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.
Gueguen L, Henry S, Delbos M, Lemasson A, Hausberger M.(1) Background: Since antiquity, it is considered that sounds influence human emotional states and health. Acoustic enrichment has also been proposed for domestic animals. However, in both humans and animals, effects vary according to the type of sound. Human studies suggest that frequencies, more than melodies, play a key role. Low and high frequencies, music tuning frequency and even EEG slow waves used for 'neurofeedback' produce effects. (2) Methods: We tested the possible impact of such pure frequencies on racehorses' behavior and physiology. A commercial non-audible acoustic stimulus, co...
Pérez-Nogués M, López-Sanromán J, Spirito M, Manso-Díaz G.Subchondral cystic lesions (SCLs) in equines and their treatments have been mainly studied in the medial femoral condyle of the femur. SCLs in the distal extremities affecting the fetlock or interphalangeal joints are frequent, but treatment or prognosis studies in horses are currently sparse. Our objective was to compare four treatments for SCLs in the distal extremities (intralesional injection of corticosteroids, transcortical drilling, cortical screw placement, and absorbable hydroxyapatite implant placement) and report the racing prognoses for affected thoroughbred yearlings. Data from 11...
Daniel CR, Taylor SE, McPhee S, Wolfram U, Schwarz T, Sommer S, Kershaw LE.Fatigue-related subchondral bone injuries of the third metacarpal/metatarsal (McIII/MtIII) bones are common causes of wastage, and they are welfare concerns in racehorses. A better understanding of bone health and strength would improve animal welfare and be of benefit for the racing industry. The porosity index (PI) is an indirect measure of osseous pore size and number in bones, and it is therefore an interesting indicator of bone strength. MRI of compact bone using traditional methods, even with short echo times, fail to generate enough signal to assess bone architecture as water protons ar...
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...
Collery A, Browne JA, O'Brien C, Sheridan JT, Murphy BA.Hair follicles (HF) represent a useful tissue for monitoring the circadian clock in mammals. Irregular light exposure causes circadian disruption and represents a welfare concern for stabled horses. We aimed to evaluate the impact of two stable lighting regimes on circadian clock gene rhythmicity in HF from racehorses. Two groups of five Thoroughbred racehorses in training at a commercial racehorse yard were exposed to standard incandescent light or a customized LED lighting system. The control group received light from incandescent bulbs used according to standard yard practice. The treatment...
Dosi MCM, Riggs CM, May J, Lee A, Cillan-Garcia E, Pagan J, McGorum BC.There is a paucity of data relating to the vitamin D status of racehorses. We hypothesised that the management of racehorses in Hong Kong (HK) predisposes to low vitamin D status unless they receive dietary supplementation. Serum concentrations of 25-hydroxyvitamin D2 (25OHD2), 25-hydroxyvitamin D3 (25OHD3) and total 25-hydroxyvitamin D (total 25OHD) for 79 non-grazing HK racehorses were compared with those for 22 racehorses training in the United Kingdom (UK) that grazed for ≥1 h/d, and for which published data exists. A nested group of 41 HK horses was sampled twice to determine the effect...
Shan R, Steel CM, Sykes B.The impact of recommended withholding periods (RWPs) for omeprazole on the recurrence of Equine Gastric Ulcer Syndrome (EGUS) is unknown. The study was designed to compare the effect of two RWPs on EGUS recurrence post-omeprazole treatment and to determine if a nutraceutical supplement would reduce EGUS recurrence when administrated during an RWP. The study was a blinded, randomized clinical trial. Part 1: Horses were allocated to an RWP0 or RWP2 and crossed over after 4-weeks. Horses received oral omeprazole once daily, except during the RWPs at the end of the treatment periods. Part 2: Horse...
Anderson KA, Morrice-West AV, Wong ASM, Walmsley EA, Fisher AD, Whitton RC, Hitchens PL.Musculoskeletal injuries in racehorses are difficult to detect prior to catastrophic breakdown. Lameness is commonly attributed to orthopaedic pain in horses, therefore, subtle lameness may be a pre-clinical sign of injury and, if identified early, could allow for preventative intervention. Our objective was to determine if facial expressions could be used to detect mild lameness as an indicator of orthopaedic pain in 'fit to race' horses. The Horse Grimace Scale (HGS) and the facial expressions in ridden horses (FEReq), were used to score images (n = 380) of mildly lame (n = 21) and non-lame ...
