Comparison of the trimming procedure of six different farriers by quantitative evaluation of hoof radiographs

Hoof preparation and shoe fit are integral to the long term soundness and athletic ability of horses. The farrier influences the balance of the hoof by both the trimming and the shoeing procedure. The goal of this study was to investigate and quantify the influence of the farrier on hoof parameters by trimming. Forty Warmblood horses ranging in age from 6–12 years and withers height 162–172 cm were included. They were divided into six groups consisting of six or seven horses each, shod by one of six different farriers. The hoofs of the horses were radiographed twice using a standardised method before and after trimming. Measurements were taken from digitalised radiographs using a software program.Significant differences were identified between farriers for almost all parameters on the lateromedial radiographic views after two consecutive trimming procedures. Comparing the results of both trimming procedures, significant differences for several farriers were found in the lateromedial and dorsopalmar views. There were significant differences for most of the measured hoof parameters between the six farriers and between consecutive trimmings of the same farrier. The results underline the individual influence of the farrier on hoof shape and balance.     

Relationship of foot conformation and force applied to the navicular bone of sound horses at the trot

REASONS FOR PERFORMING STUDY: Collapsed heels conformation has been implicated as causing radical biomechanical alterations, predisposing horses to navicular disease. However, the correlation between hoof conformation and the forces exerted on the navicular bone has not been documented. HYPOTHESIS: The angle of the distal phalanx in relation to the ground is correlated to the degree of heel collapse and foot conformation is correlated to the compressive force exerted by the deep digital flexor tendon on the navicular bone. METHODS: Thirty-one shod Irish Draught-cross type horses in routine work and farriery care were trotted over a forceplate, with 3-dimensional (3D) motion analysis system. A lateromedial radiograph of the right fore foot was obtained for each horse, and various measurements taken. Correlation coefficients were determined between hoof conformation measurements and between each of these and the force parameters at the beginning (15%) of stance phase, the middle of stance (50%) and at the beginning of breakover (86% of stance phase). Significance was defined as P<0.05. RESULTS: The force exerted on the navicular bone was negatively correlated (P<0.05) to the angle of the distal phalanx to the ground and to the ratio between heel and toe height. This was attributed to a smaller extending moment at the distal interphalangeal joint. There was not a significant correlation between the angle of the distal phalanx and the degree of heel collapse, and heel collapse was not significantly correlated to any of the force parameters. CONCLUSIONS: Hoof conformation has a marked correlation to the forces applied to the equine foot. Heel collapse, as defined by the change in heel angle in relation to toe angle, appears to be an inaccurate parameter. The forces applied on the foot are well correlated to the changes in the ratio of heel to toe heights and the angles of the distal phalanx. POTENTIAL RELEVANCE: Assessment of hoof conformation should be judged based on these parameters, as they may have clinical significance, whereas parallelism of the heel and toe is of less importance.     

Effects of barefoot trimming on hoof morphology

Objective To monitor changes in hoof morphology in response to barefoot trimming. Methods Seven horses were trimmed every 6 weeks according to barefoot trimming principles, which involved levelling the hoof to live sole, lowering the heels, bevelling the toe and rounding the peripheral wall, while leaving the sole, frog and bars intact. A 4‐month period was allowed to lower the heels sufficiently to achieve a hoof shape representative of the barefoot trim. This was regarded as the starting point for morphological adaptations in response to maintenance of the trim. Hoof morphology was measured from lateral, dorsal and solar view photographs and lateromedial radiographs taken at 0, 4 and 16 months. Changes from 0 to 4 months represented differences between a natural hoof shape and the trim, while changes from 4 to 16 months represented adaptive effects during hoof growth. Results Establishment of the barefoot trim involved significant shortening of the toe, heel and medial and lateral walls, with increases in angulation at the toe, medial and lateral walls, but not at the heel. Maintenance of the trim resulted in a palmar/plantar migration of the heels, with increases in support length, heel angle and solar angle of the distal phalanx (P3). Conclusions Bevelling the toe and engaging the frog and bars in the weight‐bearing function of the foot resulted in elevation of the heel angle and solar angle of P3. These changes may be beneficial in treating under‐run heels and negative solar plane angulation of P3.     

