Thoroughbreds are a breed of horse known for their agility, speed, and spirit, often associated with horse racing and equestrian sports. Originating from crossbreeding native English mares with imported Arabian, Barb, and Turkoman stallions, Thoroughbreds have a well-documented pedigree that traces back to the late 17th and early 18th centuries. This breed is characterized by a refined head, deep chest, and long legs, contributing to their athletic capabilities. Thoroughbreds are primarily bred for their performance in racing but are also utilized in other equestrian disciplines. This page compiles peer-reviewed research studies and scholarly articles that explore the genetics, physiology, and performance characteristics of Thoroughbreds, as well as their management and welfare in various equine activities.
McGivney BA, Hernandez B, Katz LM, MacHugh DE, McGovern SP, Parnell AC, Wiencko HL, Hill EW.Durability traits in Thoroughbred horses are heritable, economically valuable and may affect horse welfare. The aims of this study were to test the hypotheses that (i) durability traits are heritable and (ii) genetic data may be used to predict a horse's potential to have a racecourse start. Heritability for the phenotype 'number of 2- and 3-year-old starts' was estimated to be = 0.11 ± 0.02 (n = 4499). A genome-wide association study identified SNP contributions to the trait. The neurotrimin (NTM), opioid-binding protein/cell adhesion molecule like (OPCML) and prolylcarboxypeptidase ...
Kuroda T, Nagata SI, Tamura N, Mita H, Kusano K, Mizobe F, Takizawa Y, Fukuda K, Kasashima Y.To investigate the pharmacokinetics and antihistaminic effects (pharmacodynamics) of olopatadine in a small population of healthy horses after administration via nasogastric tube. Methods: 4 healthy adult Thoroughbreds. Methods: Olopatadine (0.1 mg/kg, once) was administered via nasogastric tube. Blood samples were collected at predetermined time points for pharmacokinetic analyses of the drug in plasma. Olopatadine effects were investigated by measurement of cutaneous wheals induced by ID histamine injection (0.1 mL [10 μg]/injection) at predetermined time points. Inhibition effect ratios we...
Jeong MJ, Jeong BH.Prion diseases are fatal neurodegenerative diseases characterised by the accumulation of an abnormal prion protein isoform (PrP), which is converted from the normal prion protein (PrP). Prion diseases have been reported in an extensive number of species but not in horses up to now; therefore, horses are known to be a species resistant to prion diseases. The prion-like protein gene () is closely located downstream of the prion protein gene () and the prion-like protein (Doppel) is a homologue with PrP. Previous studies have shown that an association between prion diseases and polymorphisms of t...
Mitchell ARM, Scott CJ, Cheong SH, Carrigan P, Diel de Amorim M, Collins CD.Minimizing the interval between parturition and successful rebreeding of thoroughbred broodmares is important in maintaining annual foal production and broodmare profitability. Routine postpartum uterine lavage may help achieve this by aiding uterine clearance and involution in the early postpartum period and increasing pregnancy rates. This retrospective study investigates the effect of postpartum uterine lavage in 32 thoroughbred mares housed on a single farm in Australia in 2014 and 2015. In the control year (2014), postpartum uterine lavage was not performed. In the treatment year (2015), ...
Yokomori T, Tozaki T, Mita H, Miyake T, Kakoi H, Kobayashi Y, Kusano K, Itou T.According to oral traditions of horse caretakers and trainers, the differences in the position and number of facial hair whorls may be associated with temperamental traits. Elucidating genetic background of facial hair whorls and its relationship to temperamental traits may promote more efficient breeding and maintenance of racehorses. In this study, we estimated heritabilities of the position and number of facial hair whorls in Japanese Thoroughbred horses. Results: The number of facial hair whorls varied from one to four and heritability estimate in 4024 Thoroughbred horses was low (h2= 0....
Latham CM, Fenger CK, White SH.Responses of equine skeletal muscle characteristics to growth and training have been shown to differ between breeds. These differential responses may arise in part because muscle fiber type and mitochondrial density differ between breeds, even in untrained racing-bred horses. However, it is not known when these breed-specific differences manifest. To test the hypothesis that weanling Standardbreds (SB) and Thoroughbreds (TB) would have higher mitochondrial measures than Quarter Horses (QH), gluteus medius samples were collected from SB (mean ± SD; 6.2 ± 1.0 mo; n = 10), TB (6.1 ± 0.5 mo; n ...
