A Preliminary Study of an Inertial Sensor-based Method for the Assessment of Human Pelvis Kinematics in Dressage Riding

Kinematic studies of horse and rider often suffer from their limitation to laboratory conditions because of video-based measurement techniques. To date, there are no suitable sensor-based methods published for the assessment of the rider's pelvis. The aim of this study was to reveal the possibilities and limitations of inertial sensors to assess the motion of the rider's pelvis in walk, trot, and canter, with particular attention to repeatability. Two female riders rode the same horse in repeated trials wearing an inertial sensor attached to their pelvis. Both riders were tested in walk, sitting trot, rising trot, and canter. Gait-dependent and interindividual characteristics of pelvis rotation in dressage riding under field conditions could be demonstrated. The possibility of obtaining kinematic data of horse and rider under field conditions using inertial sensors seems to be promising not only for researchers and horsemen but also for objectifying progress in therapeutic riding.     

Kinematic Analysis of the Rider According to Different Skill Levels in Sitting Trot and Canter

The purpose of this study was to analyze and compare the kinematics of a group of 10 professional riders (PROs) and a group of 10 beginners (BEGs) in sitting trot and canter. Therefore, the relative joint angles of the knee and elbow as well as the absolute segment angles of the riders' pelvis, trunk, and head were measured using a full-body inertial measurement system under field conditions. Two further sensors were attached to the horse and collected the motions and steps of the horses. The waveform parameters of each rider–horse combination were statistically and qualitatively analyzed over 30 gait cycles. At sitting trot, the ranges of motion of the left elbow and left knee were significantly higher in the BEG group. Furthermore, the BEGs' heads tilted notably more anterior than PROs' heads in sitting trot. In canter, BEGs moved their trunks significantly more over the mediolateral axis than PROs. Statistical differences in the ranges of motion of the riders' elbows and knees could be found in canter. Considering this, it can be presumed that a smaller range of motion in the elbows and knees and a more upright head are indicators for a more skilled rider in sitting trot. Furthermore, the results of canter pointed out that a more stable and calmer trunk could be important for a good riding performance. Based on these quantitative findings, the performance of inexperienced riders could be improved in the future.     

Long-Term and Immediate Effects of Whole Body Vibration on Chronic Lameness in the Horse: A Pilot Study

The effects of whole body vibration (WBV) in horses with chronic lameness were evaluated in an experimental, single subject, repeated measure design. To assess the long-term effect of WBV, eight horses not previously exposed to WBV were subject to WBV, 30 minutes twice daily, five days a week, for 60 days in addition to their regular exercise routine. Lameness was assessed subjectively and objectively 30 days before the start, at the start and 30 and 60 days after the start of the treatment (WBV). The immediate effect of WBV was assessed in four horses accustomed to WBV, by comparing lameness before and within 30 minutes of a single 30-minute WBV session at four different time intervals. Change in lameness was sought using paired t tests on the kinematic data. A P-value of <.05 was considered statistically significant. Intraindividual change was sought using a subjective and objective scoring system. No statistically significant change in lameness was seen after 30 or 60 days of WBV, respectively, in the chronically lame horses not previously exposed to WBV. However, a trend toward improvement was observed after the first 30 days of WBV, but this improvement appeared to be lost during the second 30 days of WBV. Although a statistically significant worsening of front limb lameness was seen immediately after a single 30-minute WBV session in the chronically lame horses accustomed to WBV, this result was largely attributed to a very significant worsening of the front limb lameness in one horse within that group.     

A Quantitative Review of the Equinalysis System for Equine Locomotion Analysis

Movement analysis techniques allow objective and quantitative assessment of kinematic gait analysis. Consistent repeatability of the kinematic data is essential for such assessments. This study investigated whether the repeatability of a standardized Equinalysis Elite gait analysis system is sufficient to allow its use in clinical evaluation of equine lameness with reliable documentation of individual locomotion patterns. The extent to which examinations on different days affected the results when a standardized protocol was used was investigated. The repeatability of distal limb kinematics in nine sound horses over three successive days at one location was investigated. Measurements were performed at the examination area, for three motion cycles at the walk and trot, in each direction per day. Skin markers were placed on the lateral aspect of the coffin joint, forelimb fetlock joint, hindlimb fetlock joint, carpus, tarsus, elbow, and stifle, at clipped sites marked with a permanent marker. The inter-day repeatability of angular measurements of the carpus, tarsus, forelimb fetlock, and hindlimb fetlock joints was determined. A low degree of inter-day repeatability was found with statistically significant (P ≤ .05) differences between findings on different days, observed in the time-angle diagrams of left and right carpus, tarsus, forelimb fetlock, and hindlimb fetlock joints of all horses, at both walk and trot. The standardized Equinalysis Elite system for gait analysis of distal limb kinematics in the horse did not provide highly repeatable data in this setting.     

