Influence of functional rider and horse asymmetries on saddle force distribution during stance and in sitting trot

Asymmetric forces exerted on the horse's back during riding are assumed to have a negative effect on rider–horse interaction, athletic performance, and health of the horse. Visualized on a saddle pressure mat, they are initially blamed on a nonfitting saddle. The contribution of horse and rider to an asymmetric loading pattern, however, is not well understood. The aim of this study was to investigate the effects of horse and rider asymmetries during stance and in sitting trot on the force distribution on the horse's back using a saddle pressure mat and motion capture analysis simultaneously. Data of 80 horse-rider pairs (HRP) were collected and analyzed using linear (mixed) models to determine the influence of rider and horse variables on asymmetric force distribution. Results showed high variation between HRP. Both rider and horse variables revealed significant relationships to asymmetric saddle force distribution (P < .001). During sitting trot, the collapse of the rider in one hip increased the force on the contralateral side, and the tilt of the rider's upper body to one side led to more force on the same side of the pressure mat. Analyzing different subsets of data revealed that rider posture as well as horse movements and conformation can cause an asymmetric force distribution. Because neither horse nor rider movement can be assessed independently during riding, the interpretation of an asymmetric force distribution on the saddle pressure mat remains challenging, and all contributing factors (horse, rider, saddle) need to be considered

Comparison of limb kinematics between collected and lengthened (medium/extended) trot in two groups of dressage horses on two different surfaces

Background: Dressage horses are often asked to work in lengthened paces during training and competition, but to date there is limited information about the biomechanics of dressage-specific paces. Preliminary work has shown increased fetlock extension in extended compared with collected paces, but further investigation of the kinematic differences between collected, medium and extended trot in dressage horses is warranted. Objectives: Investigation of the effect of collected versus medium/extended trot on limb kinematics of dressage horses. Study design: Prospective kinematic evaluation. Methods: Twenty clinically sound horses in active dressage training were used: Group 1) ten young horses (≤ 6 years) were assessed at collected and medium trot; Group 2) ten mature horses (≥9 years) were assessed at collected and extended trot. All horses were evaluated on two different surfaces. High-speed motion-capture (240Hz) was used to determine kinematic variables. Forelimb and hindlimb angles were measured at midstance. Descriptive statistics and mixed-effect multilevel-regression analyses were performed. Results: Speed and stride length were reduced and stride duration increased at collected compared with medium/extended trot. Lengthened trot (medium/extended trot) was associated with increased fetlock extension in both the forelimbs and hindlimbs in both groups of horses. Changes were greater in Group 2 compared with Group 1. Shoulder and carpus angles were associated with forelimb fetlock angle. Hock angle was not significantly influenced by pace. Surface had no effect on fetlock or hock angles. Main limitations: Only 2D motion analysis was carried out. Results may have been different in horses with more extreme gait characteristics. Conclusions: Medium/extended trot increases extension of the forelimb and the hindlimb fetlock joints compared with collected trot in both young and mature dressage horses, respectively

Functional Locomotor Consequences of Uneven Forefeet for Trot Symmetry in Individual Riding Horses

ABSTRACT: Left-right symmetrical distal limb conformation can be an important prerequisite for a successful performance, and it is often hypothesized that asymmetric or uneven feet are important enhancing factors for the development of lameness. On a population level, it has been demonstrated that uneven footed horses are retiring earlier from elite level competition, but the biomechanical consequences are not yet known. The objectives of this study were to compare the functional locomotor asymmetries of horses with uneven to those with even feet. Hoof kinetics and distal limb kinematics were collected from horses (n = 34) at trot. Dorsal hoof wall angle was used to classify horses as even or uneven (1.5° difference between forefeet respectively) and individual feet as flat (55°). Functional kinetic parameters were compared between even and uneven forefeet using MANOVA followed by ANOVA. The relative influences of differences in hoof angle between the forefeet and of absolute hoof angle on functional parameters were analysed using multiple regression analysis (P<0.05). In horses with uneven feet, the side with the flatter foot showed a significantly larger maximal horizontal braking and vertical ground reaction force, a larger vertical fetlock displacement and a suppler fetlock spring. The foot with a steeper hoof angle was linearly correlated with an earlier braking-propulsion transition. The conformational differences between both forefeet were more important for loading characteristics than the individual foot conformation of each individual horse. The differences in vertical force and braking force between uneven forefeet could imply either an asymmetrical loading pattern without a pathological component or a subclinical lameness as a result of a pathological development in the steeper foot