Ochi A, Sekiguchi M, Tsujimura K, Kinoshita T, Ueno T, Katayama Y.Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with equine herpesvirus type 5 (EHV-5). This disease has been reported in North and South America, Europe and Oceania but not, to our knowledge, in horses in Japan. We diagnosed EMPF in two Thoroughbred horses in Japan on the basis of gross and histopathological findings. In both cases, significant gross lesions, restricted to the lungs, consisted of numerous firm and coalescing nodules widely distributed throughout the lung. The nodules were <3 cm in diameter and pale white to t...
Shaw DJ, Rosanowski SM.Epiglottic entrapment is a condition in racing horses, associated with abnormal respiratory noises and exercise intolerance. Epiglottic entrapment has been linked to both poor and superior athletic performance, leading to concerns regarding whether surgery is indicated, and whether surgical correction may have a deleterious effect on future race performance. The objective of the current study was to assess the race-day performance of horses racing with epiglottic entrapment and the effect of surgical correction on performance outcomes using an intra-oral technique in anaesthetised horses. A ca...
Hibi H, Hatama S, Obata A, Shibahara T, Kadota K.A case of laryngeal squamous cell carcinoma (SCC) and squamous papilloma in a 19-year-old Thoroughbred stallion is described. The animal exhibited severe wheezing caused by laryngopharyngeal stenosis. Histological examination identified laryngeal, laryngotracheal, and guttural pouch tumor masses consisting of areas of SCC. In the epiglottic lesion, the overlying epithelium was replaced by papilloma cells, and superficial cells frequently had nuclear inclusion bodies that expressed oncoprotein E6, which is characteristic of high risk human papillomaviruses. The papillomatous epithelium was cont...
Brown LJ, Brown G, Kydd J, Stout TAE, Schulman ML.Equid herpesvirus type 1 is primarily a respiratory tract virus associated with poor athletic performance that can also cause late gestation abortion, neonatal foal death and encephalomyelopathy. Horizontal transmission is well described, whereas evidence of vertical transmission of equid herpesvirus type 1 associated with the birth of a healthy foal has not been demonstrated. This study sampled a population of Thoroughbred mares (n = 71), and their healthy neonatal foals and foetal membranes, to test for the presence of both equid herpesvirus types 1 and 4 using a quantitative polymerase chai...
Buck AM, Hunt RJ.To describe the surgical correction of a closed meningoencephalocele in a thoroughbred filly. Methods: Case report. Methods: One thoroughbred filly, 1.5 months old at the time of surgery. Methods: A meningoencephalocele was identified at birth and diagnosed with radiography and MRI. The abnormal tissue was excised and submitted for histopathology, the dura was closed, and the defect in the skull was corrected with a titanium mesh. Results: Histopathology confirmed the presence of neural parenchyma consisting of neurons and glial cells. The filly remained without neurologic deficits 7 month...
Legg KA, Breheny M, Gee EK, Rogers CW.Jumps racing involves a higher risk of accident and fatality than flat racing. The wide accessibility of media, combined with alternate views regarding the place of animals in society, raises the question of the acceptability of the continuation of jumps racing. Racing data and media articles from Newztext and Google news search were collected for the 2016/2017 and 2017/2018 jumps racing seasons, during which the fatality rate was 5.8 per 1000 starters. Jumps racing articles comprised 3.4% of all race reporting, and the volume of discussion about jumps racing was minimal (2.9% of jumps race ar...
Griffin RA, Baker M, Aitken RJ, Swegen A, Gibb Z.Stallions experience lower per-cycle conception rates compared to other livestock species, largely because they are selected for breeding based on athletic prowess and not reproductive fitness. Mares are seasonal breeders, and pregnancies cannot be detected until 10-14 days post cover via transrectal ultrasonography. This means the detection of stallion fertility fluctuations is delayed by at least 2 weeks, which within the short breeding season employed by the thoroughbred horse breeding industry, can prove quite costly. For these reasons, there is increased demand for robust laboratory assay...
Lee SK, Lee I.Equine herpesvirus (EHV) 2 and equine herpesvirus 5 (EHV-5) have been getting attention as potential causative pathogens of reproductive disorders in horses. Equine herpesviruses 2 and 5 are widespread among horses and have been detected in various samples including nasal swabs, blood, and ocular swabs. However, the detection of these pathogens in genital swabs has not been determined. The aims of this study were to determine the positive rate of EHV-2 and EHV-5 DNA in genital swabs taken from clinically normal mares and to define the genetic diversity of these EHV-2 and EHV-5 DNA sequences by...
