Racehorses are a distinct category of horses bred and trained for competitive racing events, characterized by their speed, agility, and stamina. These horses are primarily Thoroughbreds, Standardbreds, or Quarter Horses, each with specific attributes suited to different types of racing. The physiology and management of racehorses focus on optimizing performance through training, nutrition, and veterinary care. Research in this area often explores aspects such as biomechanics, cardiovascular health, and injury prevention. This page gathers peer-reviewed research studies and scholarly articles that investigate the physiology, training methodologies, and health management practices associated with racehorses, providing insights into the factors influencing their performance and welfare.
Kamada M, Ando Y, Fukunaga Y, Kumanomido T, Imagawa H, Wada R, Akiyama Y.A primary enzootic of equine Getah virus infection involving 722 of 1,903 racehorses occurred at a training center in Japan between September and November of 1978. Sixty-two viral agents were isolated from the plasma of 209 sick horses which exhibited pyrexia with rectal temperatures ranging from 38.5--40 degrees C, urticarial rash on various portions of the body, and edema of the hind legs. The viruses were antigenically related to the AMM 2021, Haruna, and Sagiyama strains of Getah virus. Infection and disease were produced experimentally in horses when inoculated by the intramuscular or int...
Goodship AE, Brown PN, Yeats JJ, Jenkins DH, Silver IA.The results of an assessment of carbon fibre for biological use are given, with particular reference to the clinical use of the material in the treatment of equine tendon injury. Biocompatability of the fibres is assessed using fibroblast cell cultures and replacement of normal tendon with carbon fibre prostheses in experimental animals. The rationale and technique for using this material in clinical cases of tendon injury in the racehorse are described. Results are given from 62 implant operations in a limited series of 40 horses.
Webbon PM.Skin temperature measurements were recorded of the legs of 13 racehorses between 2 and 5 years old. The normal limb temperature patterns are described. In over 90 per cent of the normal horses the difference between contralateral limbs was less than 1 degree C, but in the remainder differences of up to 8 degree C were recorded due to the excessive cooling of one limb. One horse had a constant temperature elevation of one foreleg, but it remained in training for 7 weeks without any obvious ill effects. Because of the small numbers of horses in the survey and their freedom from tendon injuries i...
Pratt GW, O'Connor JT.A biomechanical model of running has been presented. A basic premise has been that the swing time is nearly independent of speed. In fact, both the racehorse and the trotter have nearly equal swing times. Consequently, as speed increases and the stance phase becomes shorter, the horse must compensate by increasing his extension or the length of the airborne phase (or both). The safe speed which allows the horse adequate preparation time for contact of a leg with the ground is calculated, using a stride-by-stride analysis of the motion of the horse. This is seen to be a very sensitive function ...
Strömberg B, Tufvesson G.Four autologous tendon grafting techniques, bipedicle, pedicle and free grafts of the deep digital flexor tendon and free grafts from the lateral digital extensor tendon were described. The vascularization and remodelling of the transplant and the reactions in the donor, as well as the recipient tendon, were studied by means of microangiographic and histochemical methods. The results indicated that regardless of the technique used the grafts were revascularized and replaced by a highly orientated and organized tendon. The use of free grafts may therefore be worthwhile in treatment of severe te...
Pfaff G.In South Africa 2,41% of horses bleed in a race. If all raced until they were 7 years old probably another 2,12% would bleed. Many others bleed after the race or during exercise or at rest. The incidence of epistaxis is significantly greater in geldings than in females and uncastrated males (P less than 0,001). There is an age distribution of bleeding which is highest at 4 years and lowest at 2 years of age (P less than 0,001).
Johnson JH, Garner HE, Hutcheson DP.Indirect systolic and diastolic arterial pressure measurements of 456 Thoroughbred horses of various ages and sex stabled at 9 different race tracks were measured with an ultrasonic-Doppler device interfaced with a sphygmomanometer cuff. The mean systolic pressure was 111.8 +/- 13.3 mmHg and the mean diastolic pressure was 69.6 +/- 13.8 mmHg in this population.