An investigation of the relationships between angles and shapes of the hoof capsule and the distal phalanx

Reasons for performing study: There is little scientific evidence to support the premise that poor foot conformation predisposes to foot pain and lameness. Objectives: To determine relationships between external characteristics of the hoof capsule and angles of the distal phalanx; to determine variability in shape of the distal phalanx; and to investigate association between distal phalanx angles and the injury causing lameness. Materials and methods: Feet were documented photographically and radiographically. Linear and angle measurements were obtained for the hoof capsule and distal phalanx and compared statistically. Horses were categorised according to injury group, and angles and linear ratios were compared between groups. Results: There was modest correlation between hoof wall and heel angles and angles of the distal phalanx. There was variation in shape of the distal phalanx. There was no significant association between injury type and angles of the distal phalanx, although there was a trend for the angle of the dorsal aspect of the distal phalanx with the horizontal to be smaller in horses with injuries of the podotrochlear apparatus or deep digital flexor tendon compared with other groups. Conclusions: There are variations in shape of the distal phalanx largely due to differences in orientation of the concave solar border and the solar border to the horizontal. Variations in shape of the distal phalanx were not accurately correlated with external characteristics of the hoof capsule. There were weak associations between injury groups and angles of the distal phalanx. Clinical relevance: Further work is required to elucidate risk factors for foot‐related lameness.     

Density and morphologic features of primary epidermal laminae in the feet of three-year-old racing Quarter Horses

OBJECTIVE: To quantify the density of primary epidermal laminae (PELs) around the solar circumference and evaluate the relationship between regional PEL density and hoof capsule morphology in horses. SAMPLE POPULATION: Forefeet from nine 3-year-old Quarter Horse cadavers. PROCEDURES: Data pertaining to gross features of hoof morphology and PEL variables, including number, density, and distribution patterns around the perimeter of the hoof wall and number of bar PELs, were collected. Tissues of the laminar junction were examined histologically. RESULTS: No significant differences were found between left and right forefeet with respect to gross hoof morphologic measurements. Mean +/- SD number of PELs, including those at the bars of the hoof, was 551 +/- 30. Primary epidermal laminar density in the toe was significantly higher, compared with that in the quarter and heel regions, and was higher on the lateral aspect of the foot, compared with the medial aspect. Feet were significantly wider on the lateral aspect of the foot, compared with the medial aspect, as measured across the widest point of the solar surface. Histologic examination revealed atypical laminar morphology at the toe. CONCLUSIONS AND CLINICAL RELEVANCE: Variations were detected in PEL density and morphology around the solar circumference of hooves from 3-year-old racing Quarter Horses. A better understanding of relationships between laminar density, laminar morphology, and gross morphology of the hoof capsule in different populations of horses may aid practitioners in diagnosis and treatment of disease involving the hoof wall in horses.     

A singular case of traumatic total hoof capsule avulsion

Total, full thickness hoof wall avulsion is rare in horses. Sometimes complications such as fracture of the distal phalanx, osteomyelitis, septic arthritis and degenerative joint disease have been reported. Limiting motion at the affected site and hoof stabilisation are essential to obtain a good hoof regeneration. This case report reviews the clinical features including diagnostic techniques (radiographic examination and venography) of a Quarter Horse filly presented with a complete and full‐thickness traumatic hoof capsule avulsion complicated by an open fracture of the third phalanx. A transfixation casting technique was performed followed after one month by 2 short limb casts applied for 2 months each. Twenty‐four months after trauma the foot had completely regrown. The dorsal aspect of the hoof wall appears to be remarkably shorter compared to the heels. From a radiographic viewpoint, the lateral aspect of the left hind foot shows diffuse bone remodelling and a deformed distal phalanx.     