Oheida AH, Shalgum AA, Alrtib AM, Booker AO, Ben-Naser KM, Davies HMS.Carpal conformation is an important factor in relation to joint soundness. The equine carpometacarpal joint (CMCJ) was reported to have variations in its three palmaromedial articulations. Lacking one or more of these articulations has not been radiographically evaluated in Thoroughbred (TB) and Standardbred (SB) racehorses. The study aimed to identify the prevalence of the variation in the palmaromedial articulation of the carpometacarpal joint (PM-CMCJ) in TB and SB horses. Additionally, to detect the probability of having each of the three articulations within and between the breeds. Finall...
Steel C, Ahern B, Zedler S, Vallance S, Galuppo L, Richardson J, Whitton C, Young A.Radiographs underestimate the extent of bone injury in horses with third carpal bone (C3) fractures (Fx). We aimed to describe bone pathologies identified using computed tomography (CT) and compare the diagnostic value of digital radiography (DR) and CT in horses with C3 Fx. CT images of 15 racehorses with C3 Fx and 10 controls were reviewed (Part 1) then DR and CT images of 26 racehorses (24 Thoroughbred, 2 Standardbred) with C3 Fx (Part 2) were evaluated. Agreement on fracture geometry and concomitant bone lesions was tested between DR and CT using the kappa statistic (Part 2). For agreement...
Busechian S, Conti MB, Sgorbini M, Conte G, Marchesi MC, Pieramati C, Zappulla F, Vitale V, Rueca F.Equine gastric ulcer syndrome (EGUS) is the most common disease of the stomach in horses and treatment is based on the oral administration of omeprazole for at least 28 days. Aim of this study was to compare the efficacy of two formulations of oral omeprazole-powder paste and gastro-enteric resistant granules-in the treatment of naturally occurring gastric ulcers in racehorses. Thirty-two adult racehorses, aged between 2 and 10 years old, with clinical signs of EGUS were included in this blinded, randomized clinical trial. Two gastroscopies were performed to evaluate gastric lesions in the squ...
Yokomori T, Ohnuma A, Tozaki T, Segawa T, Itou T.Considering the personality traits of racehorses (e.g., flightiness, anxiety, and affability) is considered essential to improve training efficiency and decrease accident frequency, especially when retraining for a second career that may involve contact with inexperienced personnel after retiring from racing. Studies on human personality-related genes are frequently conducted; however, such studies are rare in horses because a consistent methodology for personality evaluation is lacking. Using the recently published whole genome variant database of 101 Thoroughbred horses, we compared horse ge...
Li C, Li X, Guo R, Ni W, Liu K, Liu Z, Dai J, Xu Y, Abduriyim S, Wu Z, Zeng Y, Lei B, Zhang Y, Wang Y, Zeng W, Zhang Q, Chen C, Qiao J, Liu C, Hu S.As a domesticated species vital to humans, horses are raised worldwide as a source of mechanical energy for sports, leisure, food production, and transportation. The gut microbiota plays an important role in the health, diseases, athletic performance, and behaviour of horses. Here, using approximately 2.2 Tb of metagenomic sequencing data from gut samples from 242 horses, including 110 samples from the caecum and 132 samples from the rectum (faeces), we assembled 4142 microbial metagenome-assembled genomes (MAG), 4015 (96.93%) of which appear to correspond to new species. From long-read data, ...
Zielińska P, Soroko-Dubrovina M, Śniegucka K, Dudek K, Čebulj-Kadunc N.The aim of this study was to investigate the differences in the effects of high-intensity laser therapy (HILT) on skin surface temperature and vein diameter in the carpal joint region in racehorses with clipped and non-clipped treatment areas. The study included 20 Thoroughbreds split into two equal groups: clipped coat and non-clipped coat. Horses underwent thermographic examination to detect changes in skin surface temperature at the medial surface of the carpal joint, followed by ultrasonographic examination to assess changes in the diameter of the medial palmar vein before and after HILT. ...