Equine Surfaces White Paper

This white paper has been drafted as a collection of published scientific papers and data. It is considered a work in progress and will be updated as new scientific studies and surface data become availabl

Science in brief: Highlights from the biomechanics and physiotherapy abstracts at the International Conference on Equine Exercise Physiology.

Although human observations of equine locomotion are as old as our relationship with the horse, today's scientists still have much to learn about horse–human interactions. Two approaches are commonly used to study equine biomechanics and both were evident in abstracts presented at the International Conference on Equine Exercise Physiology (ICEEP) 2014. One approach is to use simplified methods of measurement and analysis that provide simple but meaningful objective information that can ultimately be used by the clinician or practitioner. Alternatively, more complex equipment and techniques may be used that directly measure or infer loading on the equine musculoskeletal system to provide detailed structural and functional information. Whichever methods are used, it is important that they are reliable and robust and that the errors and limitations of the measurement system are fully recognised when interpreting data. In his keynote speech, Professor René van Weeren proposed that the biomechanical techniques available to scientists today provide a gateway to a better understanding of the horse–rider interaction that must ultimately improve equine welfare while maintaining peak performance. The abstracts presented in this Editorial therefore cover key topics that are relevant to welfare and performance, lameness and asymmetry, locomotion and sports performance, a focus on the axial system, and the foot

An exploration of the influence of diagonal dissociation and moderate changes in speed on locomotor parameters in trotting horses

Background. Although the trot is described as a diagonal gait, contacts of the diagonal pairs of hooves are not usually perfectly synchronized. Although subtle, the timing dissociation between contacts of each diagonal pair could have consequences on gait dynamics and provide insight into the functional strategies employed. This study explores the mechanical effects of different diagonal dissociation patterns when speed was matched between individuals and how these effects link to moderate, natural changes in trotting speed. We anticipate that hind-first diagonal dissociation at contact increases with speed, diagonal dissociation at contact can reduce collision-based energy losses and predominant dissociation patterns will be evident within individuals. Methods. The study was performed in two parts: in the first 17 horses performed speedmatched trotting trials and in the second, five horses each performed 10 trotting trials that represented a range of individually preferred speeds. Standard motion capture provided kinematic data that were synchronized with ground reaction force (GRF) data from a series of force plates. The data were analyzed further to determine temporal, speed, GRF, postural, mass distribution, moment, and collision dynamics parameters. Results. Fore-first, synchronous, and hind-first dissociations were found in horses trotting at (3.3 m/s � 10%). In these speed-matched trials, mean centre of pressure (COP) cranio-caudal location differed significantly between the three dissociation categories. The COP moved systematically and significantly (P D :001) from being more caudally located in hind-first dissociation (mean locationD0.41�0.04) through synchronous (0.36 � 0.02) to a more cranial location in fore-first dissociation (0.32 � 0.02). Dissociation patterns were found to influence function, posture, and balance parameters. Over a moderate speed range, peak vertical forelimb GRF had a strong relationship with dissociation time (RD:594; P 0:05) or speed (RD:223; P D:023). Discussion. The results indicate that at moderate speeds individual horses use dissociation patterns that allow them to maintain trunk pitch stability through management of the cranio-caudal location of the COP. During the hoof-ground collisions, reduced mechanical energy losses were found in hind-first dissociations compared to fully synchronous contacts. As speed increased, only forelimb vertical peak force increased

Veterinary student competence in equine lameness recognition and assessment: a mixed methods study

