Early life jumping traits: Are they good proxies for success in show jumping competitions in Belgian warmblood horses?

The main goal of the Belgian Warmblood horse studbook (BWP) is to breed successful competition horses, with emphasis on show jumping. However, competition results are only available later in life and competition traits are lowly heritable. Hence, the use of phenotypes that record performance-related traits at an early life stage could help increase genetic progress. In this study, we evaluated the potential of eleven linear scored early life jumping traits assessed during jumping in freedom (2-5 years old) or under the saddle (4-6 years old) as proxies for later success in show jumping competitions. To this end, we estimated their heritabilities and genetic correlations with the competition trait, adjusted fence height, by using 2170 free jumping records, 1588 jumping under saddle records, 674,527 show jumping competition records and almost 81,000 informative horses in the pedigree. As participation of young horses in these contests is on a voluntary basis, a pre-selection most probably exists. To verify this hypothesis, we investigated the association between participation to young horse contests and participation to show jumping competitions later on (called here start status phenotype). We also estimated heritabilities for "start status in free jumping contest", "start status in jumping under saddle contest" and "start status in free jumping or jumping under saddle contest" by fitting threshold models. Furthermore, we calculated genetic correlations between these traits and adjusted fence height and calculated the correlations between EBVs for start status in young horse contests and EBVs for success in competitions. Estimated heritabilities of early life jumping traits ranged between 0.05 and 0.30. Their genetic correlations with adjusted fence height were moderate to high (rg = 0.37-0.63). Relatively more horses that participated in young horse contests competed later on compared to horses that did not participate in young horse contests (p-value < 0.001). They were also significantly more successful in show jumping competitions. Furthermore, start status in young horse contests was moderately heritable in BWP horses (h2 = 0.56-0.65) and moderately to highly correlated with later success in competitions (rg = 0.30-0.77). Hence, we showed that ELJ traits are good proxies for later success in competitions and that a pre-selection of horses occurs in young horse contests. It is suggested to stimulate participation to young horse contests to achieve a more representative sample of the population. Early life jumping traits can therefore optimize the genetic progress for show jumping performance.

Plasticity effect of rider-horse interaction on genetic evaluations for Show Jumping discipline in sport horses.

To obtain a sport horse that excels in the highest levels of competition, breeders must take into account certain genetic and environmental factors that could influence the sport horse's performance, such as the rider-horse interaction (RHI). The main aim of this study was to describe this interaction in a genetic model by modelling it in relation to the horse's age. A total of 31,129 sport results from Spanish Sport Horses were used from a total of 1,101 animals evaluated, and these were grouped in three age levels and had been ridden by 606 different riders. Only riders who had ridden more than one horse (and vice-versa) were considered for the analyses. Five linear models with different random effects were analysed according to the covariates, the homogeneity/heterogeneity of the RHI and the relevant residual random effects. The model of best fit was then selected for the genetic evaluation of the animal. In general, models including the RHI effect (M2, M4 and M5) fitted better than the other models, and the best fit was obtained for M4 (with heterogeneous residual variance). The genetic variance increased constantly with age, whereas heritability showed a response on three intervals. This study revealed the varied evolution of the RHI with age, showing the different "plastic abilities" of this relationship.

Management and Rehabilitation of Joint Disease in Sport Horses.

Joint disease is one of the most common issues effecting sport horses. Because there is no cure for joint disease, treatment goals surround slowing progression of the disease, minimizing pain, increasing function, and optimizing performance. Accomplishing these goals often requires a multimodal approach that combines systemic medications or supplements; intra-articular therapies, such as corticosteroids or biologics; management considerations; and physical therapy exercises.

Cardiac/Cardiovascular Conditions Affecting Sport Horses.

Cardiac murmurs are not uncommonly detected in the equine athlete. Although most are benign in nature, differentiation and quantification of murmurs due to valvular regurgitation are important for prognosis and recommendations. Arrhythmias can be associated with structural disease or occur independently and may range in severity from minimal clinical effect to poor performance to presenting a safety risk to rider and horse. This article discusses commonly encountered cardiac conditions in the sport horse. Physical examination, diagnostic approach, valvular disease, and arrhythmias with an impact on performance or ridden safety are discussed.