A Cross-Sectional Survey of Forelimb Hoof Conformation and the Prevalence of Flat Feet in a Cohort of Thoroughbred Racehorses in New Zealand

Racehorses in New Zealand predominantly train counter clockwise. This training pattern has been associated with between forelimb differences in bone mineral density profile and asymmetrical limb loading after training. At present, there is limited data on the hoof conformation of these racehorses. Distal forelimb and digital hoof conformation data were collected from 75 Thoroughbred racehorses (2–5 years old) from two training yards. Digital conformation was subjectively graded, and multiple hoof measurements were made with a modified tire gauge (sole and sulci depth) and from digital photographs. All the horses were shod by two registered master farriers within a median of 15 (interquartile range [IQR], 1–25) days before measurement. There were few distal limb conformation abnormalities scored. Most (62/75) horses presented with some deviation from normal hoof parameters, with 2 (IQR, 1–3) abnormalities reported per horse. The most common hoof abnormality was uneven sulci, which was identified in 43 horses and 59 affected hooves, followed by higher medial hoof wall height in 38 horses and 53 affected hooves. Many of the linear and hoof angle measurements and their ratios were within the bounds reported within the literature and indicative of a balanced foot. The length and width measurements increased with horse age. The dorsal hoof wall (DHW) length:heel length ratios were consistently less than 3:1, and the absolute difference between toe and heel angle was generally greater than 5°. Between limb hoof variation was identified for a number of the morphologic measurements including frog length and sole length and the ratio of sole width:sole length. Flat feet (lack of concave solar surface) were identified in 21/75 (28%) horses and in 28/150 (19%) forelimb hoofs. More horses had a flat left foot (10/75) than right foot (4/75), but seven horses had both feet classified as being flat. Flat feet had 2.4 (1.1–5.6, P = .036) greater odds of presenting with uneven sulci. These data indicate that uneven sulci depth and flatter hooves with may be a typical presentation of Thoroughbred feet. Asymmetry in measurements between limb may reflect the greater loading of the left forelimb when race training counter clockwise.     

The treatment of laminitis in horses

The structural and vascular anatomy of the healthy equine foot is compared with the pathologic changes in the foot of horses with acute and chronic laminitis. The structural and vascular abnormalities present in the foot of horses with laminitis are demonstrated in order to explain the abnormal manner in which their feet grow. The medical, surgical, dietary, and endocrine management of acute and chronic laminitis is discussed. Various forms of hoof trimming beneficial to the reestablishment of normal digital perfusion, normal hoof growth, and normal spatial orientation among the distal phalanx, hoof wall, and sole are described. Guidelines for the provision of frog support provided by adjustable heart-bar shoes are presented.     

Effects of toe angle on hoof growth and contraction in the horse

The effects of toe angle on the growth of the unshod hooves of mature horses were measured over 126 days. The hooves of 4 horses were trimmed long in the toe and short in the heel (“LT”), with toe angles of 40° for the forelimb and 50° for the hind limb hooves; 4 others were trimmed short in the toe and long in the heel (“ST”), with toe angles of 50° for the forelimb and 55° for the hind limb hooves. Growth of the hoof wall at the toe ranged between .19 and .28 mm/day, and was slowest in the forelimb hooves trimmed ST. After 126 days, the hooves trimmed LT were 7% smaller in width than they had been at day 0. Narrowing of the hoof walls and frogs was accompanied by deformation of the angles of the walls (bending outward of their weightbearing surfaces). Frog lengths and sole areas were not affected by toe angle. Regardless of trimming method, all forelimb hooves tended to return to a toe angle of 45° between trimmings, while all hind limb hooves tended toward toe angles of 52° to 53°. The soles of all hooves were basically circular in shape, although the hooves trimmed LT tended to be skewed to the left, as viewed from above, after 126 days.     

Changes in walking parameters of milking cows after hoof trimming

We examined the walking parameters of milking cows in relation to hoof trimming. The hooves of eight Holstein cows were trimmed. Two days before and after the hoof trimming, walking behavior, limb angles, back posture and vertical movement of the back while walking were measured. Walking rate (1.27 vs 0.87 m/s; P = 0.003), step length (1.46 vs 1.33 m; P = 0.009) and stepping rate (0.78 vs 0.65 steps/s; P = 0.046) were found to increase significantly after hoof trimming. Limb angles at the start and end of the support phase changed significantly after hoof trimming, thus indicating an improvement in the ‘on tiptoe’ appearance. The parameters relating to backline indicated that the marked arched shape of the back diminished after hoof trimming. Before hoof trimming, the positions of the withers varied widely and irregularly while walking; however, it changed after hoof trimming as the sinusoid curve and the range of vertical movement of withers decreased significantly. Overall, it has been quantitatively indicated that walking characteristics are improved after hoof trimming. The parameters used in the present study are expected to be useful for monitoring the walking characteristics of cows.     

