Effects of induced weight shift in the hind limbs on claw loads in dairy cows.

The modern dairy industry is plagued by a high prevalence of claw horn lesions in cows, which cause lameness, affect well-being, limit milk production, and are responsible for premature removal of cows from the herd. The lateral hind claws are primarily affected, and this has been linked to a relatively higher load being exerted on the lateral claws when cows shift weight from one hind limb to the other. The vertical ground reaction forces and mean and maximum pressures under the claws were measured in 40 nonlame dairy cows before and during a shift in weight from one hind limb to the other, which was accomplished by applying pressure manually to one side of the pelvis. During square standing on firm ground, about two-thirds of the entire hind limb load was exerted on the 2 lateral claws, and the remaining one-third was exerted on the medial claws combined. At the moment of maximum weight shift, the lateral claw of the loaded limb bore almost two-thirds of the entire load of both hind limbs, with the heel zone bearing almost half of the load of both hind limbs. Subsequently, the load of the lateral claw of the contralateral hind limb decreased, as did the load of both medial claws. Thus, the weight redistribution had occurred predominantly between the lateral hind claws. The high load exerted on a lateral hind claw during weight shift and at maximum weight shift is assumed to play a role in the pathogenesis of claw horn lesions, particularly when accentuated by a softened claw horn and hard flooring.

Comparative investigations on the upper respiratory tract in Norwich terriers, brachycephalic and mesaticephalic dogs.

For some time Norwich terriers have been known to suffer from respiratory problems. In order to assign this weakness to a pathophysiology, 23 terriers were examined clinically, with laryngoscope and with rhinomanometry. In addition their skulls were dimensioned on radiographs. Widened nostrils, overlong soft palates and the everted laryngeal pouches were consistent with brachycephalic syndrome. Resistance values in the nasal passage corresponded to the appearance in brachycephalic dogs. Skull measurements gave inconsistent results, because length to width ratios and craniofacial angles denoted mesaticephaly, whereas the facial to cranial length ratios (S-index = 0.65) lay in the brachycephalic sector. It can be concluded, that the Norwich terrier breed is in transition towards brachycephaly with some individual dogs already suffering from the brachycephalic syndrome. Breeders are requested to introduce necessary counter measures.

On sait depuis longtemps déjà que le Norwich Terrier souffre de plus en plus de problèmes respiratoires. Afin de pouvoir donner une explication pathophysiologique à ces problèmes, on a examiné 23 Norvich Terriers sur le plan clinique, laryngoscopique, rhino-manométrique ainsi qu'avec des radiographies du crâne. Des narines larges, un voile du palais trop long et des ventricules laryngés éversés, de même que des mesures de résistance augmentées dans les conduits nasaux correspondaient à l'image du syndrome brachycéphale. Les mesures du crâne présentaient un tableau non uniforme. L'index longueur-largeur et l'angle cranio-facial correspondaient à ceux de chiens mésocéphales, alors que l'index splanchnocrâne-neurocrâne (Index S de 0.65) était clairement dans la zone du brachicéphalisme. On peut en déduire que le Norwich Terrier se trouve sur le chemin du brachicéphalisme et que certains chiens souffrent déjà d'un syndrome brachycéphale. Les éleveurs doivent donc prendre des mesures pour lutter contre cette évolution.

Repair of a canine patellar ligament rupture using the ComPact UniLock 2.4/3.0 mm System.

An 11-year old, female, Mix Breed dog was presented after being hit by a car with a rupture of the left patellar ligament. Due to a suspected wound infection close to the stifle joint, surgical repair was delayed for 10 days. The ruptured ligament was sutured and augmented with fascia lata. Additionally, two ComPact UniLock 2.4/3.0 mm plates connected with 1.0 mm orthopaedic wire were used to protect the primary repair. No immobilization of the stifle joint was needed. The implants were removed after 7 weeks, because of suspected infection and loosening. The successful utilization of an alternative surgical technique for the repair of the patellar ligament rupture in the dog has also been documented by pre- and post-operative temporal-spatial gait analysis (GaitFour®).

Effect of dog breed and body conformation on vertical ground reaction forces, impulses, and stance times.

