An Investigation into the Frequency of Occurrence of Asymmetric Pairs
of Front Feet in Mature Equines
Summary
REASONS FOR PERFORMING STUDY: Asymmetric pairs of front feet have been
identified using only visual assessments or comparison between the dorsal hoof wall
angles of each foot in a pair. Existence of the condition is viewed as a potential
unsoundness that may be a predictor of early pathology and lameness. Limited research,
however, exists into how frequently the condition occurs in the mature equine, or what
shape or forms it may take.
AIMS: To identify in a limited population of adult horses the frequency of occurrence of
asymmetric front feet, and any dimensional variations.
MATERIALS AND METHODS: A study group of 40 (n=40), general purpose, mature
horses was selected and measurements of both front feet taken. All of the study
population had their front feet trimmed following a standard protocol. Four linear and one
angular measurement of each front feet were taken from each of the equines using a
digital vernier caliper, brass hoof gauge and a standard metric ruler.
RESULTS: None of the total study population (n=40) demonstrated matching pairs of
front feet. Four subjects demonstrated significantly different measurements between left
and right feet. These differences where noted in the width of the hoof, distance between
the heels and dorsal hoof wall angle. Length of foot and width of coronet appeared less
relevant for asymmetry in this population
CONCLUSION: Mismatched pairs of front feet occurred with a 16.66% rate of incidence
within the study population. Sufficient evidence exists from the literature, to indicate the
condition manifests itself as the result of skeletal asymmetry and the preference to use
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one limb over the other. The syndrome appears to be multidimensional and cross species
in nature. Using visual identification or dorsal hoof wall angle alone may be insufficient
to accurately describe the condition.
CLINICAL SIGNIFICANCE: A more comprehensive understanding of the influences for
asymmetric front feet, and the conditions multidimensional nature, may lead to further
research into trimming and shoeing protocols. These protocols should be bases on the
biomechanical needs of the equine rather a preference to achieve an aesthetic appearance.
Finally, objective information about the incidence of mismatched front feet may then
allow research into whether the condition is associated with certain pathologies
1. Introduction
Asymmetric pairs of front feet, (also referred to as mismatched hooves, uneven hooves or
the “high/low” syndrome), have been identified both anecdotally and empirically (Bell
1996, Gonzales 1991). From a practical perspective this phenomenon is considered to be
aesthetically displeasing by the horse owner, particularly in the show ring as it may have
an affect on appearance to the judge, or for sale. In the athletic equine it is felt that the
condition may affect the range or level of performance. From a veterinary and farriery
perspective it is believed that the condition may be an indicator of underlying pathology,
or unsoundness, or it may predispose the equine to future pathology (Wilson et al 2009.).
Concerned owners and veterinarians often call upon the Farrier to effect change and
produce a more aesthetically pleasing pair of front feet. This is done with the belief that
the changes will potentially enhance quality and length of performance and minimise the
risks of pathology. The usual approach to trimming and shoeing of these feet; is to trim
the long heels of the steeper angled hoof and fit the shoe with width and length. This is
believed to give this hoof a larger appearance and a similar angle to its contra lateral
partner. The other hoof has no heel removed, and the hoof wall is trimmed to make it
appear less acute in angle. The shoe is then fitted to the periphery of the hoof with the
minimum of width and length to make it appear smaller (Butler 1985). These actions are
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often undertaken without regard to the biomechanical needs of the individual hooves or
the conformation of the limbs that they support and therefore the author considers these
actions to be ill advised without a more in depth understanding of the condition.
It should be also noted that, in many of the instances of attempts to “correct” the
condition, the equine is usually performing to a reasonable level, with no sign of
lameness or infirmity. Wilson et al (2009) postulated that some type of compensatory
mechanism may exist to assist the equine to cope with the condition. Should this
mechanism exist, then it is theorised that the trimming of the hoof to produce the
aesthetically pleasing model, rather than for biomechanical efficiency, could interfere
with, or remove that compensatory mechanism.
The aim of this study was to identify the frequency of occurrence of asymmetric
front feet in a limited population of adult, general purpose equines. It also aimed to
identify to what differences may exist, and any variations of the condition. Once the
condition is better understood, a suitable trimming and shoeing protocol could be
devised. Further objective data may then allow other Farriers and Veterinary
Surgeons, to conduct further research on how and why the condition exists.
1.1 The “Ideal” Foot
The “ideal” equine foot is believed to fit within an acceptable range, rather than comply
with an exact number (Craig 2009). The equine is usually regarded to be in the “normal”
range, if the front foot is basically round, symmetrical in nature around the long axis of
the limb, with an angle of between 50º and 55º (Hickman and Humphrey 2004, Floyd and
Mansmann 2007). The angle of the equine foot is usually measured at the dorsal aspect of
the hoof wall as demonstrated in figure eight, and this will be referred to as the Dorsal
Hoof Wall Angle (DHWA) for the rest of this paper. Casonova and Oosterinck (2012)
demonstrated in a population of young Catalan Pyrenean horses that, the width of feet
and the length of foot were approximately the same, suggesting a relationship which
could also be considered to be a “normal” observable fact whatever the size of the feet in
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question. Further research work has suggested that ideal feet show quantitative geometric
proportions (Balchin et al 2009). If this ideal is achieved, and the equine has symmetrical
limb conformation, it should follow that pairs of front feet should follow the same
principles and appear as a reasonably matched pair. Figure one demonstrates a pair of
feet that, although they do not display perfect symmetry, are visually of similar angles
and dimensions.
Figure 1: A reasonably matching pair of feet?
It is further expected that, even when pairs of feet do not fit into the “ideal” scenario, that
they still should still exist with similar dimensions and angles. Wilson et al (2009)
however noted in their study into skeletal asymmetry, that in 358 pairs of measurements
(of front feet) taken only 11 instances demonstrated no difference between left and right
measurements.
Asymmetric pairs of front feet are usually reported as one hoof having a steep angle with
a long heel (the “high” foot). This foot is often described as being “upright, “boxy” or
“club” in relation to its partner, regardless of its actual angle. The other hoof has a more
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acute angle and generally appears slightly larger (the “low” foot). Quite often the
condition appears with one foot in the previously described ideal range, with the other
having a more acute or steeper angle in relation to its contralateral partner. This is in
contrast to what is regarded as an “ideal” pair of front feet which are expected to have
similar dimensions. It should be pointed out that these asymmetrical feet often present
with other characteristics.
1.2 The Steeply Angled or “High” Foot
The terms “upright”, “boxy” and “club” footed are used liberally when asymmetric pairs
of front feet are observed; to describe any foot with a steeper angle than its contralateral
partner. Floyd and Mansmann (2007) states that when mismatched feet present, the
condition (the steeper angled foot) should not be confuses with a “club foot”. Stashak
(1976) defines an upright front foot as one with an angle between 55º and 60º, a boxy
foot between 60º and 65º and a club foot as being greater than 65º. In asymmetric pairs of
front feet, the steeper foot is often referred to as being the “more upright” (boxy or Club)
foot, without regard to this definition. There is very little evidence to suggest that the
more steeply angled foot does not still fall within ideal parameters.
Redden (1992) describes a foot as being “upright” if it is more than three degrees steeper
than its partner. This however may lead to an inaccurate evaluation of a pair of feet as it
is being judged against its contralateral partner that may, in itself be outside the expected
range. Thus, there are problems in definition of “upright” that derive from being relative
(to the other foot), making any judgement subjective in nature.
Other characteristics that may be displayed by the more steeply angled foot are;

Long, sometimes contracted heels.