Byrne CA, Lumsden JM, Lang HM, O'Sullivan CB.Synovial sepsis of unknown origin is a rare cause of lameness in the adult horse, and a haematogenous pathogenesis has been proposed in previous cases. Objective: To describe the features and outcome of synovial sepsis of unknown origin in adult Thoroughbred racehorses. Methods: Retrospective case series. Methods: Hospital records for admissions between 2005 and 2015 were reviewed to identify adult horses diagnosed with synovial sepsis of unknown origin. Presentation, clinicopathological, microbiological and diagnostic imaging findings were recorded. Treatment methods, surgical findings, compl...
Chidlow H, Giguère S, Sanchez LC.Limited information exists on the long-term outcome of foals that survive following hospitalisation for disease as a neonate. Significant financial investment is required to raise foals to racing age, therefore improved understanding of factors that affect long-term outcome and future athletic performance is important. Objective: To analyse racing performance in Thoroughbred foals hospitalised as neonates, compared with their maternal siblings and to determine factors associated with failure to race and racing performance. Methods: Retrospective cohort study. Methods: Medical records of Thorou...
Catalano DN, Coleman RJ, Hathaway MR, Neu AE, Wagner EL, Tyler PJ, McCue ME, Martinson KL.Adding breed type, height, and neck circumference to body length and girth circumference improves bodyweight (BW) estimation in different breeds of horses; however, equations have not been developed for all breed types. The objectives were to develop BW estimation equations for Miniature, saddle-type, and Thoroughbred horses using morphometric measurements. Measurements were collected on adult (≥3 years, nonpregnant) saddle-type (n = 209), adult (n = 249) and juvenile (<3 years, n = 61) Miniatures, and adult Thoroughbreds (n = 100). Personnel determined body condition score (BCS), m...
Kinter CK, Gorko MA, Schaefer E.This study was conducted to determine whether xylazine administration is associated with clinically significant changes on leukocyte numbers in horses, as has been previously reported in other species. The study was designed to detect 20% changes in primary endpoint leukocyte parameters with 85% statistical power. No clinically significant changes in leukocyte numbers meeting the requirements of the statistical analysis were detected; no consistent changes capable of confounding a clinical diagnosis or treatment were detected. No gross changes in secondary endpoints including erythrocyte and p...
Derham AM, O'Leary JM, Connolly SE, Schumacher J, Kelly G.Racehorses may perform poorly because of impinging dorsal spinous processes (DSPs) of the thoracolumbar vertebrae. No study has looked objectively at the long-term outcome of racehorses undergoing desmotomy of the interspinous ligament as a treatment for horses with poor performance caused by impinging DSPs. The aim of this study was to examine objectively, by using pre-operative and post-operative racing records, the effectiveness of desmotomy of the interspinous ligament (DISL) in improving the performance of racehorses with impinging DSPs. Medical records of all horses undergoing desmotomy ...
Curtiss AL, Aceto H, Embertson RM.Epiglottic entrapment can occur in yearling Thoroughbreds (TB); however, race performance following surgical correction is unknown. Objective: To determine the race performance of horses treated surgically for epiglottic entrapment as yearlings as compared to an untreated cohort. A second objective was to identify risk factors for treated horses not racing post-operatively. Methods: Retrospective cohort and case-control studies. Methods: Medical (1989-2014) and race records of 66 treated TB racehorses were reviewed. Observed abnormalities on pre- and post-operative endoscopic images and surgic...
Curtiss AL, Parente EJ.To report an epiglottopexy technique for the treatment of epiglottic retroversion (ER) in 2 horses. Methods: Case report. Methods: A 2-year-old thoroughbred gelding and a 6-year-old standardbred gelding, both with ER. Methods: Epiglottic retroversion was diagnosed via exercising endoscopic examination in both horses. Epiglottopexy technique was performed in both cases. Results: Both horses returned to previous racing class within 1 year after surgery. Repeat exercising endoscopy of 1 horse 6 months postoperatively revealed resolution of the ER. Conclusions: Epiglottopexy should be consider...
Negi NJ, Swanberg JE, Clouser JM, Harmon-Darrow C.The American agricultural industry is heavily reliant on Latina/o workers, yet there is scant understanding regarding the mental health of this population. This gap in the literature is glaring as Latina/o farmworkers are a highly vulnerable group who experience high rates of occupational risks and health hazards. This study is the first, to our knowledge, to examine individual, social and work-related correlates of depression among Latina/o horse workers. Methods: A community survey ( = 225) administered by lay health workers was implemented with Latina/o horse workers who were employed in th...