Asheim A, Lindblad G.Forty-five race-horses with arthritis of non-in-fectious type in 54 joints were treated with sodium hyaluronate intra-articularly. All joints had previously been treated without lasting success by conventional methods, such as firing, blistering or intraarticular injection of cortisone. In most cases only 1 injection of 2 ml (20 mg) sodium hyaluronate was needed. To avoid subjective evaluation, the effects of the treatment were based on the joint’s capacity of withstanding extreme stress, which means that the horse should be able to train and race again. The treatment was concentrated on the...
Strömberg B.Thermography in veterinary medicine has hitherto been proven to be a method of great value in the detection of orthopaedic lesions in racehorses. Lesions of the musculo-skeletal system affecting tendons, joints, bones and skeletal muscle can be demonstrated and documented at an early stage thereby preventing the development of more serious lesions.
Robinson RC.Most practitioners will have experienced the
frustration encountered in the treatment of sprains
of the flexor tendons and suspensory ligaments
of racehorses. After apparent recovery, the
damaged structure will often break down again
when the horse returns to hard training. Milne
(1960), Reed (1962), Jubb and Kennedy (1963)
and Hickman (1964) have written detailed ac-
counts of the pathology of tendon injuries and the
mechanism of repair of tendon tissue. These
writers substantiate that when a tendon is
sprained, there is a tearing or rupture of some of
the tendon fibres, varying i...
Charlton C, Tulleners E.Two male racehorses (1 Standardbred, 1 Thoroughbred) were examined because of intraluminal cervical tracheal lesions, located 60 to 70 cm from the nares. A contact neodymium:yttrium aluminum garnet laser with a chisel probe attached to the fiber end was used to transendoscopically debride a nonhealing tracheal ulcer and to excise a pyogranulomatous mass. In both horses, the surgical sites healed quickly and the lesions did not redevelop.
Morlock M, Nassutt R, Bonin V.INTRODUCTION:: Cohesive bandages are applied to the legs of racehorses and horses with limb injuries for protection (prevention of abrasion) and support (reduction of movement at the fetlock joint). The support capacity of all commercially available bandages has been questioned. Consequently, the protection aspect of bandaging and the negative side effects, which can be caused by bandaging (eg pressure induced ischemia with subsequent necrosis), were emphasized. High pressures underneath bandages were shown to cause reduced blood flow. Pressures underneath certain types of bandages were shown ...
Harkins JD, Tobin T.Fentanyl and other opioid drugs have their effect in the central nervous system; however, activity at peripheral sites has also been demonstrated. Pain-suppression activity at peripheral sites raises the possibility of skilled individuals producing local anaesthetic effects with small doses of opioid drugs that would be difficult to detect forensically and could be used to affect the outcome of a race. Therefore, the local pain-suppression effect (peripheral nerve inhibition) of fentanyl was tested using an abaxial sesamoid block/hoof withdrawal model. With this model, fentanyl did not produce...
Fousse SL, Stern JA.There have been some advances in understanding the genetic contribution to ventricular septal defects in Arabians, sudden death in racehorses, and atrial fibrillation in racehorses. No genetic analyses have been published for aortic rupture in Friesians or atrioventricular block in donkeys despite strong evidence for a genetic cause. To date, no genetic mutation has been identified for any equid cardiac disease. With the advancement of genetic tools and resources, we are moving closer to discoveries that may explain the heritable basis of inherited equid cardiac disease.
Oda D, Onogi A.The inheritance of racing performance in Thoroughbreds is of interest to breeders and geneticists. Therefore, the genetic parameters of racing performance have been investigated in various populations of Thoroughbreds. However, the predictability of the racing performance of a racehorse has not been assessed well. In this study, we built mixed-effects models for Japanese Thoroughbreds and assessed their predictability of racing performance. We used the average velocity as an index of racing performance and treated each category of racecourse and distance as different traits. Model selection us...