A small, often atrophic frog.

A concave slope on the dorsal wall.

A deeply vaulted sole around the apex of the frog.
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
A flattened, compressed area of sole in the toe area.

An idiopathic deterioration of the white line (seedy toe/white line disease) in the
toe area.
It should be noted that in some cases that a crena or dorsal notch can be observed on xray plates of these feet at the juncture of the distal border and dorsal surface of the distal
phalanx. It should also be noted that despite demonstrating distinctly different
characteristics, asymmetric pairs of front feet are still routinely identified by differences
by eye or dorsal hoof wall angle alone. This is quite often done by comparing one foot
against the other (i.e. a relative difference) without regard to any stable norm (an
objective measure versus a population data set).
1.3 The Acute Angled or “Low” Foot
This foot type displays a distinctly more acutely angled foot pastern axis in comparison
with its contralateral partner. Quite often this is accompanied by a broken back foot
pastern axis and other deformities usually identified with pairs of flat feet such as

Collapsed or under-run heels

Over-developed frog

Long toe with a stretched white line in the toe area

Bent or displaced bars

A broken back foot pastern axis
A particular characteristic of the flat foot in the mismatched hoof scenario is that it is
usually has a toe-in conformation. This conformation defect may be a simple
misalignment from the fetlock, or a more distinct base narrow deviation from the
shoulder. As the limb with the flat foot is hypothesised to be longer than its partner, this
may be an adaptation facilitate an easier break-over.
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As with most pairs of feet of this nature there is a tendency for the problem to become
exacerbated with time, particularly if there is a lack of appropriate trimming or lack of
support at the caudal aspect of the hoof. The example in Figure two demonstrates the
typical scenario. The right hoof appears to have a steeper dorsal wall angle than its
collateral partner, and longer heels. The left hoof appears more acutely angled and wider
than the right hoof.
Figure 2: An obviously asymmetric pair of front feet
1.4 Environmental Influences
The effects of the environment on the equine hoof are well documented (Bradley et. al.
2002, Reilly 2006). However any extremes of temperature, humidity, diet and general
management would be expected to affect all feet in the same manner. The traditional
preference of the owner/rider to lead, mount and generally work with the equine from the
left side may have some significance should the study show a bias of one of the
asymmetric feet (e.g. the steeper foot), being on one particular side. McGreevy and
Rogers (2005) identified this preference to work from one side and considered that it may
have a possible side bias. They went on to state that data from unhandled foal ay
therefore be of particular value. It should also be considered that where the equine is
working predominately on the road, that the camber may have some effect on weight
distribution and result in disparity in hoof conformation between left and right feet. Any
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effects caused by the camber, would however, be expected to be cancelled out should the
subject return to working on an even surface.
Most working Farriers will be familiar with the change in dimensions that are associated
with feet that are subject to habitual shoe loss. These feet tend to become more upright.
Almost stumpy in appearance due to the loss of horny wall often associated with
premature shoe loss and the need to carry out some foot dressing in effort to replace the
lost shoe. Should this habitual shoe loss be unilateral (i.e. affect only one foot), whilst the
other foot retains its shoe, then a pair of feet will take on a mismatched appearance.
Usually however, if the habitual shoe loss ceases, the affected foot will begin to take on a
more matched appearance to its contralateral partner over a period of time. There is poor
understanding however, as to why habitual shoe loss should affect only one foot and not
both.
Other examples of mismatched feet where observed by Ivan Bell FWCF (personal
communication) during his study of Household Cavalry horses in Hyde Park Barracks in
1996. He noted that the right fore hoof was often slightly larger that the left and reasoned
that it was due to the Farrier habitually dressing the left foot first, and then spending less
time dressing the right hoof. This situation occurred when the Farrier was put under
pressure to keep up with another Farrier who was fitting the shoes. This problem was
overcome by the simple change of procedure of starting on the right foot on alternative
occasions which resulted in situation being reversed.
Other ways in which asymmetry may be introduced in the shoeing process is by the
existence of a medio-lateral imbalance in the hoof. The imbalance may be due to
conformational anomalies (e.g. an angular limb deformity), or by inaccurate dressing of
he hoof during the shoeing process. Effectively the hoof is just a thick layer of skin
(epidermis), with a form that is constantly being modified through growth, wear,
compression and concussion, as well as any act of farriery (Gill 2007). Should the
imbalance not be recognised, then over time it would be expected that the hoof will
change in shape, (and possibly size). If the imbalance exists in only one hoof, then
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predictably it will alter in relation to its partner as well as possibly causing pathology,
which in itself may lead to changes in the configuration of the hoof.
Whereas Farrier-related inducement of asymmetry should always be considered as a
possible source of the condition, modern training methods tend to indoctrinate the Farrier
into the production of symmetry and balance using consistent, definable parameters in
pairs of hooves. This is therefore unlikely to be a significant contributor to the condition.
1.5 Pathological Acquired Asymmetry
Acquired pathological conditions are another possible source of mismatched front feet.
Changes in the size, shape and configuration have long been noted by both Farrier and
Veterinarian (Pollitt 2001, Stastak 1976), as the result of trauma and certain chronic
pathological conditions. These changes tend to be more apparent when the condition or
its associated lameness, affect only one foot or limb (unilateral lameness). As the
pathology progresses over time the affected hoof develops distinct characteristics of its
own that set it apart from the (presumably unaffected) contralateral hoof (Floyd and
Mannsmann 2007). The changes in the hoof may be due to an impairment of natural
function associated with this acquired pathology, and/or a change in foot placement to
compensate for the impaired function. The development of a difference may also be due
to the unaffected, contralateral foot being subject to different stresses in effort
compensate for the discomfort/pain in the opposing limb. In many incidences of chronic
lameness there is if course the possibility of both situations contributing to the
asymmetry.
The example in Figure three illustrates the distortion that can occur (assuming the feet
where reasonably matched to begin with) when pathology is involved. In this case, severe
inflammation of the carpal joint has resulted in a misaligned lower limb. The resultant
misplaced weight bearing (through the long axis of the limb) has apparently caused
distortion in the conformation of the hoof capsule. The right foot may have become more
acute in angle due to compensatory weight bearing.
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Plate 3:
Front feet asymmetry attributed to pathology. Severe pathology has
affected the left Carpal joint which has led to a change in the conformation of the
associated hoof capsule.
One of the most common examples of this is the ossification of the contralateral
cartilages (sidebone). In this example the contralateral cartilages lose there function as
part of expansion/contraction mechanism of the hoof due to the chronic ossification
process. Usually the condition affects only the lateral (contralateral) cartilage, causing the
lateral aspect of the hoof capsule to become more upright and occasionally contracted
(unilateral sidebone). The hoof then becomes asymmetrical in its own right in relation to
its contralateral partner. Should the condition affect both the lateral and medial cartilages
(bilateral sidebone), then the hoof tends to develop contracture at the heels and take on a
more upright, almost “boxy appearance, which again makes it notably different from its
partner.
A more graphic example of hoof capsule deformity is seen in the equine with chronic
laminitis (Pollitt 2001); where the pedal rotation is moderate to severe in one foot, but
exists to a lesser degree (or not at all) in the other foot. The resulting malformation of the
hoof capsule may produce distinct differences between any pair of feet involved. It
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should be pointed out however, that for pathology to be suspected as the cause of any
asymmetrical hoof pair, some evidence must first exist that the pair of feet in question
where at some juncture reasonably well matched!
1.6 Unresolved Flexural Deformities
Flexural deformities in the neonatal and immature equine are well documented (Curtis
1999, Redden 1992,). Should these deformities remain unresolved and persist into
adulthood, then they will almost certainly have some direct influence on the shape and
form of the hoof capsule. Flaccid tendons in infancy are known to predispose the equine
to developing a broken back pastern axis (and associated flat feet). Unresolved flexor
tendon contracture is known to contribute to the formation of a steeper foot angle (Floyd
and Mansmann 2007).
These authors attribute the formation of the upright (with a broken forward pastern foot
axis), “boxy”, or clubfoot appearance to an unresolved flexural deformity in the juvenile
equidae. Redden (1992) states that “club feet are characterised by irregular horn growth,