Strand E, Össurardóttir S, Wettre KB, Fjordbakk CT.To report clinical findings and performance in horses in which alar fold collapse (AFC) had been diagnosed and surgically treated and to assess form and degree of respiratory obstruction. Methods: Retrospective case series. Methods: Twenty-one standardbreds, 2 coldblooded trotter racehorses, 1 thoroughbred, and 1 Icelandic horse. Methods: Alar fold collapse was diagnosed on the basis of continuous abnormal expiratory flutter noise coinciding with filling of the false nostrils during exercise on a high-speed treadmill that was alleviated by suturing the alar folds (AF) temporarily in a dorsal p...
To T.A 15-year-old thoroughbred non-pregnant mare was presented with ongoing inappropriate lactation. The most likely cause, equine Cushing's disease, was ruled out through biochemical testing. Milk cytology and bacterial culture showed no evidence of mastitis or neoplasia. Idiopathic inappropriate lactation was diagnosed and treatment with pergolide was recommended. Lactation inappropriée chez une jument Pur-sang âgée de 15 ans. Une jument Pur-sang non gravide âgée de 15 ans a été présentée avec une lactation continue inappropriée. La cause la plus probable, la maladie de Cushing, a ét...
Hannan MA, Murase H, Sato F, Tsogtgerel M, Kawate N, Nambo Y.The peripheral blood concentrations of insulin-like peptide 3 (INSL3) have been detected in many mammalian species, but the level of INSL3 in horse remains unknown. The objectives were to develop a time-resolved fluorescence immunoassay (TRFIA) to detect INSL3 concentrations from horse blood as well as to determine the age-related and seasonal changes of plasma concentrations of INSL3 and testosterone from birth to early-puberty in Thoroughbred male horse (n = 11). Monthly blood sample and measurement of body weight, height, chest and cannon bone size were done from birth until 16 mo. Th...
Mercer MA, McKenzie HC, Davis JL, Wilson KE, Hodgson DR, Cecere TE, McIntosh BJ.There are no published studies on the pharmacokinetics of acetaminophen at the dosage used clinically (20 mg/kg), nor has the safety of multiple doses in horses been investigated. Objective: Define the pharmacokinetic parameters of oral acetaminophen at 20 mg/kg in adult horses as a single dose, and twice daily for 14 days to assess the safety of multiple dosing. Methods: Pharmacokinetic study, multiple dose safety study. Methods: Eight healthy Thoroughbred geldings were given acetaminophen (20 mg/kg; 500 mg tablets) orally as a single dose followed by doses every 12 h for 14 days. Seri...
Felkel S, Vogl C, Rigler D, Dobretsberger V, Chowdhary BP, Distl O, Fries R, Jagannathan V, Janečka JE, Leeb T, Lindgren G, McCue M, Metzger J....Analysis of the Y chromosome is the best-established way to reconstruct paternal family history in humans. Here, we applied fine-scaled Y-chromosomal haplotyping in horses with biallelic markers and demonstrate the potential of our approach to address the ancestry of sire lines. We de novo assembled a draft reference of the male-specific region of the Y chromosome from Illumina short reads and then screened 5.8 million basepairs for variants in 130 specimens from intensively selected and rural breeds and nine Przewalski's horses. Among domestic horses we confirmed the predominance of a young'c...
Ramsay JD, Evanoff R, Mealey RH, Simpson EL.In racehorses, serum gamma-glutamyltransferase (GGT) activity is positively correlated with cumulative days in training and, when ≥100 IU/L, has been associated with poor performance. The prevalence of increased GGT activity in North American Thoroughbreds and its aetiopathogenesis are unknown. Four emerging viruses, pegivirus E (PgV E; equine pegivirus), hepacivirus A (HcV A; equine hepacivirus), pegivirus D (PgV D; Theiler's disease virus), and equine parvovirus-hepatitis (EqPV-H) have been identified in horses with clinical and subclinical hepatopathy. Available prevalence data indicate ...
Davison JA, Wylie CE, McGladdery CE, Fettes C, Haggett EF, Ramzan PHL.Despite their implication in the pathogenesis of lower airway inflammation, limited baseline data exists for airborne particulates in Thoroughbred racehorse stalls in the United Kingdom. This study documents airborne particulate size and concentrations in Newmarket training yards using a nephelometer (DustTrak DRX 8534, TSI). Each stall was sampled on a summer and winter day at three time points (morning, midday and evening). Minimum, mean and maximum/min ranges were calculated for the fraction of particulates with an aerodynamic diameter smaller than 2.5 μm (particulate matter (PM) 2.5) an...