Application of a Dual Force Sensor System to Characterize the Intrinsic Operation of Horse Bridles and Bits

An equine bridle tension system, with electronic force gauges in both the line of the reins and that of the cheekpiece (CP) on one side of the horse, is used to study the dynamic response of the CP tension to rein tension in the ridden horse. The objective is to quantify so-called “poll pressure.” Bits designed to give strong poll pressure using simple pulley or lever principles show a much attenuated transfer of the rein tension through the bit to the poll. The attenuation is readily understood when the equine mouth is recognized as a “floating” fulcrum degrading the otherwise required fixed pivot point of an ideal lever. Furthermore, any use of a curb chain diverts higher rein-induced CP tension to the chin rather than to the poll. Unexpectedly, however, a simple loose ring bit is found to give modest poll pressure, transferring rein tension through a pulley-like action. Finally, the curb bit of a double bridle is examined, and physical interference between the curb and bridoon mouthpieces is found. Standard, yet powerful computational signal processing of the dynamic time series tension data reveals that the poll pressure produced by the curb bit is predominantly due to tension in the bridoon reins and not the curb reins. Physical overlaying of the bridoon on the curb mouthpiece is implicated.     

High or Low Body Fat Deposition in the Presence of a Normal Oral Sugar Test is Not Associated With Postthaw Semen Parameters in Stallions

This study compared the postthaw semen parameters of stallions with high and low body condition score (BCS) and evaluated associations between body morphometric parameters and postthaw semen parameters. Twenty stallions were split into Low BCS (BCS<7, n = 11) and High BCS (BCS ≥7, n = 9) groups, and underwent a complete morphometric analysis (e.g., neck scores and circumference, crest neck height, body weight, and height), and subcutaneous body fat thickness (SFT) at the tail head, withers, shoulders, and retroperitoneal space. A fasted oral sugar test (OST) was conducted on all stallions. One ejaculate from each stallion was frozen with a commercial egg yolk-based extender. Postthaw sperm motility parameters, plasma membrane integrity, mitochondrial membrane potential, hydrogen peroxide and intracellular superoxide production, and lipid peroxidation were analyzed for all stallions. The circumference at 25% and 50% of the neck’s length were larger for High-BCS stallions (P < .05). There were no differences between groups for the neck crest height (P > .05). Stallions with High BCS had greater SFT at the tail head than stallions with Low BCS (P < .05); however, there were no differences between groups in the SFT at the shoulders and withers (P > .05). All stallions had resting blood glucose below the cutoff for equine metabolic syndrome. There were no differences between groups for resting glucose concentrations or for a peak at 30 or 60 minutes after initiation of the OST (P > .05). There were no differences in sperm parameters between groups (P > .05). Collectively, the findings of the present study suggest that High BCS or Low BCS in the presence of normal OST do not explain post-thaw semen parameters.     

Effects of a synthetic all‐weather waxed track versus a crushed sand track on 3D acceleration of the front hoof in three horses trotting at high speed

Reasons for performing study: Inadequate track surfaces are believed to be a risk factor in the occurrence of musculoskeletal injuries, but quantification of the shocks and vibrations provoked by hoof impact on different ground surfaces (including new synthetic tracks) has been insufficiently documented in trotters under high‐speed training conditions. Objectives: To test the reliability and sensitivity of an accelerometric device to discriminate between the biomechanical effects of 2 different tracks at high speed. Methods: Three French Trotters were used and their right front hooves were equipped with one triaxial accelerometer. Two different track surfaces (crushed sand track: S and all‐weather waxed track: W) were tested when horses were trotting in a straight line. For each session of measurements, trials were repeated 3 times in a Latin square design. The speed of the runs was set at 10 m/s, controlled by the driver and recorded synchronously. Sample rate was set at 6 kHz. Acceleration of the hoof (resultant vector and 3D components), power spectral density at impact and variability (between strides, trials, sessions and horses) were analysed. Statistical differences were tested using a GLM procedure (SAS). Least square mean differences were used for comparisons between tracks (P<0.05). Results: Results showed that the deceleration of the hoof (magnitude of the resultant vector) was statistically different between the 2 tracks with an attenuation of the shock of about 50% on the all‐weather waxed track. Magnitude of the power spectral density was reduced at higher frequencies on W. Conclusions and clinical relevance: These preliminary results demonstrate the sensitivity of the tool to discriminate between the different behaviours of the hoof on the different track surfaces at high speed. Deceleration and vibration of the hoof at impact were reduced on W compared to S, suggesting a better shock‐absorbing quality of this track.     