usually of the front feet, with one foot being more involved than both”. He goes on to
state that the condition may be inheritable or due to a nutritional deficiency. Figure 4
demonstrates an unresolved Superficial Digital Flexor Tendon contracture that has
persisted into adulthood. The proximal and middle phalanges have been moved in a
dorsoventral direction by the contracture, to place the pastern at an almost perpendicular
angle to the ground. The distal phalanx (and its associated hoof capsule), have been also
moved backwards sufficiently for the digit to mature with the hoof capsule at a steeper
angle than that of its contralateral its partner.
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Figure 4: The effects of contraction of the superficial digital flexor tendon. The
contracture has moved the proximal and middle phalanges to a much steeper angle
in this mature horse.
The unresolved flexural deformity theory may give some explanation as to why some feet
have a greater angle than their contralateral partners when some contracture is in
evidence, despite not being classified as upright, “boxy” or club in appearance. However
this theory does not explain (when the foot with the steeper angle has a more desirable
conformation), why the contralateral foot has a more acute angle and is larger. It should
always be considered that the more acutely angled foot may be the result of an
unresolved flaccid tendon and the steeper angled foot is within the expected range.
Further to this, there is no explanation as to why one limb is affected differently than the
other, or not at all.
1.7 Limb Length Discrepancies
Angular/flexural limb deformities are regularly identified by the Farrier when evaluating
the subject prior to shoeing. Whereas it is usual to observe examples of similar
angular/flexural limb deformities in pairs of front limbs, it is less common to observe a
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relatively straight limb accompanied by a limb with deformities. It is also uncommon to
observe a pair of limbs with different deformities. It is reasonable therefore, to consider
that should asymmetrical pairs of limbs be in evidence, they will influence the associated
hooves in a different manner.
A study into skeletal asymmetry in the racehorse (Watson et al 2003); found that in 76%
of the study group, the right third Metacarpal (MCIII) was greater in length than the left.
It further found that only 4% had the left MCIII longer than the right. Only 20% of the
study group had MCIII of a similar length. The study stated (after Fretz et al. 1984) that,
since the growth in length of the third metacarpal had ceased after 10 weeks, the length of
this bone should not be influenced by any subsequent training conditions. One would
imagine that the difference in length between left and right MCIII, (in 16 of the 46 horses
in the study group, the difference was as much as 5-9 mm), would in some manner affect
the performance of the horses investigated. The study however, concluded that the
differences in MCIII length appeared to not affect the performance of the study group,
regardless of whether they ran clock-wise or anticlock-wise around a race track.
Limb length discrepancy (LLD) has been shown to exist in the Human (McCaw et. al.
1991, Čuk et.al. 2001), the Canine and other mammals (Hackert et.al. 2008). LLD in the
human is known to affect both the upper and lower limb (Čuk et.al. 2001), and is
described as a limb length inequality (LLI) or anisomelia. It is subdivided into
“functional” LLI, and “actual” LLI. Functional LLI indicates that although the limbs are
comparable in length, they function in different ways to compensate for either a
misalignment in the appendicular skeleton (usually the pelvis and lower limbs), or as a
response to pain. Actual LLI indicates that total or segmental length of one limb is less
that the other (Hemiatrophy), or greater than the other (Hemihypertrophy). Although
there is no direct anatomical comparison between the lower limb of the human which is
attached to the pelvis, and the equine forelimb which has no direct attachment to the
spine, the biomechanical implications may be the same and worthy of further study.
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It is clear from the research into Human LLI, and that of other mammals, that not only
does LLI exist; it is cross species in nature and endemic within a given population. With
this information and the limited study of Watson et. al. (2003), it should therefore be
reasonable to hypothesise that LLI will exist within the equine population.
Wilson et. al. (2009) examined the relationship between elbow height and “hoof spread”
in the adult equine and found that an inverse relationship existed. It was concluded that of
a pair of hooves, the one with the most “spread” was on a shorter limb, but the authors
did not explain as to why this would be. Traditionally it has been suggested that the
steeper angled hoof with the longer heels is a compensation for a shorter limb. However
there appears to be a lack of scientific evidence to support this in the equine, and the
findings of Wilson et. al. (2009) seems to contradict this traditional view. However given
that, in the human the toe on the shorter limb is drawn back on the shorter limb (McCaw
et. al 1991), should this happen in the equine, it could be postulated that the hoof capsule
conformation and development of longer heels is a compensation for a shorter limb.
Clearly the limited research to date and contradictions in the evidence give an area for
further study.
It must be considered therefore, that to work soundly (at least in the short term), and in a
reasonably balanced manner, that equines have in some way developed some form of
mechanism to cope with this discrepancy in the length between left and right MCIII. This
coping mechanism may involve the development of mismatched pairs of front feet, where
one foot has adopted a more upright conformation with a longer heel to counter the
discrepancy in the possible shorter length of MCIII. Again there seems to be no
explanation as to why the condition exists in the first place.
1.8 “Handedness” and the Preferred Lead Syndrome
Much of the research into LLI’s draws attention of the preference of use of one limb over
another, in the species studied (Equine, Human, and Canine). In the equine world, those
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involved in the training and schooling of the equine often report that a particular subject
performs better on one rein, and feels less agile or flexible on the other.
Preference for using a particular limb as a priority over the other (either by preferring to
use it first or more frequently than the other), has been documented by a number of
authors. Gill (1996) noted in his observations of immature equines that when grazing,
most of the subjects took a particular stance. He noted that in effort to reach the ground
that the subject would habitually protract one limb in front or the body, and retract the
other under the body to maintain tripodal support. He noted over a period of time that this
protracted/retracted pattern in the subject usually involved the same “preferred” limbs.
These observations where also noted by van Heel et. al. (2006) when examining
conformational traits in the foal in relation to lateralised grazing behaviour and the
development of uneven (mismatched feet). It was determined that about 50% of the foals
developed a preference to protract the same limb and therefore develop uneven feet. It
was found be van Heel et. al. (2006), in their study, that this preference was more
predominant in foals with small heads; and this conformational trait may lead to the need
to protract a specific limb to facilitate a comfortable grazing stance.
The existence of “handedness” has been well documented in the human (McCaw and
Bates 1991, Čuk et. al. 2001), and physiological differences in skeletal symmetry and
behavioural compensations observed in response to this preference. This asymmetrical
locomotion tends to manifest itself when the equine is put into training. Riders/trainers
regularly report that young horses show reluctance to lunge or be ridden on a particular
rein, or find it difficult to lead off with one particular leg. Indeed the usual purpose of
training and schooling of the equine is to produce a more balanced subject with better
symmetry of motion. This one sided preference tends to become less of a problem as the
training and conditioning progresses. Should however, there be failure to reinforce this
training, or should it cease altogether, then one-sidedness is usually noted to re-assert
itself.
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Mcgreevy and Rodgers (2005) studied lateralised behaviour in thoroughbred horses and
identified that the lateralisation occurred on two levels, motor and sensory. Mcgreevy and
Rogers (2005) further identified in their study of the motor lateralisation, (using standing
observations of the horse), that 52% preferred to protract the left fore, 13% preferred to
protract the right fore, and 41% demonstrating a non-significant (ambidextrous)
preference. This study also gathered data over a limited age range of its subjects. It found
that preference to protract one limb over the other demonstrated a statistically significant
increase with the older (over two year old) horses, with the number of ambidextrous
horses decreasing with age.
It seems however, that despite showing lateralised motor behaviour from an early age,
and the skeletal asymmetry that results from this preferred behaviour, the equine still
manages to perform to a reasonable level without dysfunction at least in the short term.
There is only weak evidence to suggest that the condition itself is a predictor of
unsoundness, and much more research is required in this area.
2. Materials and Methods
2.1 Selection Criteria for the Study Population
A total of 40 (n=40), general purpose equines were selected (as listed below) from the
author’s business in the North East of England between May and December 2011 to form
the study population. The study population was subdivide into shod (n=30) and unshod
(n=10) subjects to ascertain whether the attachment of a shoe had any influence on the
outcome of the condition.
The selection criteria used were as follows

