Hoof Care for Angular Deformities 6-17-07 Pete Ramey
Little has been
written about hoof trimming for angular deformities. Most
writers have avoided the subject and with good reason. Every
situation is different, and nothing could be written that would
work every time. The professional in the field must be willing
to pay close attention to detail, adapt and switch tactics.
Following a rigid protocol of any kind will be detrimental to
some cases. That said, I’ll lay out my basic protocols and the
way I approach the hooves on crooked limbs. Somebody has to do
it.
This article is
clearly written from a standpoint of my opinion and
experience, because that is honestly all I have on the subject.
To my knowledge there is no research to deliver. Almost every
imbalanced hoof is being caused by an issue somewhere above the
hairline, so every imbalanced hoof you see should send you on a
detective mission, trying to determine what is wrong in
the body or limb and what can be done about it.
Foals vs. Adults
From a trimming
standpoint I approach foals and adults the same. The big
differences between the two come in “Importance” and “What to
expect.” With a foal, you are faced with rapidly closing window
of opportunity to achieve permanent correction to the limbs. By
the time the foal is one year old (or less), the changes you can
make to the joints are much more limited. When a foal fails to
become straight-limbed within one to two weeks after birth, it is time
for immediate action.
I view the
veterinary role as offensive and the farrier role as defensive
(I’ll explain later). Farriers should not approach these cases
alone. Blood work and/or forage testing (for mare and foal) needs to be done to test
for nutritional problems. Most angular deformities in foals have
mineral imbalance, dietary excess, inadequate nutrition and/or
disease as the primary cause. If this is the case, you will not
trim or shoe your way out of the problem. Also vet turf: There
is a time to “wait and see,” a time to splint, a time for
surgery... All on a quickly evolving time schedule. If you wait
until you have already failed and the horse is a year old, there
will be very little the best equine vet can do for the horse.
With proper hoof
care and movement, even adult limbs/joints can become straighter
over time, but it should not be something we push for or dwell
on. For the most part we should accept a crooked-limbed horse
over two years old as is, set up the hooves accordingly and then
"wait and see." Cutting a straight hoof onto a crooked limb is
just as harmful as cutting a crooked hoof onto a straight limb -
don't try to force balance onto an adult horse.
Balance in General
Before we get into imbalance, I have to discuss balance. Also read http://www.hoofrehab.com/Balance.html for greater detail.
No one can balance a
foot. If you show me a “perfectly balanced" foot, I’ll lead the
horse through a slight turn, and we’ll watch together as one
heel hits the ground before its partner. So what is mediolateral
hoof balance? The horse needs both heels to hit the ground
simultaneously as often as possible. Therefore terrain,
movement, type of work, body issues and limb conformation all
create variables to “proper” balance. This sounds complicated,
but in reality it’s quite simple, because the lateral cartilages
(the foundation for the back half of the foot – similar in
function to the coffin bone, but with much greater flexibility)
adjust their pre-load position for the most common way the foot
hits the ground. Then they allow the entire back half of the
foot to flex and twist to accommodate other types of impacts
(uneven terrain, turns, or standing on a flat surface). I’ve seen countless complicated balance
situations, but have never seen a horse that needed more “skin”
(sole, wall, bars) covering one lateral cartilage than the other
on the same foot. So at least this little part is easy. [Well,
I do remember one exception: The coffin bone had matured in a
distorted hoof capsule and was actually twice as "tall" on one
side than the other. None of this can be "put in a box." Again
the professional in the field must be willing to adapt and able
to think.]
The distance from
the bottom of the collateral groove (Read
http://www.hoofrehab.com/HorsesSole.html for deep explanation) to the lateral cartilage is
consistent on each side of the foot, so you can balance the
amount of material covering each lateral cartilage by
balancing the distance from the collateral groove depth (at the
deepest point beside the bars) to the heel – or put
another way, balance the collateral groove height off the ground
on each side of the foot.
This is far more
accurate than looking at hairline to heel distance. The hairline
is highly dynamic, always moving, so it is not an
accurate place to measure from. Excess stress on one heel often
moves the hairline upward, relative to the lateral cartilages
over time. The callused sole plane is the next-most-accurate
guide to the amount of material covering the lateral cartilages,
but in some cases of severe imbalance, uneven wear can create a
thicker sole on one side. The collateral groove balance doesn’t
lie (except in very rare cases of subsolar abscessing under one
side and when the grooves have been eaten deeper by fungal
infection) so that is my primary means of ensuring that both
lateral cartilages on a given foot are covered by the same
amount of material: My view of perfect heel balance,
if there is such a thing.
Furthermore, I
see no reason why heel balance and toe balance should relate to
each other. Specifically, I see no reason why the heel plane and
toe plane should be parallel with each other. Heel balance
should reflect the way the heels impact with the limb extended.