Overview of the Current Situation in a Sample of Headshakers and Owner Assessment of Effective Therapeutic Measures Used in Germany

Equine headshaking syndrome is a problematic behavior that has been described in literature for more than 100 years. The signs of headshaking syndrome appear frequently and violently so that riding the horse can be dangerous. The aim of this research was to gain an overview of the underlying causes of equine headshaking syndrome to identify effective treatment options, reduce the distress of horses and, in a second step, potentially improve therapeutic possibilities for horse owners and veterinarians. Most studies on prevalence originate from Anglo-American countries, so this research was to provide an overview of German horses; therefore, an online survey was designed by experts in the field (researchers and veterinarians) and answered by German horse owners. Questionnaires were pretested by a small group of horse owners (n = 5) and redesigned accordingly. The final questionnaire consisted of 27 questions, which were divided into seven open questions with an associated text field and 20 multiple-choice questions (Supplementary Material 1). For some of the multiple-choice questions, multiple answers were permitted. In total, 163 completed questionnaires were obtained from owners of headshaking horses (n_total = 163). Gender distribution of the horses resulted in 64.4% geldings, 33.7% mares, and 1.8% stallions. Most horses were German warmbloods (55.4%). The average age was 12.7 years (with a wide range of 5 to 34 years). The vertical movement of the head was the most frequently mentioned symptom in 75.5% of the evaluated horses. In 18.4% of the cases, the horse owners identified stress as the main trigger for headshaking. Furthermore, 18.4% claimed that their horses suffered from additional stereotypical behavior. The percentages do not refer to the same horses here. 11.0% of the participants in this study tried scientifically evaluated therapies such as surgical therapy (1.2%) or medical treatment (9.8%). In addition, 54.0% of the owners utilized a nose cover to reduce the symptoms of the headshaking syndrome. A high percentage of 84.0% used alternative therapies such as physiotherapy (31.9%), change of equipment (22.7%), or change of riding style (29.4%). Overall, this study provides a useful overview of causes and effective therapies.     

Effect of a 12-Week Conditioning Period on Nitrogen Balance in Horses

Fourteen horses were used in two 12-week experiments. Horses were fed to meet crude protein needs for exercising horses and participated in light-to-moderate exercise. Total feces and urine output were measured in 4-day collections at the beginning and the end of each experiment. Fecal nitrogen (FN) and urine nitrogen (UN) were used to calculate nitrogen balance and digestibility. Nitrogen intake (NI) was higher in the end collection (P = .001). Fecal nitrogen expressed as a daily amount or as a percentage of NI was not different (P = .63 and .39, respectively). Nitrogen digestibility was not different (P = .39); however, the amount of nitrogen absorbed (NA) was lower in the initial collection (P = .001). Urine nitrogen was lower in the end collection when expressed as a total loss per day (P = .041), percent of NI (P = .001), or as a percent of NA (P = .001). Daily nitrogen retention (NR), NR expressed as a percentage of NI and as a percentage of NA, was higher in the end collection (P = .001). The improvement in NR in the end collection is due to the reduction in UN loss. This suggests more efficient use of dietary protein because there was no difference in FN loss; but without a significant change in body weight or body condition score, it cannot be concluded that the additional retained nitrogen was because of a need to support additional muscle mass.     

Use of a Grading System to Facilitate Treatment and Prognosis in Horses with Negative Palmar Angle Syndrome (Heel Collapse): 107 Cases

Negative palmar angle syndrome refers to the condition of progressive heel collapse and its consequences on gait and performance. Treatment and prognosis are facilitated by grading the severity of biomechanical disorder according to physical and radiographic features. Although negative palmar angle syndrome in grades I (mild) and II (moderate) can be corrected with trimming and routine shoeing, grades III (severe) and IV (complicated by flexor contracture) require more intensive mechanical intervention and patience—however, comfort and function can be improved immediately.     