The development of perceptual skills is an important aspect of veterinary education. The authors investigated veterinary student competency in lameness evaluation at two stages, before (third year) and during (fourth/fifth year) clinical rotations. Students evaluated horses in videos, where horses were presented during trot on a straight line and in circles. Eye-tracking data were recorded during assessment on the straight line to follow student gaze. On completing the task, students filled in a structured questionnaire. Results showed that the experienced students outperformed inexperienced students, although even experienced students may classify one in four horses incorrectly. Mistakes largely arose from classifying an incorrect limb as lame. The correct detection of sound horses was at chance level. While the experienced student cohort primarily looked at upper body movement (head and sacrum) during lameness assessment, the inexperienced cohort focused on limb movement. Student self-assessment of performance was realistic, and task difficulty was most commonly rated between 3 and 4 out of 5. The inexperienced students named a considerably greater number of visual lameness features than the experienced students. Future dedicated training based on the findings presented here may help students to develop more reliable lameness assessment skills

Genetic analysis of foal and studbook traits in selection for racing performance in trotters

The objective of this thesis was to evaluate the usefulness of body measurements and functional and conformation traits of foals and studbook horses in the breeding programmes of Finnhorse and Standardbred. Thus, nongenetic effects, heritability and repeatability, and genetic correlations for foal and studbook traits were estimated. In addition, genetic parameters for trotting race performance and genetic correlations for foal and studbook traits with racing traits were assessed. Genetic response and accuracy were estimated using records of animal, half-sibs, and parents in selection scenarios for racing traits, for foal and racing traits, and for studbook and racing traits, and using records of animal, half-sibs, and parents for foal traits and racing traits of parents. Single racing time and annual earnings were the breeding objectives in the selection scenarios. High heritability estimates (0.50 to 0.80) indicated that most part of the variation for body measurements of foals and studbook horses is additive genetic. High genetic correlations (0.74 to 0.99) between body measurements of foals and studbook horses indicated that the traits are determined by the same additive genes at all ages. Low to moderate genetic correlations between body measurements and racing traits suggested that selection favours a larger body size at all ages. Heritability of conformation and functional traits in foals were low to moderate (0.08 to 0.46), being generally higher than studbook traits (0.06 to 0.21). Leg stances of Finnhorse foals, type, body conformation, and overall grade of foals, and leg quality of studbook Finnhorses were of moderate heritability. Genetic correlations among the traits were from low to moderate. Partially based on the previous study, there were less unfavourable genetic correlations among foal than studbook traits. Genetic correlations between the same traits in foals and studbook horses were relatively high (over 0.60), indicating that scant new information would be received through studbook traits in genetic evaluation. In addition, the foal traits of type, trot, and overall grade were moderately to highly genetically correlated (0.50 to 0.70) with several studbook traits. Being mainly favourable for the breeding objective, genetic correlations for conformation and functional traits with racing traits were highest for the foal traits of type, trot, and overall grade and for the studbook traits of character and movements (0.37 to 0.90). Conformation traits in Finnhorse mainly had low genetic correlations with racing traits, whereas in Standardbred leg quality of studbook horses, body conformation, leg stances, and hooves of foals and studbook horses had moderate to high genetic correlations with several racing traits. The foal trait of walk is of little value in genetic evaluation of trotters due to a low heritability and low or unfavourable genetic correlations with racing traits. The most effective way to make genetic progress for the breeding objective is direct selection for racing time and earnings. No more than the individual records of one racing year are necessary for reasonable accuracy if the average number of racing records from different information sources is available for selection. The conformation and functional traits in foals are useful in genetic evaluation because they are less pre-selected than the traits in studbook horses, which are mostly determined by selection based on racing records. The most beneficial for the breeding objective is to use the foal traits of moderate heritability and genetic correlations with racing traits (type, trot, overall grade) in selection before a racing career in the index with racing records of relatives. The greatest gain in this scenario is due to a shorter generation interval. It is possible to implement for AI stallions. Functional