Retrospective analysis of distal limb conformation and lameness in mature horses after desmotomy of the accessory ligament of the deep digital flexor tendon for management of a flexural deformity

Mature horses that present with flexural deformity of the distal interphalangeal joint and lameness isolated to the foot may obtain long‐term benefits from desmotomy of the accessory ligament of the deep digital flexor tendon (ALDDFT). This retrospective analysis of medical records and radiographs included 13 horses, aged ≥2 years, presented for lameness isolated to the hoof region and diagnosed with flexural deformity of the distal interphalangeal joint. Radiographic angles of the hoof and distal interphalangeal joint and lameness scores were compared before and after desmotomy of the ALDDFT. Follow‐up data including the ability to perform the intended use were obtained at least one year after surgery. There was improvement in the angle between the dorsal aspect of the third phalanx and the weightbearing surface of the hoof, improved alignment between the dorsal hoof wall and dorsal aspect of the third phalanx, and improved alignment of the distal interphalangeal joint. Lameness was decreased in 9/13 horses and 10/13 horses were performing at their level of intended use. Evidence of improved hoof conformation and lameness following desmotomy of the ALDDFT in lame horses with flexural deformity of the distal interphalangeal joint would indicate this procedure should be considered in mature horses.     

Toe white line separation associated with the notch (crena marginalis) on the distal phalanges in Thoroughbred yearling horses

The shape of the white line of the hoof is closely related to the shape of the notch on the dorsal distal bearing border of the distal phalanx (P3). In this study, a radiographic survey of the P3 of both forelimbs of 163 Thoroughbred yearling horses was conducted. The correlation of the depth and width of the notch were analyzed with the toe white line separation grades (0 to 3). As a result, the toe white line separation grade increased, the depth and the width of the notch also increased significantly. Radiographic examination of the P3 of the forelimbs might be useful for deciding whether to implement hoof care to prevent onset of toe white line separation.     

Analysis of strain and stress in the equine hoof capsule using finite element methods: comparison with principal strains recorded in vivo

Finite-element (FE) methods have great potential in equine biomechanics in evaluating mechanical stresses and strains in tissues deep within the hoof. In this study, we critically assessed that potential by comparing results of FE analyses of capsular strain with in vivo data. Nine FE models were developed, corresponding to the shape of hooves for which in vivo principal strain data are available. Each model had the wall, laminar junction, sole and distal phalanx (PIII). In a first loading condition (LC1), force is distributed uniformly to the bearing surface of the wall to determine reaction forces and moment on PIII. These reaction forces were subsequently applied to PIII in loading condition 2 (LC2) to simulate loading via the skeleton. Magnitude of the force resultant was equivalent to the vertical force on the hoof at midstance. Principal compressive strains epsilon2 were calculated at the locations of 5 rosette gauges on the real hooves and are compared with the in vivo strains at midstance. FE strains were from 16 to 221% of comparable in vivo values, averaging 104%. All models in this, and reports by other workers, show predominance of stress and strain at the toe to a greater extent than in the real hoof. The primary conclusion is that FE modelling of strain in the hoof capsule or deeper tissues of individual horses should not be attempted without corroborating experimental data.     