Dyke TM, Sams RA.The objective of this study was to determine the urinary excretion of methylxanthines in horses following ingestion of chocolate over eight days. The study was performed in response to gas chromatography-mass spectrometry (GC-MS) confirmation of the presence of caffeine in a positive urine test in a racehorse. The trainer of the horse alleged that he often administered chocolate-coated peanuts as treats to his horses, and he believed that the ingestion of chocolate was responsible for the positive urine test. The urinary excretion of theobromine and caffeine after the ingestion of chocolate-co...
Benoit M, Lingen K, Taddei LM, Heffron BT, Hurt L, Lokanc JA, Lingner K, Cardenas E, Flores S, Mayer D, Pilipiak D, Folker-Calderon D, Negrusz A.Pyrilamine (mepyramine) is an H1-receptor antagonist used in human and veterinary medicine. It has the potential to produce central nervous system effects in horses and therefore may have some impact on an outcome of a horse race. A single oral dose of pyrilamine (300 mg/horse) was given to three animals. Serum samples were collected before drug administration and at 0.25, 0.5, 1, 2, 4, 6, 24, 48, 72, 96, 120, and 144 h, and 7, 8, 9, 10, 11, 12, and 13 days post-administration. Urine samples were collected at 0-1, 1-2, 2-4, 4-6, 24, 48, 72, 96, 120, and 144 h, and 7, 8, 9, 10, 11, 12, 13 days ...
Chassain AP, Dauriac E, Blanc P, Antonini MT, Nicolas A, Villeneuve P, Marquet P, Dalmay F, Valade M.Five steeplechase race horses were observed during incremental and constant-load exercises with the aim of separating effects of work rate and time on blood lactate. Each independent exercise (an incremental and three constant load tests) was a sequence of three two-minute runs, separated by two one-minute rest intervals for jugular blood sampling. The following observations were made: 1. During constant load exercises, in the five horses, blood lactate stabilized below 4 mmol.l-1: lactatemia critical velocity (LVC) = 3.33 +/- 0.16 mmol.l-1. Nevertheless, VCL, critical lactate velocity inducin...
McIlwraith CW.The article discusses the key findings and discussions from the fifth Welfare and Safety of the Racehorse Summit. This summit presented several ways in which data collection and analysis can […]
Terlinden A, Szymkowiak M, Jonville E, Hatrisse C, De Azevedo E, Coudry V, Denoix JM, Pilot-Storck F, Desquilbet L, Bertoni L.Evaluate the short-term effects of acupuncture on the dynamic manifestations of axial stiffness in steeplechase racehorses. 12 steeplechase racehorses presenting signs of axial stiffness during training. Horses were randomly assigned to either an acupuncture treatment by an experienced certified acupuncturist (n = 6) or no treatment as negative controls (6). The horses' locomotion was evaluated during training before treatment (D0) and 7 (D7) and 14 (D14) days after by their rider and trainer through a questionnaire. Additionally, the improvement of their dorsal flexibility 2 days after treatm...
Knych HK, Katzman S, McKemie DS, Arthur RM, Blea J.Lidocaine is a local anesthetic that is sometimes administered in combination with epinephrine. The addition of epinephrine increases the time lidocaine remains at the site of administration, thus prolonging the duration of effect. Due to their potential to prevent the visual detection of lameness, the administration of local anesthetics is strictly regulated in performance and racehorses. Recent reports of positive regulatory findings for lidocaine in racehorses suggests a better understanding of the behavior of this drug is warranted. The objective of the current study was to describe serum ...
