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.
Knych HK, Finno CJ, Katzman S, Ryan D, McKemie DS, Kass PH, Arthur RM.Clodronate is a potent antiresorptive agent labelled for use in horses over 4 years of age, for the treatment of navicular syndrome. Concerns regarding the extra-label use of clodronate in equine athletes, such as racehorses, have been raised as inhibition of osteoclast activity by clodronate has been postulated to interfere with normal bone healing, which is imperative to the repair of microfractures. The paucity of data describing the long-term pharmacokinetics of clodronate and effects on biomarkers of bone resorption necessitates further study. Objective: (1) To determine clodronate conc...
Kudrimoti S, Machin J, Arojojoye AS, Awuah SG, Eisenberg R, Fenger C, Maylin G, Lehner AF, Tobin T.Based on structural similarities and equine administration experiments, Barbarin, 5-phenyl-2-oxazolidinethione from Brassicaceae plants, is a possible source of equine urinary identifications of aminorex, (R,S)-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine, an amphetamine-related US Drug Enforcement Administration (DEA) controlled substance considered illegal in sport horses. We now report the synthesis and certification of d -barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D -barbarin synthesis commenced with production of d -2-oxo-2-phe...
Sielhorst J, Roggel-Buecker U, Neudeck KC, Kahler A, Rohn K, Luettgenau J, Bollwein H, Hollinshead F, Sieme H.The aim of this double-blinded placebo-controlled study was to investigate the effect of acetylsalicylic acid (ASA) on uterine blood flow, gestation length, placental and foal weights in pregnant mares. Sixteen Thoroughbred mares of different age (13.3 ± 4.1) and parity (7.4 ± 3.1) were randomly assigned to three treatment groups. Mares in group C (n = 4) served as controls and received 5,000 mg lactose orally once daily from D 120 (D 0 = day of ovulation) until parturition. Mares in group ASA1 (n = 7) received 5,000 mg ASA orally once daily from D 120 until parturition. Mares in group...
Pye J, Spriet M, O'Brion J, Carpenter R, Blea JA, Dowd JP.To assess the repeatability of equine 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) findings, and to evaluate the ability of PET to monitor the progression of areas of increased radiopharmaceutical uptake (IRU) in the fetlocks of Thoroughbred racehorses. Methods: 25 racehorses with clinical signs related to fetlock injuries. Methods: This study is a prospective, longitudinal clinical study. Twenty-five racehorses (54 fetlocks) underwent three 18F-NaF PET scans 6 weeks apart. The first 18F-NaF PET scan was performed at the start of a 12-week period of rest from racing (lay-up...
Rocchigiani G, Verin R, Uzal FA, Singer ER, Pregel P, Ressel L, Ricci E.Exercise-induced pulmonary hemorrhage (EIPH) is a common condition of Thoroughbred racehorses that is usually responsible for reduced performance, while exercise-associated fatal pulmonary hemorrhage (EAFPH) is characterized by severe pulmonary bleeding of unknown pathogenesis resulting in sudden death during strenuous exercise. The aim of the study was to characterize and compare anamnestic data together with pulmonary gross, histologic, and ultrastructural findings in racehorses with EIPH (n = 10), EAFPH (n = 10), and control horses (n = 5). No differences in anamnesis were identified betwee...
Mouncey R, Arango-Sabogal JC, de Mestre A, Verheyen K.The study aimed to (1) describe the use of reproductive therapeutics; (2) estimate the incidence of disease and injury; and (3) describe non-reproductive medications administered during pregnancy in Thoroughbred broodmares. A prospective birth cohort was established on seven farms across the UK and Ireland. Details of dams' signalment, breeding history, reproductive management during the breeding season(s) and veterinary-attended episodes of illness or injury and medication usage during gestation were retrieved retrospectively for 275 pregnancies in 235 mares over two breeding seasons. Results...
Kondo T, Sato F, Tsuzuki N, Yamada K.Cervical vertebral stenotic myelopathy (CVSM), a common cause of cervical spinal cord compression, is a neurological disease characterized by general proprioceptive ataxia and weakness of hindlimbs that tends to develop in young adult Thoroughbred horses. Although male horses seem to be at increased risk for CVSM, the mechanism for the occurrence of sex differences in the prevalence of CVSM is still poorly understood. Hence, we hypothesized that sex differences in the development of cervical spinal cord and spinal canal would affect the development of CVSM. This study aimed to evaluate sex dif...
