Horse racing is a competitive equestrian sport involving horses ridden by jockeys over set distances, often on flat tracks or over obstacles. It is characterized by a variety of race types, including thoroughbred, harness, and steeplechase, each with distinct rules and traditions. The sport emphasizes speed, stamina, and strategy, with races typically categorized by distance, surface type, and horse age or breed. Horse racing plays a significant role in the equine industry, influencing breeding, training, and veterinary care practices. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological demands, training methodologies, and health considerations associated with horse racing.
Gold JR, Knowles DP, Coffey T, Bayly WM.Exercise-induced pulmonary hemorrhage (EIPH) refers to bleeding from the lungs in association with strenuous exercise. It has been documented in race horses but little information exists on EIPH in barrel racing horses. Objective: Our goals were to evaluate the presence of EIPH in barrel racing horses and estimate its prevalence in the Pacific Northwest. Methods: 149 barrel racing horses enrolled at events in WA (11), ID (3), and MT (33). Methods: Observational cross-sectional study. Data collected included signalment, history of illness, respiratory disease, race division, and pre-race medica...
Martig S, Hitchens PL, Stevenson MA, Whitton RC.The repetitive large loads generated during high-speed training and racing commonly cause subchondral bone injuries in the metacarpal condyles of racehorses. Adaptive bone modelling leads to focal sclerosis at the site of highest loading in the palmar aspect of the metacarpal condyles. Information on whether and how adaptive modelling of subchondral bone changes during the career of a racehorse is sparse. The aim of this cross-sectional study was to describe the changes in subchondral bone micromorphology in the area of highest loading in the palmar aspect of the metacarpal condyle in thorough...
Moulin N, François I, Coté N, Alford C, Cleary O, Desjardins MR.Despite the recommendation of plate fixation for propagating condylar fractures of the third metacarpal (McIII) or third metatarsal bone (MtIII), lag screw fixation can be a viable surgical option. Objective: To evaluate short-term outcome and long-term racing performance of horses that underwent lag screw fixation of long condylar fractures of the McIII/MtIII. Methods: Retrospective case series. Methods: Medical records, post-surgical racing performance and outcome of 26 horses with propagating fractures of the medial and/or lateral condyle of McIII/MtIII were reviewed. Medical information in...
Schemann K, Annand EJ, Reid PA, Lenz MF, Thomson PC, Dhand NK.To evaluate the effect of Equivac® HeV Hendra virus vaccine on Thoroughbred racing performance. Methods: Retrospective pre-post intervention study. Methods: Thoroughbreds with at least one start at one of six major south-eastern Queensland race tracks between 1 July 2012 and 31 December 2016 and with starts in the 3-month periods before and after Hendra virus vaccinations were identified. Piecewise linear mixed models compared the trends in 'Timeform rating' and 'margin to winner' before and after initial Hendra virus vaccination. Generalised linear mixed models similarly compared the odds of...
Negro S, Bartolomé E, Molina A, Solé M, Gómez MD, Valera M.The stress level is suggested to have a negative effect on horses during equestrian competitions, specifically in trotter racing. The main objectives of this study were to measure stress levels in Spanish Trotter Horse races with a reliable non-invasive method, and determining the threshold level of stress that leads to the best performance results and also shows when the stress perceived by the horse becomes distress. One hundred and thirty individuals were evaluated, measuring their performance (based on racing time per kilometre (TPK)) and their stress (based on eye temperature, assessed wi...
Walsh R, Smith MRW, Wright IM.Osteochondral fragmentation of the dorsoproximal margin of the proximal phalanx is commonly recognised in racing Thoroughbreds. Frequency distribution has been documented in racing Thoroughbreds and Quarter Horses in the USA and in European Warmbloods but no data have been published from the UK. Concurrent intra-articular soft tissue lesions and radiographic accuracy of fragment distribution in racing Thoroughbreds have not previously been reported. Objective: To document frequency distribution of dorsoproximal fragmentation of the proximal phalanx in a UK population of racing Thoroughbreds an...
Hopper N, Singer E, Henson F.The exact aetiology and pathogenesis of microdamage-induced long bone fractures remain unknown. These fractures are likely to be the result of inadequate bone remodelling in response to damage. This study aims to identify an association of osteocyte apoptosis, the presence of osteocytic osteolysis, and any alterations in sclerostin expression with a fracture of the third metacarpal (Mc-III) bone of Thoroughbred racehorses. Methods: A total of 30 Mc-III bones were obtained; ten bones were fractured during racing, ten were from the contralateral limb, and ten were from control horses. Each Mc-II...