Self Davies ZT, Spence AJ, Wilson AM.Horse locomotion is remarkably economical. Here, we measure external mechanical work of the galloping horse and relate it to published measurements of metabolic cost. Seven Thoroughbred horses were galloped (ridden) over force plates, under a racing surface. Twenty-six full strides of force data were recorded and used to calculate the external mechanical work of galloping. The mean sum of decrements of mechanical energy was -876 J (±280 J) per stride and increments were 2163 J (±538 J) per stride as horses were accelerating. Combination with published values for internal work and metabolic c...
Lendal S, Larsen MM, Bjørn H, Craven J, Chriél M, Olsen SN.A questionnaire survey to obtain information on endoparasite control practices and management on 68 Danish horse farms was undertaken in 1995. The study revealed that foals, young horses and adults were on average, annually treated 4.3, 4.0 and 3.7 times, respectively. The most commonly used drug from 1993-1995 was ivermectin. On average 2.4 different drugs were used annually. The most used method of weight estimation was eye measure: for foals by 78%, for youngsters by 81% and adults by 82% of the herd owners. The most commonly used weight in the dosing of anthelmintics was individual weights...
Palmer SE.Laparoscopic laser instrumentation and endoscopic stapling techniques were used to perform 10 unilateral ovariectomy procedures on 5 standing Thoroughbred mares. In all instances, mares had a clinically normal reproductive tract and estrous cycle, and ovariectomy was performed to eliminate regular estrous behavior. All procedures were accompanied by minimal trauma and uncomplicated postoperative recovery. Mares were able to resume normal activity 2 weeks after surgery. Regular estrous behavior was eliminated in all 5 mares, although 1 mare continued to have signs of estrous behavior occasional...
Mohammed HO, Rebhun WC, Antczak DF.A retrospective case-control study was conducted to identify risk factors in horses associated with the development of the common skin tumours known as sarcoids. The study involved 503 sarcoid cases diagnosed (January 1980-December 1989) at New York State College of Veterinary Medicine and a similar number of controls (non-sarcoid cases). Data on age, breed and sex of cases and controls were obtained from computerised records. Multiple logistic regression analysis was used to identify risk factors. Separate data were obtained for the same 10-year period from the Veterinary Medical Data Program...
Colborne GR, Birtles DM, Cacchione IC.Muscle fatigue can be quantified using Fourier analysis of the recorded EMG signal. Median frequency is the frequency at which the Fourier profile is bisected, and this measure typically shifts to smaller values during fatigue. This technique was combined with kinematic analysis to describe the time course of fatigue in horses galloping on an inclined treadmill. It was hypothesised that EMG median frequency would decrease in tandem with changes in kinematic variables through the exercise test. Three fit Thoroughbred horses had retroreflective markers placed on their hooves and withers. Surface...
Blissitt KJ, Bonagura JD.Reference values were established for selected Doppler derived variables from a group of 40 normal Thoroughbred and Thoroughbred cross horses. Standard two-dimensional (2-D) images used for guiding the Doppler sampling site allowed accurate alignment with flow. Tricuspid inflow velocities during rapid filling (E) and atrial contraction (A) were significantly higher when recorded from a right parasternal angled view than from a right parasternal long-axis view. In 8 horses the tricuspid inflow peak A velocity was higher than the peak E velocity. The peak acceleration of blood flow was higher (P...
Dymock DC, Brown MP, Merritt KA, Trumble TN.To determine whether stromal cell-derived factor-1 (SDF-1) concentrations in serum, plasma, and synovial fluid differed among untrained, race-trained, and osteochondral-injured Thoroughbred racehorses. Methods: 22 racehorses without osteochondral injury and 37 racehorses with osteochondral injury. Methods: Horses without osteochondral injury were examined before and after 5 to 6 months of race training. Horses with osteochondral injury were undergoing arthroscopic surgery for removal of osteochondral fragments from carpal or metacarpophalangeal or metatarsophalangeal joints (fetlock joints). S...
Metcalfe LV, O'Brien PJ, Papakonstantinou S, Cahalan SD, McAllister H, Duggan VE.A 15 year-old grey Thoroughbred gelding presented for investigation of chronic weight loss and recent onset of respiratory difficulty. Clinical examination confirmed tachypnoea with increased respiratory effort. Thoracic ultrasound examination detected pleural effusion. The dyspnoea was related to the large volume of pleural effusion and, following post-mortem examination, to the presence of a large mediastinal mass. Multiple pigmented masses, likely melanomas, were detected peri-anally. Thoracic radiography, cytological examination of the pleural fluid and a fine needle aspirate of a thoraci...