Asin J, Nyaoke AC, Samol MA, Arthur RM, Uzal FA.Epiploic foramen entrapment (EFE) is a common cause of small intestinal colic in horses and may lead to intestinal strangulation. Strangulating intestinal obstruction impairs the gastrointestinal outflow and can lead to secondary gastric rupture and endotoxemia. Clostridioides difficile can cause enterotyphlocolitis with colic in horses of all ages, and the process is commonly referred to as C. difficile-associated disease (CDAD). Here we report the results of the postmortem examination of a 7-y-old Thoroughbred racehorse with concurrent CDAD, EFE, and gastric rupture that was euthanized follo...
Panizzi L, Vignes M, Dittmer KE, Waterland MR, Rogers CW, Sano H, McIlwraith CW, Pemberton S, Owen M, Riley CB.to determine the accuracy of infrared (IR)-based serum biomarker profiling to differentiate horses with early inflammatory changes associated with a traumatically induced model of equine carpal osteoarthritis (OA) from controls. Methods: unilateral carpal OA was induced in 9 of 17 healthy Thoroughbred fillies, while the remainder served as sham operated controls. Serum samples were obtained before induction of OA (Day 0) and weekly thereafter until Day 63 from both groups. Films of dried serum were created, and IR absorbance spectra acquired. Following pre-processing, partial least squares dis...
Ravanetti P, Kühnle C, Lechartier A, Zucca E.To date, only a few reports describe the treatment. The present report describes an extraarticular surgical approach, with the insertion of an absorbable implant, to treat a Subchondral cystic lesion (SCL) in the humeral head 3year old racing Thoroughbred & in the talus of a 11year old Arabian horse. SCLs were radiographically visible and associated with severe lameness. Scintigraphy showed focal intense radiopharmaceutical uptake in both cases, and CT scan revealed signs of osteoarthrosis associated with SCL in the talus. The use of a biocompatible, osteoinductive and osteoconductive implant ...
Campos Schweitzer A, Mespoulhès-Rivière C, Möller D, Ducharme N, Genton M, Farfan M, Rossignol F.Selective laryngeal reinnervation using the first and second cervical nerve (C1C2) is a treatment option for recurrent laryngeal neuropathy that aims to restore the function of the cricoarytenoideus dorsalis (CAD) muscle. Despite the technique's satisfying success rate, it has several limitations. These triggered the search for another potential donor nerve that could reduce CAD muscle fatigue and shorten rehabilitation. The ventral branch of the spinal accessory nerve, providing motor innervation to the sternomandibularis (SM) muscle, was identified as a potentially well-adapted nerve. Object...
Kambayashi Y, Nemoto M, Tsujimura K, Ohta M, Bannai H.Equine coronavirus (ECoV) causes fever, lethargy, anorexia and gastrointestinal signs in horses. There has been limited information about the prevalence and seasonality of ECoV among Thoroughbreds in Japan. Objective: To understand the epidemiology and to evaluate the potential risk of ECoV infection to the horse industry in Japan. Methods: Longitudinal. Methods: The virus-neutralisation (VN) test was performed using sera collected three times a year at 4 months intervals from 161 yearlings and at 6-7 months intervals from 181 active racehorses in Japan in 2017-2018, 2018-2019 and 2019-2020....
Busse NI, Gonzalez ML, Wagner AL, Johnson SE.Optimal athletic performance requires meeting the energetic demands of the muscle fibers, which are a function of myosin ATPase enzymatic activity. Skeletal muscle with a predominant oxidative metabolism underlies equine athletic success. Sodium butyrate, a short-chain fatty acid, can affect muscle fiber composition in pigs. To determine if a similar scenario exists in horses, 12 adult Thoroughbred geldings (7.4 ± 0.6 yr of age; mean ± SEM) were fed 16 g of calcium butyrate (CB) or an equivalent amount of carrier (CON) daily for 30 d in a crossover design. Middle gluteal muscle biopsies were...
Park JW, Kim KH, Kim S, So JR, Cho BW, Song KD.The integration of metabolomics and transcriptomics may elucidate the correlation between the genotypic and phenotypic patterns in organisms. In equine physiology, various metabolite levels vary during exercise, which may be correlated with a modified gene expression pattern of related genes. Integrated metabolomic and transcriptomic studies in horses have not been conducted to date. The objective of this study was to detect the effect of moderate exercise on the metabolomic and transcriptomic levels in horses. In this study, using nuclear magnetic resonance (NMR) spectroscopy, we analyzed the...