Virtanen J, Hautala K, Utriainen M, Dutra L, Eskola K, Airas N, Uusitalo R, Ahvenainen E, Smura T, Sironen T, Vapalahti O, Kant R, Virtala AK....Parapoxviruses (PPV) cause skin and mucous membrane lesions in several animal species, and of the five recognized PPVs, at least three are zoonotic. Equine PPV (EqPPV) is the sixth one initially described in humans in the United States and later in a severely sick horse in Finland in 2013-2015. In 2021-2022, a large-scale pustulo-vesicular pastern dermatitis outbreak occurred in horses all over Finland. This study aimed at analysing the outbreak, identifying and describing the causative agent, describing clinical signs, and searching for risk factors. EqPPV was identified as a probable causati...
Ratcliffe TOC, Robinson P, Rosanowski SM.To evaluate and compare the prognosis for Thoroughbred racehorses to return to galloping and racing with injuries to the palmaroproximal metacarpus diagnosed with MRI. Methods: 29 flat racing Thoroughbreds at the Hong Kong Jockey Club that underwent MRI between 2014 and 2022. Methods: Clinical, radiographic, ultrasonographic, and MRI reports were collected from veterinary clinical records, and these were combined with training and racing data. Horses were categorized on the basis of MRI diagnosis: (1) proximal suspensory ligament (PSL) involvement only, (2) PSL and concurrent proximal third me...
Wilcox CV, Knych HK, Katzman SA, Arthur RM, Rodriguez V, Finno CJ.There are two FDA-approved bisphosphonate products, clodronate (Osphos®) and tiludronate (Tildren®), for use in horses. It is hypothesized that bisphosphonates can produce analgesic effects and prevent proper healing of microcracks in bone. Therefore, bisphosphonate use is banned in racehorses. However, bisphosphonates have a short detection window in the blood before sequestration in the skeleton, making the reliability of current drug tests questionable. Seven exercising Thoroughbred horses were administered clodronate (1.8 mg/kg i.m.), and four were administered saline. RNA was isolated...
Wall KE, Prestel AL, de Oliveira BIC, Darós R, de Freitas Santi T, Michelotto PV.In the present study we aimed to investigate superficial skin temperature of racehorses' distal limbs after training in a racetrack. Male and female Thoroughbred racehorses were investigated in summer, after light training, and in the winter, after light and intense training. Horses were exercised (Exercise group, EG) under trainers' protocol while others were maintained inside their stalls (Control group, CG). Thermographic images were obtained from the front (fetlock, cannon, and carpus) and hindlimbs (fetlock, cannon, and tarsus), before exercise and 45, 60, 120 and 180 min after exercisin...
Kowalik S, O'reilly M, Niedźwiedź A, Kędzierski W.(1) Background: The number of horses suffering from chronic respiratory diseases, resembling human asthma, is increasing but there is still a lack of reliable and accurate methods to detect these disorders. Numerous studies have found elevated plasma concentrations of one of the myokines, namely, myostatin (MSTN), in people suffering from severe asthma. MSTN normally inhibits myoblast proliferation and differentiation through autocrine or paracrine signals. Therefore, given the pathogenesis of asthma, we hypothesize that MSTN could be a useful biomarker of equine asthma. Thus, this study aimed...
Knych HK, Weiner D, McKemie DS, Traynham M, Blea J.Butorphanol is commonly administered, both by the intravenous and intramuscular routes, to racehorses to facilitate handling for diagnostic procedures. As the administration of butorphanol for therapeutic purposes is considered appropriate, in order to avoid inadvertent positive drug tests, a thorough understanding of the pharmacokinetics of this drug is necessary. In the current study, 12, exercised Thoroughbred horses were administered a single intramuscular dose of 0.1 mg/kg butorphanol, and serum and urine samples were collected at various times post drug administration for determination...
