Sound Warmblood Horses Research Articles

Normal variation in pelvic roll motion pattern during straight-line trot in hand in warmblood horses

In horses, hip hike asymmetry, i.e. left–right difference in hip upwards movement during hind limb protraction in trot, is a crucial lameness sign. Vertical hip movements are complex, influenced by both pelvic roll and pelvic vertical motion. Veterinarians find it challenging to identify low-grade lameness, and knowledge of normal variation is a prerequisite for discerning abnormalities. This study, which included 100 clinically sound Warmblood horses, aimed to describe normal variation in pelvic roll stride patterns. Data were collected during straight-line trot in hand using optical motion capture. Stride-segmented pelvic roll data, normalised with respect to time (0–100% of the stride) and amplitude (± 0.5 of horse average stride range of motion), were modelled as a linear combination of sine and cosine curves. A sine curve with one period per stride and a cosine curve with three periods per stride explained the largest proportions of roll motion: model estimate 0.335 (p < 0.01) and 0.138 (p < 0.01), respectively. Using finite mixture models, the horses could be separated into three groups sharing common pelvic roll characteristics. In conclusion, pelvic roll motion in trot follows a similar basic pattern in most horses, yet there is significant individual variation in the relative prominence of the most characteristic features.

Adaptation strategies of horses with induced forelimb lameness walking on a treadmill.

BackgroundThere is a paucity of research describing the gait pattern of lame horses at the walk.ObjectivesTo describe the changes in motion pattern and vertical ground reaction forces (GRFz) in horses with induced forelimb lameness at the walk and compare those changes with the changes observed at the trot.Study designExperimental study.MethodsIn 10 clinically sound Warmblood horses, moderate forelimb lameness was induced using a sole pressure model followed by trot and walk on a treadmill. Kinematic data were collected using 3D optical motion capture (OMC), and GRFz by an instrumented treadmill. Mixed models were used to compare sound baseline versus forelimb lameness (significance was set at P < .05).ResultsLameness induction significantly reduced peak GRFz on the second force peak, and vertical impulse in the lame limb. Stride and stance duration in all limbs were reduced. Lameness significantly affected the vertical movement symmetry of the head and withers. Maximum limb retraction angle, fetlock extension and protraction speed were reduced in the lame limb. Body centre of mass (COM) translation was reduced in the side‐to‐side direction and increased in the vertical and fore‐aft directions. Several compensatory kinetic and kinematic changes were observed in the nonlame limbs. The observed changes in both kinetics and kinematics were generally smaller at walk with fewer variables being affected, compared to the trot.Main limitationsOnly one degree and type of orthopaedic pain (sole pressure) was studied.ConclusionsCompensatory strategies of forelimb lameness at the walk include alteration of several kinetic and kinematic parameters and have some specific patterns and inter‐individual differences that are not seen at the trot. However, much like at the trot, head movement and forelimb vertical force symmetry seem to be the most useful parameters to detect forelimb lameness at walk.

The Effect of Perineural Anesthesia and Handler Position on Limb Loading and Hoof Balance of the Vertical Ground Reaction Force in Sound Horses

IntroductionTo facilitate interpretation of limb loading and hoof balance obtained by pressure plate analysis in lame horses, the effects of handler position and perineural anesthesia in sound horses need investigation.MethodsSix sound Warmblood horses were walked and trotted over a pressure plate, with the handler at the left and subsequently the right side, and before and after a bilateral palmar digital nerve block. One week later, this procedure was repeated before and after a bilateral abaxial sesamoid nerve block. Peak vertical force (PVF), vertical impulse (VI) and stance time (ST) of 5 hoof prints of both forelimbs were obtained (126 Hz). Asymmetry ratios were calculated.Toe‐heel and medio‐lateral hoof balance curves of the vertical force were calculated. Mixed model ANOVA was used for statistical analysis of asymmetry ratios (α = 0.05). Hoof balance curves were assessed qualitatively.ResultsThere were no significant effects of handler position and perineural anesthesia on PVF and VI; small but significant effects of perineural anesthesia on ST at walk were associated with variability in horses′ speed between sessions at walk (P = 0.046); no significant differences at trot. Hoof balance curves were not affected by handler position or perineural anesthesia, and were highly repeatable within each individual horse.ConclusionsThe lack of any effect of handler position or perineural anaesthesia on limb loading and toe‐heel and medial‐lateral hoof balance in sound horses makes it probable that significant aberrations found using pressure plate analysis are related to abnormalities and hence may be relevant in lameness diagnosis.Ethical Animal ResearchThe study was approved by the ethical committee of the Faculty of Veterinary Medicine of Ghent University (n° 2012/151). Sources of funding: Ghent University. Competing interests: none.