Kim J, Jung H, Choi JY, Lee JW, Yoon M.Dopamine (DA) is known to be a key modulator of animal behaviors. Thus, the plasma concentration of DA might be used as a biomarker for the behavioral characteristics of horses. The behavioral characteristics of horses vary depending on the breed, age, and sex. Moreover, the DA receptor genotypes are also related to horse behaviors. Thus, the aim of this study was to investigate the DA concentration variations of horse plasma by breed, age, sex, or genotype of its receptor. The horses were divided by breed into Thoroughbred (n = 13), Pony (n = 9), Warmblood (n = 4), and Haflinger (n = 5). The ...
Cappelli K, Ciucis CG, Mecocci S, Nervo T, Crescio MI, Pepe M, Gialletti R, Pietrucci D, Migone LF, Turco S, Mechelli L, Passamonti F, Drago C....Equine Papillomavirus 2 (EcPV2) is responsible for squamous cell carcinomas (eSCCs) of external genitalia of both male and female horses. However, few studies report the EcPV2 prevalence among healthy horses. Currently, the lack of these data does not permit identifying at-risk populations and, thus, developing screening protocols aimed at the early detection of the infection, as for humans. The aim of our study was to estimate the genoprevalence of EcPV2 in clinically healthy horses in Italy and to evaluate their innate immune response. For this purpose, penile and vulvar swabs of 234 healthy...
Wen X, Luo S, Lv D, Jia C, Zhou X, Zhai Q, Xi L, Yang C.The horse gut is colonized by a rich and complex microbial community that has important roles in horse physiology, metabolism, nutrition, and immune functions. Fewer across-breed variations in horse gut microbial diversity have been illustrated. In this article, the gut microbiota of Thoroughbred, Mongolian, and Hybrid horses [first filial generation (F1) of Mongolian (maternal) and Thoroughbred (paternal)] were studied by second-generation high-throughput sequencing technology. Differences in gut microbiota composition and function between breeds were determined using diversity and functional...
Dias De Castro LL, Oliveira Júnior GA, Perez BC, Carvalho ME, De Souza Ramos EA, Ferraz JBS, Molento MB.Cyathostomins are considered one of the most important parasites of horses. A group of horses within a herd can be responsible for eliminating the majority of parasite eggs. This phenotype might be explained by genetic factors. This study aimed to identify genomic regions associated with fecal egg count (FEC) and hematological parameters by performing a genomic-wide association study (GWAS) in Thoroughbred horses naturally infected with cyathostomins. Packed cell volume (PCV), differential leukocyte, and FEC were determined from 90 horses. All animals were genotyped using the Illumina Equine 7...
Salem SE, Sinnott A, Roach JM, Verheyen KLP, de Mestre AM.Multiple pregnancies (MPs) are commonly diagnosed during breeding management of mares. Whilst some studies have reported on factors associated with the risk of MPs, few have utilised multivariable data analysis to control for confounding variables. A prospective cohort study of Thoroughbred broodmares was conducted with information collected on 27 factors. Mixed-effects logistic regression was used to determine risk factors for MPs. Mare, stallion, stud, and veterinarian were evaluated as random effects. The prevalence of MPs in 1754 mares and 2245 pregnancies was 16.06% (95% confidence interv...
Müller A, Glüge S, Vidondo B, Wróbel A, Ott T, Sieme H, Burger D.Prediction of impending foaling is highly desirable as early intervention may improve mare and foal outcomes. However, monitoring the peripartum mare is a time-consuming challenge for breeders and many foaling prediction systems have limitations. "Heating up" of the mare is empirically used by breeders as a sign of upcoming parturition in mares. The purpose of this study was to investigate if an increase in skin temperature shortly before parturition is detectable and to determine whether such physiological changes could be an additional valuable parameter to predict foaling. For that, 56 foal...
Bimson NH, Morrice-West AV, Wong ASM, Hitchens PL, Rocca MR, Whitton RC.Catastrophic musculoskeletal injuries (CMI) pose a major welfare concern to horses and their riders, yet limited data are available describing their occurrence in South America. Using a retrospective cohort and case-control design, the objective of the study was to determine the incidence of CMI for Thoroughbreds in training and racing, and associated horse-level risk factors in Uruguay. Seventy-seven Thoroughbreds sustained a CMI, 37 of which were age- and sex-matched to 111 control horses in the same race. Training and racing data from 2011 to 2017 were collected. Incidence of race day CMI p...
