Essays by Kirk Adkins
Shoeing for
Performance
As with other technological advancements,
horseshoeing, as we largely practice it today, came from the requirements of
war. The ancient northern Europeans known as the Vikings had no navigation
technology, which forced them to stay in view of the shore while navigating the
oceans. Having plundered the coastal villages of northern
They found that the distance they could travel
was limited because the horses got sore footed. The Viking smiths found that
they could make shoes from strips of iron, a very precious metal at the time, fashion nails and nail the shoes on. The technique
worked so well that the Vikings were able to move their armies across
After the Vikings withdrew the rest of
In as much as the
techniques and the reasons for shoeing have remained the same, new materials
have been added and some of the theories of trimming and shoe application have
changed. The advantages of applying a horseshoe for enhancement of a horse's
athletic potential are many.
Horseshoe Materials
Steel is by far the most common shoe material
for many good reasons. It is strong and inexpensive and can be formed into a
variety of shapes. It does have some drawbacks because of the hardness that can
create lameness.
Aluminum is an excellent shoe material. It is
relatively inexpensive and can be forged in the same manner as steel. The
softness of the aluminum is beneficial because the shoe more readily conforms
to the horse’s
way of going and the light weight is less fatiguing for a performance horse. A
shoe made of aluminum is a fraction of the weight of a steel shoe with the same
dimensions. A drawback to the aluminum shoe is they wear quickly in highly
abrasive footings.
Plastic shoes have some superior properties
for absorbing concussion and some have excellent wear properties. However I
find that the all plastic shoe has some shortcomings that keep it from being as
useful as a metal shoe. Attatchment is difficult
because nails are prone to drive through the shoe and shatter the wall during
the shoeing period. Some can be bonded to the hoof eliminating the nails however
bonding is difficult and expensive.
Composite shoes are outstanding in certain
areas of performance enhancement. Traction on pavement is best when a shoe with
a urethane tread is used and concussion absorption is superior to any pad
nailed between the shoe and the hoof. The main drawbacks for the composite
shoes are the cost, which can be many times the cost of standard shoe and pad
combinations.
Traction
Traction is improved by shoes over the bare
foot by the addition of shoes that:
Correction
The correction aspect of horseshoeing is when
the application of the shoe affects a permanent change in the horse's
conformation. This is only possible when the horse is still growing.
Differential loading of the physeal growth plates
causes a permanent change in the conformation of the leg. Mature horses with
fused physes are not able to have angular or
rotational deviations changed with shoes.
Compensatory
All other corrective shoeing measures applied
after the animal is mature are what I call compensatory. Poor
conformation is the primary cause for interference of the limbs when the horse
is doing its job. Shoes are constructed with different features designed to
correct the foot flight so the limbs do not collide. Configuring the shoe to
provide more support or to modify the breakover can
help deficient conformation.
Therapeutic
Injury and disease can cut short a performance
horse's career. The use of the shoe may help to counter those effects and
prolong the use of the horse. Increasing the coverage of the foot and
decreasing concussion helps slow cartilage and bone degeneration. The support
feature of a bar shoe helps prevent tendon and ligament strains. Increasing the
web of the shoe or the addition of pads can help with sore feet by increasing
the coverage of the sole. Concussion can be reduced by the use of pads or
special shoes with treads.
Conclusion
Shoes are necessary for the optimum
performance of our equine athletes. They can, in the quest for the blue ribbon
or to be first over the finish line, create a dangerous condition for the
horse. For example, increased strain on bones and joints caused by increased
traction is going to show up as injuries over the long term. However, shoes
have undoubtedly helped countless horses to cope with the job they are required
to do with comfort and safety when chosen and applied correctly.
The trouble with tradition
Many practices in the husbandry of the horse’s
hoof are carried out without exploring the validity of what is being done or if
there are new alternatives to old techniques. A variety of traditional
practices and beliefs are in fact harmful to the horse and yet are promoted as
being beneficial. Practices such as greasing the hoof, treating injuries with
toxic chemicals, trimming and shoeing techniques can lead to additional costs
of ownership because of lameness or loss use of the horse.
Hoof preparations that are grease or oil based
have been shown to increase the incidence of bacterial and fungal infections in
the hoof. The notion that a soft flexible hoof is healthier is prevalent in the
industry. In fact the hoof capsule should be hard and tough when the
environment is dry and abrasive. Hooves adapt to the environment they are in
and efforts to stop that adaptation result in problems. The truly ironic thing
about this is that great effort and expense is expended to potentially harm the
horse.
In treating the hoof, poisons are routinely
used to treat wounds. Somehow the tough outer hoof capsule leads people to
think that it can be treated with the same chemicals as a piece of wood.
Formaldehyde, concentrated solutions of Iodine, turpentine and used motor oil have been used on the hoof. There are many reasons not to
use these compounds because they are toxic, even less reason when there are far
better treatments available today.
Trimming the hoof to fit the shoe has always
been viewed as improper shoeing technique, however there are many farriers and
owners who advocate "backing the toe up" for horses that they
perceive to have a long toe. Shaping the hoof to this pattern is the same as
shaping it to a shoe. The result is a weakened hoof and related shoeing
problems.