Toe balance should reflect the way the foot leaves the ground
with the limb in the back position. These limb positions are six
feet away from each other from the horse’s perspective and may
not need to be exactly parallel. In most cases, in the front of
the foot, the coffin bone also needs the same amount of sole
covering both sides, and the same amount of hoof wall standing
longer than that sole on both sides. Read
http://www.hoofrehab.com/Balance.htm
for exceptions and more clarity.
Defensive Trimming
When faced with
angular limb deformities, I view the farrier’s role as
critically important but completely defensive, not offensive.
Attempts to push a limb straight by cutting exaggerated,
crooked hooves tend to adversely affect the coffin joint while
having either no effect or sometimes an adverse effect to
the offending joint (fetlock, carpus, etc.). Of particular
concern is causing sensitivity at the crooked joint and causing
the horse to “lean away” from the pain, making the problem
worse. I do not think properly applied lateral extensions
are particularly bad, except that in the real world their
presence tends to lead to infrequent trimming, creating a very
important negative. I always stand ready to use one if a horse
can't stand up onto his foot at all, but rarely see that
need.
With an angular
deformity in a foal, it is critical that we not put something
on and walk away. The hooves will need constant attention.
The best way to
explain my view on this is to get more specific. Any angular
deformity affects and is affected by the hooves the same way,
but I’ll discuss the most-common pigeon toe (toed-in, fetlock varus)
in which the fetlock joint turns or deviates inward. These
horses tend to primarily load the outside wall/heel (though some
will load the inside heel and outside toe if the coffin joint is
valgus or deviated outward). These horses can often be corrected
quickly in a foal - or in an adult, over the course of many years.
Either way “the fix” is miles and miles of straight-line
movement on hooves that have the internal structures balanced to
the ground. The challenge or “catch” to this comes
with the fact the imbalanced limb usually creates a crooked hoof
in less than a week – then all the movement in the world will
only hold the joint in a crooked position.
These horses will
usually carry most of the load on the outside wall. The horse
grows enough extra hoof wall everywhere to accommodate the extra
load/wear to that outside wall. This translates to constant
excess growth at the inside wall that can’t wear away because it
isn’t used. This crooked hoof that can develop overnight locks
the limb in the incorrect position and also increases wear to
the outside wall/heel even more – a vicious snowball effect. So
the farrier’s job is simply to keep the inside wall from
overgrowing – ever. This is easier said than done, but I can
give you some real-world tips that help.
A secondary role we
need to be prepared to fill, is coping with excess wear to the
outside wall/sole. This is extremely rare IF the inside wall is
not allowed to overgrow, thus dumping more pressure onto outside
of the foot. Regardless of the cause, though, when the sole is worn too thin, I
build it back with Equethane Superfast or shoe glue and carry on as usual.
I rarely have to do it twice to the same horse, because again,
the true cause of the excess wear is usually excess wall that
was previously allowed to exist on the other side.
Battling the excess
growth at the inside wall on a “pigeon-toed” horse is best done
with weekly trims ($$$ Sad but true). If this isn’t done,
constant imbalance and flaring of the inside wall will probably
persist to some degree. This can get expensive, but most horse
owners who know or care nothing about hoof trimming can easily
learn to carry the bulk of that load, because they have a
built-in guide. I usually show them very specifically where the
foot overgrows, and have them rasp that spot (only) to match
the other side of the foot exactly (based on the wall height
above the sole plane). I have them do this once a week, and then
I come along at 4-5-week intervals to address the rest of the foot and
critique or change their work. It works wonders, and any owner
that can pick out a foot can be trained to do it. Avoiding
paying the farrier for weekly visits provides excellent
motivation.
The bottom line is:
to maximize success, we need many miles of straight-line
movement and the hooves must stay balanced 24/7, rather than
having their balance “corrected” at each trim.
Heel First Impact
Above all,
prioritize heel-first impact. A flat impact at the walk is okay,
but at any faster gait (including a fast walk) the hooves should
obviously land heel-first. One of the biggest reasons I mention
this here is that very often these (pigeon-toed or fetlock
varus) horses will have an outside heel that is windswept
or caved underneath the horse with bent horn tubules, or they
may be severely under-run. Rasping away these bent tubules is a
counterproductive addiction. Every rasp stroke
delightfully pulls the heel back farther under the horse, and it
is hard to make yourself stop. But if that “one more stroke”
causes sensitivity and a toe first impact you will not
make progress – period. It is better to primarily focus on the
constantly overgrowing inside wall and prioritize heel first
impact over everything else, even when that means leaving an
“ugly” folded under heel. Correct movement and frequent trims
will straighten it out.
Almost any type of
heel contraction, including this one will be accompanied with a
lack of digital cushion and lateral cartilage development
(Robert Bowker VMD, PhD) thus sensitivity in the back of the
foot. If the horse lands toe-first the internal foot cannot
develop, so fit the horse in boots with thick, padded insoles
for exercise. You cannot cut a healthy foot onto a horse. It
must be forged by natural movement. A pea gravel loafing area
will also work wonders for developing these horses.