Kinnison T, McGilvray TA, Couëtil LL, Smith KC, Wylie CE, Bacigalupo SA, Gomez-Grau E, Cardwell JM.Current consensus defines mild-moderate equine asthma (mEA; previously inflammatory airway disease) by a hierarchy of indicators of lung pathology: cough, poor performance, increased tracheobronchial mucus, inflammatory bronchoalveolar lavage (BAL) cytology and pulmonary dysfunction. Exclusion criteria include fever, systemic disease, or increased resting respiratory effort. The aim of this review was to inform future research by identifying gaps, strengths and weaknesses in the current body of evidence supporting this consensus-proposed definition. Objectives were to critique evidence support...
Fitzharris LE, Hezzell MJ, McConnell AK, Allen KJ.Little is known about the response of the equine respiratory muscles to training. Objective: To measure an index of inspiratory muscle strength (IMSi) before and after a period of conventional exercise training (phase 1) and inspiratory muscle training (IMT), comparing high-load (treatment) and low-load (control) groups (phase 2). Methods: Prospective randomised controlled trial. Methods: Phase 1: Twenty National Hunt Thoroughbred racehorses performed an inspiratory muscle strength test (IMST) twice on two occasions; when unfit at timepoint A (July), and when race fit at timepoint B (October)....
Morrice-West AV, Hitchens PL, Walmsley EA, Tasker K, Lim SL, Smith AD, Whitton RC.Fatigue life (FL) is the number of cycles of load sustained by a material before failure, and is dependent on the load magnitude. For athletes, 'cycles' translates to number of strides, with load proportional to speed. To improve previous investigations estimating workload from distance, we used speed (m/s, x) per stride collected using 5 Hz GPS/800 Hz accelerometer sensors as a proxy for limb load to investigate factors associated with FL in a Thoroughbred race start model over 25,234 race starts, using a combination of mathematical and regression modelling. Fore-limb vertical force (NKg) w...
Patterson Rosa L, Whitaker B, Allen K, Peters D, Buchanan B, McClure S, Honnas C, Buchanan C, Martin K, Lundquist E, Vierra M, Foster G, Brooks SA....Commonly known as "Kissing Spines" (KS), the pathological mechanisms underlying impingement and overriding of spinous processes (ORSPs) in horses are poorly understood. Thoroughbreds, Warmbloods, and stock-type breeds, including Paint Horses and Quarter Horses are at increased risk for developing clinical signs of KS. A total of 155 stock-type and Warmblood horses presented at collaborating veterinary clinics and hospitals were examined using a strict clinical and radiographical phenotyping scheme to grade each horse from 0 for unaffected controls to 4 for severe KS. Following genotyping with ...
Hill EW, Stoffel MA, McGivney BA, MacHugh DE, Pemberton JM.Small effective population sizes and active inbreeding can lead to inbreeding depression due to deleterious recessive mutations exposed in the homozygous state. The Thoroughbred racehorse has low levels of population genetic diversity, but the effects of genomic inbreeding in the population are unknown. Here, we quantified inbreeding based on runs of homozygosity (ROH) using 297 K SNP genotypes from 6128 horses born in Europe and Australia, of which 13.2% were unraced. We show that a 10% increase in inbreeding () is associated with a 7% lower probability of ever racing. Moreover, a ROH-based g...
Ochi A, Nishioka T, Kurimoto S, Kishi D, Ueno T, Nukada T.A 2-year-old male Thoroughbred horse presented with a mass in the maxilla. The focally ulcerated mass, approximately 8 cm in diameter, covered the upper left intermediate and corner incisor teeth (nos. 602 and 603 according to the modified Triadan system) and radiographic examination revealed displacement and lysis of the incisors. Histologically, the tumour was composed of a dense proliferation of spindle-shaped cells and neoplastic odontogenic epithelial cells arranged in island, follicular, plexiform or sheetlike patterns. The spindle-shaped cells were immunopositive for cytokeratins AE1/A...
Rojas-Núñez I, Gomez AM, Palmer S, Mohammed HO.Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in inju...
Pearce DJ, Hitchens PL, Malekipour F, Ayodele B, Lee PVS, Whitton RC.Fatigue-induced subchondral bone (SCB) injury is common in racehorses. Understanding how subchondral microstructure and microdamage influence mechanical properties is important for developing injury prevention strategies. Mechanical properties of the disto-palmar third metacarpal condyle (MCIII) correlate poorly with microstructure, and it is unknown whether the properties of other sites within the metacarpophalangeal (fetlock) joint are similarly complex. We aimed to investigate the mechanical and structural properties of equine SCB from specimens with minimal evidence of macroscopic disease....