Race track shoeing creates problems by
cultivating a hoof shape in the opposite direction. The notion is that a longer
toe helps to win races by increasing the length of stride and increasing
traction. Studies have shown that the long toe does nothing for speed but does
greatly increase the chance of injury. The construction of the shoe also
creates a poor hoof capsule because fine nails and lack of shoe support cause
the farrier to adopt practices that are harmful to the hoof.
Traditional trimming theory is based on the
assessment of the hoof and pastern alignment as the criteria for
anterior/posterior balance. This requires that the heels of the hoof are
sometimes left very long in order to accommodate this alignment. The excessive
heel length has been shown to create soft tissue injuries. A new criterion for
proper anterior/posterior balance of the hoof is to use the solar plane of the
coffin bone. This requires different criteria for trimming the hoof and
sometimes radiographs to be able to accurately find this anatomical reference.
There are other times
when tradition is still the most practical way of doing things. To break with
tradition requires reasoning not rationalization. Question authority and require
that the accepted ideas and techniques withstand scrutiny and challenges from
new information.
CARE AND MANAGEMENT OF THE HOOF
CAPSULE
Exercise
Exercise is an extremely important factor in
the health of the hoof and the horse in general. The absence of muscles below
the knee and hock require compression of the venous plexi
in the hoof to return blood back up the leg. Without exercise blood circulation
is slow and inefficient and delivery of the vital components for hoof health is
impaired.
Nutrition
The hoof capsule is a hornified cornified
epithelium with a requirement for sulfur bearing amino acids. Good quality
feeds are necessary for good strength and growth rate. Lysine, cystine and methionine are the
critical amino acids for the strengthening disulfide bonds in the keratinized
cells. These amino acids are found in good quantity in feeds based on milk or
soybean protein. Gelatin is not rich in these amino acids and probably only
plays a role in the sparing of the essential amino acids in the diet. Biotin is
only a cofactor vitamin that assembles the amino acids. Diets low in the
essential amino acids will show a very poor response to biotin supplementation.
Trace minerals and micronutrients are also a vitally important factor in the
health of the hoof. Supplementation of these is important in that most of the
diets of our domestic animals are produced in a region that is not likely to
have the variety of sources of these nutrients. Kelp has been shown to be a
very effective supplement to provide these micronutrients. Probiotics
are also very effective in promoting good hoof growth. They act on the gut
flora to enhance digestion and absorption of the nutrients in the feed making more
efficient use of the nutrients. Also the microflora produce biotin which is a natural source for this vitamin.
Environment
Horses that are stall bound suffer the most
insults to the hoof capsule. The environment the hoof is in is quite different
than what is encountered just a few inches up. The bedding is s source of
harmful ammonia, which attacks the hoof and destroys the quality of the protein
in the hoof by breaking down the bonds in the keratinized protein. The hoof,
from the feces and urine in the bedding absorbs excessive moisture. Fungus and
bacteria thrive in the bedding and attack the hoof. It has been my experience
that the incidence of fungus infections in the wall is much lower in pasture
horses than stall bound horses.
Excessively wet conditions are damaging to the
hoof. The keratinized protein has a soluble phospholipid "glue" that is leached out. The
cells swell with the osmotic pressure of the water and break the intercellular
bonds. These bonds cannot be reformed, as the cells are no longer alive and
capable of repair.
Many problems have been associated with
excessively dry conditions such as cracks and contracted feet. It is my
experience that aside from extremely difficult trimming and bruising from
concussion on the hard ground there are no great ill effects from a foot that
is dry. The hardness of the foot is necessary to withstand the conditions of
the hard ground. It is not unlike calluses on our hands in response to hard
work. Contraction of the hoof is a symptom related to a problem in the hoof or
leg. Atrophy occurs when hoof is not fully loaded. Without proper stimulation
the hoof contracts as a result of the change in weight bearing. There are
normal variations of the hoof size throughout the year due to the content of
water in the hoof. Wetter seasons are going to cause the hoof to swell and
could possibly require a larger shoe. This is not necessarily a problem if the
hoof remains reasonably healthy in the other respects.
Poor Shoeing Techniques
The largest problem with foot care is the
removal of the wall unnecessarily. The reasons for this practice are numerous
and most of the time is damaging to the hoof. Improving the appearance,
"backing the toe up" or compensating for the lack of skill in fitting
the shoe to the hoof are a few of the reasons the wall
is removed. I am not advocating the wall should never be rasped on the outside
but it should be undertaken with the greatest care and consideration of what is
the benefit to the animal. Shoe design is another factor in the removal of the
wall. Nail placement in the shoe sometimes makes it impossible to place the
shoe securely and have a cosmetically good-looking job without removing the
wall back to the shoe.
Poor Shoe Design
Horseshoe design greatly affects the hoof. The
primary factors negatively impacting the hoof are the nail set in the shoe and
the width of the web. If the nails are punched too fine, a common problem of
racing and training plates, leads to all sorts of problems. To present a neat
job the wall is rasped back to the shoe, ultimately removing enough wall to weaken the hoof. The narrow web shoe doesn't provide
enough coverage of the sole to prevent pathologies from bruising and
concussion. They are widely used because they are relatively easy to shape
cold.
