
“Doc – What's a 'Good' Foot?”
© A.J. Neumann, D.V.M.
published in The Draft Horse
Journal, Spring 2001
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The old saying “no foot, no leg,
no horse” is as true today as it was years ago when the
horse was the primary source of power and transportation for
the nation. From day one of its domestication the horse has
been subject to multiple uses, many of which have been performed
under very harsh circumstances. This, coupled with continual
reproduction of hereditary tendencies and defects, has produced
animals who are unsound in the foot, and their period of usefulness
for any job is short-lived. It is interesting to note that
the most common cause for the retirement of geldings serving
in the professional show hitches is lameness due to inherited
hoof problems. But yet today many judges and breeders of draft
horses are paying less attention to the horse’s feet
and are just looking at his size, color and action. The value
of most horses depends upon their ability to move and perform
work or do a job; therefore the animal must have a sound
foot which is free of pain and devoid of injuries and disease.
In defining the foot of the horse, old time literature would
describe the part of the animal’s body from the knee
or hock down. This comes from the zoological fact that the
horse’s knee is the same as our wrist, and his hock is
the equivalent to our ankle. So basically the horse walks on
what would correspond to one of our fingers or one toe. At
one time, eons ago, the horse is thought to have been a five-toed,
grass-eating animal about the size of a fox.
Today when we speak or write about the foot of the horse or
mule we are talking about the structure of the foreleg or hind
leg from the coronary band on down.
The coronary band is directly above the hoof wall. It is that
portion of the skin which produces the horn which grows down
and becomes the hoof wall. This horn tissue is composed of
very minute cylindrical tubes which are cemented together by
a very tough and tenacious material.
This horn tissue is very similar to the toenails and fingernails
of man. The hoof wall is the “thickest” at the
toe and “thinner” by the heels. The outside hoof
wall is covered with a hard waxy material called the periople.
Its function is to seal the moisture in the hoof wall. If the
periople is disturbed by cracking of the wall or by rasping
the wall, the hoof wall will dry and become more prone to further
cracking or in some cases “scaling” of the horn
tissue.
Technically the hoof is a container or box of horn consisting
of the horn wall, sole and the frog. The box, so to speak,
contains the lower section of the pastern bone, the coffin
bone, the navicular bone, the plantar cushion and the two lateral
cartilages.
In the rear or back of the foot is the heel, made up of tissue
known as the two “bulbs of the heel.”
It is interesting to note that the sole of the foot is made
of horn tissue produced by special cells which cover the bottom
of the plantar cushion and other tissues immediately below
the coffin bone. Its cylindrical tubes are not straight, as
in the case of the hoof wall, so therefore the sole “scales
off” in pieces, either due to normal wear or when the
farrier’s knife is applied. The sole is always concave
on its lower surface in the normal healthy unshod foot.
The frog is the triangular-shaped mass of special elastic
horn tissue which is found to the rear of the foot in the sole.
It has a deep cleft dividing it into two halves, called the
cleft of the frog. This cleft continues rearward and is known
as the cleft of the heel, as it separates the bulbs of the
heel. The horn tissue of the frog differs from that of the
hoof wall and sole in that it is relatively soft, moist and
very elastic or resilient. It is the outside function of the
frog to prevent the barefooted horse from slipping and to alleviate
shock when the foot strikes the ground.
Excellent rear foot on a draft stallion. Measurement from bulb
of heel around bottom
edge of hoof wall to other bulb was 19 inches. Hoof head measured
17 inches.
The weight of the horse is borne on the hoof wall and the
frog. It is never borne on the sole. When viewing the bottom
of the foot, the forefoot is generally round, and the hind
is more pointed at the toe, or “heart-shaped.” This,
of course, is seen in the horse. Donkeys, mules, hinnies and
other members of the ass family have feet which are longer
than wider, both front and rear. Their hoof walls are usually
quite straight on the sides. These breeds of animals will also
have a narrow heel, but this is entirely normal for them.
A thick pad of spongy, fibrinous tissue is found under the
navicular and coffin bone and rests on the sole and frog. It
is called the plantar cushion. One of its functions is to destroy
shock or provide a cushion to the downward thrust of the leg
bones on the coffin bone. This tissue contains many blood vessels
and therefore is very vascular.
The lateral cartilages are located one on either side of the
hoof and are attached to the wings of the coffin bone. They
are surrounded by a large number of blood vessels. When the
foot moves, these cartilages will in turn move inside the hoof
and act to keep the coffin bone and adjacent structures properly
aligned.
The navicular bone is located behind the coffin bone. The
two flexor tendons, the big ones on the rear of the cannon
bone, pass over the navicular bone and attach to the rear of
the coffin bone. Thus the navicular bone acts as a fulcrum
for these powerful flexor tendons.
The bulbs of the heels are the most rear portion of the foot.
These bulbs are very vascular and so is the underlying tissue.
The cleft of the frog continues back into the heel tissue,
separating it into the two bulbs. They act as a cushion for
the rear of the foot.
In addition to the functions already outlined for the frog,
lateral cartilages, and the bulbs of the heel, they play a
very important part in the health of the tissues in the hoof,
as they act as blood pumps inside the hoof structure. If one
or more of these pumps are deactivated, due to disease, improper
shoeing, or hereditary factors, the foot will suffer irreversible
damage.
protractor
Now that we have defined the foot and discussed its anatomy,
let’s see what it should look like.
A foot should be level. To determine this, the foot should
be held up so that the wearing surface can be viewed from back
to front. One imaginary line is drawn which bisects the cannon
bone, pastern and heels and is crossed by an imaginary line
crossing the lateral and medial wearing surface at the heels.
Where these two lines intersect each angle should be 90 degrees.