Suagee JK, Corl BA, Crisman MV, Hulver MW, McCutcheon LJ, Geor RJ.Laminitis is a painful, inflammatory disease of the equine hoof that often results in euthanasia. Elevated plasma insulin concentrations are a predictive factor for laminitis, and in previously healthy horses and ponies, laminitis was induced by infusion of insulin. Thus, we chose to determine if an infusion of insulin would increase plasma concentrations of inflammatory cytokines and cytokine mRNA abundance in subcutaneous adipose tissue, skeletal muscle, and white blood cells. Ten mature Thoroughbred mares received an insulin infusion that elevated plasma insulin concentrations for 6h or an ...
Schrimpf A, Single MS, Nawroth C.Dogs and cats use human emotional information directed to an unfamiliar situation to guide their behavior, known as social referencing. It is not clear whether other domestic species show similar socio-cognitive abilities in interacting with humans. We investigated whether horses ( = 46) use human emotional information to adjust their behavior to a novel object and whether the behavior of horses differed depending on breed type. Horses were randomly assigned to one of two groups: an experimenter positioned in the middle of a test arena directed gaze and voice towards the novel object with eith...
Osteochondrosis (OC) develops in growing horses due to disturbed differentiation and maturation of cartilage, particularly at the predilection sites of the fetlock, hock and stifle joints. Horses with osteochondrotic lesions are at a high risk of developing orthopaedic problems later in life. This article briefly reviews the published heritability estimates for OC and offers perspectives for selection in the horse industry. Heritabilities for OC in Warmblood and Standardbred horses have been estimated at 0.1-0.4 in animal threshold models. Whole genome scans using microsatellites have identifi...
Bartholomew S, Owens SD, Ferraro GL, Carrade DD, Lara DJ, Librach FA, Borjesson DL, Galuppo LD.Stem cells derived from umbilical cord tissue (UCT) and umbilical cord blood (UCB) in human subjects and horses can be obtained in a minimally invasive fashion with successful propagation of mesenchymal stem cells (MSCs). Currently there are no detailed protocols documenting a procedure to harvest UCB and UCT safely for equine stem cell propagation. Objective: UCB and UCT could be collected without harm to mare or foal. Objective: To develop a standard and safe method for UCB and UCT collection, and prospectively to compare foal and mare health between groups of animals where tissue was and wa...
Schönbom H, Kassens A, Hopster-Iversen C, Klewitz J, Piechotta M, Martinsson G, Kißler A, Burger D, Sieme H.Pregnancy diagnostics in equine reproduction are routinely performed using transrectal ultrasonography, although it is also possible to visualize the fetus by transabdominal ultrasound examinations from the 90th day of gestation onward. We hypothesized that ultrasound examinations may stress the mare and that the gestational stage status and lactation may influence the mare's stress reaction. To investigate the stress reaction, 25 thoroughbred mares of different age, pregnancy and lactational status underwent a transrectal examination. In pregnant mares, an additional transabdominal examinatio...
Bennet ED, Parkin TDH.To identify risk factors associated with race-related sudden death in Thoroughbred racehorses in the US and Canada. 4,198,073 race starts made by 284,387 Thoroughbred horses at 144 racetracks in the US and Canada between 2009 and 2021. Study data were extracted from the Equine Injury Database, which contains detailed records of 92.2% of all official race starts made in the US and Canada during the study period. Forty-nine potential risk factors were analyzed using univariable and multivariable logistic regression. Cases were defined as race starts that resulted in fatality within 3 days of rac...
Bellone RR, Ocampo NR, Hughes SS, Le V, Arthur R, Finno CJ, Penedo MCT.Catastrophic fractures are among the most common cause of fatalities in racehorses. Several factors, including genetics, likely contribute to increased risk for fatal injuries. A variant in the procollagen-lysine, 2-oxoglutarate 5-dioxygenase1 gene (PLOD1 c.2032G>A) was shown to cause Warmblood fragile foal syndrome type 1 (WFFS), a fatal recessive defect of the connective tissue. Screening of multiple horse breeds identified the presence of the WFFS allele in the Thoroughbred. PLOD1 is involved in cross-linking of collagen fibrils and thus could potentially increase the risk of catastrophic b...