Application of the 51Cr-EDTA urinary recovery test for assessment of intestinal permeability in the horse

Altered intestinal permeability is implicated in the pathogenesis of diverse equine medical conditions including alimentary laminitis and protein-losing enteropathies associated with parasitic infection. The aims of this study were to assess the feasibility of applying the 51Cr-EDTA absorption test for the assessment of intestinal permeability in the horse, and to apply this test in horses with experimentally induced alterations in gastrointestinal function. Four healthy ponies were administered 36 MBq of 51Cr-EDTA via naso-gastric tube, and urine samples were collected into polythene bags strapped to the pony's abdomen. Total urine voided every 6 h was collected during each test, and 1 ml samples were taken for measurement of gamma-radiation. Urinary recovery of 51Cr-EDTA was measured following intravenous atropine sulphate or bethanecol, and following 22 and 46 days of administration of 250,000 third-stage cyathostome larvae. There was no significant difference in urinary 51Cr-EDTA recovery following the control treatment, and following atropine or bethanecol administration, but significant increases were detected in the animals with experimental cyathostome infection consistent with increased permeability of the intestinal membrane. Motility modifying agents (bethanecol and atropine) did not affect absorption of 51Cr-EDTA, suggesting that subtle changes in motility might not affect the ability of this test to detect altered intestinal permeability. The finding of increased urinary recovery of 51Cr-EDTA in ponies with cyathostome infection suggests that 51Cr-EDTA may be a useful marker for assessment of intestinal permeability in the horse.     

Application and evaluation of a mailed questionnaire for an epidemiologic study of Corynebacterium pseudotuberculosis infection in horses

The objective of this study is to describe the design, application and validity of a self-administered (mailed) questionnaire to collect data on potential risk factors for Corynebacterium pseudotuberculosis infection in California horses. Horses admitted to the UC Davis Veterinary Medical Teaching Hospital (VMTH) between 1 July 1992 and 30 June 1994 served as the study base for case identification and simple random sampling of 800 control horses. A questionnaire was mailed to owners of the study horses, followed by a reminder postcard and a second copy of a questionnaire. Data were collected on owner and horse identity and demographics, horse management and use, geographic location, and general health-related issues. Return pattern over time as well as differential return proportions were described. The overall return proportion was 66% (587/890), and the completion proportion 55% (491/890). The number of returns over time followed a negative binomial distribution, with over 90% of all returns being in by the end of the fifth week after mailing, and over 99% at the end of the tenth week. Some categories within the variables age (between 2 and 3 years), breed (Thoroughbred and Standardbred horses) and gender (stallions) had significantly lower return proportions than expected (differential return; p<0.05). The profile of these horses fits a section of the racehorse population that is served by the VMTH. Age, breed and disease status information was available from the VMTH medical records and from the questionnaire, and was used to determine the validity of the survey data. There was good agreement between the data from the two sources, and we therefore concluded that the quality of the survey information was sufficient to perform a risk-factor analysis. The mailed survey provided a rapid and cost-effective method of collecting additional information to supplement existing medical records.     

Surgical treatment of tarsometatarsal joint luxation in a miniature horse foal

A 2-week-old Miniature Horse foal was referred for evaluation and treatment of a luxated right tarsometatarsal joint. Treatment consisted of closed reduction and internal fixation using two partially threaded Steinmann pins placed in normograde fashion through the tuber calcis into the proximal third metatarsus. Traumatic luxation has been reported to occur in the tarsocrural, proximal intertarsal and tarsometatarsal joints within the equine tarsus. Treatment for luxation of the distal intertarsal joint has not been documented. The treatment method most commonly suggested for tarsal luxation is closed reduction and cast immobilisation. Internal fixation using lag screws and plating has also been described. A combination of internal fixation and external coaptation is thought to achieve maximal stability and allow faster convalescence in cases of tarsal luxation. This case report describes for the first time a technique using two Steinmann pins to achieve successful internal fixation of a traumatic tarsometatarsal joint luxation in a 2-week-old Miniature Horse foal.     