Olave CJ, Ivester KM, Couetil LL, Burgess J, Park JH, Mukhopadhyay A.Racehorses commonly develop evidence of mild asthma in response to dust exposure. Diets deficient in omega-3 polyunsaturated fatty acids (Ω-3) might exacerbate this response. Objective: To compare dust exposure, bronchoalveolar lavage fluid (BALF) cytology, and plasma Ω-3 and specialized pro-resolving mediators (SPM) concentrations amongst racehorses fed dry hay, steamed hay, and haylage. Methods: Forty-three Thoroughbred racehorses. Methods: Prospective clinical trial. Horses were randomly assigned to be fed dry hay, steamed hay, or haylage for 6 weeks. Measures of exposure to dust in the...
Jager MC, Tomlinson JE, Henry CE, Fahey MJ, Van de Walle GR.Theiler's disease, a.k.a. equine serum hepatitis, is a devastating, highly fatal disease of horses. Equine parvovirus-hepatitis (EqPV-H) has been identified as the likely cause of this disease. While the incidence of Theiler's disease is low, the prevalence of EqPV-H DNA in horses is high, with up to 37% in some regions, suggesting that subclinical or persistent infection is common. To determine the prevalence and pathogenicity of EqPV-H infection at New York racetracks, DNA was extracted from archived formalin-fixed, paraffin-embedded liver tissues from racehorses submitted for necropsy to th...
Spriet M, Arndt S, Pige C, Pye J, O'Brion J, Carpenter R, Blea J, Dowd JP.This retrospective, methods comparison study aimed to compare skeletal scintigraphy and F-NaF positron emission tomography (PET) for the detection of abnormalities in the fetlocks of Thoroughbred racehorses. Thirty-three horses (72 limbs) imaged with both scintigraphy and F-NaF PET, for investigation of lameness or poor performance related to the fetlock, were included. Seven observers, including experienced racetrack practitioners, surgery and imaging residents, and a board-certified veterinary radiologist, independently reviewed all data for evidence of increased radiopharmaceutical uptake...
Nocera I, Puccinelli C, Sgorbini M, Bagnoli E, Citi S.In adult horses, specific ultrasound (US) features and reference values have been reported for the appearance of the joint cartilage and thickness according to the type of joint, such as femoropatellar and tarsocrural. The US appearance of the fetlock has been described in several diseases. The present research evaluates the US features of the metacarpal/tarsal-phalangeal joints in healthy racehorses according to age and breed, since no information is available in the literature. Seventy-one fetlocks in 28 healthy horses (15/28 thoroughbreds and 13/28 standardbreds) were assessed. The horses w...
McLean NL, McGilchrist N, Nielsen BD.Racehorses are often supplemented extra iron with the expectation that the iron will improve overall performance and health. A survey of 120 U.S. Thoroughbred trainers, representing 1978 Thoroughbreds from various regions of the U.S., was conducted to determine the average amount of dietary iron fed to Thoroughbred racehorses per day. Survey results indicated racehorses were fed an average of 3900 mg of iron per day from hay and grain alone. This exceeds the 0.8 mg/kg BW or 400 mg for a 500 kg working horse that the NRC 2007 recommends per day. Supplements increased the daily average intake of...
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....
Adepu S, Ekman S, Leth J, Johansson U, Lindahl A, Skiöldebrand E.Native biglycan (BGN), which can undergo proteolytic cleavage in pathological conditions, is well known to be involved in bone formation and mineralization. This study aimed to delineate the specific cleavage fragment, a neo-epitope for BGN (BGN), in synovial fluid (SF) from young racehorses in training, osteoarthritic (OA) joints with subchondral bone sclerosis (SCBS), and chip fracture joints. A custom-made inhibition ELISA was developed to quantify BGN in SF. Cohort 1: A longitudinal study comprising 10 racehorses undergoing long-term training. Cohort 2: A cross-sectional study comprising j...