All subjects were between the ages of four and twenty.
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
All shod subjects were have been reshod on an approximately 6 week basis for the
last 12 months (from shoeing records), and every eight weeks or less for the
unshod subjects.

None of the subjects had any significant history of shoe loss within the previous
12 months (this was considered as it is often noted that habitual shoe loss from
one hoof causes it to become smaller and steeper in angle).

None of he subjects were lame at the time of the study, and have no known
history of lameness in the previous 12 months.

None of the subjects should have any pre-diagnosed hoof pathology

All subjects were in regular work, and be involved in a broad range of activities
on varying types of surfaces (including the unshod subjects).
It should be noted that differences in the colour of the front feet, or patterns of colour,
where not considered to be relevant in the selection as it is believed that pigmentation
does not heave any direct effect on the conformation or soundness of the equine (Pollitt
2001, Reilly 2004).
2.2 Foot Trimming Protocols
All feet were trimmed to the same protocols described by Caldwell et al 2010 (after
Savoldi 2006).

White line exfoliated to reveal the sole and horny wall interface.

Removal of the remaining exfoliating solar horn to reveal the true solar plane.
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
The bars were trimmed to normal proportions, removing only damaged or weak
horn.

The frog was trimmed back to live tissue and proportionate to the foot.

Excess hoof wall at the bearing border was removed to a horizontal solar plane.

The heels were trimmed approximately to the widest part of the trimmed frog.
Figure 5: The hoof exfoliated prior to trimming. The proposed trim line is shown in
red (after Savoldi 2006).
It should also be noted that the front feet where trimmed on an alternative left/right foot
first basis to avoid any bias (Bell 1992)
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2.3 Materials Used
The following were be used to take measurements and record the data;

A 15cm (six inch) steel ruler and marker pen was used to inscribe lines on the
hoof at the positions that were to be measured.

A standard brass hoof gauge (marked in degrees).

A digital vernier calliper (measurements in mm).

Callipers

Excel spreadsheet packages were used to record the data.
Figure 6: Equipment used to carry out measurements of the hooves of the study
population.
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2.4 Foot Measurements Taken
The following measurements of both front feet were taken and recorded after trimming.
All angles where recorded in degrees, and all distances where recorded in millimetres.

Each hoof was measured medio-laterally at the widest point of the foot (WOF) on
the solar surface (measurement A in figure seven).

Each hoof was measured at its longest point (LOF) from the apex of the toe
through the frog to a line drawn between the lateral and medial heels at the
widest point (measurement B in figure seven).

Each was measured was taken between the lateral and medial heels (DBH) at the
widest point (measurement C in figure seven).

Each hoof was measured at the widest part of the coronet (WAC) (measurement
D in figure eight).