Gunther-Harrington CT, Arthur R, Estell K, Martinez Lopez B, Sinnott A, Ontiveros E, Varga A, Stern JA.Exercise induced cardiac fatigue (EICF) and cardiac dysrhythmias are well described conditions identified in high-level human athletes that increase in frequency with intensity and duration of exercise. Identification of these conditions requires an understanding of normal pre- and post-race cardiac assessment values. The objectives of this study were to (1) characterize selected indices of cardiac function, electrophysiologic parameters, and biochemical markers of heart dysfunction prior to and immediately after high level racing in Thoroughbred horses receiving furosemide; and (2) create pre...
Popot MA, Jacobs M, Garcia P, Loup B, Guyonnet J, Toutain PL, Bailly-Chouriberry L, Bonnaire Y.Tiludronate is a bisphosphonate drug marketed to treat different bone conditions in horses. Objective: The goal of this study was to measure the plasma concentrations of tiludronate in a population of race and sport horses under field conditions, and using pharmacokinetic population modelling, to estimate detection times for doping control. Methods: Prospective cohort. Methods: This study was conducted under field conditions on 39 race or sport horses diagnosed with bone conditions based on a lameness examination and treated with tiludronate. Each horse received 1 mg/kg of tiludronate (Tildren...
Burns TA, Dembek KA, Kamr A, Dooley SB, Dunbar LK, Aarnes TK, Bednarski LS, O'Brien C, Lakritz J, Byrum B, Wade A, Farmer R, Tan S, Toribio RE.Cobalt chloride (CoCl ) is administered to racehorses to enhance performance. The purpose of this study was to evaluate the clinical, cardiovascular, and endocrine effects of parenterally administered CoCl . Objective: To describe the effects of weekly intravenous doses of CoCl on Standardbred horses. Methods: Five, healthy Standardbred mares. Methods: Prospective, randomized, experimental dose-escalation pilot. Five Standardbred mares were assigned to receive 1 of 5 doses of CoCl (4, 2, 1, 0.5, or 0.25 mg/kg) weekly IV for 5 weeks. Physical examination, blood pressure, cardiac output, and e...
Bohák Z, Szenci O, Harnos A, Kutasi O, Kovács L.Temperament has not been taken into account in previous studies evaluating the stress response to exercise in horses. The aim of the present study was to investigate the cortisol response in Thoroughbred racehorses to a single exercise bout, and to analyse the results based on the basic personality of the horse examined. Twenty healthy Thoroughbred horses were selected for the study based on a 25-item rating questionnaire survey used for characterising equine temperament. Eight temperamental and twelve calm horses took part in the experiment. The horses trotted as a warm-up activity, and then ...
Lee W, Park KD, Taye M, Lee C, Kim H, Lee HK, Shin D.This study was intended to identify genes positively selected in Thoroughbred horses (THBs) that potentially contribute to their running performances. Methods: The genomes of THB and Jeju horses (JH, Korean native horse) were compared to identify genes positively selected in THB. We performed cross-population extended haplotype homozygosity (XP-EHH) and cross-population composite likelihood ratio test (XP-CLR) statistical methods for our analysis using whole genome resequencing data of 14 THB and 6 JH. Results: We identified 98 (XP-EHH) and 200 (XP-CLR) genes that are under positive selection ...
Farries G, McGettigan PA, Gough KF, McGivney BA, MacHugh DE, Katz LM, Hill EW.Adaptation to early training and racing (i.e. precocity), which is highly variable in racing Thoroughbreds, has implications for the selection and training of horses. We hypothesised that precocity in Thoroughbred racehorses is heritable. Age at first sprint training session (work day), age at first race and age at best race were used as phenotypes to quantify precocity. Using high-density SNP array data, additive SNP heritability (hSNP2) was estimated to be 0.17, 0.14 and 0.17 for the three traits respectively. In genome-wide association studies (GWAS) for age at first race and age at best ra...
Wilson G, Lucas D, Hambly C, Speakman JR, Morton JP, Close GL.To formulate individualized dietary strategies for jockeys, it is vital that energy requirements are quantified. We measured total energy expenditure (TEE) over two separate weeks in spring and summer using doubly labelled water in a group of male flat jockeys (n = 8, 36.9 ± 5.7 years, 164 ± 8 cm, 54.6 ± 2.5 kg). Total energy intake (TEI) was self-recorded, as were all riding and structured exercise activity. Mean daily TEE was 10.83 (±2.3) and 10.66 (±1.76) MJ, (p = .61) respectively. Self-reported TEI were 6.03 (±1.7) and 5.37 (±1.1) MJ (p = .40), respectiv...