OBJECTIVES: To assess whether fully normalised vertical ground reaction forces and stance times obtained at a trot depend on dog breed or body conformations. METHODS: Peak vertical forces (PVF), vertical impulses (VI), stance times (ST), and ratio of forelimb impulse to total impulse (RVI) of 54 dogs of seven different breeds were normalised to body weight and body size according to the theory of dynamic similarity, and were tested for differences between breeds. Breeds were Borzoi, Bernese Mountain dog, Great Dane, Labrador Retriever, Landseer, Rhodesian Ridgeback, and Rottweiler. Body length ratio (BLR) and body mass index (BMI) were also compared between breeds. RESULTS: Significant differences between breeds were found for the normalised forelimb PVF, VI and ST, and hindlimb PVF. Looking at individual breeds, it was most evident that Borzois had a lower forelimb VI, and a higher hindlimb PVF than the other breeds. This resulted in Borzois having a lower RVI compared to other dogs, indicating a more caudally located centre of gravity. Only a few differences in gait parameters were found between other dog breeds. The BMI was significantly lower in Borzois than in other breeds, but was otherwise not associated with gait parameters. CLINICAL SIGNIFICANCE: Force plate data of dogs of different breeds are not necessarily comparable, even after full normalisation to body weight and body size. Group comparisons should only be made when the groups consist of breeds with similar body conformations.

Hoof conformation in Icelandic competition horses and its interrelationship with hoof pathologies and tölt performance.

In order to improve the four-beat-rhythm and forelimb action of the tölt in Icelandic horses (ICE), special shoeing techniques are applied particularly in the front hooves by increasing hoof length and height, or by adding weight to the distal limbs. Although regulations limit dorsal hoof wall length (LDHW) in competition ICE, their shoeing often deviates from a biomechanically optimal distal limb conformation. This study aimed to qualitatively and quantitatively describe current shoeing practices of ICE in competition. Moreover, the influence of LDHW on the occurrence of deviations from a standard hoof conformation, as well as on tölt performance was investigated. At four European competition sites, hoof dimensions of 133 randomly selected ICE were measured manually, and limb conformation and hoof balance were described. Dorsopalmar/-plantar and lateromedial radiographs of the left front and hind hooves were taken of each horse. Various parameters related to hoof dimensions and balance were measured on radiographs using the Metron-Hoof-Pro software. Flares of the dorsal hoof wall had the highest prevalence of all investigated hoof deformities. Multiple logistic regression analysis revealed that longer LDHW was associated with the occurrence of toe flares (P = 0.045), a broken hoof pastern axis (P = 0.003), and asymmetry of the quarter wall heights (P = 0.015). However, horses with a longer LDHW achieved higher scores in competition. In spite of its positive effect on tölt performance, a long LDHW is not recommendable as it may be associated with a higher prevalence of certain hoof deformities.

Relationship between the forces acting on the horse's back and the movements of rider and horse while walking on a treadmill.

REASONS FOR PERFORMING STUDY: The exact relationship between the saddle pressure pattern during one stride cycle and the movements of horse and rider at the walk are poorly understood and have never been investigated in detail. HYPOTHESIS: The movements of rider and horse account for the force distribution pattern under the saddle. METHOD: Vertical ground reaction forces (GRF), kinematics of horse and rider as well as saddle forces (FS) were measured synchronously in 7 high level dressage horses while being ridden on an instrumented treadmill at walk. Discrete values of the total saddle forces (FStot) were determined for each stride and related to kinematics and GRF. The pressure sensitive mat was divided into halves and sixths to assess the force distribution over the horse's back in more detail. Differences were tested using a one sample t test (P < 0.05). RESULTS: FStot of all the horses showed 3 peaks (P1-P3) and 3 minima (M1-M3) in each half-cycle, which were systematically related to the footfall sequence of the walk. Looking at the halves of the mat, force curves were 50% phase-shifted. The analysis of the FS of the 6 sections showed a clear association to the rider's and horse's movements. CONCLUSION: The saddle force distribution during an entire stride cycle has a distinct pattern although the force fluctuations of the FStot are small. The forces in the front thirds were clearly related to the movement of the front limbs, those in the mid part to the lateral flexion of the horse's spine and the loading of the hind part was mainly influenced by the axial rotation and lateral bending of the back. POTENTIAL RELEVANCE: These data can be used as a reference for comparing different types of saddle fit.

Kinetics and kinematics of the passage.