The angle of the hoof at the dorsal wall (DHWA) was measured in degrees
(measurement E in figure eight).
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C
A
B
Figure 7: Measurements taken of the solar surface of the hoof capsule.
Measurement A: Width of Foot (WOF).
Measurement B: Length of Foot (LOF)
Measurement C: Distance Between Heels (DBH).
D
E
Figure 8: Measurements taken of the dorsal wall and the coronet.
Measurement D: Width Across Coronet (WAC).
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Measurement E: Dorsal Hoof Wall Angle (DHWA).
In addition to the foot measurements taken, the following data was also recorded on the
spreadsheet:

The height of each subject in centimetres from the passport.

An estimation of weight of using a calibrated weight tape around the thorax.

The breed/type of the subject from the passport.
2.5 Data Analysis
In the study a total 320 morphometric and 80 angular measurements where taken of the
left and right front feet of 30 shod horse (Appendix I), and 10 unshod horses (Appendix
II). All data was recorded on a Microsoft Excel™ spreadsheet. The data was then
separated into that taken for left and right (shod horses Appendix Ia and Ib; unshod
Appendix IIa and IIb). The mean, median, maximum, minimum (range) and standard
deviation where calculated and are summarised in the table one (all shod and unshod
horses), and table two (data split between left and right feet).
Using the data, scatter graphs comparisons were done of left against right for both shod
and unshod results and are shown in tables’ three to seven. Frequency histograms where
produced to evaluate distribution of data using Minitab 15™ and are shown in Appendix
III (a) and (b).
A Chi square test was used to evaluate the fitness of the data summary in table eight. A
paired t test was used to compare any relationships between the hoof measurements, and
any differences or similarities between the shod and unshod study groups.
22
3.0 Results
3.1 Results of the Study
Most previous published data has relied on trimming being carried out by “experienced
Farriers” with no apparent specific protocol being followed. Further to this, the practical
aspects of the accuracy of the data collection receive little mention. As this authors data
was collected from live (in vivo) horses (usually in stable yards); and there being no
apparent precedent, it was considered that the margin for error in the measuring protocols
for use in the descriptive data with regard to differences in metric measurements between
front feet should be 5mm. Any measurement difference of 5mm or less would be classed
as within the normal range. Any difference greater than 5mm would be considered to be
notable.
Given the accuracy of the method used to measure DHWA and the conditions in which it
was done the author determined, as per Redden (1992) that differences in angles of three
degrees or less would be considered within the normal range.
Table 1: Summary of means, standard deviations and ranges measured of shod and
unshod subjects.
Shod
horses
Unshod
(n=60)
horses(n=20)
Mean ± s.d (mm)
Range (mm)
Mean ± s.d (mm)
Range (mm)
WOF
131.12 ± 8.08
114.34-145.80
120.75 ± 13.14
97.62-140.62
LOF
130.29 ± 8.85
116.93-152.15
119.84 ± 13.36
97.66-145.47
DBH
70.43 ± 10.16
53.21-97.92
62.44 ± 13.63
48.26- 87.12
DOC
113.65 ± 6.11
98.47-126.39
104.21 ± 10.23
87.80-120.99
DHWA
52.82 ± 2.49(º)
48.00-59.00(º)
54.75 ± 2.17(º)
51.00-59.00(º)
23
Table 2: Comparison of mean data from left and right feet of all subjects.
Left Foot
Right foot
(n=30)
(n=30)
Mean ± s.d (mm)
Range (mm)
Mean ± s.d (mm)
Range (mm)
WOF
130.74 ± 8.57
114.34-145.80
131.50 ± 7.68
115.64-145.10
LOF
129.75 ± 9.14
116.93-152.15
130.83 ± 8.67
119.41-151.36
DBH
70.25 ± 10.14
53.21-97.92
70.62 ± 10.35
55.00-97.08
DOC
113.07 ± 5.98
100.92-124.53
114.22 ± 6.27
98.47-126.39
DHWA
52.80 ± 2.63
48.00-59.00
52.83 ± 2.39
48.00-59.00
Unshod
(n=10)
WOF
120.70 ± 13.32
97.62-140.62
120.89 ± 13.69
97.72-139.33
LOF
118.61 ±13.36
97.66-142.46
121.07 ± 13.96
98.45-145.47
DBH
61.82 ± 12.92
48.26-82.47
63.03 ±14.98
48.24-87.12
DOC
104.20 ± 10.34
87.80-119.43
104.23 ± 10.67
88.57-120.99
DHWA
54.65 ± 2.01
52.00-58.00
54.90 ± 2.42
51.00-59.00
Shod
(n=10)
Width of Foot
Of all the widths measured of both left and right front feet, the maximum was145.80 mm,
and the minimum was 114.34 (mean width 131.12). Of these feet, 24(80%) subjects had a
difference in width of 5mm or less. 6 subjects (20%) had a difference greater that 5mm
between hoof widths, and this can be seen on the table three scatter graphs Of the 5 feet
with the disparity of greater than 5mm, 4 subjects (nos.4, 7, 9, 27) had a wider right foot.
Two subjects (nos. 12, 18) had a left foot wider than the right. Notably, of these 5
subjects, only 2 (nos. 18 and 27) demonstrated a foot angle difference of more than 3º.
The frequency histogram displayed an even distribution of data (P = 0.271)
24
Of the measurements taken of unshod subjects, the maximum width was 140.62 mm and
the minimum was 97.62mm (mean width 120.79). Only one subject (10%) demonstrated
a difference in width between left and right feet; and in this case (no10) the right
demonstrated the greater measurement. This subject demonstrated no notable difference
in hoof angle. The frequency histogram displayed an even distribution of data (P = 0.267)
Table 3: Scatter graph comparisons of X v Y for width of foot for shod (a) and
unshod (b) subjects.
Scatterplot of left WOF vs right WOF
Scatterplot of left WOF vs right WOF
150
140
130
left WOF
left WOF
140
130
120
110
120
100
110
115
120
125
130
right WOF
135
140
145
100
(a) Shod Feet.
110
120
right WOF
130
140
(b) Unshod feet.
Length of Foot
Of the lengths of foot measured in the shod subjects, the maximum was152.15mm and
the minimum was 116.93mm (mean length 130.29mm). Of these, three subjects (10.00%)
demonstrated foot length differences of more than 5mm. Of these, two subjects (nos.3
and 28) had the right foot longer than the left, and one (no. 4) had the left foot longer than
the right. Neither of these subjects demonstrated any notable differences in dorsal wall
hoof angle. The frequency histogram for this set of data was not normally distribute and
was skewed right (P = 0.011), however the data set was transformed using a log10
conversion to produce more normally distributed data (P = 0.024)
25
Of the measurements taken in the unshod subjects, the maximum length was 145.57mm
and the minimum was 97.66mm (mean width 119.84). Only one subject (10%)
demonstrated a difference of length between left and right feet; and in this case (no.8) the
right demonstrated the greater measurement. This subject demonstrated no notable
difference in hoof angle. The histogram data for this measurement was normally
distributed (P = 0.186)
Table 4: Scatter graph comparisons of X v Y for length of foot for shod (a) and
unshod (b) subjects.
Scatterplot of left LOF vs right LOF
Scatterplot of left LOF vs right LOF
155
140
150
145
130
left LOF
left LOF
140
135
130
120
110
125