Hitchens PL, Blizzard CL, Jones G, Day LM, Fell J.Apprentice thoroughbred racing jockeys have a higher fall rate than their more experienced counterparts. The authors describe rates of occurrence and investigate risk factors for falls among less-experienced thoroughbred flat racing jockeys in Australia who commenced their race riding career between August 2002 and July 2009. Methods: Data on race-day falls were extracted from stewards' reports. Denominator data were provided by Racing Information Services Australia on races conducted in Australia. HRs were estimated using time-to-event (survival analysis) methods. Results: Factors found to be...
Rakesh V, Rakesh NG, Datta AK, Cheetham J, Pease AP.Computational fluid dynamics (CFD) models provide the means to evaluate airflow in the upper airways without requiring in vivo experiments. Objective: The physiological conditions of a Thoroughbred racehorse's upper airway during exercise could be simulated. Methods: Computed tomography scanned images of a 3-year-old intact male Thoroughbred racehorse cadaver were used to simulate in vivo geometry. Airway pressure traces from a live Thoroughbred horse, during exercise was used to set the boundary condition. Fluid-flow equations were solved for turbulent flow in the airway during inspiratory an...
Sullivan SL, Anderson GA, Morley PS, Hinchcliff KW.Exercise-induced pulmonary haemorrhage (EIPH) is associated with impaired short-term race performance but consequences to long-term race performance of Thoroughbred racehorses are unknown. Knowledge of effects of EIPH on performance over a prolonged time would inform the need for management and treatment of this disorder. Objective: To determine the relationship between EIPH detected on a single occasion and long-term athletic performance in Thoroughbred racehorses. Methods: Prospective, longitudinal, observational epidemiological study conducted from 2003 to 2012. Methods: Seven hundred and f...
Salz RO, Ahern BJ, Boston R, Begg LM.To determine the variation of tracheal mucus scores, tracheal blood scores and transendoscopic tracheal wash (TW) cytology in a population of Thoroughbred (TB) racehorses and assess their association with racing performance. Methods: A total of 220 endoscopic examinations were performed and TWs obtained from 155 TB racehorses. Samples were collected 60-120 min following gallop work. Tracheal mucus score, tracheal blood score and TW cytology were analysed and their association with racing performance assessed. Results: Of the total examinations and samples, 194 from 135 horses fitted the criter...
Rocchigiani G, Ricci E, Navarro MA, Samol MA, Uzal FA.Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cell...
Butcher MT, Hermanson JW, Ducharme NG, Mitchell LM, Soderholm LV, Bertram JE.Racing and training related lesions of the forelimb superficial digital flexor tendon are a common career ending injury to racehorses but aetiology and/or predisposing causes of the injury are not completely understood. Objective: Although the injury takes place within the tendon, the lesion must be considered within the context of the function of the complete suspensory system of the distal limb, including the associated muscles. Methods: Both muscle and tendon function were investigated in vivo using implanted strain gauges in 3 Thoroughbred horses walking, trotting and cantering on a motori...
Fougerolle S, Legrand L, Garrett D, Birand I, Foursin M, D'Ablon X, Bayssat P, Newton RJ, Pronost S, Paillot R.Numerous equine influenza (EI) epizooties are reported worldwide. EI vaccination is the most efficient methods of prevention. However, not all horses develop protective immunity after immunisation, increasing the risk of infection and transmission. This field study aimed to understand the poor response to primary EI vaccination. The EI antibody response was measured in 174 Thoroughbred foals set in 3 stud farms (SF#1 to SF#3) over a 2years period. All foals were immunised with a commercial recombinant canarypox-based EI vaccine. Sera were tested by single radial haemolysis against the A/equine...
Ohmura H, Mukai K, Takahashi Y, Takahashi T, Jones JH.Hypoxic training is effective for improving athletic performance in humans. It increases maximal oxygen consumption (V̇Omax) more than normoxic training in untrained horses. However, the effects of hypoxic training on well-trained horses are unclear. We measured the effects of hypoxic training on V̇Omax of 5 well-trained horses in which V̇Omax had not increased over 3 consecutive weeks of supramaximal treadmill training in normoxia which was performed twice a week. The horses trained with hypoxia (15% inspired O) twice a week. Cardiorespiratory valuables were analyzed with analysis of varia...
Freeman DE, Mooney A, Giguère S, Claire J, Evetts C, Diskant P.Measurements of water consumed by fed healthy horses might not apply to horses that are unwilling or unable to drink or are not fed for any reason. Objective: To examine the effects of feed deprivation on voluntary water consumption compared with fed conditions. Methods: In vivo experiment. Methods: Eight healthy adult Thoroughbred geldings were used in a randomised crossover design so that each horse served as its own control for fed vs feed-deprived conditions. Water intake, bodyweight, physical findings and vital signs were measured during 4 days of feeding and 4 days of feed deprivation....