and conformation traits in foals would also benefit from multi-trait selection in terms of prediction accuracy in the combined index with racing traits. The use of multivariate models for whole trait sets in estimation of covariance components would further correct for selection, resulting in more accurate estimates of genetic correlations than in this study. Investigating the economic value of foal traits and their relationship with veterinary records would elucidate the relevance of sound conformation and movements in breeding programmes. To have more effective conformation traits in selection for breeding programmes, judging based on biological variation for a specific trait using linear scores or all-or-none variables is recommended.Tutkimuksen tavoitteena oli arvioida varsojen ja kantakirjahevosten näyttelyominaisuuksien hyödyllisyys suomenhevosten ja lämminveristen ravihevosten jalostusohjelmissa, kun jalostustavoitteena on ravikilpailujen aika ja vuosittainen voittosumma. Näyttelyominaisuuksia ovat rungon mitat ja arvosteltavat rakenne-, luonne- ja liikeominaisuudet. Varsojen ja kantakirjahevosten näyttelyominaisuuksien perinnöllisyyden selvittäminen on tärkeää, koska niiden oletetaan olevan hyödyllisiä ravihevosen käyttökelpoisuuden ja kestävyyden jalostamisessa. Varsojen ja hevosten koko on hyvin periytyvää, sillä suurin osa eläinten välisistä eroista rungon mitoissa johtuu perinnöllisestä vaihtelusta. Rungon mittojen välillä on korkea perinnöllinen yhteys hevosen kaikissa ikävaiheissa ja jalostusvalinta ravimenestyksen suhteen suosii suurikokoisempia yksilöitä. Näyttelyissä arvosteltavat rakenne-, luonne- ja liikeominaisuudet ovat heikommin periytyviä kuin rungon mitat, sillä niiden periytyminen on alhaista tai kohtalaisen korkeaa. Varsojen arvosteltavat ominaisuudet ovat kuitenkin yleisesti paremmin periytyviä kuin kantakirjahevosten. Kohtalaisen korkeasti periytyviä arvosteltavia ominaisuuksia ovat jalkojen asento suomenhevosvarsoilla, varsan tyyppi, rungon rakenne ja näyttelypalkinto sekä jalkojen kovuus kantakirjasuomenhevosilla. Varsojen ja kantakirjahevosten vastaavilla ominaisuuksilla (rungon rakenne, jalka-asennot, kaviot ja raviliikkeet) on korkea perinnöllinen yhteys. Lisäksi varsan tyypin ja näyttelypalkinnon ja usean kantakirjaominaisuuden välillä on kohtalainen tai korkea perinnöllinen yhteys. Arvosteltavat ominaisuudet ovat suurimmaksi osaksi myönteisessä geneettisessä yhteydessä jalostustavoitteen kanssa. Korkeimmat geneettiset yhteydet ravikilpailutuloksiin arvioitiin varsojen tyypille, raviliikkeille ja näyttelypalkinnolle, ja kantakirjahevosten luonteelle ja liikkeille, mitkä vaihtelivat kohtalaisesta korkeaan. Suomenhevosten rakenneominaisuudet ovat enimmäkseen heikossa ja monet lämminveristen ravihevosten rakenneominaisuudet kohtalaisessa tai korkeassa perinnöllisessä yhteydessä ravikilpailumenestyksen kanssa. Molempien rotujen ravihevosvarsojen käynnin arvostelu näyttelyissä ei ole jalostuksellisesti hyödyllistä, koska käynnillä on alhainen periytyvyys, ja sen ja ravikilpailutulosten välinen geneettinen yhteys on lähellä nollaa tai jopa epäsuotuisa. Ravikilpailutulosten kohtalaisen korkean periytyvyyden ja toistuvuuden sekä keskenään korkeiden geneettisten yhteyksien seurauksena, yhden vuoden ravikilpailutulokset ovat riittävät arvosteluvarmuudelle jalostusindeksivalinnassa, kun keskimääräinen kilpailutulosmäärä on käytettävissä. Myönteisen perinnöllisen yhteyden ansiosta, ravikilpailumenestyksen jalostaminen edistää myös näyttelyissä arvosteltavia ominaisuuksia, vaikka niitä ei huomioitaisikaan valinnassa. Kaikki arvosteltavat ominaisuudet kuitenkin hyötyvät jalostusindeksivalinnasta ravikilpailutulosten kanssa arvosteluvarmuuden suhteen, koska ei-geneettiset tekijät kuten sukupuoli, ikä, vuodenaika, arvosteluvuosi ja hevosjalostusliitto vaikuttavat suuresti rakenne-, luonne- ja liikeominaisuuksiin. Varsojen rakenne- ja liikeominaisuudet ovat hyödyllisempiä jalostukselle kuin kantakirjahevosten vastaavat ominaisuudet, koska perinnölliset erot varsojen välillä ovat suurempia ja ympäristön vaihtelu pienempää kuin kantakirjahevosilla. Jalostusarvostelussa ravikilpailutulokset ja aineiston valikoituneisuus vaikuttavat enemmän kantakirjahevosten kuin varsojen ominaisuuksiin. Kantakirjaominaisuudet on mahdollista korvata varsanäyttelyiden ominaisuuksilla, koska nämä ominaisuudet ovat suurelta osin geneettisesti samoja ja sen vuoksi vain vähän uutta tietoa saadaan kantakirjanäyttelyissä arvosteltavien ominaisuuksien kautta. Jalostukselle suurin hyöty näyttelyissä arvosteltavista ominaisuuksista saadaan käyttämällä eläimen ja sen sukulaisten varsanäyttelyominaisuuksia sekä sukulaisten ravikilpailutuloksia jalostusindeksivalinnassa ennen omaa kilpailu-uraa, mikä on lyhyen sukupolven välisen ajan ansiota. Tämä valintaskenaario on mahdollista toteuttaa nuorilla keinosiemennysjalostukseen käytettävillä oriilla. Jalostusvalinnalle tehokkaampien rakenneominaisuuksien luomiseksi on suositeltavaa kehittää yksityiskohtaiset arvostelukohteet, jotka perustuvat ominaisuuksien biologiseen vaihteluun käyttäen lineaarista tai joko-tai arvostelumallia. Tulevaisuudessa ravihevosen kestävän rakenteen ja liikkeiden jalostusta voi tutkia arvioimalla näyttelyominaisuuksien taloudellisia arvoja ja yhteyttä hevosen terveyteen