The Forelimb and Hoof Conformation in a Population of Mongolian Horses

This article describes the lower limb and hoof conformation of a population of semi-feral Mongolian horses living on an open tundra/steppe environment. Data were collected from a convenience sample of 120 Mongolian horses used in the 2011 Mongolian Derby. Digital images of the hooves were obtained, and the lower limb conformation was assessed by four veterinarians involved in the screening of the horses offered for the derby. The horses were predominantly geldings (96%, 100/104), approximately 8.6 ± 2.5 years old, and 137 ± 8 cm at the withers. None of the horses were subjected to routine hoof trimming. Based on a 7-point linear score, lower limb conformation was normal, with a trend (>1 linear score deviation) slightly toward carpal valgus, mildly offset cannon (third metacarpal), and valgus at the matacarpophalangeal joint. Hoof measurements were within the norm for horses of this size. Fetlock valgus was associated with a smaller hoof width:length ratio (P = .016). None of the other hoof measurements were significantly associated with abnormal conformation scores. Overall, few conformation abnormalities were observed, and hoof shape and size was within the normal expected range for horses of this size. The hoof conformation in this population of Mongolian horses represented the natural interaction of the hoof with the environment.     

An investigation of the shape of the hoof capsule in hindlimbs,its relationship with the orientation of the distal phalanx and comparison with forelimb hoof capsule conformation

There is limited information documenting hind foot conformation. The objectives of the study were to describe the shape of the hoof capsule of hindlimbs from the lateral aspect in horses of variable breeds, and, within horses, to compare the conformation of the hoof capsule of forelimbs and hindlimbs and determine the orientation of the distal phalanx within the hoof capsule in hindlimbs. Lateral photographs of the fore and hind feet (n = 225) and lateromedial radiographs of the hind feet (n = 29) were obtained. Differences among breed and shoeing status groups were assessed using multivariable mixed-effects linear regression models. Angular parameters and ratios of linear measurements were compared between fore and hind feet; angular radiological variables and photographic parameters of the hind feet were compared. The mean dorsal hoof wall angle for hind feet (50.9°±3.7°) was smaller than forefeet (51.8°±3.9°) (P = 0.04). The mean heel angles for hind feet (36.4°±9.6°) were smaller than forefeet (40.1°±9.3°; P < 0.001). Dorsal hoof wall (P < 0.001) and heel (P = 0.002) angles were larger in unshod than shod feet. In the hind feet, the dorsal hoof wall was parallel to the dorsal aspect of the distal phalanx. The median angle of the distal phalanx to the horizontal (angle S) was 0.6° (interquartile range: −1.4, 2.3°). There was a positive relationship between angle S and the hoof wall angle (W); each 1° increase in angle S was associated with 0.6° increase in angle W (P < 0.001). Angle S was also positively associated with photographic heel angle; each degree increase in the angle S was associated with 1.8° increase in the heel angle (P < 0.001). It was concluded that the angle of the distal phalanx to the horizontal in hindlimbs is smaller than published values for forelimbs. The orientation of the distal phalanx in hindlimbs is correlated with external characteristics of the hoof capsule.     

Morphometry and abnormalities of the feet of Kaimanawa feral horses in New Zealand

Objective The present study investigated the foot health of the Kaimanawa feral horse population and tested the hypotheses that horses would have a large range of foot morphology and that the incidence of foot abnormality would be significantly high. Procedures Abnormality was defined as a variation from what the two veterinarian assessors considered as optimal morphology and which was considered to impact negatively on the structure and/or function of the foot. Fifteen morphometric variables were measured on four calibrated photographic views of all four feet of 20 adult Kaimanawa feral horses. Four morphometric variables were measured from the lateromedial radiographs of the left forefoot of each horse. In addition, the study identified the incidence of gross abnormality observed on the photographs and radiographs of all 80 feet. Results There was a large variation between horses in the morphometric dimensions, indicating an inconsistent foot type. Mean hoof variables were outside the normal range recommended by veterinarians and hoof care providers; 35% of all feet had a long toe conformation and 15% had a mediolateral imbalance. Abnormalities included lateral (85% of horses) and dorsal (90% of horses) wall flares, presence of laminar rings (80% of horses) and bull-nose tip of the distal phalanx (75% of horses). Both hypotheses were therefore accepted. Conclusions The Kaimanawa feral horse population demonstrated a broad range of foot abnormalities and we propose that one reason for the questionable foot health and conformation is lack of abrasive wearing by the environment. In comparison with other feral horse populations in Australia and America there may be less pressure on the natural selection of the foot of the Kaimanawa horses by the forgiving environment of the Kaimanawa Ranges. Contrary to popular belief, the feral horse foot type should not be used as an ideal model for the domestic horse foot.     