Baldwin CM, Ireland JL, Barakzai SZ.There is no objective information reporting the effect of unilateral laser ventriculocordectomy (VeC) on arytenoid abduction or stability. Objective: To evaluate arytenoid stability and abduction in horses with severe recurrent laryngeal neuropathy (RLN) before and after unilateral laser VeC. Methods: Prospective cohort. Methods: Eight horses with grade C or D exercising laryngeal function that underwent unilateral laser VeC were included. Exercising endoscopy was performed before and ≥6 weeks after left-sided laser VeC. Arytenoid stability at maximal exercise was calculated by measuring t...
Hewitt-Dedman CL, Kershaw LE, Schwarz T, Del-Pozo J, Duncan J, Daniel CR, Cillán-García E, Pressanto MC, Taylor SE.Magnetic resonance spectroscopy (MRS) has been used to investigate metabolic changes within human bone. It may be possible to use MRS to investigate bone metabolism and fracture risk in the distal third metacarpal/tarsal bone (MC/MTIII) in racehorses. Objective: To determine the feasibility of using MRS as a quantitative imaging technique in equine bone by using the H spectra for the MC/MTIII to calculate fat content (FC). Methods: Observational cross-sectional study. Methods: Limbs from Thoroughbred racehorses were collected from horses that died or were subjected to euthanasia on racecourses...
Allen SE, Taylor S, Given J, Verheyen KL.The British horseracing industry is committed to reducing equine fatalities in jump racing. Race-related fatalities are a major welfare concern and threaten the sport's social licence to operate. Objective: To describe the risk of, and determine risk factors for, fatality in British jump racing. Methods: Retrospective cohort. Methods: Analyses included all starts made in British jump races between January 2010 and April 2023. Available information for each horse, race, racecourse, trainer and jockey was collated and combined with details of all fatalities recorded by official veterinary office...
Yildirim İG, Karaarslan S, Erkan A.Musculoskeletal injuries (MSI) are a major concern in the horse racing industry, often leading to career-ending outcomes. Contributing factors include conformation, limb and joint defects, hoof structure, age, and hard track surfaces. Objective: This study aimed to evaluate the distribution of MSI in Thoroughbred and Arabian racehorses during racing and training, categorised by breed and track surface. Methods: Retrospective cohort study. Methods: The data from 2018 to 2023 were collected at the Turkish Jockey Club's Şirinyer Hippodrome (38°23'03.7″ N 27°09'01.0″ E), covering 553 MSI ca...
Orozco Lopez D, Garcia-Lopez JM, Carpenter R, Bras JJ, Richardson DW, Ortved KF.To describe the outcome of metacarpophalangeal (MCPJ) and proximal interphalangeal joint (PIPJ) arthrodesis using a locking compression-distal femur plate (LCP-DFP) in Thoroughbred racehorses with traumatic disruption of the suspensory apparatus (TDSA) at risk of PIPJ subluxation. Methods: Multicenter retrospective study. Methods: Twenty-six Thoroughbred racehorses. Methods: Records of Thoroughbred racehorses with TDSA that had undergone MCPJ and PIPJ arthrodesis using an LCP-DFP at three referral hospitals between 2020 and 2024 were reviewed for inclusion. The preoperative data collected incl...
Bennet ED, Parkin TDH.The Equine Injury Database (EID) is a census-level record of Thoroughbred racing in North America, currently recording 95.6% of all race starts in 2023, along with partial training and veterinary histories of each horse. Objective: To identify horse-, race- and track-level risk factors associated with race-related fatal musculoskeletal injury (MSI) of Thoroughbred racehorses in North America. Methods: Retrospective cohort study. Methods: The study cohort included all race starts made by horses born after 31 December 2006, at tracks that fully report to the EID and consisted of 3,851,659 race s...
Annan R, Trigg L, Allen K, Hockenhull J, Valenchon M, Mullan S.Racehorse welfare continues to be a focus of stakeholders both within and outside of the industry, and there is a need for evidence-based animal welfare data. Objective: To gather data on racehorse welfare through a combination of animal-based observations and information about management practices, and to ascertain the feasibility of trained industry assessors carrying out a racehorse welfare assessment. Methods: Cross-sectional. Methods: Sixteen trained industry assessors conducted individual observations of 737 racehorses in 21 Flat racing (F), 27 National Hunt (NH) and 26 Dual-purpose (D) ...