Assessment Scores in Morphological Competitions of Pura Raza Español Horse

The aim of this work was to establish the external factors affecting morphological scores in competitions of Pura Raza Español (PRE – Spanish Purebred) horses. The dataset included 8633 participations, in 69 different morphological competitions of 5097 horses, belonging to 1113 studs. In total, the dataset had 21,760 records (each with eight partial morphological scores) with a balanced frequency of males and females. Our results showed that there are several external factors that influence the judges’ scores. Morphological competition (15.70% of the total variance), judge (9.65%), judge*morphological competition (7.45%) and judge*type (2.41%) were the most important external factors in the analyzed traits. The reliability of judgements was evaluated by the index of disagreement, and results showed that it might be necessary to train judges to get more agreement in these scores. Moreover, for a breeding program it is very important that judges use all the range of scores in order to collect the maximum level of variation. The analyses showed that competitions with three judges were the most appropriate. © 2014 Friends Science Publisher

Sagittal plane fore hoof unevenness is associated with fore and hindlimb asymmetrical force vectors in the sagittal and frontal planes

Asymmetry in forelimb dorsal hoof wall angles, termed unevenness, is associated with forelimb gait asymmetries, but compensatory mechanisms and out of plane ground reaction forces (GRFs) due to unevenness have yet to be documented. The aim of this study was therefore to investigate the effects of fore hoof unevenness on contralateral fore and hind limb force vectors patterns, in both sagittal and frontal planes. A group of n = 34 riding horses were classified into four groups: hoof angle difference of more than 1.5 degrees (UNEVEN; n = 27), including higher left fore (HIGH-LF; n = 12), higher right fore (HIGH-RF; n = 15), and hoof angle difference of less than 1.5 degrees (EVEN; n = 7). Three dimensional ground reaction forces GRFs were collected during trotting. GRF summary vectors representing the magnitude (VecMag) and angular direction (VecAng) of the entire stance phase in the sagittal and the frontal plane were calculated. The effects of unevenness on GRF production were explored using linear regression, repeated measures ANOVA and statistical parametric mapping (SPM) with significance at (P0.05) were found between hindlimb pairs in the EVEN group. Unbalanced sagittal and increased frontal plane GRFs in uneven horses suggest that they have greater locomotory challenges, as the equine musculoskeletal system is not constructed to withstand movement and loading in the frontal plane as effectively as it is in the sagittal plane