It’s simple but it’s not easy. This saying can be used to describe so much about our horses. Surely it’s simple to keep your heels down, shoulders back, and eyes up and yet I definitely don’t find it easy! Proper trimming of a horse’s foot is similar. There are a few basic principles to proper trimming and yes they are simple but they often aren’t easy.
Our horses are a marvel of engineering and the foot is the epitome of that marvel. Just think about your horse cantering across a field. On the left lead the right front foot is carrying all of the weight along with the forces created by cantering during the stance phase of the gait. What does all this mean for your horse and his foot? Back to high school Physics we go….
During movement the coffin bone rotates around the very center of the short coffin bone creating a center of rotation. Our goal when trimming feet is to put this center at the ideal spot for forces on the navicular bone, deep digital flex-or, and the structure of the heel. This generally translates to half the hoof mass being behind this line and half in front. For the geekiest among us, that gets us the shortest moment arm possible. In the picture here that means this horse should have his toe and heels brought back since too much of the foot is in front of the vertical line right now. The lateral (image from the side) view only gives us part of the information we need to give our horses the perfect foot. The bottom of the foot tells us even more.
There are three important lines on the bottom of the foot. The first one is across the heels. The second is drawn down the center of the foot from front to back and the third is across the foot at its widest point from inside to outside. These lines give you a guide to the structure of the hoof capsule, the bones underneath, and the best way to trim the hoof.
Let’s begin with the line at the heel. The heel should be at the widest point of the frog and the inside and outside heel should be at the same place. The heel must be rasped down to this level! We have all heard don’t touch the heel so they can grow more but it just doesn’t work that way. The heel must be brought back to the widest part of the frog or it is mechanically compromised and this WILL cause big problems later.
Next, the line down the center of the hoof. This line should not only cut the foot in half but also cut the frog in half. If it doesn’t the frog is telling you there are problems! This line does have some wiggle room based on your horse’s conformation but it is only a little wiggle room. For instance, a pigeon toed horse will carry more foot to the inside and that will be normal for them.
Finally, the line across the widest part of the hoof. Again half the foot should be in front of this line and half behind. The half behind is determined by the spot where the heels hit the ground. This is why it is so important to have the heels at the widest part of the frog. If the foot starts with the heels at the right place, this line will give you an excellent guide to proper break-over location.
These lines are the start of everything we do with feet. A horse with good feet keeps these proportions without the need for shoes. However, bad feet, lameness, or laminitis cause the need for shoes to recreate these proportions. And that’s exactly what a good farrier does with shoes: recreates these proportions. It’s not easy but it really is simple!