120
100
115
120
125
130
135
140
right LOF
145
150
155
(a) Shod feet.
100
110
120
right LOF
130
140
(b) Unshod feet.
Distance between heels
Of the measurements taken of shod subjects, between the heels the maximum was
97.92mm and the minimum was 53.21mm (mean distance 70.43mm). Of the subjects
measured nine (30%) demonstrated a disparity in distance between the heels of greater
than 5mm. Of these, six (nos. 1, 7, 16, 20, 22, 27) had a greater distance between the
heels on the right foot, and three (nos.12, 13, 18) had a greater distance on the left foot.
Of these nine subjects, three demonstrated a disparity of more than 3º in the dorsal hoof
wall angle. The data demonstrated even distribution (P=0.239)
Of the measurements taken of unshod subjects, the maximum distance between the heels
was 87.12mm and the minimum was 48.26mm (mean distance 62.44). Only one subject
26
150
(10%) demonstrated a disparity of distance; and in this case (no.10) the right
demonstrated the greater measurement. This result differed from that of the shod subjects
and the data was not evenly distributed (P=0.011)
Table 5: Scatter graph comparisons of X v Y for distance between heels for shod (a)
and unshod (b) subjects.
Scatterplot of left DBH vs right DBH
Scatterplot of left DBH vs right DBH
100
85
80
90
80
left DBH
left DBH
75
70
70
65
60
55
60
50
50
50
60
70
80
90
100
50
right DBH
(a) Shod feet.
60
70
right DBH
80
(b) Unshod feet.
Width across Coronet
Of the measurements taken of the widest part of the coronet band, the maximum was
126.39mm and the minimum was 98.47mm (mean distance 113.65). Of the subjects
measured, two (6.66%) demonstrated a disparity of more than 5mm. both of these
subjects (nos. 14, 20) demonstrated the larger measurement on the right foot. Neither of
these subjects demonstrated a significant difference in hoof angle. The data was normally
distributed (P=0.874).
Of the measurements taken of unshod subjects, the maximum distance at the widest part
of the coronet was 120.99mm and the minimum was 87.80mm (mean distance 104.21).
None of the subjects demonstrated a measurement of more than 5mm. the data was
normally distributed (P=0.332).
27
90
Table 6: Scatter graph comparisons of X v Y for width across coronet for shod (a)
and unshod (b) subjects.
Scatterplot of left WAC vs right WAC
Scatterplot of left WAC vs right WAC
125
120
120
115
left WAC
left WAC
110
115
110
105
100
95
105
90
100
100
105
110
115
right WAC
120
125
130
(a) Shod feet.
90
95
100
105
110
right WAC
115
120
(b) Unshod feet.
Dorsal Hoof Wall Angle
Of the angles measured, the maximum angle was 59º and the minimum angle was 48º
(mean angle 52.82º). 3 subjects (10%) demonstrated disparity of hoof angles of more
than 3º. Of the 27 subjects showing angle differences of less than 3º, 8 subjects (26.66%)
had no difference in hoof angle at the dorsal wall. Of the three feet with angle differences
of more than 3º, two subjects (nos.12 and 18) had a steeper angle on the right foot. Only
one subject (no.27) had a steeper angle on the left foot. The data was not normally
distributed (P=0.049), but was subjected to a Log10 conversion (P=0.73).
Of the angles measured, the maximum was 59º and the minimum was 51º (mean angle
54.75). Only one subject displayed a disparity of angle of more than 3º; and in this case
the right demonstrated the steeper angle. The data was normally distributed (P=0.560).
28
125
Table 7: Scatter graph comparisons of X v Y for dorsal hoof wall angle for shod (a)
and unshod (b) subjects.
Scatterplot of left DHWA vs right DHWA
Scatterplot of left DHWA vs right DHWA
60
58
58
57
56
left DHWA
left DHWA
56
54
52
50
55
54
53
52
48
48
50
52
54
right DHWA
56
58
60
50
51
52
53
54
55
right DHWA
56
57
58
3.2 Summary of results
It was noted in the results that the four (3 shod, 1unshod) subjects displaying a dorsal
wall angle disparity of greater than 3º, also displayed a measurement difference of more
than 5mm at the width of foot and heel distance (nos. 12, 18, 27). No subject displayed
hoof angle disparity without a difference in the other measurements. This seems to
suggest that there is a relationship between dorsal wall angle, foot width and heel
distance.
Further to this, three subjects (nos. 4, 7, 20) displayed a disparity of
measurement of more than 5mm without a significant difference in dorsal wall angle.
Seven subjects displayed disparity of more than 5mm in only one measurement. Fifteen
subjects displayed no significant difference in any of the measurements taken.
Within this study it was found that a mean angle of 53º ± 2.49° existed for all the shod
subjects; and 54º ± 2.17° for the unshod horses (although it should be noted that this was
a relatively small sample size). Other texts (Floyd and Mansmann 2007) have
demonstrated similar results and variably concluding that the expected normal range of
hoof angles to be between 50-55º.
29
59
Table 8: Summary of results, (summary of unshod subjects in brackets)
WOF
LOF
DBH
WAC
DHWA
1
3
0
1
Right greater 4
2
6
2
2
measurement
(1)
(1)
(0)
(1)
3 (10%)
9 (30%)
2 (6.66%)
3(10%)
(1)
(1)
(1)
(0)
(1)
7 (17.5%)
4 (10%)
10 (25%)
2 (6.66)
4 (10%)
Left
greater 2
measurement
Total
(1)
larger 6 (20%)
measurement
Shod (unshod)
Combined
study (n=40)
A Chi-Square goodness of fit test for observed counts was carried out on the data in table
eight using Minitab 15™ and the following results were recorded
Using category names in Type
Category
WOF
LOF
DBH
WAC
DHWA
N
27
DF
4
Observed
7
4
10
2
4
Chi-Sq
7.25926
Test
Proportion
0.2
0.2
0.2
0.2
0.2
Expected
5.4
5.4
5.4
5.4
5.4
Contribution
to Chi-Sq
0.47407
0.36296
3.91852
2.14074
0.36296
P-Value
0.123
The observed values for WOF and DBH are greater than the expected values of these
measurements, demonstrating that the Null Hypothesis (that pairs of feet are the same) is
not proven. LOF and DHWA are lower than expected, but only by a small margin. WAC
is much lower that expected, and this may be due to the relatively small population
sample and it is suggested that the study be conducted with a larger sample to confirm
this finding. However the P value of 0.123 indicates a reasonable level of confidence in
30
the data. The overall data appears to suggest that WOF and DBH are more significant
when attempting to identify and describe the condition, whereas LOF, WAC and DHWA
have a lower significant relevance.
It appears from the table that in the shod horse study that were a greater measurement is
found, it is predominately the right foot that displays the greater measurement on a 2/1
ratio. In the study of the unshod subjects, despite the small study group, where a disparity
in measurement of greater than 5mm exists, it was found to be in the right foot. This
suggests that, in this study, where foot size disparity does exist it is predominately the
right foot that is larger than the left.
In this study only 4 subjects (2 shod, 2 unshod) presented with pairs of feet with hoof
angles greater than 55º. Only one subject (shod) presented with a pair of feet with angles