This is exactly what the farrier is doing when he holds the
foot up and levels it with his rasp.
Often when looking at the foot, one need not hold it up to
see if it is level. In the so-called “crooked foot” one
side of the wall is higher than the other. If the inside wall
is higher, the fetlock joint is thrown outward and the toe
is turned inward. This condition can easily be seen, and the
animal is called “pigeon-toed,” or in horseman’s
terms “a bear-tracker.” In exactly the opposite
condition the outside of the hoof wall is higher, and the fetlock
is tipped in with the toe turned out. This condition is called
a “splay foot,” or in horseman’s lingo a “Charlie
Chaplin foot.”
Another conformation fault which can easily be seen is the “club
foot.” In this condition the wall of the foot is nearly
straight up and down, or perpendicular. The heels are very
high, and the animal’s weight is carried on the toe of
the hoof. It is interesting to note that many mules are club
footed in the rear feet, but it does not seem to cause them
much trouble in their gait.
Excellent rear foot on a draft stallion. Measurement from bulb
of heel around bottom
edge of hoof wall to other bulb was 19 inches. Hoof head measured
17 inches.
bad front
The so-called “flatfoot” is another conformational
fault of the horse. The problem is often seen in certain breeds
of the draft horse and is found usually only involving the
front feet. These feet are generally very broad, flat and with
low heels. The wall of the foot is always less upright, will
crack easily and the weight of the animal is borne on the sole,
frog and heels. These hoof walls are always white in color.
I have never seen this condition in a black-hooved draft horse.
Contracted heels of the horse are easy to spot. The whole
foot is narrowed, and the width of the heels, when viewed from
behind, is greatly reduced. If the bottom of the foot is examined,
the frog will be atrophied and recessed into the foot. The
rear portion and sides of the foot will give the appearance
of having been squeezed. This condition generally involves
the forefeet of the horse, but it may involve all four of the
feet.
Most every horse person has heard of a “coon-footed” horse.
It is a very honest and descriptive term applied to the foot
of the horse if the pastern slopes more than does the front
of the hoof wall. In a normal horse, when viewed from the side,
the slope of the pastern should blend into the slope of the
front of the hoof wall to form a straight line. When this does
not happen, it appears that the pastern has “dropped” and
very closely resembles the foot of the raccoon.
There are many other conditions of the hoof wall which can
be seen by an individual if he or she just takes the time to
look. One obvious thing is the presence of one or more “rings’ in
the wall of the hoof. There are many causes for these rings,
laminitis or founder being probably the foremost. Changes in
the diet, a high fever, damage to the coronary band and overheating
of the animal are other factors which will produce the rings.
The most casual examination of the foot, perhaps just a glance,
will reveal the presence of cracks, sand cracks, quarter cracks,
tags on the quarters, brittle feet and “shelly” hooves.
Longitudinal or horizontal fractures or cracks in the wall
of the hoof can be easily seen. These will sometimes appear
in the best of manicured hooves.
Excellent rear foot on a draft stallion. Measurement from bulb
of heel around bottom
edge of hoof wall to other bulb was 19 inches. Hoof head measured
17 inches.
hoof
I believe the color of the hoof wall is very important. I
read not long ago that this does not matter, but I beg to differ
with anyone holding that opinion. The white hoof wall seems
to be far more prone to pathology such as cracking. The black
and white striped hoof wall is more resistant, and the black
hoof becomes very resistant to cracking and the presence of
tags at the quarters. I have enclosed with this article a number
of pictures taken of individual horses whose feet were trimmed
in March of the previous year. These horses all received the
same ration and were together on the same type of soil. None
were used for any work, and none were used on any hard surface
such as gravel, asphalt or concrete. These pictures were taken
nine months later to show what happens between white and black
feet.
So now we come back to the original question: “What
is a good foot?”
You should know the answer already from having read this article.
In the draft horse the good foot has to be large. It must have
a good wide heel—called the width of heel. The heel must
grow at the same angle as the toe. The sole must be concave,
and the white line where it fastens to the hoof wall must be
the same width all around. The frog must be large, healthy
and at least four inches across in its widest part by the bulbs
of the heel. By the way, did you know that many old time breeders
would not keep a mare or stallion for breeding unless the frog
was four inches wide or better at the heel?
The wall of the foot must be thick, shiny and free of rings
and cracks. If it is black in color, so much the better. The
quarters should be reinforced with heavy bars to hold that
part of the foot in place.
Excellent rear foot on a draft stallion. Measurement from bulb
of heel around bottom
edge of hoof wall to other bulb was 19 inches. Hoof head measured
17 inches.
hoof
If the foot itself is large, wide and lengthy, the hoof head
or coronary band area must be large in circumference to match
it. A wide flared foot with a small hoof head is an anomaly
brought on by Scotch bottom shoes, body shop putty and paint;
and it is often seen in our draft horse shows.
Such a good foot as I have described must also be healthy,
free of disease and inheritable unsoundness such as side bones
or ring bone.
There is only one way to put such a foot on the horse. That
is strictly by breeding its qualities into your stock. You
cannot do the job with show shoes and body putty. You cannot
fool a good judge or a breeder that knows what the score is.
But take a look around. I have! Look at some of the top mares
and stallions in shows today. They’ve got the feet of
a saddle horse or 1200 pound mule under an 18.2 hh, 2,000 lb.
mare, gelding or stallion; and that’s our breeding stock
or the product of our draft horse breeding programs today?
I wonder how long these animals will last. I’m afraid
I know, and I wouldn’t want to pay a big price to have
them around for any job. I too well remember what happened
to a well-known light horse breed that got caught up in the
same scenario a few years ago!
Now you really knew what a good foot was, anyway—didn’t
you? |