REASONS FOR PERFORMING STUDY: The load acting on the limbs and the load distribution between fore- and hindlimbs while performing specific dressage exercises lack objective assessment. HYPOTHESIS: The greater a horse's level of collection, the more load is shifted to the rear and that during the passage the vertical load on the limbs increases in relation to the accentuated vertical movement of the centre of mass. METHODS: Back and limb kinematics, vertical ground reaction force and time parameters of each limb were measured in 6 Grand Prix dressage horses performing on an instrumented treadmill at the trot and the passage. Horses were ridden by their own professional rider. RESULTS: At the passage, horses moved at a slower speed (-43.2%), with a lower stride frequency (-23.6%) and, therefore, higher stride impulses (+31.0%). Relative stance duration of fore- and hindlimbs and suspension duration remained unchanged. While at the trot the diagonal limbs impacted almost simultaneously, the hindlimbs always impacted first at the passage; the time dissociation between landing and lift-off remained unchanged. Because of the prolonged stride duration, stride impulse and consequently limb impulses were higher at the passage in the fore- as well as in the hindlimbs (+24.8% and +39.9%, respectively). Within the diagonal limb pair, load was shifted from the forehand to the hindquarters (percentage stride impulse carried by the forehand -4.8%). Despite the higher impulses, peak vertical forces in the fore- and hindlimbs remained unchanged because of the prolonged absolute stance durations in fore- and hindlimbs (+28.1% and +32.2%, respectively). CONCLUSIONS: Based on the intralimb timing, the passage closely resembles the trot. Compared to other head-neck positions, the higher degree of collection resulted in a pronounced shift in impulse towards the hindquarters. Despite the higher limb impulses, peak forces acting on the limbs were similar to those observed at the trot. POTENTIAL CLINICAL RELEVANCE: An understanding of load distribution between fore- and hindlimbs in relation to different riding techniques is crucial to prevent wear-and-tear on the locomotor apparatus.

Influence of different head-neck positions on vertical ground reaction forces, linear and time parameters in the unridden horse walking and trotting on a treadmill.

REASONS FOR PERFORMING STUDY: It is believed that the head-neck position (HNP) has specific effects on the loading pattern of the equine locomotor system, but very few quantitative data are available. OBJECTIVE: To quantify the effects of 6 different HNPs on forelimb-hindlimb loading and underlying temporal changes. METHODS: Vertical ground reaction forces of each limb and interlimb coordination were measured in 7 high level dressage horses walking and trotting on an instrumented treadmill in 6 predetermined HNPs: HNP1--unrestrained; HNP2--elevated neck, bridge of the nose in front of the vertical; HNP3--elevated neck, bridge of the nose behind the vertical; HNP4--low and flexed neck; HNP5--head and neck in extreme high position; and HNP6--forward downward extension of head and neck. HNP1 served as a velocity-matched control. RESULTS: At the walk, the percentage of vertical stride impulse carried by the forehand (Iz(fore)) as well as stride length and overreach distance were decreased in HNP2, HNP3, HNP4 and HNP5 when compared to HNP1. At the trot, Iz(fore) was decreased in HNP2, HNP3, HNP4 and HNP5. Peak forces in the forelimbs increased in HNP5 and decreased in HNP6. Stance duration in the forelimbs was decreased in HNP2 and HNP5. Suspension duration was increased in HNP2, HNP3 and HNP5. Overreach distance was shorter in HNP4 and longer in HNP6. CONCLUSIONS: In comparison to HNP1 and HNP6, HNPs with elevation of the neck with either flexion or extension at the poll as well as a low and flexed head and neck lead to a weight shift from the forehand to the hindquarters. HNP5 had the biggest effect on limb timing and load distribution. At the trot, shortening of forelimb stance duration in HNP5 increased peak vertical forces although Iz(fore) decreased. POTENTIAL RELEVANCE: Presented results contribute to the understanding of the value of certain HNPs in horse training.

Quantification of the effect of instrumentation error in objective gait assessment in the horse on hindlimb symmetry parameters.