Shields E, Seiden-Long I, Massie S, Leguillette R.A "high-sensitivity" cardiac troponin-T (hscTnT) assay recently has been validated for use in horses and is a specific biomarker of myocardial damage. Postexercise release kinetics of cTnT utilizing the hscTnT assay have yet to be established in horses. Objective: To determine: (1) cTnT release kinetics in racing Thoroughbreds after a high-intensity 5/8th mile Chuckwagon race; (2) the effects of age on pre- and postrace cTnT concentrations; and (3) sampling guidelines for clinicians evaluating horses presenting after exercise. Methods: Samples were obtained from 38 Thoroughbred geldings aged 5...
O'Connor S, Warrington G, McGoldrick A, Cullen S. Professional horse racing is considered a high-risk sport, yet the last analysis of fall and injury incidence in this sport in Ireland was completed between 1999 and 2006. Objective: To provide an updated analysis of the fall and injury incidence in professional flat and jump horse racing in Ireland from 2011 through 2015, compare it with the previous analysis, and detail the specific types and locations of injuries. Methods: Descriptive epidemiology study. Methods: A medical doctor recorded all injuries that occurred at every official flat and jump race meeting for the 2011 th...
Knych HK, Wilson WD, Vale A, Kass PH, Arthur RM, Jones JH.Due to the high prevalence of EIPH in racehorses and its potential impact on the horse's health, furosemide administration is permitted up to 4-h prior to post time in most North American racing jurisdictions. Anecdotal reports suggest that administration of furosemide 24-h prior to strenuous exercise may be equally effective in decreasing the severity of EIPH. Objective: To 1) compare the efficacy of furosemide in reducing the presence and severity of EIPH when administered 4- or 24-h prior to strenuous exercise 2) characterise electrolyte and blood parameters following administration of furo...
Crevier-Denoix N, Audigié F, Emond AL, Dupays AG, Pourcelot P, Desquilbet L, Chateau H, Denoix JM.OBJECTIVE To evaluate the effect of track surface firmness on the development of musculoskeletal injuries in French Trotters during 4 months of race training. ANIMALS 12 healthy 3-year-old French Trotters. PROCEDURES Horses were paired on the basis of sex and body mass. Horses within each pair were randomly assigned to either a hard-track or soft-track group. The counterclockwise training protocol was the same for both groups. Surface firmness of each track was monitored throughout the training period. Radiography, ultrasonography, MRI, and scintigraphy were performed on all 4 limbs of each ho...
Rosanowski SM, Chang YM, Stirk AJ, Verheyen KLP.The incidence of race-day injuries in Great Britain (GB) is higher on all-weather (AW) surfaces than on turf. However, to date no studies have focused on identifying risk factors for injury specific to AW racing. Therefore, the objective of the current study was to determine risk factors for fatality, distal limb fracture (DLF) and episodes of epistaxis in flat racing Thoroughbreds racing on AW surfaces in GB. Data included all flat racing starts on AW surfaces (n=258,193) and race-day veterinary events recorded between 2000 and 2013. Information on additional course-level variables was gather...
Miyakoshi D, Senba H, Shikichi M, Maeda M, Shibata R, Misumi K.This study aimed to evaluate whether radiographic abnormalities at yearling sales were associated with the failure to start racing at 2-3 years of age. Radiographic abnormalities in the carpal (n=852), tarsal (n=976), metacarpophalangeal (n=1,055), and metatarsophalangeal joints (n=1,031) from 1,082 horses, recorded at yearling sale, were reviewed. Eighty-two horses (7.6%) failed to start racing. Radiographic abnormalities such as wedged or collapsed tarsal bones, irregular lucency of a sagittal ridge at the distal aspect of the distal third metatarsal bone, and proximal dorsal fragmentation o...
Wylie CE, Newton JR.Racing performance is often used as a measurable outcome variable in research studies investigating clinical diagnoses or interventions. However, the use of many different performance measures largely precludes conduct of meaningful comparative studies and, to date, those being used have not been collated. Objective: To systematically review the veterinary scientific literature for the use of racing performance as a measurable outcome variable in clinical studies of racehorses, collate and identify those most popular, and identify their advantages and disadvantages. Methods: Systematic literat...