Genetic correlations between dressage, show jumping and studbook-entry inspection traits in a process of specialization in Dutch Warmblood horses.

Sport performance in dressage and show jumping are two important traits in the breeding goals of many studbooks. To determine the optimum selection scheme for jumping and dressage, knowledge is needed on the genetic correlation between both disciplines and between traits measured early in life and performance in competition in each discipline. This study aimed to estimate genetic parameters to support decision-making on specialization of breeding horses for dressage and show jumping in Dutch warmblood horses. Genetic correlations between performance of horses in dressage and show jumping were estimated as well as the genetic correlation between traits recorded during studbook-entry inspections and performance in dressage and show jumping competitions. The information on competition comprised the performance of 82 694 horses in dressage and 62 072 horses in show jumping, recorded in the period 1993-2012. For 26 056 horses, information was available for both disciplines. The information on traits recorded at studbook-entry inspections comprised 62 628 horses, recorded in the period 1992-2013. Genetic parameters were estimated from the whole dataset and from a subset without horses recorded in both disciplines. Additionally, the genetic parameters were estimated in three different time periods defined by horses' birth year. The genetic correlation between dressage and show jumping in the whole dataset was -0.23, and it was -0.03 when it was estimated from horses recorded in only one discipline. The genetic correlation between dressage and show jumping was more negative in the most recent time period in all the cases. The more negative correlation between disciplines in more recent time periods was not reflected in changes in the correlations between competitions traits and the traits recorded in the studbook-first inspection. These results suggest that a breeding programme under specialization might be most effective defining two separate aggregate breeding goals for each of the disciplines.

Analysis of competition performance in dressage and show jumping of Dutch Warmblood horses.

Most Warmblood horse studbooks aim to improve the performance in dressage and show jumping. The Dutch Royal Warmblood Studbook (KWPN) includes the highest score achieved in competition by a horse to evaluate its genetic ability of performance. However, the records collected during competition are associated with some aspects that might affect the quality of the genetic evaluation based on these records. These aspects include the influence of rider, censoring and preselection of the data. The aim of this study was to quantify the impact of rider effect, censoring and preselection on the genetic analysis of competition data of dressage and show jumping of KWPN. Different models including rider effect were evaluated. To assess the impact of censoring, genetic parameters were estimated in data sets that differed in the degree of censoring. The effect of preselection on variance components was analysed by defining a binary trait (sport-status) depending on whether the horse has a competition record or not. This trait was included in a bivariate model with the competition trait and used all horses registered by KWPN since 1984. Results showed that performance in competition for dressage and show jumping is a heritable trait (h2 ~ 0.11-0.13) and that it is important to account for the effect of rider in the genetic analysis. Censoring had a small effect on the genetic parameter for highest performance achieved by the horse. A moderate heritability obtained for sport-status indicates that preselection has a genetic basis, but the effect on genetic parameters was relatively small.

Genetic conditions of joint Nordic genetic evaluations of lifetime competition performance in warmblood sport horses.

Breeding programmes for warmblood sport horses are similar in the Nordic countries Sweden, Denmark, Finland and Norway, and stallions of same origin are used. The aim was to investigate whether a joint Nordic genetic evaluation based on lifetime competition performance is feasible and beneficial for breeding competitive sport horses in the Nordic countries. Results for almost 45,000 horses in show jumping and 30,000 horses in dressage were available. The larger populations in Sweden and Denmark contributed with 85% of the results. Heritabilities and genetic correlations between performances in the different countries were estimated, and comparisons of accuracies of estimated breeding values (EBVs) and number of stallions with EBVs based on national or joint data were studied. The heritabilities ranged between 0.25 and 0.42 for show jumping and between 0.14 and 0.55 for dressage. The genetic correlations between competition performances in the Nordic countries were estimated to 0.63-1.00. EBVs based on joint data increased accuracies for EBVs for stallions by 38-81% and increased the number of available stallions with EBVs by 40-288%, compared to EBVs based on national data only. A joint Nordic genetic evaluation for sport horses is recommended.

Effect of specialization on genetic parameters of studbook-entry inspection in Dutch Warmblood horses.