BACKGROUND: Objective gait analysis is becoming more popular as a tool assisting veterinarians during the clinical lameness exam. At present, there is only limited information on the effect of misplacement of markers/motion-sensors. OBJECTIVES: To investigate and describe the effect of marker misplacement on commonly calculated pelvic symmetry parameters. STUDY DESIGN: Experimental study. METHODS: Each horse was equipped with custom-made devices consisting of several reflective markers arranged in a predefined manner with a reference marker correctly positioned regarding the anatomical landmark and several misplaced markers along the sagittal and transverse planes. Linear regression analysis was used to estimate the effect of marker misplacement. RESULTS: For the tubera sacrale, each cm of left/right misplacement led to a difference in minimum position of the pelvis (PDmin) of ±1.67 mm (95% CI 1.54-1.8 mm) (P<0.001); maximum position of the pelvis (PDmax) was affected by ±0.2 mm (95% CI 0.071-0.33 mm) (P = 0.003). With respect to cranial/caudal misplacement, each cm of misplacement resulted in a PDmin difference of ±0.04 mm (95% CI -0.09 to 0.16 mm) (P = 0.56) and a PDmax difference of ±0.008 mm (95% CI -0.13 to 0.12 mm) (P = 0.9). For the tubera coxae, each cm of vertical misplacement led to a difference in the displacement amplitude between left and right tubera coxae (Hip-Hike_Diff) of ±1.56 mm (95% CI 1.35-1.77 mm) (P<0.001); for the cranial/caudal misplacement, this was ±0.82 mm (95% CI 0.66-0.97 mm) (P<0.001). MAIN LIMITATIONS: Only three horses were used in this experiment and the study design did not permit to determine the influence of marker misplacement on the evaluation of different degrees of lameness. CONCLUSIONS: Marker misplacement significantly affects calculated symmetry parameters of the pelvis. The observed errors are overall small but significant. In cases of mildly asymmetrical horses, this error might influence the decision-making process whereas in more severe asymmetries, the influence of the error effect may become less significant.

[Kinetics of heifers and cows walking on an instrumented treadmill]. / Kinetische Auswertung des Schrittes von Jungrindern und Kühen auf einem instrumentierten Laufband.

OBJECTIVE: Kinetic data of stride characteristics and ground reaction forces of cattle become increasingly important as automated lameness detection may be installed in dairy cow housing systems in the future. Therefore, sound heifers and cows were measured on an instrumented treadmill to collect such basic data. MATERIAL UND METHODS: Nine heifers and 10 cows were trained to walk on an instrumented treadmill. Vertical ground reaction forces as well as step and stride timing and length variables were measured for all limbs simultaneously. On average, 16 stride cycles in cows and 24 strides in heifers were analysed in each case. RESULTS: The cows walked on the treadmill at an average speed of 1.2 ± 0.05 m/s (mean ± standard deviation), with a stride rate of 43.0 ± 1.9/min and a stride length of 1.68 ± 0.1 m. The heifers had average values of 1.3 ± 0.04 m/s, 53.7 ± 2.2/min and 1.49 ± 0.05 m, respectively. The stance duration relative to stride duration (the duty factor) was for the cows significantly longer in the forelimbs (67%) than in the hind limbs (64%). Force-time-curves of all limbs showed two peaks, one after landing (FP1) and another during push off (FP2). Vertical ground reaction force was highest for FP1 in the hind limbs, but for FP2 in the forelimbs. At all limbs, force minimum between the peaks occurred shortly before midstance. The vertical impulse carried by both forelimbs amounted to 53.7% of the total stride impulse in cows and to 55.0% in heifers. The location of the centre of body mass varied during the stride cycle but was always located more towards the front limbs. CONCLUSIONS: Cows and heifers showed a symmetrical walk with minimal intra-individual variations. Relative stride impulse of the front limbs was higher than that of the hind limbs. Peak vertical force in the hind limbs was highest at landing and in the forelimbs at push off. The present study offers kinetic data of sound cows and heifers which might be helpful as guidelines for automated systems for lameness detection in cattle.

Compensatory load redistribution of horses with induced weightbearing hindlimb lameness trotting on a treadmill.

