The 'Perfect Circle'
Is there a 'perfect circle' when dealing with hooves? While the answer can get very complex, the simple answer is...
The front feet of the horse, while reputed to be circular in shape, just simply does not fit every front hoof on every horse.
The rear feet of the horse, while reputed to be oval in shape, simply doesn't fit every horse's rear hooves either.
There are several points to take into serious consideration when looking at a healthy hoof.
We'll discuss a couple of them here:
The Front Feet
In the front feet of a horse, the general rule of thumb for healthy hooves is Gene Ovnicek's 1/3 : 2/3 ratio.
What does that mean? This is explained in the photo below:
1/3 : 2/3 means that two thirds of the foot should be behind the apex of the frog (apex of frog to heel). The other one third of the foot in front of the apex of the frog (apex of frog to toe).
(I actually use the breakover point more on the hoof rather than the apex).
The Rear Feet
In the rear feet of a horse, the general rule of thumb for rears is the same as for fronts when determining ratios:
How does the Shape of the Hooves Contribute to the Movement of the Horse?
The consensus is that the front feet bear 60% of the horse's weight when the horse is static. Then that weight is transferred to the rear hooves upon forward movement. Thus the 'round shape' on the front hooves for stability and the 'oval shape' for the rears hooves.
Think in terms of the rears acting like shovels. One wants a more oval shaped shovel to 'dig' into the ground, rather than one that is square or round. I don't think I've ever seen a 'round' shovel and what the heck would it be used for anyway?
What is Locomotion?
Locomotion, in simple terms: when the horse wants to move forward then the weight is shifted back to the hind quarters (the engine of the horse) and the rear hooves 'dig' into the ground to propel the horse's body forward.
I bet you don't know what part of the body of the horse moves first, do you?
This makes a great exercise for people! Have them bareback on the horse, have them close their eyes and feel what muscle group their horse moves first when they begins to move forward! Kids love this exercise!
I get a lot of answers from this exercise. Primarily I get "the back end of the horse moves first". Nope, this is incorrect.
The first group of muscles that moves when a horse moves forward, are the muscles in the back, the lumbar, of the horse.
That's right! The back muscles move to gather up the energy in the hindquarters which then get the hind hooves moving and propelling, pushing the horse forward!
When a horse is allowed to move 'naturally', that is, from the hindquarters, then one will see the rear hooves maintaining their shape much better than the front hooves.
When a horse is 'pulling' itself forward (on the forehand) then one will see more flares, more cracks, more stress on the fronts compared to the back hooves.
Have you ever thought of it this way? Think about it a bit and see if this makes perfect sense to you.
The 1/3 : 2/3 Ratio
So, back to the general criteria for healthy hooves...
We have Gene's 1/3 : 2/3 ratio and then we have 'Uniform Sole Thickness' as depicted by Michael Savoldi in his paper 'Uniform Sole Thickness: How to Define a Heel'
Now think of uniform wall thickness. The walls of a healthy hooves *should* be between 1/2 and 3/4 inch thick! All the way round from heel to heel.
Of course, when we trim back the toes that have been allowed to grow too long then this won't be the case. However, this needs to be a goal to reach for healthy hooves.
A hoof that is balanced true and wears in balance, with a balanced rider, will maintain that uniform wall thickness as the hoof grows and the trimming will need to be 'uniform' around the wall of the hoof.
Another general rule of thumb we want to see is 1" of collateral groove depth under the seat of corn/heel buttress for both fronts and back hooves. This will ensure that the hoof is landing correctly on its heels and the heels are in the best supportive position possible. That means that the toes have to be maintained back where they belong.
When the heels are trimmed too short, the hoof begins to collapse and the inner foot begins to 'slide' down and forward with 'long toe-low heel' being the ultimate result. Then we see navicular issues begin to crop up and so on and so forth.
There are may more criteria to the maintenance of healthy hooves but as a general rule, these are 3 most important ones.
What Shape Should I Trim my Horse's Hooves?
Oh, wait, I didn't mention what shape to trim the hooves! Round for fronts and oval for backs! Ummmmmm, get that idea out of your head as a fixed 'rule'. The fixed rule is to 'follow the shape of the sole'.
In other words, if the sole forms the shape more like a triangle (which one will see many times in the larger draft breeds) then that's the shape one should follow for trimming.
(photo from foxhuntingfriesian blogspot per Fair Use Law)
If the other criteria that I've mentioned above is maintained, then the hoof will morph into the shape that nature intended it to be.
Yes, follow the sole! Keep that as a 'mantra' when trimming your horses' hooves.
In summary we have the following points:
- 1/3 : 2/3 Ratio
- Uniform Sole Thickeness
- Uniform Wall Thickness
- 1" of Collateral Grooves Depth Under the Heel Buttress/Seat of Corn
- Follow the Sole!
Basics, basics. Stick to the basics!
Trimming pathologies is not the same, however... although these guidelines do remain. But pathological hooves are a whole other critter to deal with! There is way too much to go over there and not information that a 'weekend barefoot trimmer' or lay-trimmer needs to know. Pathological hooves are for the experienced hoof care providers!
If you're trimming your own horses due to COVID-19, then simply stick to the basics. See my former articles here: https://scootboots.com/blogs/blog/quarantine-maintenance-trim-scoot-boots
Gwenyth Browning Jones Santagate is the best-selling author of 10 Secrets to Healthy Hooves as well as a noted author for various international equine publications including The Horses Hoof, Equine Wellness, Natural Horse Planet as well as a contributing author for the 2001 United States Federal Mounted Border Patrol Training Manual. For the last 37+ years, she has maintained healthy hooves with natural trimming on thousands of horses and specialized in pathological rehabilitation hoofcare for the last 18 years. She and her husband John keep a small herd of their own equine in NE Connecticut and continue to offer consults for horses in need. For further information please click here: www.thepenzancehorse.com