Mukai K, Hiraga A, Takahashi T, Matsui A, Ohmura H, Aida H, Jones JH.OBJECTIVE To determine whether racehorses undergoing regular exercise at 2 intensities or stall rest during a period of reduced training (detraining) would differentially maintain their cardiopulmonary and oxygen-transport capacities. ANIMALS 27 Thoroughbreds. PROCEDURES Horses trained on a treadmill for 18 weeks underwent a period of detraining for 12 weeks according to 1 of 3 protocols: cantering at 70% of maximal rate of oxygen consumption ([Formula: see text]o) for 3 min/d for 5 d/wk (canter group); walking for 1 h/d for 5 d/wk (walk group); or stall rest (stall group). Standardized treadm...
Reardon RJ, Boden LA, Mellor DJ, Love S, Newton JR, Stirk AJ, Parkin TD.Superficial digital flexor (SDF) tendinopathy is a common injury in Thoroughbred horses racing over hurdles. Identification of risk factors may allow the introduction of measures to minimise the incidence of this injury. Objective: To identify risk factors for SDF tendinopathy in Thoroughbred horses in hurdle races in the UK. Methods: Potential risk factors for SDF tendinopathy were studied between 1 January 2001 and 31 December 2009 using a retrospective cohort study design with 1031 case starts and 168,637 control starts. Potential risk factors were screened using univariable logistic regres...
Firth EC, Rogers CW, Anderson BH.To determine the weight, volume, density and cross-sectional area (CSA) of the digital flexor tendons, common digital extensor tendon (CDET) and suspensory ligament (SL) of the forelimb of young Thoroughbred horses in early training, and to assess the response to a training programme of known parameters of superficial digital flexor tendon (SDFT) tissue at mid-metacarpal level. Methods: The tendons of seven 2-year-old Thoroughbred horses in training were inspected, transected into segments of known length, and compared with those from seven untrained horses matched for age, sex and breed. The ...
Tozaki T, Sato F, Ishimaru M, Kikuchi M, Kakoi H, Hirota KI, Nagata SI.Ligand-dependent nuclear receptor compressor-like (LCORL) encodes a transcription factor, and its polymorphisms are associated with measures of skeletal frame size and adult height in several species. Recently, the single nucleotide polymorphism (SNP) BIEC2-808543 located upstream of LCORL was identified as a genetic diagnostic marker associated with withers height in Thoroughbreds. In this study, 322 Thoroughbreds-in-training were genotyped for BIEC2-808543 to evaluate the association between genotype and body composition traits, including body weight, withers height, the ratio of body weight...
Kirschvink N, Art T, de Moffarts B, Smith N, Marlin D, Roberts C, Lekeux P.Exercise-induced oxidative stress is investigated as a potential performance-limiting factor in human sports medicine. Therefore, the present study aimed to assess whether physiological variables that change with exercise intensity were correlated with blood oxidant markers in healthy and heaves-affected horses. Seven healthy horses, 8 heaves-affected in remission and 7 heaves-affected in crisis performed a standardised exercise test (SET) of stepwise increasing intensity. Variables monitored during exercise were heart rate (HR), venous plasma lactate (LA), packed cell volume (PCV) and arteria...
Peloso JG, Vogler JB, Cohen ND, Marquis P, Hilt L.To compare bony changes in the metacarpophalangeal joint (MCPJ) of racehorses with (cases) and without (controls) biaxial proximal sesamoid bone (PSB) fracture as determined by 2 grading scales applied to images of cadaveric forelimbs obtained by means of standing MRI (sMRI). Methods: Case-control study. Methods: Forelimbs from 74 Thoroughbred racehorses (21 cases and 53 controls) that were euthanized at a Florida racetrack. Methods: Both forelimbs were harvested from cases and controls. Each forelimb underwent sMRI to obtain images of the MCPJ. Two grading scales were described and used for i...
Jago RC, Corletto F, Wright IM.Peri-anaesthetic complications are relatively common in equine patients and further investigations are warranted to identify manageable risk factors. Objective: To report morbidity and mortality rates and identify associated risk factors for horses undergoing general anaesthesia, within a predominantly racing Thoroughbred (TB) population. Methods: Single centre retrospective observational study. Methods: Anaesthetic and case records of all horses ≥12 months old undergoing general anaesthesia at Newmarket Equine Hospital between August 2010 and April 2012 were analysed, excluding emergency ab...