REASONS FOR PERFORMING STUDY: The compensatory mechanisms of horses with weightbearing hindlimb lameness are still not fully understood. HYPOTHESIS: That weightbearing, unilateral hindlimb lameness would not only alter stride characteristics to diminish structural stress in the affected limb but also induce compensatory load adjustments in the other supporting limbs. OBJECTIVE: To document the load and time shifting mechanisms of horses with unilateral weightbearing hindlimb lameness. METHODS: Reversible lameness was induced in 8 clinically sound horses by applying a solar pressure model. Three degrees of lameness (subtle, mild and moderate) were induced and compared with the nonlame (sound) control measurement. Vertical ground reaction forces were recorded for all 4 limbs simultaneously on an instrumented treadmill. RESULTS: Compared to the sound situation, moderate hindlimb hoof lameness induced a decrease in stride duration (-3.3%) and stride impulse (-3.1%). Diagonal impulse decreased selectively in the lame diagonal stance (-7.7%). Within the diagonal limb pair, vertical impulse was shifted to the forelimb during the lame diagonal stance (+6.5%) and to the hindlimb during the sound diagonal stance (+3.2%). Peak vertical force and vertical impulse decreased in the lame limb (-15%), but only vertical impulse increased in the contralateral hindlimb (+5.7%). Stance duration was prolonged in both hindlimbs (+2.5%). Suspension duration was reduced to a greater extent after push-off of the lame diagonal limb pair (-21%) than after the sound diagonal limb pair (-9.2%). CONCLUSIONS: Four compensatory mechanisms could be identified that served to reduce structural stress, i.e. peak vertical force on the affected limb: 1) reduction of the total vertical impulse per stride; 2) diagonal impulse decreased selectively in the lame diagonal; 3) impulse was shifted within the lame diagonal to the forelimb and in the sound diagonal to the hindlimb; and 4) the rate of loading and peak forces were reduced by prolonging the stance duration. POTENTIAL RELEVANCE: Load shifting mechanisms are not only effective in diminishing peak forces in the affected limb, but also suppress compensatory overload in other limbs. Selected force and time parameters allow the unequivocal identification of the lame limb. Future studies have to examine how far these compensatory mechanisms may be generalised for other defined orthopaedic problems in the hindlimb.

Effect of intra-abdominally induced pressure on the urethral pressure profiles of healthy and incontinent bitches.

OBJECTIVE: To determine whether reduced pressure transmission is of importance in the pathophysiologic mechanism of urinary incontinence in bitches. ANIMALS: 20 sexually intact, continent bitches and 21 spayed, incontinent bitches. PROCEDURE: Urethral pressure profiles before (resting) and after (stressed) insufflation of gas in the abdominal cavity were recorded in bitches under general anesthesia. Differences (stressed minus resting) were calculated for all variables. On the basis of these values, the pressure transmission ratio was determined. RESULTS: Resting pressure profiles of incontinent bitches indicated significantly (P < 0.05) lower maximal closure pressure (4.5 +/- 3.0 cm of H2O) than did those of continent bitches (11.2 +/- 7.2 cm of H2O). The intra-abdominal pressure increase lead to a shortening of total profile length, which was equal in both groups and caused an increase in maximal urethral pressure. The change in maximal urethral pressure was significantly (P < 0.05) greater in incontinent bitches (12.4 +/- 4.1 cm of H2O) than in continent bitches (8.8 +/- 4.5 cm of H2O). The profile areas and the pressure transmission ratios did not differ significantly (P < 0.05) between the 2 groups. CONCLUSION: The effect of decreased pressure transmission on the urethra is not a factor in the pathophysiologic mechanism of urinary incontinence attributable to urethral incompetence in bitches.

Reproducibility of urethral pressure profiles in clinically normal sexually intact female dogs by use of microtransducer catheters.

Urethral pressures profiles (UPP) obtained by use of microtransducer catheters were determined in 8 anestrous sexually intact female Beagles during general anesthesia. A UPP study consisted of 3 consecutive recordings, and 4 UPP studies were repeated at an interval of 5 days in each dog. Maximal urethral pressure (cm of H2O), bladder pressure (cm of H2O), and anatomic urethral length (cm) were recorded. Maximal urethral closure pressure (cm of H2O) was calculated. Mean +/- SD (for all measurements) maximal urethral closure pressure was 12.8 +/- 5.6 cm of H2O (range, 2.4 to 25.2 cm of H2O). Maximal urethral closure pressure was significantly (P < 0.05) decreased during the first recording period (11.4 +/- 5.8 cm of H2O), compared with the second (13.0 +/- 5.2 cm of H2O) or third (14.1 +/- 5.7 cm of H2O) recording periods within a UPP study (3 consecutive recordings). Mean maximal difference in urethral closure pressure during a single UPP study was 4.8 +/- 2.4 cm of H2O. Significant difference in maximal urethral closure pressure was not observed between studies. Mean (for all measurements) anatomic urethral length was 6.2 +/- 0.9 cm (4.1 to 7.8 cm). Anatomic urethral length was significantly (P < 0.05) less during the first recording period (6.1 +/- 0.9 cm), compared with values for the second and third periods (6.3 +/- 0.9 cm, 6.4 +/- 0.9 cm respectively). Anatomic urethral length for time 3 was significantly (P < 0.05) less than the value for time 1 (5.8 +/- 0.7 cm vs 6.6 +/- 0.8 cm).(ABSTRACT TRUNCATED AT 250 WORDS)