Bani Hassan E, Mirams M, Mackie EJ, Whitton RC.To investigate the prevalence of microscopic subchondral bone injury in the distal metacarpi/tarsi of Thoroughbred racehorses and associations with recent and cumulative training history. Methods: Metacarpi/metatarsi were obtained from postmortem examination of Thoroughbred racehorses. The severity of palmar/plantar osteochondral disease (POD) was graded in forelimbs from 38 horses and in hindlimbs from a separate cohort of 45 horses. Forelimb samples were embedded in methyl methacrylate and examined using backscattered scanning electron microscopy. Microfracture density in the condylar subcho...
Williamson AJ, Sims NA, Thomas CDL, Lee PVS, Stevenson MA, Whitton RC.Palmar/plantar osteochondral disease (POD) and third metacarpal/-tarsal condylar fractures are considered fatigue injuries of subchondral bone (SCB) and calcified cartilage due to repetitive high loads in racehorses. In combination with adaptive changes in SCB in response to race training, the accumulation of SCB fatigue is likely to result in changes of joint surface mechanical properties. Objective: To determine the spatial relationship and correlation of calcified articular surface biomechanical properties with SCB microstructure and training history in the distal palmar metacarpal condyle ...
Mizobe F, Nomura M, Kato T, Nambo Y, Yamada K.Problems associated with the proximal metacarpal region, such as an osseous injury associated with tearing of Sharpey's fibers or an avulsion fracture of the origin of the suspensory ligament (OISL), are important causes of lameness in racehorses. In the present study, four Thoroughbred racehorses (age range, 2-4 years) were diagnosed as having forelimb OISL and assessed over time by using standing magnetic resonance imaging (sMRI). At the first sMRI examination, all horses had 3 characteristic findings, including low signal intensity within the trabecular bone of the third metacarpus on T1-we...
Sprayberry KA, Slovis NM.Pericarditis is a sporadic, but important cause of critical illness in horses of all ages. There is limited information on whether Thoroughbred horses that survive pericarditis are able to reach athletic potential. Objective: To determine how pericarditis affected horses that had the disease as young animals with regard to selling price in public sales and the ability to race successfully. Methods: Retrospective case series. Methods: Medical records were searched to identify pericarditis cases. Signalment and month of diagnosis were noted and Thoroughbreds with ultrasonographically confirmed p...
Davison JA, Lumsden JM, Boston RC, Ahern BJ.To review a large number of equine overground endoscopy (OGE) examinations to determine the incidence of dynamic upper airway obstructions (DUAO); correlations were explored with laryngeal endoscopy findings at rest and abnormal exercising respiratory noise. Methods: Retrospective analysis of horses presenting for OGE because of perceived poor performance and/or history of abnormal exercising respiratory noise between 2010 and 2014. Signalment, history and examination findings during resting laryngeal endoscopy and OGE were reviewed. Results: Of the total examinations, 311 were reviewed. One o...
Wright IM, Minshall GJ.Chip fractures of the dorsoproximal articular margin of the proximal phalanx are common injuries in racehorses. Large fractures can extend distal to the joint capsule insertion and have been described as dorsal frontal fractures. Objective: To report the location and morphology of short frontal plane fractures involving the dorsoproximal articular surface of the proximal phalanx and describe a technique for repair under arthroscopic and radiographic guidance. Methods: Single centre retrospective case study. Methods: Case records of horses with frontal plane fractures restricted to the dorsopro...
Takahashi Y, Takahashi T.Domesticated horses adapt to environmental conditions through seasonal fluctuations in their metabolic rate. The seasonal change of metabolic rates of domesticated horses in pastures is documented. However, there are few investigations on seasonal body weight change of domesticated horses housed in stables, which are provided constant energy intake throughout the year. Both seasonal changes and gain in body weight of racehorses during their athletic career is known to a lesser extent because their body weight are not measured in most countries. Here, we used a seasonal-trend decomposition meth...
Bolwell C, Rogers C, Gee E, McIlwraith W.The objective of the study was to determine the incidence of veterinary events that resulted in a horse failing to finish a race and identify risk factors for musculoskeletal injury (MSI) during a race. Data were obtained on Thoroughbred flat race starts in New Zealand between 1 August 2005 and 31 July 2011 (six racing seasons). Stipendiary Steward's reports were key-word searched to identify veterinary events that prevented a horse from finishing a race. Race data were used calculate the incidence of veterinary events per 1000 horse starts and Poisson regression was used to investigate risk f...
