Center for Equine Studies

Newmarket, United Kingdom

Center for Equine Studies

Newmarket, United Kingdom
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Dyson S.,Center for Equine Studies
Applied Animal Behaviour Science | Year: 2017

The quality of equine performance can be influenced by pain, whether or not that results in overt lameness. Recognition of low-grade lameness is challenging, but with careful observation there are many clues which veterinarians, riders and trainers should recognise. Riders and trainers are frequently unable or unwilling to recognise lameness or other behavioural changes that are a manifestation of pain. Work discipline, body size and conformation may be risk factors for lameness. Work surfaces may also have a role. There is an integral relationship between limb and thoracolumbosacral function. There is also an interaction between the rider and thoracolumbosacral function and health. The saddle is an interface between the rider and the horse and saddle-fit for both horse and rider is crucial for optimal thoracolumbar health and function. The tendency of a saddle to persistently slip to one side is most commonly secondary to hind limb lameness. The rider communicates with the horse via the reins and the bit. The design of the bit, its position and size influence oral comfort. Training aids such as draw reins or a Pessoa Training Aid, appropriately used may improve hind limb propulsion. However, there are still wide gaps in our knowledge about strategies to minimise the risks of injuries to the ridden horse, and a need for further research making use of technological advances in the fields of equine biomechanics with the results applied in equitation science. © 2017 Elsevier B.V.


Dyson S.,Center for Equine Studies | Blunden T.,Center for Preventative Medicine | Murray R.,Center for Equine Studies
Equine Veterinary Journal | Year: 2012

Reasons for performing study: There is limited knowledge about both histological features in early navicular disease and what histological features are represented by increased signal intensity in fat-suppressed magnetic resonance (MR) images of the navicular bone. Objective: To characterise increased signal intensity in the spongiosa of the navicular bone in fat-suppressed MR images and to compare this with histopathology; and to compare objective grading of all aspects of the navicular bone on MR images with histological findings. Methods: One or both front feet of 22 horses with foot pain and a median lameness duration of 3 months were examined using high-field MR imaging (MRI) and histopathology. The dorsal, palmar, proximal and distal borders of the navicular bone and the spongiosa were assigned an MRI grade (0-3) and a histological grade and compared statistically. Results: Increased signal intensity in the spongiosa of the navicular bone was associated with a variety of abnormalities, including fat atrophy, with lipocytes showing loss of definition of cytoplasmic borders, a proliferation of capillaries within the altered marrow fat, perivascular or interstitial oedema, enlarged intertrabecular bone spaces, fibroplasia and thinned trabeculae showing loss of bone with irregularly spiculated edges of moth-eaten appearance. There were significant associations among histological lesions of the fibrocartilage, calcified cartilage and subchondral bone. There were also significant associations between MRI grading of the spongiosa and both histological marrow fat grade and the combined maximum of the MRI grades for the fibrocartilage. Conclusions and potential relevance: Increased signal intensity in the spongiosa of the navicular bone in fat-suppressed MR images may occur in association with lesions of the fibrocartilage with or without subchondral bone or may represent a separate disease entity, particularly if diffuse, reflecting a variety of alterations of trabecular bone and marrow fat architecture. © 2012 EVJ Ltd.


Dyson S.,Center for Equine Studies | Pool R.,Center for Preventive Medicine | Blunden T.,Texas A&M University | Murray R.,Center for Equine Studies
Equine Veterinary Journal | Year: 2010