Kodama S, Maeda T, Mita H, Tamura N, Chiba K, Matsukawa M.Despite the prevalence of lower limb disease in racehorses, outdoor bone evaluation equipment is lacking. Consequently, a secure and cost-effective field screening system for bones is required to identify early-stage leg illness. Elastic stiffness cannot be measured using x-ray techniques and is closely associated with bone quality, which is recognized as a significant determinant of fracture risk. Quantitative ultrasound has garnered attention as a viable option, offering insights into elastic stiffness. Understanding the characteristic behaviors of ultrasonic wave properties (velocity, atten...
Schild CO, Nyaoke A, Asin J, Henderson EE, Blea JA, Stover SM, Uzal FA.Radial fractures are relatively uncommon (0-1%) injuries in postmortem studies of racehorses, and few cases have been published. We describe here a series of 42 cases of radial fractures observed in California racehorses. Autopsy findings from all racehorses submitted for postmortem examination between 2006 July 1 and 2022 June 30 that had a recorded radial fracture were evaluated. We included 42 horses (30 Thoroughbreds, 12 Quarter Horses), most of which were 3-5-y-old. Catastrophic radial fracture was observed in 30 (71%) horses; in the remaining 12 (29%) horses, the fracture of the radius w...
Choi Y, Rosanowski SM, Parkin TD.To identify risk factors associated with complete humerus fractures in Thoroughbreds in South Korea. Unassigned: A retrospective case-control design with multivariable logistic regression was used. This study included 131 Thoroughbreds diagnosed with complete humerus fractures following racetrack activity between 2009 and 2022 (inclusive). Additionally, 660 healthy Thoroughbreds (699 observations) with at least 1 racetrack activity during the same period were included as controls. Unassigned: A total of 8 variables were associated with the risk of complete humerus fractures. Notably, horses wi...
Bozzola C, Sala G, Stancari G, Ferrucci F, Zucca E.Exercise-Induced Pulmonary Hemorrhage (EIPH) results from alveolar capillary stress failure after strenuous exercise, leading to bleeding and pulmonary inflammation. Bronchoalveolar lavage fluid (BALF) cytology is considered the gold standard for the assessment of airway inflammation; however, it is often considered more invasive compared to tracheal wash (TW). It has been demonstrated that TW is a reliable diagnostic tool that may substitute BALF to diagnose and grade the severity of EIPH in racehorses; however, no information about airway inflammation in EIPH-affected horses has been reporte...
Verna M, Amitrano FN, Boeder ZJ.To assess the clinical impact of the cricoarytenoideus dorsalis (CAD) myectomy in the short- and long-term postoperative abduction grade in racehorses. Unassigned: Records from horses presented for surgical treatment of recurrent laryngeal neuropathy from January 2019 through December 2023 were divided into 2 groups: horses that received standard prosthetic laryngoplasty and horses that received a complete myectomy of the CAD (modified myectomy laryngoplasty). Outcomes were compared through endoscopic evaluation after anesthetic recovery, both short term (7 to 10 days) and long term (80 to 90 ...
Pan M, Malekipour F, Pivonka P, Morrice-West AV, Flegg JA, Whitton RC, Hitchens PL.Fractures of the distal limb in Thoroughbred racehorses primarily occur because of accumulation of bone microdamage from high-intensity training. Mathematical models of subchondral bone adaptation of the third metacarpal lateral condyles are capable of approximating existing data for Thoroughbred racehorses in training or at rest. To improve upon previous models, we added a dynamic resorption rate and microdamage accumulation and repair processes. Our ordinary differential equation model simulates the coupled processes of bone adaptation and microdamage accumulation, and is calibrated to data ...