Slowing Down Growth
The hoof is
constantly wondering how much to grow, and it figures
your trim into the equation. Therefore it is very important not
to speed growth in these horses with excess trimming. How do you
apply this? Try to avoid trimming the parts of the wall that
don’t need it. I believe that if you routinely trim 1/4-inch of
wall/heel from the heavily-used outside wall on a pigeon-toed horse, you
speed up the growth of the whole foot by that same amount
(probably more actually, because any of the outside wall you
remove will be callused or compacted horn). So if you try to
leave the outside wall alone, you can dramatically slow down the
growth of the offending inside wall. Use common sense with this.
I don’t mean blatant neglect, but if the inside wall only
needs 1/8th inch rasped away, try leaving it.
Most of the time you will come back at the next trim to find the
wall “hasn’t grown” or more accurately, the growth rate has
slowed down to match the wear rate (stopped growing enough
excess to allow for your trims). This was the most important
paragraph in this article!
Thinning the Walls?
I considered
leaving this one out, but it is a very good tool if used
correctly. It’s just a little dangerous, so use caution.
Mustang Roll Angles
When faced with an
imbalanced hoof I vary the angles of the ‘mustang roll’ or bevel
to the outer wall. In the specific case we’re discussing, for
instance (toed-in, fetlock varus, flared inside wall) I’ll trim
a very flat (almost ground-parallel) bevel on the outside wall or just a soft roll
of the outer edge. On
the flared inside wall I trim a very steep or exaggerated bevel
on the outer wall including the heel. I feel that the mustang
roll seeks balanced angles at ground level and that this little
trick helps me push a foot under the horse. This could
just be in my head – maybe the flatter roll on the outside wall
just doesn’t contribute to contraction, and the steep bevel on
the inside wall helps grow out the flare. Either way, it works.
I’m just not positive about the “why?”
I’ve used the one
example of the pigeon-toed horse because it is the most common,
but I use the exact same thoughts and principles for any lower
limb deformity. Basically, I use constant defensive prevention
of hoof imbalance that enables the horse to walk out of the
problem when/if we will. I focus on removing the constant
excess, and occasionally build any areas of excess wear. If wall
flare persists in the areas of less wear, you should
automatically know that more could be done to maintain constant
balance. The wall flare is the horse’s defense mechanism for
excess wall growth.
From a hoof care
standpoint, I’m convinced that the best we can do is constantly
keep the coffin bone and lateral cartilages balanced with the
ground plane, then keep the horse comfortable and constantly
moving. I’ve “been there, done that” with more aggressive
approaches. This way isn't always a magic wand but it
works better and more often than anything else I’ve done, seen
or studied.
Diet
Don’t forget the
nutrition. I must stress again that improper diet and mineral
imbalance in the mare and foal are at the heart and soul of most
cases of angular deformity in foals. Often this means inadequate
nutrition, but excess carbohydrate and/or excesses of certain
minerals can be worse than inadequate amounts. The most common
example is probably excess calcium. Calcium and phosphorus are
utilized by the same receptor. Excess calcium can create an
effective depletion of phosphorus, even if plenty is available.
It is the ratio that is important. Timothy hay often has over
3 times as much calcium as phosphorus. Alfalfa usually has at
least 7 times more calcium. Many feeds and supplements add even
more calcium, without balancing it with phosphorus. The body
tries to balance the situation by robbing phosphorus from the
bones, contributing to bone loss in mature horses and angular
deformities in foals.
Some breeders
cause these problems by adding more, more, more; effectively
“loving their horses to death.” The only way to know is to test.
So a sharp equine vet and/or equine nutritionist are worth their
weight in gold in these cases. If you forget that part early-on,
you may stick yourself with a permanent deformity that could
have been easily fixed or prevented. Read
http://www.hoofrehab.com/Diet.html.
Early Trimming and Movement
Remember that all
foals are “born crooked.” They’ve spent their whole life wrapped
up in a ball! Movement is essential for straightening them out.
Unless directed by a veterinarian for a specific injury or
condition, do not confine foals in stalls. Every aspect of their
proper development requires movement. I also firmly believe that
if every foal received routine competent hoof trimming from the
very beginning and if all foals were allowed 24/7 freedom to
move, angular limb deformities in adult horses would
virtually disappear from the horse world. I've seen this with my
own eyes in my own clientele. Severe birth defects do happen but
they are far more rare than most people think. Instead, what is
very common is that foals get off to a slightly wrong start,
this skews the hoof balance and then their joints, ligaments,
tendons and muscles are allowed to grow and form on the
imbalanced, neglected hooves. Eventually the horse matures and
the conditions are effectively permanent.
Most people think
that hoof trimming for adult horses is a necessity and foal
trimming is a luxury. If anything it should be the other way
around. If I financially had to pick out two years to neglect
the hooves on MY horse, I’d choose the last two or maybe a
period in the middle – absolutely not the first two years! There
was never a truer statement said than, “An ounce of prevention
is worth a pound of cure.” With angular deformities, that's
actually an understatement.