Reasons for performing study: There is limited knowledge about the interpretation of alterations in the distal sesamoidean impar ligament (DSIL) detected using magnetic resonance imaging (MRI) and their correlation with histopathology. Hypotheses: There would be: 1) a correlation between histopathology and MRI findings; and 2) a relationship between MR abnormalities at the origin and the insertion of the DSIL, between insertion and body; and origin and body. Methods: Fifty limbs from 28 horses were examined using high-field MRI and histopathology. MR abnormalities of the DSIL, its origin on the navicular bone and its insertion on the distal phalanx were graded. Sections of the axial third of the DSIL were examined histologically and graded according to fibre orientation, integrity of fibroblasts, collagen architecture and vascularity. Associations between MRI and histology findings were tested by Spearman rank correlation and Chi-squared tests. Results: There were significant correlations between the presence of a cystic structure in the distal third of the navicular bone, or a distal border fragment, or increased signal intensity in fat suppressed images at the insertion of the DSIL on the distal phalanx and the histological grade of the body of the DSIL. There were significant associations between a cystic structure in the distal third of the navicular bone and the presence of either a distal border fragment or entheseous new bone at the insertion of the DSIL, swelling of the DSIL and increased signal intensity in the DSIL in fat suppressed images; between distal elongation of the flexor border of the navicular bone and the presence of one or more distal border fragments and between swelling of the body of the DSIL and irregularity of its palmar border or increased signal intensity in fat suppressed images in the DSIL. Conclusions and clinical relevance: The presence of a cystic structure in the distal third of the navicular bone detected using MRI, a distal border fragment or increased signal intensity at the insertion of the DSIL are suggestive of significant alterations in the infrastructure of the DSIL. © 2010 EVJ Ltd.


Greve L.,Center for Equine Studies | Murray R.,Center for Equine Studies | Dyson S.,Center for Equine Studies
Veterinary Journal | Year: 2015

Recommendations concerning saddle-fit are empirical rather than based on scientific information. A saddle needs to fit the horse in motion, but there has been no investigation of whether the thoracolumbar region changes in dimensions in association with exercise. The objectives of this study were to quantify exercise-induced back dimension changes and to describe the association with work quality, saddle-fit and rider skill. Sixty-three sports horses in regular work were assessed prospectively in a non-random, cross-sectional survey. Thoracolumbar dimensions/symmetries were measured at predetermined sites before and immediately after a 30 min exercise period; widths for two levels at each site were measured and the shape-ratio calculated. The work quality and rider skill were graded and the presence of lameness and saddle-fit were recorded. Descriptive statistics, univariable and multivariable mixed-effect linear regression were performed to assess the relationship between horse-saddle-rider factors and changes in back dimensions. The mean back width after ridden exercise was greater compared with before exercise. Mean changes were greater in horses working correctly vs. those not working correctly, in those with correctly-fitting vs. ill-fitting saddles, and in horses ridden by good > moderately > poorly skilled riders. Back-width changes were significantly associated with saddle-fit. The back dimensions of horses working correctly change transiently with work. If a saddle does not fit properly before exercise, this increase in size does not occur. Saddle-fit should be assessed both before and after exercise to ensure correct fit. © 2015 Elsevier Ltd.


Greve L.,Center for Equine Studies | Dyson S.,Center for Equine Studies
Equine Veterinary Journal | Year: 2015

Reasons for performing study: No previous studies have investigated interrelationships between saddle fit/management, equine thoracolumbar asymmetries, rider and horse health. Objectives: To assess associations between data obtained by clinical assessment and those provided by riders via a questionnaire. Study design: Clinical assessment of a convenience sample of horses and riders compared with a Web-based questionnaire survey (n = 205). Methods: Horse thoracolumbar asymmetries at predetermined sites, the presence of lameness (in hand and/or ridden), saddle slip, saddle fit/management and rider straightness were assessed. Kappa statistics were used to assess the relationship between categorical clinical data and questionnaire data from riders. Spearman's correlation was used to investigate associations between outcomes from clinical assessment (horse, saddle and rider data) and information provided by riders. Results: There was a 40.5% (205 of 506) questionnaire response rate. Thirty horses (14.6%) had saddle slip, which was significantly associated with hindlimb lameness or gait abnormalities (P<0.001), but only 2 riders had considered a link between saddle slip and lameness. Rider back pain was common (38.5%) and associated with ill-fitting saddles (P = 0.03) and either a quadrupedally reduced cranial phase of the step or a stiff, stilted canter (P = 0.006). Well-fitted saddles were associated with frequent saddle fit checks (P = 0.004). Minor thoracolumbar asymmetries (P = 0.04) were negatively associated with ill-fitting saddles and positively associated with rider skill level (P = 0.001). Conclusions: The interaction between the horse, saddle and rider is complex. Ill-fitting saddles and a stiff, stilted canter or quadrupedally reduced cranial phase of the step are associated with rider back pain. Equine back pain and minor thoracolumbar asymmetries are associated with ill-fitting saddles. Saddle fit should be checked more often than once yearly to lower the number of ill-fitting saddles. Riders, trainers and other professionals involved in equine care and performance need better education to recognise ill-fitting saddles, lameness, saddle slip and rider crookedness. © 2014 EVJ Ltd.