Pinilla MJ, Tranquille CA, Blunden AS, Chang YM, Parkin TDH, Murray RC.A detailed histopathological study of the distal third metacarpal bone of Thoroughbred racehorses was undertaken to characterize lesions observed previously on magnetic resonance imaging (MRI). The bones were selected and grouped on the basis of MRI features. Representative sections in different planes were processed for histopathology. All lesions observed in the articular cartilage (AC) and subchondral bone (SCB) were recorded and graded with a scoring system, based partially on the Osteoarthritis Research Society International grading system. The scoring system included the severity of the ...
Gunson DE, Sweeney CR, Soma LR.Pathologic changes are described in 11 horses that died during racing or training; 9 died of acute pulmonary hemorrhage (exercise-induced pulmonary hemorrhage), 1 died of exsanguination, and 1 died of CNS trauma. Cardiac lesions were not found in any horse. Severe engorgement of pulmonary vessels, with hemorrhage into alveoli, airways, interstitium, and subpleural tissues, was observed in all 9 horses that died of exercise-induced pulmonary hemorrhage. Infiltration of eosinophils and/or lymphocytes around vessels and airways was seen in 6 horses. Focally extensive fibrosis was observed in the ...
Bolwell CF, Rogers CW, Benschop J, Collins-Emerson JM, Adams B, Scarfe KR, Gee EK.A cross-sectional survey was conducted to determine the seroprevalence of in a cohort of horses and to evaluate potential risk factors for seropositivity in horses in New Zealand. The convenience sample included 499 Thoroughbred racing and breeding horses from 25 commercial properties in North Island, New Zealand. A questionnaire was used to collect demographic data on horses and property-level information on grazing and management practices, pest (rodent) management, access to natural waterways, other livestock on the property, and possible contact with wildlife. The microscopic agglutinati...
Rose RJ, Hendrickson DK, Knight PK.To evaluate normal cardiorespiratory and metabolic responses of Thoroughbred horses to a standardised treadmill exercise test, we examined 28 horses ranging in age from 1 to 4 years. The group consisted of eight yearlings, eight 2-year-olds and twelve 3 and 4-year-olds. All horses except the yearlings were in training, and either racing or ready to race, at the time of examination. None of the horses had histories of performance problems. On the first day the horses received a full physical examination, resting electrocardiogram, upper respiratory tract endoscopy and either one or two acclimat...
Bohák Z, Harnos A, Joó K, Szenci O, Kovács L.It is generally accepted that besides cortisol concentrations, parameters of heart rate variability (HRV) are appropriate indicators of stress in horses. The aim of this study was to determine anticipatory stress in eight Standardbred stallions participating in harness race. Cortisol and HRV responses to a mild exercise performed in training circumstances were compared to a maximal effort exercise performed in real trotting race conditions. Parameters of HRV reflecting vagal (root mean square of the successive differences, RMSSD) and sympathetic nervous system activity (ratio of the low and hi...
Marr CM, Franklin S, Garrod G, Wylie C, Smith L, Dukes-McEwan J, Bright J, Allen K.Exercise-associated cardiac rhythm disturbances are common, but there is a lack of evidence-based criteria on which to distinguish clinically relevant rhythm disturbances from those that are not. Objective: To describe and characterise rhythm disturbances during clinical exercise testing; to explore potential risk factors for these rhythm disturbances and to determine whether they influenced future racing. Methods: Retrospective cohort using a convenience sample. Methods: Medical records were reviewed from two clinical services to identify horses with poor performance and/or respiratory noise ...
Whitton RC, Mirams M, Mackie EJ, Anderson GA, Seeman E.Bone remodelling is inhibited by high repetitive loading. However, in subchondral bone of racehorses in training, eroded surface doubled in association with fatigue fracture and there was greater surrounding trabecular bone volume suggesting trabecular modelling unloads the bone focally, allowing damage repair by remodelling. Background: Remodelling replaces damaged bone with new bone but is suppressed during high magnitude repetitive loading when damage is most likely. However, in cortical bone of racehorses, at sites of fatigue fracture, focal porosity, consistent with remodelling, is observ...
Palmer JL, Bertone AL, Litsky AS.Changes in contact area and pressure distribution with loading were evaluated on the proximal articulating surface of the equine third carpal bone using safranin-O dye staining and pressure sensitive film techniques. A significant increase in percentage contact area resulted as the applied load was increased from 3115 to 9000 N (54.93% +/- 7.99 vs 61.43% +/- 7.37 respectively, P = 0.016). The area in contact shifted towards the dorsal aspect of both the radial and intermediate facets of the third carpal bone. Changes were also detected in the mean pressure under the same loading conditions. Th...