Toe modifications in hind feet shoes optimise hoof‐unrollment in soundWarmblood horses at trot

It was shown that rolled-toe shoes smooth hoof-unrollment and thereby reduce peak loading of forelimbs in trotting Warmblood horses. Shoe design and shoeing technique for hind feet have been modified over recent decades from fully fitted, toe-clipped shoes to set-back, side-clipped shoes. To study the effects of different shoe modifications on loading and movement of the hind hoof. Ten clinically sound Warmblood horses were shod with 3 types of hind shoe: first, fully fitted, toe-clipped shoes, followed randomly by side-clipped shoes without a rolled toe that were set back by half the thickness of the hoof wall in the plantar direction and identical side-clipped shoes with a rolled toe, with 2 days between shoeing sessions to adapt to the shoes. Then horses were trotted in a straight line over a pressure-force plate combination. Hoof dynamics were compared statistically with the fully fitted shoe condition using a general linear model repeated measures test (P<0.05). There were no significant differences in the characteristics of limb timing, such as stance time and breakover duration nor the peak vertical and horizontal ground reaction force. By setting back the hind shoes, the centre of pressure at toe-off was positioned less dorsally. The rolled toe resulted in a smoother shift of the centre of pressure and thus more fluent hoof-unrollment. Both alternative types of shoe allowed a more lateral orientation of the centre of pressure at toe-off. Toe modifications of hind shoes can influence hindlimb kinematics positively. Setting the hind shoe back and rolling the toe leads to smoother hoof-unrollment, which enables the horse to coordinate movement correctly without loss of propulsion. Thus, shoe modifications might facilitate movement and thereby help prevent overload injuries.

Contribution of dynamic calibration to the measurement accuracy of a pressure plate system throughout the stance phase in sound horses

The aim of this study was to evaluate the accuracy of the vertical force curve of a pressure plate (PP) using dynamic calibration with a force plate (FP) in six sound Warmblood horses. The animals were walked and trotted over a combined PP-FP system sampling at 250 Hz. Five valid measurements of each forelimb were collected. The recalibration factor (RF), the ratio between the calibrated and raw PP data, was evaluated in each timeframe throughout the stance phase. Following dynamic calibration, the vertical force curve of the PP demonstrated a characteristic biphasic pattern at the walk and typical spikes at the beginning and end of stance at the trot. Both at walk and trot, the RF was considerably higher and more variable in the first 5% of stance (i.e. the impact phase) and during the final 20% of stance (i.e. the breakover phase), whereas between these phases (i.e. in the support phase), the RF was lower and remained relatively constant. These findings were confirmed by plotting the RF as a function of the vertical force and the RF in the loading part of the vertical force curve was lower than in the unloading part of the curve. Without dynamic calibration with a FP, the accuracy of the PP appears suboptimal, especially at the impact and breakover phases. However, the accuracy of the PP was relatively high and constant during the support phase, and higher loading was not associated with increasing deviation. It is therefore essential to optimise PP calibration, as this may downsize systematic measuring errors. However, in a clinical setting, where a stand-alone PP is used to objectively quantify locomotor symmetry, these errors can be readily eliminated by evaluating left:right symmetry ratios.