Recent studies on data from the Dutch Warmblood Studbook (KWPN) have shown that the ongoing specialization of horses for either dressage (DH) or show jumping (JH) has led to a decreasing genetic relationship between the two subpopulations. The aim of this study was to analyse the effect of the specialization process on the genetic parameters of traits measured in the studbook-entry inspection of KWPN during the last fifteen years. Data from 18,125 DH and 23,800 JH recorded from 1998 until 2013 were used to analyse 13 traits scored in both DH and JH. Analyses were performed in a Bayesian framework. Firstly, variance components were estimated based on the whole data set. Secondly, genetic correlations between traits measured in DH or JH were estimated using bivariate analyses. Thirdly, three time periods were defined and genetic correlations between subpopulations were estimated within each period. Heritability was moderate (0.17-0.39) for both DH and JH. Genetic correlations between traits measured in DH or JH were not different from one considering the posterior standard deviation of the estimation; however, in most of the traits, a clear trend in reduction of the genetic correlation for traits expressed in DH and JH and an increase in their posterior standard deviation for recent years was observed. These results suggest that specialization could lead to differences in traits measured in DH and JH in the recent years.

Evaluation of the length of competitive life in Hungarian sport horses.

The aim of this study was to analyse the duration of the competitive life of jumping horses in Hungary to assess the potential for genetic evaluation and to get information about the risk factors affecting jumping performance of sport horses. The data set included lifetime performance in jumping competitions for 8475 horses born from 1992 onwards with records between 1996 and 2011 (32.7% were right-censored). Longevity was measured as the number of years spent in the competition. Discrete time survival model included fixed effects of gender, age at first competition, and the time-dependent effect of competition level. All fixed effects were highly significant (p < 0.001). The highest risk of ending the race career was estimated for horses competing in the lowest level (category 1) events. The smallest risk was found in horses competing in the highest category. The culling risk for stallions was 15% higher, for geldings 20% lower when compared to mares. As the age at the first competition result increased, the risk ratio also increased. Risk ratios of horses starting as 8 years old or older were 56% higher than those of 5-year-old horses. The longest time in sport tracks belonged to horses starting their career as 4 years old. Their culling risk was 20% lower than those of 5-year-old horses. The heritability of the length of competitive life was 0.17. Breeding values were predicted for each animals, and 47 showed an accuracy greater than 0.60. The clear benefit of the analysis was shown by comparison of offspring to extreme stallion groups.

Lesion Distribution in the Metacarpophalangeal and Metatarsophalangeal Region of 341 Horses Using Standing Magnetic Resonance Imaging.

Pain localised to the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) region represents a frequent cause of lameness in sport horses, and standing magnetic resonance imaging (MRI) of these regions is increasingly being acquired. This multicentre retrospective study describes the ranges of abnormalities identified on standing MRI of the MCP/MTP region and compares patterns of abnormalities between forelimbs, hindlimbs and different sports disciplines. In total, 341 MRI reports were reviewed. Subchondral bone plate irregularities, condylar and proximal phalanx pathologies were frequently identified with subchondral bone defect, sclerosis and increased intensity on STIR images often described. Medial pathology was frequently identified in the forelimbs, and more lateral pathology was reported in the hindlimbs, which could potentially reflect differences in the loading patterns. Significant differences in MRI findings were found between different sports activities, with MCP/MTP bone pathology occurring more frequently in MRI reports from race and endurance horses and MCP/MTP soft tissue injuries being reported more frequently in dressage and show-jumping horses, particularly in the suspensory apparatus, including the distal sesamoidean ligaments. The findings of this study identify patterns of MCP/MTP abnormalities detected using standing MRI, with differences seen between forelimbs and hindlimbs and between different sports disciplines.

Long-term performance of show-jumping horses and relationship with severity of ataxia and complications associated with myeloencephalopathy caused by equine herpes virus-1.

