Part I Re: Foot Angles, Shoeing, etc (omigosh getting longer)

[Abby Bloxsom <goneriding@snet.net>]

Okay, I've been out of this discussion for a bit, but let me see if I
can play catch-up without missing any important points.

Karen Standefer wrote:

 > Since the horse's shoulders are held in place by
 > muscles and tendons and not joints like our own, the
 > conformation can be completely changed by the angles
 > in the hoof.


Well, not exactly.  The angles of the shoulder joint and elbow joint are
fixed.  Their orientation to the vertical can be changed, and thus the
*apparent* angle of the shoulder blade.  As the horse stands more
"under" or "in front of" himself (to compensate for incorrect hoof
angles) the angle of the shoulder blade will change.  Karen is right
about the muscle thing; the horse has no collarbone.

 > In a club footed
 > horse (much steeper hoof angle on the club hoof) you
 > frequently get more muscling on the club footed side
 > of the body.  The muscles are holding the shoulders in
 > an unnaturally steep angle and not allowing the
 > tendons in the lower leg to do their job.  If you
 > lower the heels on that hoof, over time, the angles in
 > the shoulders will also change and the bulkiness of
 > over-muscling will subside.


We need to distinguish here between club foot and boxy foot.  A boxy
foot is a horse who's been allowed to grow too much heel and thus has a
contracted hoof and too upright a hoof angle.  This horse will have too
steep a hoof and too shallow a pastern.  This can be corrected over time
by gradually lowering the heel to allow the hoof to expand.  This is a
farrier error.  BTW, a farrier trims feet.  A farrier is not equivalent
to a horseshoer.  They MAY be one and the same, but they are not equal.
     So yes, even a barefoot horse recevies farriery ...

If the upright hoof is aligned with an upright pastern, the horse is
truly club-footed.  This cannot be "corrected" by lowering the heels!
(thank you, Linda Merims)  The tendons that run along the back of the
leg are too short to lower the heel, *even if the coffin bone is not
ground parallel*.  Attempts to lower the heel will create tension on the
tendons, pressure on the navicular bone, dishing in the hoof wall, and
eventually possibly coffin bone rotation.  This is a pathology to be
accommodated, NOT a farriery error.  That said, it's far less common
than the former scenario.  IMO, the solution here is to remove the heel
so that the angle of the hoof itself is correct (this allows more
natural expansion, circulation, and growth than leaving the heels long)
AND THEN adding wedge pads to bring the heel up to the point where the
hoof is aligned with the pastern.  The coffin bone may not be
ground-parallel, but the horse will still be more upright.

So, let's distinguish as we converse between the "club" foot, which is
pathological, and the "boxy" foot which is a trimming error and can be
corrected over time.

 >
 > To support the hoof optimally, the coffin bone should
 > be ground parallel which provides the greatest area
 > for internal support of the boney column.  If this is
 > the case, then the front hooves will be around 45
 > degrees and the rears will be 55 or so.


MAYBE!  The hooves will be where the hooves will be.  And as I said
above, not every horse should have P3 (the third phalanx, or coffin
bone) ground parallel.  Almost all sound working horses will though.

Correct trimming that puts P3 ground parallel should also align P1,2,3.
If we have xrays to determine the location of P3, then we can also see
that the pastern will be aligned.  This will affect the placement of the
shoulder blade, but will not necessarily put it at any specific angle.
We should not imagine that all horses possess the same bone lengths,
bone orientations, or joint angles.  The angle we should be looking for
is that the horse's foreleg overall should be oriented at 90 degrees
from the ground.  This is the most important angle of all, and this must
be an angle that the horse presents voluntarily at rest.

 > I'm speaking from experience, not just theory.  We
 > trim around 200 horses a month, currently, and have
 > effected changes in many of them by changing the
 > angles in the hooves.


Effecting change is not always 100% to the good ... anyone can effect
change by changing hoof angles.

  > The pastern angle changes according to how the hoof is
  > trimmed.  The pastern angle can defitely NOT be used
  > as a gague for setting hoof angles.

The existing pastern angle is not used to SET the angle of the hoof, or
you would overshoot your corrections every time.  It is used as a guide
for the type of change that needs to be made.  If the axis of the
pastern joint is offset ventral (groundward) to a straight line, then
the hoof needs to be steeper.  If the axis of the pastern joint is
offset dorsal (upward) to a straight line, then the hoof angle needs to
be shallower.  The farrier should trim the horse slightly in that
direction each time (preferably at 2-3 week intervals while making
corrections, 1 week changes are too frequent IMO unless they are minute.
   When the pastern axis is aligned, the hoof angle should be left alone.

Deanna asked:
  > My understanding is that, when the horse is standing square, the front
  > hooves should be trimmed so that there is a smooth angle from fetlock
  > to toe. Ignore any rounding of the toe for easing break over for now.
  > If the toe is too long, the laminae stretch and the toe curls out and
  >that smooth angle becomes a curve.

Generally, yes.  They may just develop crushed heels depending on the
strength and thickness of the horn at the heel.

  > If the toe is too short or the heels too high, there is a visible
  > break in that smooth angle downward where the hoof begins.

  >The horses I've observed who get lots of exercise (turnout and a fair
  >amount of pleasure riding) "seek" the relationship I described. That
  > is, if their toes get too long, they start breaking them off and if
  >the toe is too short (usually through over trimming), they break off
  >hoof near the back of the foot. Of course, I'm talking about unshod
  >horses, since hooves ideally don't break off of shod hooves.

Again, generally this is true.  BUT many, many horses will not wear the
hoof to make this correction - it depends on the terrain where they're
working and the quality of the horn, and the degree of error in the trim.

  > It seems to me that the pastern angle is determined by the underlying
  > bone and tissue structure and cannot be changed by changing the angle
  >of the trim. I've observed that to try to do so results in gait
  > abberations and hypothesize that it would lead to joint or tissue
  >damage in the long-term in a horse that was expected to travel a few
  >hundred competitive miles per year.

Yes, again this is generally true IME, but (isn't there always a "but"?)
I have seen several (probably not "many") horses develop a better, more
average pastern angle with good shoeing and good conditioning.

TO BE CONTINUED ...
-- 
* * *
Abby Bloxsom
ARICP Certified Instructor
Level III Recreational and Distance Riding
Colebrook, CT USA
goneriding@snet.net




-- 
* * *
Abby Bloxsom
ARICP Certified Instructor
Level III Recreational and Distance Riding
Colebrook, CT USA
goneriding@snet.net