Associations between hoof shape and the position of the frontal plane ground reaction force vector in walking horses

AIMS: To determine the frontal plane position of the ground reaction force vector at its centre of pressure under the hoof of walking horses, and its projection through the distal limb joints, and to relate this to hoof geometric measurements.

METHODS: Reflective markers were glued to the forelimb hooves and skin of 26 horses, over palpable landmarks representing centres of the coffin, fetlock and carpal joints, and the dorsal toe at its most distal point. A 4-camera kinematic system recorded the position of these markers as the horse walked in hand across a force platform, to generate a frontal plane representation of the ground reaction force vector passing between the markers at the joints. The position of the vector was calculated as the relative distance between the lateral (0%) and medial (100%) markers at each joint. Digital photos were taken of the hoof in frontal and sagittal views to determine hoof geometric measurements. Associations between these and the position of the force vector at each joint were examined using Pearson correlation coefficients.

RESULTS: Mean vector position for both forelimbs at the toe, coffin, fetlock and carpal joint was 50.1 (SD 8.9), 53.0 (SD 9.2), 54.6 (SD 11.4) and 50.5 (SD17.3)%, respectively, of the distance between the lateral and medial sides of the joint in the frontal plane. Across all four joints, the vector position was slightly more medial (2–4%) for the right than left limb (p>0.05). Medial hoof wall angle was correlated (p<0.05) with force vector position at the fetlock (r=?0.402) and carpal (r=?0.317) joints; lateral hoof wall angle with vector position at the toe (r=0.288) and carpal (r=?0.34) joint, and medial hoof wall height with vector position at the fetlock (r=?0.306) and carpal (r=?0.303) joints.

CONCLUSION: The position of the two-dimensional frontal plane ground reaction force vector at the toe, and at the fetlock and carpal joints was associated with hoof shape. Mediolateral hoof balance has been shown in vitro to affect articular forces, which may be a factor in development of joint disease. The effect of hoof shape needs to be evaluated at faster gaits to determine the potential for joint injury in the presence of larger forces.     

Effect of dietary biotin supplement on equine hoof horn growth rate and hardness.

Over a 10-month period, 24 randomly selected riding horses were fed various amounts of biotin. Statistically significant improvements in growth rates and hardness of hooves were produced by biotin supplementation. Greater growth rates and hardness were achieved at a daily dose of 15 mg than at 7.5 mg. Increased hoof hardness was greatest in the hoof quarters and toe. No ring formation occurred in hooves of horses fed biotin intermittently.     

Keratomas in horses: seven cases (1975-1986)

The diagnosis of keratoma in 7 horses and their treatment and outcome were evaluated. Horses were 2 to 20 years old, of various breeds, and were intact or castrated males. All were lame, and 6 horses had had previous injuries of the affected hoof that had not responded to prior treatments. Only 1 hoof was affected in each horse. Keratomas were beneath the hoof wall (6 horses) or sole (1 horse). Radiographically, a circular or semicircular defect with a discrete margin was present in the distal portion of the third phalanx in 3 horses. Grossly, keratomas were firm solitary masses (1.5 to 5 cm diameter); gray, tan, or yellow; and oval or conical. Keratomas were excised from beneath the hoof wall by removing a section of hoof wall (5 horses) or by undermining the wall beginning at its junction with the sole (1 horse). A keratoma beneath the sole in 1 horse was excised by excavating the sole to the level of the palmar surface of the third phalanx. Keratoma was verified microscopically by the presence of characteristic rings of squamous epithelial cells with abundant keratin. Purulent exudate and inflammatory infiltrate often were present concurrently, reflecting an associated localized infection. Aftercare included daily application of an antiseptic iodine solution and foot bandages, and shoeing with a treatment plate several weeks after surgery. Hoof and sole defects healed completely between 6 months and 1 year. By 1 year after surgery, 6 horses were sound, and keratoma had not recurred.