Brounts SH, Lund JR, Whitton RC, Ergun DL, Muir P.To evaluate the diagnostic capabilities of a novel helical fan beam CT system used for imaging of horses with a range of clinical distal limb problems. 167 horses. Medical records were reviewed of horses presented for CT of the distal limb at 2 university-based veterinary hospitals. The following data were recorded: age, sex, breed, presenting complaint, sedation used for imaging, scanning time, procedure time, other diagnostic imaging methods performed, imaging diagnosis, clinical diagnosis, and complications during imaging. Most horses were Thoroughbreds and Quarter Horses. Procedure times r...
McGuire TC, Crawford TB, Hallowell AL, Macomber LE.Failure in colostral immunoglobulin G (IgG) transfer was found in 9 of 87 Thoroughbred foals. Seven (78%) of these 9 foals acquired infections requiring therapy. Twelve of the foals had partial failure in colostral IgG transfer, and 3 of these had infections requiring therapy. The remaining 66 foals had normal transfer of colostral IgG, and only 2 had detectable infections. The failure of colostral IgG transfer was attributable to nursing problems in only one case. When presuckle postpartum colostrum was collected, 2 of 4 failures of colostral IgG transfer and 4 of 6 partial failures of colost...
Brown NA, Pandy MG, Buford WL, Kawcak CE, McIlwraith CW.To determine whether muscle moment arms at the carpal and metacarpophalangeal joints can be modeled as fixed-radius pulleys for the range of motion associated with the stance phase of the gait in equine forelimbs. Methods: 4 cadaveric forelimbs from 2 healthy Thoroughbreds. Methods: Thin wire cables were sutured at the musculotendinous junction of 9 forelimb muscles. The cables passed through eyelets at each muscle's origin, wrapped around single-turn potentiometers, and were loaded. Tendon excursions, measured as the changes in lengths of the cables, were recorded during manual rotation of th...
Chapman PS, Green C, Main JP, Taylor PM, Cunningham FM, Cook AJ, Marr CM.A total of 1235 tracheal aspirates taken from 724 thoroughbreds in race training, aged from two to 10 years, were examined cytologically and bacteriologically. An inflammation scoring system on a scale of 0 to 9 was devised to allow the severity of lower airway disease to be assessed from the cytological results. The inflammation scores were closely related to the isolation of bacteria (P<0.001), and the most common bacterial isolates were Streptococcus zooepidemicus, Streptococcus pneumoniae and Pasteurella/Actinobacillus-like species. Lower airway disease was less common in older horses (...
Anderson TM, McIlwraith CW, Douay P.The relationship of conformation to future potential injury is a standard approach in practise but, at present, is largely based on subjective observations. Objective: To measure conformation in 3-year-old Thoroughbreds and objectively test its relationship with the occurrence of musculoskeletal problems. Methods: Conformation measurements were taken from photographs using specific reference points marked on the horses and processed on the computer. Clinical observations were recorded for each horse on a regular basis. Stepwise (forward) logistic regression analysis was performed to investigat...
Graham R, McManus P.Changing social values and new technologies have contributed to increasing media attention and debate about the acceptable use of animals in sport. This paper focuses on the use of the whip in thoroughbred horse racing. Those who defend its use argue it is a necessary tool needed for safety, correction and encouragement, and that it does not cause the horse any pain. For those who oppose its use, it is an instrument of cruelty. Media framing is employed to unpack the discourses played out in print and social media in the UK (2011) and Australia (2009) during key periods of the whip debate foll...
Hada T, Onaka T, Takahashi T, Hiraga A, Yagi K.This study investigated the effects of novelty stress on neuroendocrine activities and running performance in Thoroughbred horses. First, to examine the neuroendocrine responses to novelty stress, we exposed horses to two types of novel environmental stimuli (audiovisual or novel field stimuli). After the stimuli, plasma concentrations of vasopressin, catecholamines and adrenocorticotropin (ACTH), as well as heart rates, were significantly increased in each experiment. Second, we investigated neuroendocrine activities during incremental exercise. Plasma concentrations of vasopressin, catechola...
Wylie CE, McManus P, McDonald C, Jorgensen S, McGreevy P.Monitoring racehorse fatality and associated jockey falls provides benchmarks for intervention strategies. The aims of this study were to describe the incidence of and reasons for fatalities in Thoroughbred horses during flat races in the Australian Capital Territory and New South Wales (NSW), Australia, and to describe reported jockey falls and injuries associated with racehorse fatalities. A cohort study identified all racehorse fatalities reported through Racing NSW for the 2009-2010 to 2013-2014 racing seasons. Risks of racehorse fatality, fatal musculoskeletal injury, spontaneous death (a...