Greve L.,Center for Equine Studies | Dyson S.,Center for Equine Studies
Veterinary Journal | Year: 2015

Major back dimension changes over time have been observed in some horses, the speed of which may be influenced by work type, skeletal maturity, nutrition and saddle fit. Currently, there are no longitudinal data quantifying changes in back dimensions. The objectives of this study were to quantify back dimension changes over time, to identify the effects of horse, saddle and rider on these dimensions, and to determine their association with season, weight, work and saddle management. A prospective, longitudinal study was performed, using stratified random sampling within a convenience sample of 104 sports horses in normal work. Thoracolumbar dimensions/symmetry were measured at predetermined sites every second month over 1 year; weight, work and saddle management changes were recorded. Descriptive statistics, and univariable and multiple mixed effects linear regression were performed to assess the association between management changes, horse-saddle-rider factors and back dimension changes.Complete data was available for 63/104 horses, including horses used for dressage (n = 26), showjumping (n = 26), eventing (n = 26) and general purpose (n = 26), with age groups 3-5 years (n = 24), 6-8 years (n = 28), 9-12 years (n = 24) and ≥ 13 years (n = 28). There were considerable variations in back dimensions over 1 year. In the multivariable analysis, the presence of gait abnormalities at initial examination and back asymmetry were significant and had a negative effect on changes in back dimensions. Subsequent improved saddle fit, similar or increased work intensity, season (summer versus winter) and increased bodyweight retained significance, having positive effects on changes in back dimensions. In conclusion, quantifiable changes in back dimensions occur throughout the year. Saddle fit should be reassessed professionally several times a year, especially if there has been a change in work intensity. © 2014 Elsevier Ltd.


Nagy A.,Center for Equine Studies | Dyson S.J.,Center for Equine Studies | Murray J.K.,University of Bristol
Veterinary Journal | Year: 2012

The popularity of competitive endurance riding is growing worldwide and this has led to considerable changes in the discipline (e.g., fitter and faster horses and different types of injuries), which create challenges to all involved in the sport, including veterinarians. During endurance competitions, horses are closely monitored by veterinarians throughout the ride, with the aim of removing from the competition animals whose welfare appears to be endangered. This close monitoring provides veterinarians with an insight into problems during competitions. However, there is a relatively small amount of clinically relevant, evidence-based data published on endurance horses, and this article reviews the evolution of the discipline, the published information on epidemiological data on endurance rides, the problems veterinarians face at competitions, and highlights those areas where research is warranted. © 2012 Elsevier Ltd.