of less than 50º. Of the three subjects that presented with hoof angle disparity of more
than 3º, none of the steeper angled feet demonstrated a hoof angle of more than 55º, and
therefore it may be proposed that these steeper angled feet fall within the expected
normal range. Two of these subjects demonstrated hoof angles in the lower angled foot of
48º and it may be proposed that they are not within the expected range. Interestingly, the
three shod subjects that had the greatest disparity in dorsal wall angle also demonstrated a
disparity greater than 5mm in the width of the hoof, and the distance between the heels.
The greater measurements (foot width, heel distance) were consistent with the foot with
the lower angle. Of the 30 shod subjects, 10 demonstrated differences in the other foot
measurements but had dorsal wall angles that were the same or less that 3º.
4.0 Discussion of Results
Prior to this study there is limited evidence of studies that attempt to identify the
frequency of occurrence of asymmetrical pairs of front feet, or quantify any dimensional
differences of the condition in an adult population of horses. Most texts (Stashak 1976,
Floyd and Mansmann 2007) make empirical reference to asymmetric pairs of front feet
by making comparisons between the DHWA of each foot, but make no reference to
31
population traits, or any other dimensional parameters. Curtis (2011) visually identified
frequency of unilateral club foot and flexural contracture in a population of juvenile
thoroughbreds over a number of years, but made no quantitative measurements of the feet
themselves. Kroekenstoel et. al. (2006) observed asymmetric pairs of front feet in a
population of Dutch Warmbloods at 27 and 55 weeks and noted that the subjects showed
a significant difference in distal limb loading. Although pressure measurements and
radiographic analysis where evaluated, there was only limited reference to the dimensions
of the feet themselves or any population traits.
Previously, asymmetric pairs of front feet have been identified by visually distinguishing
one foot as being upright, “boxy” or club in comparison to its contralateral partner,
without reference to any measured parameters. The condition has also been identified
(Redden 1992) by making comparison measurements between the hoof angles at the
dorsal wall, but again referring to the steeper angled hoof as being upright, “boxy” or
club in comparison to its contralateral partner, regardless of the angle of the other hoof
(and without reference to any theoretical norm), or any other measured parameter.
Whereas there are a number of studies that relate the condition to skeletal asymmetry
(Kroekenstoel et. al. 2006) and behavioural preferences (van Heel et al. 2006). There
appears to be limited attempts to actually quantify the affected feet using morphometric
measurements other than DWHA.
Ducro et. al. (2009), using data from the Royal Dutch Warmblood Studbook, and the
Royal Dutch Equestrian Sports Federation records, noted a prevalence of the condition
of over 8% from 2000 onwards. The subjects where scored as either having “uneven
feet”; or not. Other than some mention of relative heel height and hoof shape, it appears
that, again no other quantitative measurements where taken. Another study carried out
by van Heel et al. (2006) noted that in 24 foals studied, 46% of the group developed a
preference at 27 weeks to protract one limb. It was noted that these subject had smaller
heads and where higher at the withers than the rest of the study group, and went on to
develop “uneven feet” by 55 weeks. This study did use hoof angle and force plate
32
analysis to describe the differences, but took no other quantitative measurements of the
foot itself.
It was noted that various different methods of evaluation where used in previous studies
to identify the existence of the condition, and that may account for the range of results
that were found in table nine. Curtis (2011) used a visual assessment to identify unilateral
club foot juvenile thoroughbred foals. Kroekenstoel et. al. (2006) stated that visual
assessment was a subjective procedure, and, concluded that it was not sensitive enough to
appreciate the alignment of the distal limb as it did not correspond with radiographic
measurements taken.
The results of this study indicate that asymmetric pairs of front feet have an incidence of
occurrence of 16.66% within this limited study population. Since other studies compared
in table nine show similar results, it may be reasonable to assume that differences in the
dimensions between pairs of front feet are the norm within the wider population. None of
the subjects in the limited study carried out by the author demonstrated the extreme
dissimilarity that has been anecdotally described (Gonzales 1991). It may therefore be
prudent to repeat the study with a larger population of equines to confirm the result of
this and other studies.
Table 9: Results comparison of frequency of occurrence from previous studies
showing outcomes in relation to population size, and methods used.
Author(Date)
Population
n=
(no.
studied
subjects)
of Measurements
used
%
identified
with disparity
Storey (2012)
Mature general 40
As per methods 16.66%.
(This Author)
purpose.
in this paper.
Curtis (2011)
Thoroughbred
373
foals.
Kroekenstoel
Warmblood
23
Visual
19% (identified
interpretation.
as ULCF).
Visual
33
and 6.5% (visual)
et. al. (2006)
(between
27
radiograph.
49%
and 55 weeks).
Ducro
Bovenhuis
Mature
Dutch 44,840
et. Warmbloods.
al. (2009)
Ducro.
(radiograph).
(from
Uneven
feet 8% from 2000
stud (0/1= n/y).
onwards.
books)
Mature
Dutch 23,116
Gorissen et. al. Warmbloods.
Uneven
feet 6.20% (basic).
(0/1= n/y).
5.78% (elite).
(2009)
Van Heel et. al. Dutch
(2006)
DHWA Visual 48%.
Warmbloods
from
foals.
photographs.
van Heel et. al. Dutch
(2010)
24
17
DHWA
Warmblood (3-
MetronPX
y-o).
software.
using 25%.
The data collected from the limited population in this study indicates that disparity in foot
size was present in 10% of the subjects if DHWA alone is used, and rose to 16.66% if
WOF and DBH are include as part of descriptive criteria. Both shod and unshod horses
where measured in the study to evaluate whether shoeing has any overt affect on the
presentation of the condition. Although the two study groups demonstrated similar trends
in regard to WOF, LOF, DAC and DHWA; it was noted there was a comparative
disparity in DBH. Whereas nine (30%) of the shod subjects displayed notable differences
in DBH, only one (10%) of the unshod study group demonstrated the same difference. As
the unshod study group was small in comparison to the shod study group, it was decided
that no conclusions could be draw about the effects of shoeing on the condition, without
gathering more data measurements on an unshod horse population with which to make
comparison.
Within the study population it was noted that, when on foot had a notably larger
measurement, or a more acutely angled foot, it was the right foot that displayed this