Newton JR, Wood JL.In an epidemiological study of risk factors for exercise-induced pulmonary haemorrhage (EIPH) in young Thoroughbreds in the UK, in which 148 horses contributed 1614 horse-months of data, there were 64 (4%) episodes of endoscopically visible tracheal bleeding and 824 (51%) episodes of increased quantities of haemosiderophages in tracheal washes. There were increases in prevalence and risk of EIPH by both definitions with age from or = 4 years, season of sampling from winter (Nov-Jan) to autumn (Aug-Oct) and several different measures of airway inflammation, including tracheal mucus, neutrophil...
Tozaki T, Hill EW, Hirota K, Kakoi H, Gawahara H, Miyake T, Sugita S, Hasegawa T, Ishida N, Nakano Y, Kurosawa M.Using 1710 Thoroughbred racehorses in Japan, a cohort study was performed to evaluate the influence of genotypes at four single nucleotide polymorphisms (SNPs) on equine chromosome 18 (ECA18), which were associated in a previous genome-wide association study for racing performance with lifetime earnings and performance rank. In males, both g.65809482T>C and g.65868604G>T were related to performance rank (P= 0.005). In females, g.65809482T>C (P = 1.76E-6), g.65868604G>T (P=6.81E-6) and g.66493737C>T (P=4.42E-5) were strongly related to performance rank and also to lifetime ...
Stull CL.Nine trailer loads of horses (n = 306) transported to slaughter facilities with distances ranging 596 to 2,496 km were studied to characterize the type of horses used in commercial markets and the physiological responses and number of injuries due to transportation under summer environmental conditions. Slaughter horse candidates were middle-aged (11.4+/-.4 yr), possessed moderately fleshy body condition, weighed 432+/-3.3 kg, and were of Quarter Horse or Thoroughbred breeding. The mean weight loss during commercial transport was 4%. The percentage of injured horses was greater (P < .05) fo...
Kiryu K, Machida N, Kashida Y, Yoshihara T, Amada A, Yamamoto T.Five racehorses in apparently normal condition succumbed to sudden cardiac death (SCD) during or shortly after intensive training exercise. Cardiopathologic examination was performed. In 1 of the 5 horses, the use of an electrocardiogram (ECG) recording taken continuously for 440 sec enabled us to analyze some of the arrhythmias in the terminal event of SCD. The ECG tracing exhibited the R-on-T phenomenon following a pair of ventricular premature contractions (VPCs). The phenomenon rapidly degenerated into ventricular fibrillation, which led to cardiac arrest. In all 5 horses cardiopathologic ...
O'Brien T, Baker TA, Brounts SH, Sample SJ, Markel MD, Scollay MC, Marquis P, Muir P.To compare digital radiography (DR), computed tomography (CT), and magnetic resonance imaging (MRI) for detection of pathology of the distal aspect of the third metacarpal bone (MC3) and to assess whether arthrography would improve detection of articular cartilage or subchondral bone cracking. Methods: Cross-sectional study. Methods: Limb specimens from 17 Thoroughbred horses after catastrophic injury and 4 age-matched control horses. Methods: Standard DR, CT, and MRI images of the metacarpophalangeal joint were acquired before and after iohexol injection. Pathologic features detected with ima...
Kamm JL, Parlane NA, Riley CB, Gee EK, Dittmer KE, McIlwraith CW.As the search for an immune privileged allogeneic donor mesenchymal stem cell (MSC) line continues in equine medicine, the characterization of the cells between different sources becomes important. Our research seeks to more clearly define the MSC marker expression of different equine MSC donors. The bone marrow-derived MSCs from two equine breeds and different blood donor-types were compared over successive culture passages to determine the differential expression of important antigens. Eighteen Thoroughbreds and 18 Standardbreds, including 8 blood donor (erythrocyte Aa, Ca, and Qa antigen ne...
Hill EW, Fonseca RG, McGivney BA, Gu J, MacHugh DE, Katz LM.Sequence variation at the equine myostatin gene (MSTN) locus has previously been shown to have a singular genomic influence on optimum race distance in Thoroughbred racehorses. Myostatin, encoded by the MSTN gene, is a member of the TGF-β superfamily that regulates skeletal muscle development in a range of mammalian species including the horse. In the Thoroughbred, the C-allele at the g.66493737C/T SNP has been found at significantly higher frequency in subgroups of the population that are suited to fast, short distance, sprint races and also influences body composition phenotypes. We investi...