[Transcranial magnetic stimulation of the motor cortex and percutaneous magnetic stimulation of the peripheral nervous structures in the dog]. / Transkranielle Magnetstimulation des motorischen Kortex und perkutane Magnetstimulation peripher-nervöser Strukturen beim hund.

The motor cortex was transcranially and peripheral nervous structures (motor roots, plexus, peripheral nerves) were percutaneously stimulated by magnetic pulses in awake dogs and in dogs awaking from general anesthesia. The compound muscle action potentials were recorded by surface or needle electrodes. The central motor conduction time as an information about central motor tracts was obtained by subtracting the peripheral latency from the corticomuscular latency. The peripheral latency was assessed by high voltage electrical and magnetic stimulation of motor roots and by the F-wave technique. The motor conduction velocity of the tibial nerve was measured by percutaneous magnetic and by electrical stimulation and the resulting values were compared.

[Clinical electroretinography in the dog. Part 2]. / Klinische Elektroretinographie beim Hund. 2. Teil.

The second part of this study deals primarily with the technical aspects of electroretinography. A custom made dark chamber for the patient is presented. The requirements for an optical stimulator are discussed in detail and the recording instrumentation--electrodes, amplifiers, averager, digitalizer--are presented. The display of the signals on a monitor and plotter concludes this technical description. The remainder of part 2 is devoted to the many factors influencing the recording of an ERG, notably pupillary diameter, anesthesia, oxygen and glucose supply to the animal, body temperature of the patient, its intraocular pressure and level of retinal adaptation, and finally the age of the patient. On the technical side the intensity, wavelength and frequency of stimulation play an important role.

Comparison of microgyro-based measurements of equine metatarsal/metacarpal bone to a high speed video locomotion analysis system during treadmill locomotion.

The aim of this study was to compare an inertial motion system (IMS) to an optical based locomotion analysis system measuring limb sagittal segment angles in horses at the walk and trot. The metatarsal/metacarpal bones of two horses (20 trials) were fitted with optical system markers and an IMS. Between the systems, measuring range of motion (ROM) of the sagittal metatarsal/metacarpal bone angles, the IMS measured higher ROM than the optical system (bias 1.6°; precision at 1.96 standard deviation 1.9°). The same angle data were used to assess inter-limb symmetry by calculating phase shift between the limbs within a stride. This showed essentially no bias and the precision was 0.025%. The IMS has potential for quantification of ROM and phase shift of equine distal limb movement.

Velocity-dependent changes of time, force and spatial parameters in Warmblood horses walking and trotting on a treadmill.

REASONS FOR PERFORMING STUDY: Gait analysis parameters are sensitive to alterations in velocity. For comparison of nonspeed-matched data, the velocity dependency needs to be known. OBJECTIVES: To describe the changes in gait pattern and determine the relationships between stride duration, vertical impulse, contact time and peak vertical force within a range of walking and trotting speeds. METHODS: Thirty-eight nonlame Warmblood horses were subjected to an incremental speed test. The spans of speed were adjusted individually to each horse and ranged from 1.1-2.1 m/s at walk and from 2.5-5.8 m/s at trot. Time, force and spatial parameters of each limb were measured with an instrumented treadmill and analysed with regression analysis using velocity as the independent variable. RESULTS: At a slow walk the shape of the force curve was generally single-peaked in the fore- and trapezoidal in the hindlimbs. With increasing speed, the curves turned into the typical double-peaked shape with a higher second peak in the fore- and a higher first peak in the hindlimbs. With increasing velocity, stride duration, stance durations and limb impulses of the fore- and hindlimbs decreased in both gaits (r2 > 0.92). Increasing speed caused a weight shift to the forehand (walk: from 56 to 59%; trot: from 55 to 57%). Despite decreasing limb impulses, peak vertical forces increased in both gaits (r2 > 0.83). The suspension duration of the trot increased with faster velocities and reached a plateau of around 90 ms at the highest speeds. At a slow trot, the forelimbs impacted first and followed the hindlimbs at lift-off; with increasing speed, the horses tended to impact earlier with the hindlimbs. Contralateral symmetry indices of all parameters remained unchanged. CONCLUSIONS: Subject velocity affects time, force and spatial parameters. Knowing the mathematical function of these interdependencies enables correction of nonspeed-matched data.