Greve L.,Center for Equine Studies | Dyson S.J.,Center for Equine Studies
Equine Veterinary Journal | Year: 2014

Reasons for performing study: Saddle slip is usually blamed on saddle fit, crooked riders or horse shape, but may reflect hindlimb lameness. There are no studies of the frequency of occurrence of saddle slip and risk factors within a tested sample population of the general sports horse population. Objectives: To quantify the frequency of saddle slip and to describe the association with lameness, thoracolumbar shape/symmetry, crooked riders and ill-fitting saddles. Study design: Nonrandom, cross-sectional survey using convenience sampling. Methods: Five hundred and six sports horses in normal work were assessed prospectively. Thoracolumbar shape/symmetry were measured at predetermined sites; the presence of lameness (in hand and/or ridden) and saddle slip was recorded. Descriptive statistics, univariable and multiple logistic regression were performed to assess the relationship between horse-saddle-rider factors and saddle slip. Results: The frequency of lameness, quadrilaterally reduced cranial phase of the stride or stiff, stilted canter was 45.7%, saddle slip 12.3%, left-right thoracolumbar shape asymmetries ≥ coefficient of variance of 8% (1.2cm) 0.6%; and 103 of 276 riders (37.3%) sat crookedly. The saddle consistently slipped to one side in 24.4% of horses with hindlimb lameness alone, 45.5% of horses with concurrent hindlimb and forelimb lameness, compared with 5.4% with forelimb lameness, 17.4% with stiff, stilted canter, 20% with quadrilaterally reduced cranial phase of stride and 5.5% nonlame horses. Nineteen horses (30.6%) with saddle slip had no detectable hindlimb lameness; however, 14 had a gait abnormality, particularly in canter. Multivariable analysis revealed that saddle slip was significantly associated with hindlimb lameness and gait abnormalities (odds ratio [OR] = 52.62, 95% confidence interval [CI] 17.3-159.7), a saddle fitted with even contact and uniform flocking (OR = 15.49, 95% CI 1.9-125.5), riders sitting crookedly (OR = 6.32, 95% CI 2.9-13.7), a well-balanced saddle (OR = 3.05, 95% 1.4-6.9) and large back shape ratio at T18 (OR = 1.2, 95% 1.1-1.3). Conclusions: Many horses with hindlimb and/or forelimb lameness go unrecognised. Saddle slip may be a sign of hindlimb lameness. Education of the equestrian population to identify lameness and saddle slip is required. The Summary is available in Chinese - see Supporting information. © 2013 EVJ Ltd.


Greve L.,Center for Equine Studies | Dyson S.,Center for Equine Studies
Veterinary Journal | Year: 2013

Common causes of poor performance in horses include factors related to the horse, the rider and/or the saddle, and their interrelationships remain challenging to determine. Horse-related factors (such as thoracolumbar region pain and/or lameness), rider-related factors (such as crookedness, inability to ride in rhythm with the horse, inability to work the horse in a correct frame to improve core strength and muscular support of the thoracolumbar spine of the horse), and saddle-related factors (such as poor fit causing focal areas of increased pressure) may all contribute to poor performance to varying degrees. Knowledge of the horse-saddle-rider interaction is limited. Traditionally, saddle fit has been evaluated in standing horses, but it is now possible to measure the force and pressure at the interface between the saddle and the horse dynamically. The purpose of this review is critically to discuss available evidence of the interaction between the horse, the rider and the saddle, highlighting not only what is known, but also what is not known. © 2012 Elsevier Ltd.


Dyson S.,Center for Equine Studies
Seminars in Nuclear Medicine | Year: 2014

Nuclear scintigraphic examination of equine athletes has a potentially important role in the diagnosis of lameness or poor performance, but increased radiopharmaceutical uptake (IRU) is not necessarily synonymous with pain causing lameness. Nuclear scintigraphy is highly sensitive to changes in bone turnover that may be induced by loading and knowledge of normal patterns of RU is crucial for accurate diagnosis. Blood pool images can be useful for identification of some soft tissue injuries, although acute bone injuries may also have intense IRU in blood pool images. Some muscle injuries may be associated with IRU in bone phase images. The use of scintigraphy together with other diagnostic imaging modalities has helped us to better understand the mechanisms of some musculoskeletal injuries. In immature racehorses, stress-related bone injury is a common finding and may be multifocal, whereas in mature sport horses, a very different spectrum of injuries may be identified. False-negative results are common with some injuries. © 2014 Elsevier Inc.

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