Ok, I'm totally confused here. Can someone point out to me what the problems you're seeing is? Cause I'm not seein' them. Where the toes are rasped, we're going to try and get the hoof to break-over and roll at the toe over the next few trims.
Fair enough.
Let's talk basics.
The equine hoof capsule serves two primary functions.
- Provide protection and support to internal structures.
- Provide primary distal support of the animals mass via the connective interdigital laminae and the distal phalanx.
This system of containment and support works best when:
- The capsule is in mechanical balance around the center of articulation of the distal interphalangeal joint.
- The capsule structural integrity is preserved. This means preservation of mass, volume and distal surface area.
Distal means "bottom" or "point furthest from the horses center". Look at the distal aspect of the hoof wall. Your trimmer used a rasp to remove nearly all of the ground surface of the wall.
From what can be seen in the photos, this is her only 'rabbit in the hat'. She reduced the total, weight bearing surface area of the distal wall. That dramatically increases the total load per unit of square measure on what little wall is left.
She has shifted primary load bearing from the wall to the softer tissues of the foot (frog and sole).
Let's look at load on the wall.
Given an average hoof (12" circumference, 3/8" wall thickness), properly trimmed, on a 1,000 lb horse, standing on an unyielding surface.
Load bearing surface = Wall circumference x wall thickness:
12" x .375" = 4.5 sq. in.
Maximum Static load on wall:
1,000 / 4.5 =
222 lbs per sq. in.
Look at your horse. Wall stripped away to 1/16" thickness or less.
Load bearing surface
12" x .0625" = 0.75 sq. in.
Maximum static load on wall:
1,000 / 0.75 =
1,333 lbs per sq. in.
Your trimmer increased load on the distal wall by a factor of 6.
What about dynamic breakover load?
Presume the anterior 1/3 of wall surface at moment of breakover.
Normal:
.375" x 4" = 1.5 sq. in.
Maximum Dynamic breakover load at toe:
1,000 lbs / 1.5 sq. in. =
1,500 lbs per sq in.
Your horse:
.0625" x 4" = 0.25 sq. in.
Maximum dynamic breakover load at toe:
1,000 / 0.25 =
4,000 lbs per sq in.
Your trimmer reduced breakover length of the phalangeal lever by about 3/8" at a cost of increasing breakover load on the wall by a factor of 3.
The structural integrity of the hoof wall has been severely compromised.
A competent farrier could have shod this horse in a manner that accomplished the same amount of breakover while dramatically increasing surface area and decreasing static and breakover load values.
Same 1,000 pound horse, shod with a 3/4" webbed shoe, rolled 3/8" at the toe.
Total static bearing surface area:
0.75 in. x 12" = 9 sq. in.
Maximum Static load on wall:
1,000 / 9 =
111 lbs per sq. in.
Total dynamic breakover surface area:
0.75 in. x 4 = 3 sq. in.
Maximum dynamic load at breakover:
1,000 / 3 =
333 lbs per sq. in.
When we increase (or preserve) the distal surface area of the weight bearing wall, we reduce pressure per unit of square measure.
Change the total mass values by whatever percentage you want, it doesn't change the comparative ratio of load per unit of square measure.
What does happen is that load is transferred to secondary weight bearing structures. The frog and sole now have to do what the missing hoof wall was designed to do; support the horse.
Should we place a small radius at the leading edge of the foot to reduce chipping/damage. Sure. Do so with an eye towards preserving as much wall thickness as possible.
What if we can't get that reduced breakover force in a manner that leaves the horse in d/p balance and still preserves hoof capsule integrity?
That's a good point at which to consider a set of shoes.
As for me being impressed with the trimmer, she knew what she was doing...
That's a matter of opinion. I'd argue she doesn't have a clue.
and provided me with a lot of information
Maybe... or maybe just an earful of barefoot dogma based on irrelevant stories about feral horses, proper hoof function and other such nonsense.
... and took the time to show and explain to me what she was doing when I said I knew next to nothing about barefoot trimming.
In other words, she bamboozled you and got away with it because you innocently didn't know any better.
She took her time with my horses (she was out here for over three hours)
She didn't take three hours because she is patient. She took three hours because she lacks knowledge, skill and experience.
... and was super nice and helpful.
Which, in the total service picture, isn't worth spit if you can't deliver a properly trimmed and/or shod horse.
Cheers,
Mark