tendency as summarised in table eight. Watson et. al. (2003) stated that “in man, the
34
dominant right hand is often larger than the non dominant left hand”. The previous
anecdotal descriptions of the condition have referred to one foot appearing larger than the
other; there is no reference as to which is predominately the largest of the pair. Although
the measurements appear to suggest an inclination for the right foot to be the larger foot;
the limited size of the study population and the lack of previous study in this area, make it
difficult to draw any definite conclusions from this information. The author however,
suggests that this is another area for further study.
Most of the authors cited seem to come to the conclusion that the development of
asymmetric pairs of feet first present in the juvenile equine. Curtis (2011) evaluated most
of his thoroughbred foals at 4 week after birth and noted that various limb deformities,
including a unilateral club foot (ULCF) could present at this early stage. Kroekenstoel et.
al. (2006) looked at Warmblood foals at 27 to 55 weeks and observed changed in loading
patterns between the asymmetrical pairs of feet, indicating that the condition was present
in that time period. van Heel et. al. (2010) noted that asymmetrical feet recorded in the
juvenile warmblood could still be observed in the three year old subject. He also noted
that not only did the condition appear to persist as the subjects matured, the incidence
actually increased with age.
Most of the authors are in agreement that the condition of asymmetrical front feet is a
manifestation of skeletal asymmetry. They further suggest that this is a result of a
preference to use one side over the other (“handedness”). Kroekenstoel et. al. (2006)
suggested that juvenile equines with proportionally longer legs and small head may be
more susceptible to the development of the condition. Opinion as to the conditions affect
on performance or as predictor of unsoundness is divided. None of the authors work
cited, make any reference to actual trimming or shoeing protocols in relation to
soundness.
Asymmetric pairs of front feet may be the result of an orthopaedic developmental
disorder (unresolved flexural deformities/limb length discrepancies, skeletal asymmetry)
and should be considered a potential issue alongside angular/flexural/rotational limb
35
deformities. The condition appears to begin to manifests itself in the post partum foal that
has started to graze. The preferred (protracted limb) stance is probably the initiating
factor in the development of the condition; As it is generally accepted that the Farrier
cannot change the conformation of the mature equine, once the horse is passed the age
that the epiphyses have ceased to grow, it can be postulated that very little can be done to
change the condition.
It is clear from both Curtis (2001) and Kroenstal that asymmetric pairs of front feet
appear in the juvenile equine with varying rates of prevalence. van Heel et. al. (2010)
notes that the condition not only persists in three year old Dutch Warmbloods, but the
may become more accentuated as the subject approaches maturity. Both Ducro et. al.
(2009) and the author’s studies demonstrate that the condition persists into adulthood. It
is unclear as to whether this persistence is due to a failure to resolve the condition before
maturity is reached, or whether resolution has been attempted and been unsuccessful. If
the results of this study and others are demonstrative of the general (mature) equine
population, it should be considered that the condition in itself may not be resolvable. If
the equine manages to work soundly and evenly, at least on a limited basis, it can be
theorised that the subject has developed a mechanism which allows it to compensate for
any asymmetry of anatomy or locomotion. It may be further theorised therefore that the
asymmetric pairs of front feet are part of compensatory mechanism, however much more
research needs to be done on a larger equine population to confirm any findings.
.
5.0 Conclusion
Asymmetrical pairs of front feet appear to occur with a varying degree of prevalence in
different equine populations. This study of this relatively small population, using five
measurements, found that 16.66% frequency of occurrence of asymmetric pairs of front
feet in the mature equine. Curtis (2011), using visual assessment, found a higher
prevalence of occurrence in juvenile Thoroughbreds. It is may be hypothesised that this
higher prevalence is related to the subjectiveness of visual assessment as described by
36
Krokenstal et. al. (2006), or may possibly be a population specific effect (i.e. using only
one breed or type of subject; in this instance the Thoroughbred).
Ducro et. al. (2009) identified a lower frequency (8%) of occurrence in Mature Dutch
Warmbloods between 2000 and 2010 using available records. Since the subjects where
scored as having, or not having “uneven” feet, rather than having morphometric
measurements taken, the results may be also be considered to be subjective. This study,
although it had a high number of subjects, was also population specific.
Some of the population in this authors study displayed notable differences between foot
measurements as well as hoof angle. Others displayed notable differences in foot
measurements but had hoof angles that where similar or the same. The data therefore
suggest that the mismatched foot condition exists in more than one form and this requires
more study. The fact that the hoof is a three dimensional structure, and the suggestion by
the data that the differences and disparities exists in more than one form; indicate that
visual identification, or description by dorsal hoof wall angle alone, may be insufficient
to fully describe the condition. It appears from the data that whereas some of the
measurements appear not to demonstrate any great significance, others, particularly in
combination with others are more significant. To this end the author would like to
suggest that the condition is three dimensional and multifaceted in nature and therefore
should be regarded as a syndrome.
6.0. References
BALCHIN, P. W. MITCHELL, D. W. and CALDWELL M. N. (2009) Dissection of 22
cadaver limb specimens trimmed to UST, Duckett’s dot & bridge, geometric proportions
& NVQ level 3 standard trimming protocols. Forge Magazine February: 4-7
BELL, I. (1996) Shoeing and associated problems of Household Cavalry Horses. Forge
Magazine April: 3-7
BRADLEY, D. DUVERNAY, B. GILDSTEIN, S. M. PARDOE, C. CURTIS, S. - ed.
(2002) Corrective Farriery - A Textbook of Remedial Horseshoeing Vol. I. 209-229.
Newmarket, R&W Publications LTD
37
BUTLER, D. (1985) The Principles of Horseshoeing Maryville: Doug Butler Publishing.
CALDWELL, M. N. REILLY, J. D. SALVOLDI, M. (2010) Quantitative horse hoof
trimming protocol for research purposes. Forge Magazine April: 4-10.
CASONOVA, P-M P. OOSTERLINCK, M. (2012) Hoof Size and Symmetry in the
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