Tanabe S, Suzuki T, Wasano Y, Nakajima F, Kawasaki H, Tsuda T, Nagamine N, Tsurumachi T, Sugaya K, Akita H, Takagi M, Takagi K, Inoue Y, Asai Y....We previously isolated the commensal bacteria lactobacilli and bifidobacteria from the Thoroughbred intestine and prepared the horse probiotics LacFi(TM), consisting of Lactobacillus ruminis KK14, L. equi KK 15, L. reuteri KK18, L. johnsonii KK21, and Bifidobacterium boum HU. Here, we found that the five LacFi(TM) constituent strains remarkably suppressed pro-inflammatory interleukin-17 production in mouse splenocytes stimulated with interleukin-6 and transforming growth factor-β. The protective effects of the probiotic on impaired intestinal barrier function were evaluated in Caco-2 cells tr...
Levine JM, Ngheim PP, Levine GJ, Cohen ND.To determine sex, breed, and age distributions in a population of horses with cervical vertebral compressive myelopathy (CVCM), compared with contemporaneous control horses. Methods: Retrospective case-control study. Methods: 811 horses with CVCM and 805 control horses. Methods: The Veterinary Medical Database was searched to identify horses with CVCM and contemporaneous control horses registered between July 1974 and August 2007. Admission date, admitting institution, sex, breed, age at the time of registration in the database, weight, and discharge status (alive, died, or euthanized) were re...
Ohmura H, Hiraga A, Takahashi T, Kai M, Jones JH.To determine prevalence of atrial fibrillation (AF) immediately after racing among racehorses that finished well behind the winners and examine potential risk factors for AF in these horses. Methods: Case-control study. Methods: 39,302 racehorses representing 404,090 race starts in races sanctioned by the Japan Racing Association between 1988 and 1997. Methods: Horses that finished > or = 4 (turf races) or 5 (dirt races) seconds behind the winner or that did not complete the race were examined for AF within 5 minutes after the race. Logistic regression and chi2 analyses were used to determine ...
Bailey CJ, Reid SW, Hodgson DR, Suann CJ, Rose RJ.Risk factors for musculoskeletal injury in racing Thoroughbreds were investigated in a case-control study conducted at racetracks administered by the Australian Jockey Club. Univariable analysis of 137 cases from the official Veterinary Surgeon's reports and an equal number of randomly selected controls from the Australian Race Results identified field size, barrier position and class of race as being significantly associated with breakdown (P < 0.05). Multiple logistic regression was then used to investigate the effect of each putative risk factor whilst controlling for all others. Horses at ...
Newton JR, Wood JL, Chanter N.A matched case control study was used to determine infections and other factors associated with clinically apparent respiratory disease in young racehorses in training in the UK. A total of 170 cases, defined as horses with sudden onset coughing, nasal discharge or pyrexia, were identified and matched to 632 non-affected controls by trainer and time period. Factors examined included age, sex, time since entry into the training yard, time since last race and different infections including tracheal and nasopharyngeal (NP) bacteria and viruses. Multivariable conditional logistic regression (CLR) ...
Kuroda T, Kinoshita Y, Niwa H, Shinzaki Y, Tamura N, Hobo S, Kuwano A.Meticillin-resistant Staphylococcus aureus (MRSA) infections have been confirmed in hospitalised Thoroughbred racehorses at the hospitals of two training centres in Japan since 2009. To investigate the source of infection, the authors examined the rate of nasal MRSA colonisation in 600 healthy Thoroughbred racehorses, 53 veterinarians and 16 office staff at the racehorse hospitals of the two training centres. MRSA was not isolated from healthy Thoroughbred racehorses or hospital office staff. However, MRSA was isolated from 16 veterinarians (30.1 per cent), and the colonisation rate was signif...
Tozaki T, Kikuchi M, Kakoi H, Hirota KI, Nagata SI.Body weight is an important trait to confirm growth and development in humans and animals. In Thoroughbred racehorses, it is measured in the postnatal, training, and racing periods to evaluate growth and training degrees. The body weight of mature Thoroughbred racehorses generally ranges from 400 to 600 kg, and this broad range is likely influenced by environmental and genetic factors. Therefore, a genome-wide association study (GWAS) using the Equine SNP70 BeadChip was performed to identify the genomic regions associated with body weight in Japanese Thoroughbred racehorses using 851 individua...
le Jeune SS, Nieto JE, Dechant JE, Snyder JR.Gastroscopic examinations were performed in 62 Thoroughbred broodmares (33 pregnant, 29 non-pregnant) at one breeding farm to investigate the prevalence of gastric ulceration. Age, pregnancy status, race earnings, last race start, herd size, medical history, number of live foals, breeding years, feed type and number of feedings were recorded, plus coat condition and body condition score were determined. Twenty-one mares were re-evaluated after foaling, and the foaling date, foal weight at birth and placenta weight were recorded. The overall prevalence of gastric ulcers was 70.9%, with a median...