BACKGROUND: Equine herpesvirus myeloencephalopathy (EHM) has severe impact on the sport horse population. OBJECTIVE: Study the influence of EHM on the likelihood of affected horses to return to their previous performance and investigate the association of clinical variables with prognosis. ANIMALS: Twenty-six horses positive for equine herpesvirus type 1 (EHV-1) were admitted to a veterinary teaching hospital (VTH) during a natural EHM outbreak at an international jumping event. METHODS: Data collected from the VTH, the International Equestrian Federation, and surveys completed by the riders and horse owners were retrospectively analyzed. RESULTS: Horses affected by EHM had 68% chance of returning to exercise, and 52.9% were able to achieve their preoutbreak performance level. Horses with an ataxia grade at admission ≥4/5 had an increased fatality rate (P < .05) and 10% chance of reaching their preoutbreak performance level. None of the horses with both vascular and urinary complications returned to their previous performance level. Finally, horses vaccinated against EHV-1 and those with urinary complications had a 71.4% and 43.7% fatality rate, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Horses affected by EHM were able to return to their previous performance levels, but certain clinical variables were negatively associated with postoutbreak performance. Ataxia grade upon admission and the development of systemic signs of vasculitis and urinary complications were potential poor prognostic indicators in sport horses. Variables linked to fatality included prior vaccination against EHV-1, ataxia grade upon admission, and the development of urinary complications.

Kinematic Responses to Water Treadmill Exercise When Used Regularly within a Sport Horse Training Programme: A Longitudinal, Observational Study.

Repeated exposure to water treadmill (WT) exercise could elicit kinematic responses reflecting adaptation to WT exercise. The study's aim was to compare the responses of a group of sport horses to a standardised WT exercise test (WTSET) carried out at three time points, week 0 (n = 48), week 20 (n = 38), and week 40 (n = 29), throughout a normal training programme incorporating WT exercise. Horses were recruited from the existing client populations of two commercial water treadmill venues for the purpose of this longitudinal, observational study. Limb, back, poll, wither, and pelvic kinematics were measured during the WTSET using videography, optical motion capture, and inertial motion sensors. Forelimb and hindlimb protraction increased (p < 0.001 for both), and forelimb and hindlimb retraction decreased (p < 0.001 for both) at week 40 compared to week 0. Caudal thoracic flexion-extension and lateral bend ranges of movement were greater at week 40 compared to week 0 (p < 0.001 and p = 0.009, respectively). Increased training speed was associated with increased craniocaudal poll movement (p = 0.021), decreased forelimb protraction (p = 0.008), and increased forelimb retraction (p = 0.021). In addition to characteristic changes in kinematics due to increasing water depth, regular WT exercise resulted in kinematic adaptation to movement in water. Factors such as the frequency of WT sessions and the type of session used with respect to depth and speed were seen to influence the nature of the adaptation. The results suggest that WT exercise sessions could be designed in accordance with specific training goals when used within a normal sport horse training programme.

Comparison of Conformation and Movement Characteristics in Dressage and Jumping Sport Warmblood Mares Based on Point Evaluation and Linear Scoring System.

The aim of this study was to analyze the influence of factors on the results of 100-point judging systems, linear scoring and basic measurements, as well as differences between systems for dressage and jumping warmblood mares. The research covered official data on 1547 warmblood mares. Analysis of variance and phenotypic correlations (Pearson and partial) were used. The analysis showed that sport type significantly influenced 1/3 of biometric measurements, 2/9 traits on the 100-point system and 7/37 of linear scored traits. The influence of horse type evaluation is more significant in linear scoring than in the 100-point evaluation, which provides an argument for using the first system in breeding. In the linear evaluation for warmblood mares grouped as jumping or dressage, the most significant differences (p < 0.001) were noted between the traits of shoulder position, line of the loins and shape of the croup. In the point-based evaluation, differences (p < 0.05) were found in forelimbs and walking, as well as chest circumference in basic measurements. None of the traits in the two evaluation systems is identical to any other (r > 0.8). The comparison of systems showed meaningful correlations only between general traits. The differences between sport types of warmblood mares were smaller than expected. More objective traits should be discovered to increase accuracy in discriminating between horse types.

Genetic Parameters of Effort and Recovery in Sport Horses Assessed with Infrared Thermography.