Bolwell CF, Rogers CW, French NP, Firth EC.To quantify the time from the start of training to the first interruption and to identify horse and training risk factors for voluntary interruptions and interruptions due to musculoskeletal injury occurring before the first trial. Methods: A prospective cohort study was used to collect data on the training activity of 2-year-old racehorses, from 14 trainers in the Northern and Central Districts of New Zealand, over two racing seasons (2008/09 and 2009/10). Daily training data were recorded for each horse, including, distances worked at canter (>15 seconds/200 m), three measures of high-spe...
Cully P, Nielsen B, Lancaster B, Martin J, McGreevy P.Laterality can be observed as side biases in locomotory behaviour which, in the horse, manifest inter alia as forelimb preferences, most notably in the gallop. The current study investigated possible leading-leg preferences at the population and individual level in Thoroughbred racehorses (n = 2095) making halt-to-gallop transitions. Videos of flat races in the UK (n = 350) were studied to record, for each horse, the lead-leg preference of the initial stride into gallop from the starting stalls. Races from clockwise (C) and anti-clockwise (AC) tracks were chosen alternately at random to ensure...
Turner M, Balendra G, McCrory P.To determine the direct and indirect cost of injuries in professional jockeys as a result of race riding. Methods: Cohort study. Methods: Professional horse racing. Methods: Professional jockeys in the UK registered with the Jockey Club. Methods: Payouts under the Professional Riders Insurance Scheme (PRIS) for injuries sustained by professional jockeys, which were recorded by the Jockey Club injury database between 1996 and 2006 inclusive. Results: In the 11-year period of the study, there were 1328 injuries that resulted in jockeys missing a total of 71,509 days of racing, and as a result PR...
Tozaki T, Miyake T, Kakoi H, Gawahara H, Hirota K, Nakano Y, Kurosawa M.This study evaluated the differences between linear and non-linear modelled heritability estimates of racing performance based on lifetime earnings (LE) and lifetime ranking (LR) in Japanese Thoroughbred racehorses. The heritability estimate (h(2) = 0.25) obtained from a non-linear model based on formal Japan Racing Association ranking was much higher than that obtained from a linear model based on the original trait phenotype (h(2) = 0.11). The linear models showed slightly higher heritability estimates under the trait categorizations than under the original phenotypes, while the non-linear c...
Crispe EJ, Secombe CJ, Perera DI, Manderson AA, Turlach BA, Lester GD.Exercise-induced pulmonary haemorrhage (EIPH) is considered a progressive disease based on histopathology, but it is unknown if tracheobronchoscopic EIPH severity worsens over time. Objective: The aim of this study was to examine tracheobronchoscopic EIPH changes over time in a population of Thoroughbred racehorses. A secondary aim was to identify factors that affect changes in tracheobronchoscopic EIPH severity between observations. Methods: Prospective, longitudinal, observational cross-sectional study. Methods: Thoroughbred racehorses were examined with tracheobronchoscopy no earlier than 3...
Grøndahl AM, Engeland A.The tarsocrural, metacarpophalangeal, and metatarsophalangeal joints of 753 Standardbred yearlings were radiographed. On the basis of radiographic findings, the horses were allotted into 4 groups. Group-1 horses had osteochondrosis in the tarsocrural joints. Group-2 horses had palmar/plantar bony fragments in the metacarpo- and metatarsophalangeal joints. Group-3 horses had radiographic changes in the metacarpo- and metatarsophalangeal joint region, such as bony fragments located at the dorsoproximal end of the proximal phalanx, osteochondrosis of the sagittal ridge of the third metacarpus/met...
Ho EN, Chan GH, Wan TS, Curl P, Riggs CM, Hurley MJ, Sykes D.Cobalt is a well-established inducer of hypoxia-like responses, which can cause gene modulation at the hypoxia inducible factor pathway to induce erythropoietin transcription. Cobalt salts are orally active, inexpensive, and easily accessible. It is an attractive blood doping agent for enhancing aerobic performance. Indeed, recent intelligence and investigations have confirmed cobalt was being abused in equine sports. In this paper, population surveys of total cobalt in raceday samples were conducted using inductively coupled plasma mass spectrometry (ICP-MS). Urinary threshold of 75 ng/mL a...
