoof walls (with their ends bent over) and you’ll understand how a horse can walk on stones barefoot when the soles and frogs are in good condition.
When we say sole, we mean true sole, not false sole.
So what is the difference?
False sole can (and almost always do) exfoliate under the right conditions. The sole can appear hard and healthy to our naked eyes and the next thing you see a spot where the sole is gone. Then you know you are looking at false sole.
Here’s what I’m talking about. In this case, at first just the hole appeared, then the sole under the sole ridge went.
And from another time, the picture below with more sole gone.
And from another foot, all the false sole is gone and after I wire brushed it, we’re left with the true sole.
Obviously, now you have more wall and heels to take away so making the hoof shorter vertically.
However, it isn’t always that false sole is hard like that. It can also be floury, like this one. In this case we can just scratch it out, while with the hard false sole we want to leave it there and let nature take it away as it is there to protect the true sole underneath and maybe it needs the extra thickness because the sole is so thin, until it is ready to cope with nature. The floury false sole is present with a completely overgrown hoof wall, while with the hard false soles I rode the horse on gravel roads. (The picture below is only to show you the floury sole, not all the other things that’s also wrong with it. You can read and see more pictures in Lucy’s Case Study page)