The way a horse activates (effort phase-EP) and recovers (recovery phase-RP) during a sport event can affect its sport performance. The aim of this manuscript was to test horses' adaptation to sport performance and its genetic basis, using eye temperature assessed with infrared thermography. EP and RP were measured in 495 Spanish Sport Horses, during a performance test, considering sex (2) and genetic lines (5) as fixed effects. The ranking position obtained on an official sport competition was also collected. Differences in variables due to genetic line and sex effects were found, showing that, regardless of the genetic line, stallions tended to recover better than mares after the sport test developed. High positive intra-class correlations (p < 0.001) were found between EP and RP for both fixed effects, so that the higher the EP, the higher the RP. However, for the ranking position, a low negative correlation (p < 0.01) was found, so that the higher the eye temperature increase, the better the position. Heritabilities showed medium-high values with a medium positive genetic correlation between them. Thus, breed origins and sex influence horses' effort and recovery during sport performance, showing a genetic basis adequate for selection.

Factors associated with the prevalence of antibodies against Theileria equi in equids of Western Pará, Brazil.

The State of Pará has one of the largest herds of equids (horse, donkey and mule) in Brazil, most of these animals are found on cattle farms. Equine theileriosis is a tick-borne disease caused by the parasite Theileria equi and is characterized by fever, anaemia, icterus, intravascular haemolysis, haemoglobinuria, spleen and hepatomegaly, and even death. The present study aimed to determine the prevalence of antibodies against T. equi in equids in the western region of the State of Pará, Brazil, and to identify potential risk factors associated with parasite infection. A cross-sectional study was conducted with cluster sampling of farm horses from 18 municipalities. In the cities visited, samples from sport and carthorses were also included. Serum was obtained to detect T. equi-specific antibodies using an indirect enzyme-linked immunosorbent assay (iELISA) based on a crude parasite antigen. In order to identify possible risk factors of the infection which are associated with the prevalence of antibodies, a chi-squared test was carried out. Of 1,117 equids, 373 tested positive for T. equi antibodies with an overall prevalence of 33.4% (31.3%-37.0% for the 95% confidence interval). Sex, animal species and breed were found not to be associated with the presence of T. equi antibodies, whereas age, the presence of dogs or ticks were associated with seropositivity (p < 0.05). Horses with ticks were 2.4 more likely seropositive than horses without ticks. The presence of dogs in the equid habitat and the presence of ticks resulted in a higher T. equi seropositive rate probably because dogs are hosts for vector ticks of T. equi. Our study represents the first report of T. equi antibodies in equids of western Pará revealing a widespread distribution of seropositive animals.

Identification and Functional Annotation of Genes Related to Horses' Performance: From GWAS to Post-GWAS.

Integration of genomic data with gene network analysis can be a relevant strategy for unraveling genetic mechanisms. It can be used to explore shared biological processes between genes, as well as highlighting transcription factors (TFs) related to phenotypes of interest. Unlike other species, gene-TF network analyses have not yet been well applied to horse traits. We aimed to (1) identify candidate genes associated with horse performance via systematic review, and (2) build biological processes and gene-TF networks from the identified genes aiming to highlight the most candidate genes for horse performance. Our systematic review considered peer-reviewed articles using 20 combinations of keywords. Nine articles were selected and placed into groups for functional analysis via gene networks. A total of 669 candidate genes were identified. From that, gene networks of biological processes from each group were constructed, highlighting processes associated with horse performance (e.g., regulation of systemic arterial blood pressure by vasopressin and regulation of actin polymerization and depolymerization). Transcription factors associated with candidate genes were also identified. Based on their biological processes and evidence from the literature, we identified the main TFs related to horse performance traits, which allowed us to construct a gene-TF network highlighting TFs and the most candidate genes for horse performance.

Response of Sport Horses to Different Formulations of Equine Influenza Vaccine.

The international governing body of equestrian sports requires that horses be vaccinated against equine influenza within 6 months and 21 days of competing. The aim of this study was to compare the antibody response of young sport horses to six-monthly booster vaccination with equine influenza vaccines of different formulations. An inactivated vaccine was allocated to 35 horses and subunit and recombinant vaccines were allocated to 34 horses each. After vaccination, all horses were monitored for evidence of adverse reactions. Whole blood samples were collected at the time of vaccination and on nine occasions up to six months and 21 days post vaccination. Antibodies against equine influenza were measured by single radial haemolysis. Transient fever and injection site reactions were observed in several horses vaccinated with each vaccine. Only two horses failed to seroconvert post booster vaccination but there was a delayed response to the recombinant vaccine. The antibody response to the recombinant vaccine was lower than that induced by the whole-inactivated and subunit vaccines up to three months post vaccination. Thereafter, there was no significant difference. By six months post vaccination, the majority of horses in all three groups were clinically but not virologically protected. There was minimal decline in antibody titres within the 21-day grace period.