Lee W, Park KD, Taye M, Lee C, Kim H, Lee HK, Shin D.This study was intended to identify genes positively selected in Thoroughbred horses (THBs) that potentially contribute to their running performances. Methods: The genomes of THB and Jeju horses (JH, Korean native horse) were compared to identify genes positively selected in THB. We performed cross-population extended haplotype homozygosity (XP-EHH) and cross-population composite likelihood ratio test (XP-CLR) statistical methods for our analysis using whole genome resequencing data of 14 THB and 6 JH. Results: We identified 98 (XP-EHH) and 200 (XP-CLR) genes that are under positive selection ...
Begg LM, Hoffmann KL, Begg AP.Cardiac troponin I is a potentially useful test to identify cardiac muscle damage in the horse. Measurements of cardiac troponin I from serum or heparinised plasma samples from 23 clinically normal Thoroughbred horses in race training were analysed through a standard Australian commercial laboratory using the ADVIA Centaur Assay. The cardiac troponin I concentrations were < 0.15 microg/L from all samples. The test was then validated using macerated equine myocardium. Cardiac troponin I concentration may be useful in determining whether poor performance in Thoroughbred horses is related to a...
Gim JA, Ayarpadikannan S, Eo J, Kwon YJ, Choi Y, Lee HK, Park KD, Yang YM, Cho BW, Kim HS.Physical exercise induces gene expression changes that trigger glucose metabolism pathways in organisms. In the present study, we monitored the expression levels of LDHA (lactate dehydrogenase) and GYS1 (glycogen synthase 1) in the blood, to confirm the roles of these genes in exercise physiology. LDHA and GYS1 are related to glucose metabolism and fatigue recovery, and these processes could elicit economically important traits in racehorses. We collected blood samples from three retired thoroughbred racehorses, pre-exercise and immediately after 30 min of exercise. We extracted total RNA and ...
Kraus M, Physick-Sheard PW, Brito LF, Schenkel FS.The number of Standardbred racehorses admitted to the Ontario Veterinary College Teaching Hospital (Guelph, Canada) for treatment of atrial fibrillation (AF) has been on the rise since the early 1990s. A small number of sires have been contributing to a large proportion of cases, indicating there may be a genetic predisposition to the arrhythmia in this breed. Objective: The objectives of this study were to determine the heritability of AF in Standardbred horses and whether heritability of the arrhythmia differs across gaits and/or sexes. Methods: Heritability study based on retrospective revi...
Paltrinieri S, Meazza C, Giordano A, Tunesi C.Thromboelastometry is used for identifying or monitoring coagulation abnormalities. It has been validated in several species but not in horses and the characteristics of the equine thromboelastogram have not yet been detailed. Objective: The purpose of this study was to validate a thromboelastometer to be used with equine blood and to define the normal equine thromboelastogram. Methods: A Rotem-gamma thromboelastometer (Pentapharm GmbH, Munich, Germany) was used on 38 citrated blood samples to investigate native coagulation, the intrinsic and extrinsic pathways, the function of fibrinogen (lar...
Gelberg HB, Zachary JF, Everitt JI, Jensen RC, Smetzer DL.We reviewed case records, necropsy reports, and histologic sections from 25 Thoroughbred racehorses that died suddenly at 3 Chicago racetracks. These were young horses ranging in age from 2 to 5 years. There were more females (n = 16) than males (n = 9), and the incidence of death increased slightly in the spring and summer. Twenty-one of the 25 horses died while racing or training. Only 8 of the 25 horses (32%) had lesions sufficient to account for the death. In 6 of those 8 cases, death was caused by massive thoracic or abdominal hemorrhage. The site or nature of the vascular defect in these...
Lam KK, Parkin TD, Riggs CM, Morgan KL.To identify the risk factors for premature retirement because of tendon injury in a Thoroughbred racehorse population. Methods: 175 Thoroughbred racehorses (cases) at the Hong Kong Jockey Club that were retired from racing because of tendon injury between 1997 and 2004 and for which the last preretirement exercise was at a fast pace were each matched with 3 control horses that were randomly selected from all uninjured horses that had galloped on the same date as that last exercise episode. Methods: Training data for all horses were examined. Conditional logistic regression analyses were perfor...
Barker SA.Beginning in 2004, the horseracing industry experienced an epidemic of drug positives for the amphetamine-like drug aminorex. Investigation of the therapeutic treatment of the horses called positive for this drug suggested that its source was from the administration of the anthelmintic levamisole. This study examines the urine concentrations of aminorex as a function of time following administration of synthetic, racemic aminorex. Confirmation of the presence of aminorex in urine samples from the horses known to be treated with levamisole is also presented as are data concerning the concentrat...
van den Hoven R, Gür E, Schlamanig M, Hofer M, Onmaz AC, Steinborn R.A single nucleotide polymorphism (SNP) in the first intron of the myostatin gene (MSTN) is associated with aptness of elite Thoroughbreds to race over sprint, middle or long distances. This intronic marker (g.66493737 T ≻ C), a short interspersed nuclear element (SINE) of 227 bp (Ins227bp) insertion polymorphism in the MSTN promoter, and the adjacent SNP BIEC2-417495 have not been studied for their association with racing aptness of the average Thoroughbreds raced in countries with lower status of the racing industry. This study investigated these markers regarding their prevalence and assoc...