Use of a pressure plate to analyse the toe–heel load redistribution underneath a normal shoe and a shoe with a wide toe in sound warmblood horses at the walk and trot

The objective of this study was to use a pressure plate to quantify the toe–heel load redistribution in the forelimbs of sound warmblood horses with normal shoes and shoes with a wide toe and narrow branches, used empirically in the treatment of superficial digital flexor tendon or suspensory ligament injuries. In a crossover-design study, six horses, randomly shod with normal shoes and shoes with a wide toe, were led over a dynamically calibrated pressure plate to record data from both forelimbs. There were no significant differences between both shoes in the toe–heel index of stance time, peak vertical force and vertical impulse. For the adapted shoe, the peak vertical pressure was slightly lower and was exerted slightly earlier in the stance phase, albeit not significantly. However, the significantly larger toe contact area of the adapted shoe resulted in a significantly lower total vertical pressure in the toe region. Hence, the pressure plate adequately visualised the individual loading of the toe and heel region, and clearly demonstrated the altered pressure distribution underneath the shoe with a wide toe. Although further research on a deformable surface is needed to confirm this hypothesis, the pressure redistribution from the toe to the heels could promote sinking of the heels in arena footing, thereby mimicking the biomechanical effects of a toe wedge and providing a rationale for its application in the treatment of SDFT or SL injuries. The pressure measuring equipment used in this study can offer to the clinician a diagnostic tool for the evaluation of the load distribution underneath the equine hoof and for the fine-tuning of corrective shoeing.

On surfaces and soreness

The objective of this study was to use a pressure plate to quantify the toe–heel load redistribution in the forelimbs of sound warmblood horses with normal shoes and shoes with a wide toe and narrow branches, used empirically in the treatment of superficial digital flexor tendon or suspensory ligament injuries. In a crossover-design study, six horses, randomly shod with normal shoes and shoes with a wide toe, were led over a dynamically calibrated pressure plate to record data from both forelimbs. There were no significant differences between both shoes in the toe–heel index of stance time, peak vertical force and vertical impulse. For the adapted shoe, the peak vertical pressure was slightly lower and was exerted slightly earlier in the stance phase, albeit not significantly. However, the significantly larger toe contact area of the adapted shoe resulted in a significantly lower total vertical pressure in the toe region. Hence, the pressure plate adequately visualised the individual loading of the toe and heel region, and clearly demonstrated the altered pressure distribution underneath the shoe with a wide toe. Although further research on a deformable surface is needed to confirm this hypothesis, the pressure redistribution from the toe to the heels could promote sinking of the heels in arena footing, thereby mimicking the biomechanical effects of a toe wedge and providing a rationale for its application in the treatment of SDFT or SL injuries. The pressure measuring equipment used in this study can offer to the clinician a diagnostic tool for the evaluation of the load distribution underneath the equine hoof and for the fine-tuning of corrective shoeing.

Lateralised motor behaviour leads to increased unevenness in front feet and asymmetry in athletic performance in young mature Warmblood horses

Foot stance in grazing significantly influences hoof conformation and development from foal to yearling age. To conduct a longitudinal study to establish if the relationship between motor laterality and uneven front feet persisted in 3-year-old horses at the time of studbook selection and to investigate if such laterality and unevenness might influence the horses' ability to perform symmetrically while trotting, cantering and free jumping. Seventeen clinically sound but untrained (with only minimal experience of handling) and sound Warmblood horses that had participated in a previous study were assessed as per the protocol reported. Laterality was tested in a preference test (PT) and z-values were calculated for analysis purposes. Laterality and hoof unevenness were related to both relative limb length and relative head size, while the ability to perform symmetrically was tested in free trot-canter transitions and free jumping exercises. Differences in performance between horses with and without a limb preference in the PT and those with 'uneven' and 'even' feet were tested for differences in performance metrics using Students' t test, while linearity was tested using a regression analysis (P<0.05). Significant laterality was still present in 24% of the 3-year-old horses and the relationship between laterality and uneven feet pairs was stronger than at foal and yearling stages. Horses with significant motor laterality had almost 4 times more unevenness, a smaller head and longer limbs and the relationship between body conformation and laterality was still present. There was a strong linear relation between unevenness, laterality and a bias or side preference for trot-canter transitions. However, this relationship was not significant during the free jumping exercise. Motor laterality and uneven feet pairs were still present and significantly related in the 3-year-old horses and both variables were also strongly related to sidedness in trot-canter transitions. Warmblood studbooks should include quantitative data on laterality at the time of studbook admission as part of the selection criteria.