Fawcett JA, Sato F, Sakamoto T, Iwasaki WM, Tozaki T, Innan H.The domestication process of plants and animals typically involves intense inbreeding and directional selection for various traits. Here, we genotyped 370 Japanese Thoroughbred horses using the recently developed 670k SNP array and performed various genome-wide analysis also using genotype data of other horse breeds. We identified a number of regions showing interesting patterns of polymorphisms. For instance, the region containing the MC1R locus associated with chestnut coat color may have been targeted by selection for a different mutation much earlier on than the recent selection for chestn...
Rose BV, Firth M, Morris B, Roach JM, Wathes DC, Verheyen KLP, de Mestre AM.Therapeutic practices in equine reproductive medicine have dramatically evolved over the last 20 years but current usage is not described. The aims of this study were to provide a description of medication use and clinical findings of reproductive examinations alongside measures of reproductive efficiency in thoroughbreds. A prospective cohort study was conducted in the 2013 and 2014 breeding seasons. Mare and stallion details, information on veterinary interventions and findings of reproductive ultrasound scans were collected using questionnaires and entered into a custom-designed Microsoft A...
Moon S, Lee JW, Shin D, Shin KY, Kim J, Choi IY, Kim J, Kim H.Using next-generation sequencing, we conducted a genome-wide scan of selective sweeps associated with selection toward genetic improvement in Thoroughbreds. We investigated potential phenotypic consequence of putative candidate loci by candidate gene association mapping for the finishing time in 240 Thoroughbred horses. We found a significant association with the trait for Ral GApase alpha 2 (RALGAP2) that regulates a variety of cellular processes of signal trafficking. Neighboring genes around RALGAP2 included insulinoma-associated 1 (INSM1), pallid (PLDN), and Ras and Rab interactor 2 (RIN2)...
Morley PS, Hanson LK, Bogdan JR, Townsend HG, Appleton JA, Haines DM.Antibodies specific for equine influenza viruses are usually quantified using single radial hemolysis (SRH), hemagglutination inhibition (HI) or virus neutralization (VN). Neutralizing antibodies are thought to provide optimum protection to challenged animals. The purpose of this study was to determine the extent to which SRH and HI assays detect antibodies which neutralize equine influenza viruses. Acute and convalescent sera from 41 horses were analyzed using VN, SRH, and HI assays. These horses were present in a population of Thoroughbred racehorses during an epidemic of upper respiratory t...
Jasko DJ, Little TV, Lein DH, Foote RH.Information pertaining to evaluation of single ejaculates of semen and records for 2 consecutive breeding seasons were obtained. In all, data for 99 individual breeding seasons (n = 43 Standardbreds and 56 Thoroughbreds) were evaluated. Included in each semen evaluation was examination of semen characteristics and computer-aided analysis of spermatozoal movement characteristics. On the basis of the analysis of breeding records for 4,175 mares (7,017 estrous cycles), a per-estrous cycle fertility rate was calculated from data for 96 of the breeding seasons. Stallions with lower fertility than t...
Hanada M, Maeda Y, Oikawa MA.Uteri from 50 necropsied nonpregnant Japanese Thoroughbred brood mares (1-30 years of age) were investigated to clarify the histopathological characteristics of endometrosis in Japanese Thoroughbred mares and the distribution pattern of endometrosis lesions in the uterus as a whole. Endometrosis was observed in all animals over 6 years of age and in all of the 21 mares aged over 12 years of age. The affected mares showed elastofibrosis of arteries, veins and lymphatic vessels in the uterine wall, atrophy of the uterine smooth muscle layers and hyperplasia of collagen fibers among the smooth mu...
Hammond CJ, Mason DK, Watkins KL.Routine post mortem examination of 195 Thoroughbreds in Hong Kong revealed that 66 per cent suffered from gastric ulceration. Racehorses killed straight out of training suffered a significantly greater incidence of ulceration (80 per cent) than those having been retired for a month or more (52 per cent). The macroscopic findings post mortem enabled a classification of equine gastric ulceration to be suggested (Types 1, 2, 3), according to severity. Severe lesions (Types 2 and 3) were present in 45 per cent of horses put down from training and 5 per cent of retired horses. This difference was s...