Cardiovascular variables in eventing and endurance horses over a season.

INTRODUCTION: The objectives of this study were to describe the changes in clinical cardiovascular examination variables over a competition season in groups of competitive eventing and endurance horses and to compare these findings to non-competitive controls of the same breeds. ANIMALS: This study included two eventing horses, 11 endurance horses, and 13 eventing and seven endurance control breed-matched horses. MATERIALS AND METHODS: Cardiovascular examinations were performed before starting the competition season, in the middle and at the peak/end of the competition season. Examinations included auscultation of the heart; M-mode echocardiographic measurements and calculated values; left atrial, pulmonary artery, and aortic diameters; color flow Doppler; exercise electrocardiograms (ECG) measuring peak heart rates and quantifying premature complexes; and 24-h continuous ECGs quantifying premature complexes per hour. RESULTS: Auscultation, echocardiograms, arrhythmias during exercise, and 24-h continuous ECGs did not change significantly throughout the season (p > 0.05 for all variables). CONCLUSION: Cardiovascular examination variables of eventing and endurance horses throughout a competition season are reported here for the first time. Although the present study did not reveal significant changes, data should be interpreted carefully as only a small number of horses were examined.

Irish Equine Industry Stakeholder Perspectives of Objective Technology for Biomechanical Analyses in the Field.

Wearable sensing technologies are increasingly used in human and equine gait research to improve ecological validity of research findings. It is unclear how these tools have penetrated the equine industry or what perspectives industry stakeholders' hold in relation to these relatively new devices. Semi-structured interviews were conducted with Irish equine industry stakeholders to understand their perception of objective tools for biomechanical analysis in the field. The study participants came from professional/elite backgrounds in both the sport horse (n = 6) and thoroughbred (n = 6) sectors. The interview data were analysed using thematic analysis, resulting in four analytical themes. The first theme conveys the importance of tacit knowledge and experience in the holistic analysis of a horse. Theme two highlights that the perfect horse does not exist therefore, equine athlete management is complex and requires a multi-layered problem-solving approach. Theme three describes an awareness among stakeholders of technologies, however they are sceptical of their value. The final theme identified that one of the key barriers to technology adoption is the economic value of the horse and the cost of implementing technology herd-wide. Our findings highlight the need for a user-centred design in this domain, which requires greater consultation and learning between technology developers and equine stakeholders to develop fit-for-purpose analysis and monitoring tools.

Equine viral arteritis in breeding and sport horses in central Spain.

Equine viral arteritis (EVA) may have a high economic impact on breeding stud farms due to the occurrence of EVA-associated abortion outbreaks and the ability of the virus to persist in carrier stallions. While the consequences of EVA in premises with sport horses are usually less severe, the first confirmed outbreak of EVA in Spain occurred in a riding club in Barcelona, but no data on the seroprevalence of EVA in sport horses have been reported in Spain. Given the importance of both Spanish Purebred (SP) breeding horses and sport horses for Spain's equine industry, the aim of this study was to determine and compare the seroprevalence of EVA in these two horse populations in central Spain. Serum samples from 155 SP breeding horses residing in 16 stud farms and 105 sport horses of different breeds housed in 12 riding clubs, collected between September 2011 and November 2013, were tested using a commercial EVA antibody ELISA test with a 100% sensitivity, and confirmed by seroneutralisation (SN) test. EVA seroprevalence in SP breeding horses was higher 21.1% (95% CI 15.3-26.8%) than that in sport horses (6.7%, 95% CI 1.89-11.45%). However, the primary use (breeding vs. sport) was not significantly associated with seropositivity to Equine Arteritis Virus (EAV), suggesting that different management factors do not affect EVA circulation in these two horse populations.