Hoof growth between two shoeing sessions leads to a substantial increase of the moment about the distal, but not the proximal, interphalangeal joint

There is little insight into the effects of routine farriery on the internal structures of the distal limb in sound horses. To measure the effect of change in hoof conformation during a shoeing interval on the moments about the proximal and distal interphalangeal joints (PIPJ, DIPJ) and to determine whether and how the horse compensates for this change in hoof conformation. Both front feet of 9 sound Warmblood horses were measured while standing on a pressure-force measuring system and radiographed in a lateromedial direction shortly after shoeing and 8 weeks later. From these data, ground reaction forces (GRF) and lever arms were measured in order to calculate joint moments. After 8 weeks, the moment about the PIPJ did not increase significantly, but the moment about the DIPJ did so, indicating a compensatory mechanism for a change in hoof conformation in the DIPJ. Standing horses compensate for hoof conformation change during an 8-week shoeing interval, which leads to increased DIPJ extension and consequently an increased loading of the deep digital flexor tendon. This study quantifies the effect of a shoeing interval on the internal structures of the foot and helps to determine an appropriate shoeing interval for individual horses in which the hoof with the lowest hoof angle is the best indicator. The exact determination of an optimal individual shoeing interval requires further study.

Shoeing sound Warmblood horses with a rolled toe optimises hoof-unrollment and lowers peak loading during breakover

Overload injuries in sport horses commonly occur; shoeing techniques are believed to be important in prevention of these injuries, but there is a paucity of scientific information identifying the potential connection. To test a horseshoe with a modified rolled toe designed to ease the process of breakover and decrease loading of lesion-prone structures of the distal limb. Twenty clinically sound Warmblood horses trotted over a track containing a pressure/force measuring system and 6 infrared cameras. The horses were measured with 2 types of shoes, standard flat shoes and shoes with a rolled toe. The shoeing procedure was randomised and horses had 2 days between measurements to adapt to the shoes. Limb placement and timing characteristics, e.g. breakover duration, did not change significantly. There was an improvement in the ease of movement to roll over the toe in the shoes with a rolled toe, due mainly to a smoother hoof-unrollment pattern. The peak indicative moment decreased substantially at the onset of breakover in the shoe with the rolled toe. With a rolled toe the process of hoof-unrollment is smoother, which improves the coordination of this process, and lowers peak loading of the distal limb during breakover. This study stresses the importance of proper shoeing in sound horses, showing that shoe modifications can optimise the loading characteristics of the distal limb and therefore might be a means to prevent sport horses from overload injuries.

Comparison of pressure plate and force plate gait kinetics in sound Warmbloods at walk and trot

Modern pressure plates (PP) could be an alternative to traditional force plates (FP) for quantitative equine gait analysis, thereby providing the clinician with objective data on the horse's gait while unravelling the loading of different regions of the hoof during the stance phase. The aim of this study was to determine whether a stand-alone PP allows reliable measurement of gait kinetics, compared to simultaneously recorded FP variables. Six sound Warmblood horses were walked and trotted over a combined PP and FP system for collection of a set of five valid kinetic measurements for each forelimb. A measurement was considered valid if the horse was moving in a straight line at a constant pace while gait velocity was within a preset range and the hoof fully contacted the plate surface. Significant differences between FP and PP data were seen for peak vertical force (PVF), vertical impulse (VI), time at which the PVF occurs (tPVF) and forelimb symmetry ratios (SymPVF and SymVI) (P < 0.05), but not for stance phase duration (ST). Nevertheless, mean agreement indices (AIs) of ST, tPVF and SymPVF and SymVI were excellent (≥ 0.92), whereas AIs of PVF and VI were moderate (≥ 0.70). The excellent agreement between PP and FP symmetry ratios confirms that observed differences between PP and FP in symmetry ratios are small (2-7%), especially when compared to the expected decrease in symmetry associated with mild lameness (> 20%). The results indicate that a stand-alone pressure plate can be used to measure absolute (ST) and relative (tPVF) temporal variables and loading symmetry ratios and offers equine veterinarians a mobile, cost-efficient and quick gait evaluation method for routine clinical use. However, the system cannot be used interchangeably with a force plate to measure absolute values of limb loading.