Relationship between saddle pressure measurements and clinical signs of saddle soreness at the withers.

REASONS FOR PERFORMING THE STUDY: Similar to human decubitus ulcers, local high pressure points from ill-fitting saddles induce perfusion disturbances of different degrees resulting in tissue hypoxia and alteration in sweat production. OBJECTIVE: To relate the different clinical manifestations of saddle sores to the magnitude of saddle pressures at the location of the withers. METHODS: Sixteen horses with dry spots after exercise (Group A) and 7 cases presented with acute clinical signs of saddle pressure in the withers area (Group B) were compared with a control group of 16 sound horses with well fitting saddles (Group C). All horses underwent a saddle pressure measurement at walk, trot and canter. Mean and maximal pressures in the area of interest were compared between groups within each gait. RESULTS: Mean pressures differed significantly between groups in all 3 gaits. Maximal pressure differed between groups at trot; at walk and canter, however, the only significant difference was between Group C and Groups A and B, respectively, (P > 0.05). Mean and maximal pressures at walk in Group A were 15.3 and 30.6 kPa, in Group B 24.0 and 38.9 kPa and in Group C 7.8 and 13.4 kPa, respectively; at trot in Group A 18.1 and 43.4 kPa, in Group B 29.7 and 53.3 kPa and in Group C 9.8 and 21.0 kPa, respectively; and at canter in Group A 21.4 and 48.9 kPa, in Group B 28.6 and 56.0 kPa and in Group C 10.9 and 24.7 kPa, respectively. CONCLUSION: The study shows that there is a distinguishable difference between the 3 groups regarding the mean pressure value, in all gaits.

Performance parameters and post exercise heart rate recovery in Warmblood sports horses of different performance levels.

REASONS FOR PERFORMING STUDY: Standardised exercise tests are used for fitness evaluation of sports horses. Standards are described for Thoroughbreds and Standardbreds; however, limited information is available for Warmbloods. OBJECTIVES: To establish normative standards of performance parameters and heart rate recovery (HRR) in Warmblood riding horses of different levels of fitness using a submaximal incremental exercise test (SIET) performed on a treadmill. METHODS: A SIET was carried out with 29 healthy and treadmill-accustomed Warmbloods: eleven 3-day event horses (TDE) and 18 horses from the National Equestrian Centre (NEC) competing in amateur jumping and/or dressage events. After a warm-up phase, horses performed 2 stages at trot and 3-5 stages at gallop at 6% incline. The first stage lasted 120 s, all others 90 s. Velocity (V) and heart rate (HR) were measured continuously and blood lactate concentration (LAC) at the end of each exercise stage. V at HR 150 and 200 beats/min (V(150), V(200)), V and HR at 2 and 4 mmol/l LAC (V(2), V(4) and HR(2), HR(4), respectively) were calculated and compared between discipline groups. For reference values, horses were divided on the basis of the V(4) -results in good (GP) and average performers (AP) (performance groups). Five minute passive HRR was compared between performance groups. Fifteen NEC horses were retested within 1-3 months. Groups were compared with t tests and P < 0.05 considered significant. RESULTS: Three-day event horses had higher V(150), V(2) and V(4) values than NEC. GP had higher values in all performance parameters compared to AP. No differences were found between test and retest. GP mean recovery HR was different from that of AP from 120 s of recovery onwards. CONCLUSION: Treadmill SIETs are suitable to objectify aerobic capacity in Warmblood riding horses. Normative standards were assessed for well and averagely-trained horses. The results can be referred to when diagnosing patients with exercise intolerance.