Meredith K, Bolwell CF, Rogers CW, Gee EK.To obtain data on the use of allied health therapy within competitive equestrian sport in the North Island of New Zealand. Methods: Data were collected during January 2010 by survey at show jumping and dressage championships in the North Island, and from racing yards in the Central Districts of New Zealand. The survey consisted of 30 open, closed and multiple-choice questions, and was conducted face-to-face, by the same interviewer. Information on the demographics of riders or trainers and horses in each discipline (show jumping, dressage, and Thoroughbred racing), the use of allied health the...
Freeman DE, Donawick WJ.An intravascular procedure was used to occlude the internal carotid artery of two horses with epistaxis caused by guttural pouch mycosis. In each horse, the affected internal carotid artery was ligated close to its origin. A balloon-tipped catheter was introduced into the artery distal to the ligature, and its tip was advanced beyond the site of infection. The balloon was then inflated so that the infected segment of artery was isolated from the cerebral vascular system. The catheters were removed at 14 and 51 days, and both horses were returned to training and racing. Neither horse had furthe...
Takahashi T, Hiraga A, Ohmura H, Kai M, Jones JH.To determine the frequency of epistaxis during or after racing among racehorses and identify factors associated with development of epistaxis. Methods: Retrospective study. Methods: 247,564 Thoroughbred and 4,045 Anglo-Arab race starts. Methods: Race start information (breed, age, sex, racing distance, and race type) was obtained for Thoroughbred and Anglo-Arab horses racing in Japan Racing Association-sanctioned races between 1992 and 1997. All horses that raced were examined by a veterinarian within 30 minutes of the conclusion of the race; any horse that had blood at the nostrils was examin...
Fonseca RG, Kenny DA, Hill EW, Katz LM.Few noninvasive measures associated with performance assessment are available for racehorse trainers. Evaluation of body composition of superior human sprinters has revealed a lower fat mass (FM), percentage (%) fat and greater fat-free mass (FFM), but to date there have been few studies evaluating this in racehorses. Objective: To determine the effects of age, gender and training on body composition and the relationship between body composition, physiological measurements and performance in Thoroughbred racehorses. Methods: At 2, 5 and 8 months of training, rump fat thickness (RFT) was ultras...
Bailey CJ, Reid SW, Hodgson DR, Rose RJ.To determine whether sex or foaling period were associated with time to first race start and whether sex, age at time of first race start, or inter-race period were associated with career duration for Thoroughbred racehorses in Australia. Methods: 553 Thoroughbred racehorses. Methods: Race records through to the end of the 6-year-old racing season were obtained for each horse. Product-limit survival analysis was used to determine whether sex or foaling period was associated with time to first race start and whether sex or age at first race was associated with career duration. A Cox proportiona...
Garrett KS, Pierce SW, Embertson RM, Stromberg AJ.OBJECTIVE-To determine the association between results of endoscopic evaluation of arytenoid function (AF) and epiglottic structure (ES) in Thoroughbred yearlings and racing performance at 2 to 4 years of age. DESIGN-Retrospective case series. ANIMALS-2,954 Thoroughbred yearlings. Procedures-Records of yearlings that had endoscopic evaluation of the larynx between 1998 and 2001 were obtained, and results were graded by use of standardized scales. A modified Havemeyer scale (grade I, II.1, II.2, III, or IV) was used to evaluate AF; ES was graded on a scale of 0 to IV. Records were annotated if ...
Pereira GL, Malheiros JM, Ospina AMT, Chardulo LAL, Curi RA.Among horses selected for speed, the racing line of Quarter Horses is characterized by high performance in sprint races, with these animals being considered the fastest horses in the world. However, few studies have investigated in more detail the polymorphisms and genes that act on this trait. The objective of this study was to analyze exomes and UTRs in regions previously associated with this trait by GWAS in Quarter Horse racehorses with contrasting maximum speed index (SImax), prospecting causal gene polymorphisms that are related to or are in strong linkage disequilibrium with racing perf...