Synthetic shoes attenuate hoof impact in the trotting warmblood horse

AbstractImpact is considered the most critical part of the stance phase for the development of chronic articular disorders such as osteoarthritis in the equine distal limb. Modern, synthetic shoeing materials are believed to modify impact and therefore are often used to treat an/r prevent lameness due to chronic joint disorders. Scientific evidence is scarce, however, to prove this. Hoof impact of forelimb was compared quantitatively in a group of horses under three conditions: unshod, classical steel shoes and shod with a synthetic shoe. Twelve sound warmblood horses were trotted by hand on an asphalt track at a mean speed of 3.5ms−1 and measured in a Latin square design (unshod condition, with steel shoes and with polyurethane (PU) shoes) using a triaxial accelerometer that had been fixed to the lateral hoof wall of the left forelimb. The sampling frequency was set at 10kHz per channel. The maximum amplitude of vertical and horizontal, forwar/ackward accelerations at hoof impact was lowest when shod using the PU shoeing condition (P&lt;0.05), but the duration of the impact vibrations was lowest when unshod. PU shoes cause more damping, less friction and slower shock absorption at hoof level compared with the other two conditions and thus modify impact. Synthetic, polyurethane shoes may help in reducing peak vibrations. These short-term effects appear to be promising enough to evaluate PU shoes under field conditions in reducing impact on the longer term after substantial wear and tear. Furthermore, the possible role of synthetic materials in repairing critical tissues or even in preventing osteoarthritis in horses warrants further investigation.

Compensation for changes in hoof conformation between shoeing sessions through the adaptation of angular kinematics of the distal segments of the limbs of horses

To determine the mechanism that enables horses to partially counteract the shift of the center of pressure under the hoof induced by changes in hoof morphology attributable to growth and wear during a shoeing interval. 18 clinically sound Warmblood horses. Horses were evaluated 2 days and 8 weeks after shoeing during trotting on a track containing pressure-force measuring plates and by use of a synchronous infrared gait analysis system set at a frequency of 240 Hz. All feet were trimmed toward straight alignment of the proximal, middle, and distal phalanges and shod with standard flat shoes. Results-Temporal characteristics such as stance time and the time between heel lift and toe off (ie, breakover duration) did not change significantly as a result of shoeing interval. Protraction and retraction angles of the limbs did not change. Compensation was achieved through an increase in the dorsal angle of the metacarpohalangeal or metarsophalangeal (fetlock) joint and a concomitant decrease of the dorsal angle of the hoof wall and fetlock. There was an additional compensatory mechanism in the hind limbs during the landing phase. Horses compensate for changes in hoof morphology that develop during an 8-week shoeing interval such that they are able to maintain their neuromuscular pattern of movement. The compensation consists of slight alterations in the angles between the distal segments of the limb. Insight into natural compensation mechanisms for hoof imbalance will aid in the understanding and treatment of pathologic conditions in horses.

Vertical ground reaction force–time histories of sound Warmblood horses trotting on a treadmill

The objective of this study was to establish representative treadmill ground reaction force (GRF) and interlimb co-ordination time data of clinically sound horses at the trot. It was anticipated that these normative standards would provide a reference data base against which lame horses could be compared. GRF–time histories were collected from 30 Warmblood riding horses with easy, wide natural gaits. Data were recorded of all four limbs simultaneously by the use of an instrumented treadmill. A total of 912 stride cycles per limb were analysed for force, time and spatial parameters and were averaged. The shape and amplitude of the treadmill force curves were very similar to force traces recorded with a stationary force plate. The horses showed a high degree of symmetry in all investigated parameters (95% reference interval of left–right asymmetry ±1.8–6.8%). No significant differences were found between left and right mean values. Intra-individual coefficients of variance of the various parameters did not exceed 2.7%. Inter-individual coefficients of variance were 2.5–3.5 times larger than the respective intra-individual coefficients. An instrumented treadmill provides a number of decisive advantages, such as time-efficient data acquisition of all four feet simultaneously over successive strides, or the high regularity of the horse’s gait pattern at controlled velocities, which allow the clinical assessment of locomotor performance of horses.