Owner Related Problems
Owners can and do create their own problems by
trying to fix something that isn’t broken. This is primarily related to
the excessive use of greasy hoof conditioners. In the desire to do the right
thing the hoof becomes so saturated with softeners that the wall can no longer
function. Splitting and peeling is misinterpreted as dryness and more
conditioner is applied until the shoes no longer stay on and the foot is
peeling because the wall is saturated with greasy softeners. The only remedy
for this is to stop the hoof preparations and grow out a new hoof. There are no
fat secreting glands in the hoof and it is not a normal constituent of the
wall. Flexibility of the hoof is restored by moisture, and care must be taken
not to over saturate the hoof so it is unable to cope with a tough environment.
Topical preparations that are sealants may be detrimental because they block
transpiration of moisture and exclude oxygen, which creates an environment
favorable to anaerobic organisms to attack the wall. There are products that don’t
block the normal "breathing" of the wall, protect from the harmful
effects of ammonia and condition the keratinized protein to be more resilient
without the use of grease. These have been shown to be beneficial in retaining
the health of the hoof.
It
seems a simple question but in fact there are many considerations whether the
shoe fits. The first thought that comes to mind is the overall size of the shoe;
does it cover the foot from heel to heel or not? In fact that is one of the
last considerations. Before taking a shoe from the shelf or beginning to build
one, many factors must be considered about the “fit” or more
appropriately the suitability of the shoe for the job. Protection, traction and
support are the most important. Other properties that we might like the shoe to
have may include gait modification and therapeutic value.
Protecting
the hoof wall from excessive wear and putting weight on the sole is the most
important feature of the shoe in most cases. A wider webbed shoe is more
desirable because of the coverage of the sole, however as the shoe width
increases, traction decreases. An example of this is a “Slider”
type shoe which is usually one inch or more in width which covers most of the
bottom of the hoof, good protection but the width of the shoe allows the
reining horse to “ski” across the arena. Not a desired effect if
the horse is an endurance or eventing horse, they
prefer a little more traction. “Fitting” the appropriate balance of
protection and traction requires a little more attention.
Support
is also important. Fitting the shoe to absolute shape of the hoof is fine if
your main concern is not to loose shoes, but not a good thing when at four
weeks the shoe is overgrown by the hoof. All shoes need to have a little extra
length and width to accommodate hoof growth during the shoeing interval of six
to eight weeks.
Support
of the structures above the hoof is achieved by elongating the rear portion of
the shoe. The added length of the shoe helps reduce the strain on tendons and
ligaments during the loading of the limb. This is best demonstrated by the
“egg bar” shoe. Lateral support is given by the shoe that extends
out from the side of the hoof for support of an injured ligament.
The
effect the shoe has on gait is well known and exploited. The general rule is
weight and length of the shoe increase the amplitude and reach of the foot in
motion. This is fine if you want to accentuate the gait of a Saddlebred show horse but not so if the horseshow class is
western pleasure class that stresses low, smooth gaits. The gaited horseshoe
should be heavier for the best fit for the job and lighter for the pleasure
horse. To make a shoe lighter you can thin the material so there is less of it,
which decreases the protection, or change the horseshoe material. Aluminum and
plastic are some alternatives to steel for shoe construction but come with
their own set of parameters of performance. Although aluminum is a softer
material it can be made wider and thicker to offset the wear. This has the
advantage of increased protection of the sole.
Another
consideration of fit that is seldom mentioned is the placement of the nail
holes in the shoe. It was common for manufacturers to place the nail holes very
close to the outer edge of the shoe, termed “fine”. This is a very
undesirable placement for a number of reasons. Nailing a shoe with fine nail
placement shaped to the perimeter of the hoof wall is very insecure because not
enough wall is clinched under the nail. Shaping the
shoe so the nail holes are over the white line improves the security but leaves
much if the wall uncovered by the shoe. The common practice is to rasp back the
overhanging wall to the edge of the shoe thinning and weakening the wall. Placement of the nail holes farther in termed
“coarse” has the benefits of conservation of the hoof wall and more
secure nailing.
The
only reason horseshoes are shaped is to place the nail holes in the shoe over
the white line. Sloppy fitting of the shoe can cause problems with pressure or
“quicking“ the
sensitive structures of the hoof. The nails should be driven to such a height
in the wall to afford secure nailing. Low nails are not necessarily a good
practice because they are weak and the chance of loosing the shoe is much
greater than the possibility of quicking with a
higher placement. In addition nails should not be driven behind the widest part
of the hoof to minimize restricting the expansion of the hoof.
In
reality, fit of a shoe has multiple factors beyond the actual placement of the
shoe. Protection, support, traction, the job of the horse, quality of the hoof
wall and construction of the shoe are all part of the fit of the shoe. Even the
best fit shoe becomes a problem when it is left too long. Be sure to do your
part and keep the shoeing intervals regular so the shoe can fit the needs of
you and your horse.