Clinical Application of Current Research Findings Toward the Prevention and Treatment of Acute Laminitis in Horses With Systemic Inflammatory Diseases: An Internist’s Perspective

Laminitis is most commonly caused by metabolic disorders or systemic inflammatory diseases. There are numerous recent publications that have reported on pathophysiology of laminitis associated with systemic inflammation. These studies include both in-vitro and in-vivo models investigating inflammatory profiles, vascular reactivity or oxidative stress at different stages of development or clinical laminitis and some studies have proposed therapeutic interventions. Although the amount of information in these studies is great and quality of the research is often outstanding, it has not always been clear how these findings might be applied to clinical practice. This article is intended to report one internist's perspective on recent research findings on the pathophysiology and prevention of laminitis in horses with systemic inflammatory diseases and how these findings might be applied to clinical practice.     

In Vivo and In Vitro Evidence of the Involvement of CXCL1, a Keratinocyte-Derived Chemokine, in Equine Laminitis

Background: C-X-C motif ligand 1 (CXCL1) is an important chemokine of epithelial origin in rodents and humans.
Objectives: To assess in vivo and in vitro the regulation of CXCL1 in equine laminitis.
Animals: Twenty adult horses.
Methods: Real-time quantitative polymerase chain reaction (PCR) was used to assess expression of CXCL1 in samples of laminae, liver, skin, and lung from the black walnut extract (BWE) model of laminitis, and in cultured equine epithelial cells (EpCs). Tissue was obtained from control animals (CON, n = 5), and at 1.5 hours (early time point [ETP] group, n = 5), at the onset of leukopenia (developmental time point [DTP] group, n = 5), and at the onset of lameness (LAM group, n = 5) after BWE administration. EpCs were exposed to Toll-like/Nod receptor ligands, oxidative stress agents, and reduced atmospheric oxygen (3%). In situ PCR was used to localize the laminar cell types undergoing CXCL1 mRNA expression.
Results: Increases in laminar CXCL1 mRNA concentrations occurred in the ETP (163-fold [ P = .0001]) and DTP groups (21-fold [ P = .005]). Smaller increases in CXCL1 expression occurred in other tissues and organs. In cultured EpCs, increases ( P < .05) in CXCL1 mRNA concentration occurred after exposure to lipopolysaccharide (LPS [28-fold]), xanthine/xanthine oxidase (3.5-fold), and H₂O₂ (2-fold). Hypoxia enhanced the LPS-induced increase in CXCL1 mRNA ( P = .007). CXCL1 gene expression was localized to laminar EpCs, endothelial cells, and emigrating leukocytes.
Conclusion and Clinical Importance: These findings indicate that CXCL1 plays an early and possibly initiating role in neutrophil accumulation in the BWE laminitis model, and that laminar keratinocytes are an important source of this chemokine. New therapies using chemokine receptor antagonists may be indicated.     

Entrapment of the small colon through a mesocolic rent in a mare

A 6-year-old mare was presented for acute abdominal pain unresponsive to analgesics. Exploratory laparotomy revealed entrapment of the small colon through a 12 cm rent in the mesocolon. The incarcerated small colon was manually reduced and the rent in the mesocolon was sutured closed. The mare made excellent postoperative recovery and was discharged from the hospital 4 days later. The cause of the rent, which was chronic in appearance, is unknown.     

Lactoferrin, a glycoprotein with immunomodulatory and mast cell stabilising properties, in skin of horses suffering from Culicoides hypersensitivity

Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from horses affected by CHS prior to and 4h following intradermal challenge with a commercial C. nubeculosus extract is modified in comparison to skin biopsies from non-affected horses. In order to obtain reliable data, real time PCR was performed and genes of interest were normalized using three different housekeeping genes, beta-actin, GAPDH, beta-2-microglobulin. In comparison to non-affected horses, higher variation in LF mRNA levels both prior to and post-intradermal challenge with C. nubeculosus extract was seen in horses affected by CHS. However, the statistical analysis demonstrated that LF mRNA expression was not significantly different between CHS affected and non-affected horses prior to intradermal challenge with C. nubeculosus extract. Intradermal injection of C. nubeculosus extract did not result in local upregulation of LF mRNA at 4h post-injection. LF mRNA expression was therefore not significantly different pre- or post-intradermal challenge with C. nubeculosus extract in either group. Our data indicate that clinically normal skin of horses affected by CHS is not characterized by modified maintenance levels of LF mRNA. In contrast to human skin allergen challenged sites, LF mRNA levels in horses affected by CHS are not significantly different to that of control sites at 4h post-injection of C. nubeculosus extract.