Göktaş EF, Kabil E, Yatanaslan L, Güneş E, Dirikolu L.Caffeine is a naturally occurring alkaloid and it is metabolized to paraxanthine, theophylline and theobromine. Analysis of caffeine and its metabolites is challenging since the metabolites theophylline and paraxanthine generate similar product and precursor ions. In this study, a new method was developed for the simultaneous analysis of caffeine, paraxanthine, theobromine and theophylline in horse urine using gas chromatography-mass spectrometry (GC-MS). Urine samples were treated using solid-phase extraction followed by the elution with dichloromethane-isopropanol (90:10) after the pH was ad...
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...
Xu C, Wei Z, Tan F, Liu A, Yu F, Zhao A, Zhang L, Qi M, Zhao W.Cryptosporidium is a protozoan parasite causing diarrhoea in humans and animals. Although Cryptosporidium has been found in domestic horses (farmed or kept at pasture), there has been only one published study of Cryptosporidium infections in Chinese racehorses, which was restricted to a very small geographical area. Objective: To investigate the presence of Cryptosporidium spp. in the faeces of racehorses in China and to perform molecular characterisation of the parasite. Methods: Cross-sectional. Methods: A total of 621 fresh faecal samples were collected for DNA extraction from racehorses at...
Lo Feudo CM, Stancari G, Collavo F, Stucchi L, Conturba B, Zucca E, Ferrucci F.Dynamic upper airway obstructions (DUAO) are common in racehorses, but their pathogenetic mechanisms have not been completely clarified yet. Multiple studies suggest that alterations of the pharyngo-laryngeal region visible at resting endoscopy may be predictive of the onset of DUAO, and the development of DUAO may be associated with pharyngeal lymphoid hyperplasia (PLH), lower airway inflammation (LAI) and exercise-induced pulmonary hemorrhage (EIPH). The present study aims to investigate the possible relationship between the findings of a complete resting evaluation of the upper and lower ai...
Lucassen A, Hankel J, Finkler-Schade C, Osbelt L, Strowig T, Visscher C, Schuberth HJ.Feed supplements such as fermentation products (SCFP) alter immune responses in horses. The purpose of this study was to analyze whether a prebiotic activity of the SCFP alters the gut microbiome in horses. Racehorses were fed either SCFP (Olimond BB, OLI, = 6) or placebo pellets (PLA, = 5) for 43 days. Fecal microbiota analysis was performed using 16S rRNA gene sequencing. The numbers and function of circulating immune cell subpopulations were analyzed by flow cytometry. SCFP supplementation resulted in non-consistent differences in fecal microbiota between the PLA and OLI during the feedi...
Iimori M, Tamura N, Seki K, Kasashima Y.The onset of severe injury to the superficial digital flexor tendon (SDFT) is extremely difficult to predict from slight changes in ultrasonographic findings in cases with no apparent clinical signs. This study investigated the relationship between an increased cross-sectional area (CSA) or edema in the subcutaneous tissue around the tendon and the subsequent onset of severe SDFT injury in Thoroughbred racehorses. Horses were classified into three groups based on ultrasound diagnosis (USD) findings: Group A included cases with enlarged tendons; Group B included cases with tendons of normal siz...
Nyerges-Bohák Z, Nagy K, Rózsa L, Póti P, Kovács L.Changes in heart rate and heart rate variabilty (HRV) were investigated in untrained (UT; starting their first racing season) and detrained (DT; with 1-3 years of race experience) racehorses before and after 14-week conventional training. HRV was measured at rest over 1 h between 9:00 and 10:00 AM on the usual rest day of the horses. The smallest worthwhile change (SWC) rate was calculated for all HRV parameters. UT horses had significantly higher heart rate compared to DT (P<0.001). There were no gender- or training-related differences in heart rate. The root-mean-square of successive diff...
Johnston GCA, Ahern BJ, Palmieri C, Young AC.(1) Background: Parasagittal groove (PSG) changes are often present on advanced imaging of racing Thoroughbred fetlocks and have been suggested to indicate increased fracture risk. Currently, there is limited evidence differentiating the imaging appearance of prodromal changes in horses at risk of fracture from horses with normal adaptive modelling in response to galloping. This study aims to investigate imaging and gross PSG findings in racing Thoroughbreds and the comparative utility of different imaging modalities to detect PSG changes. (2) Methods: Cadaver limbs were collected from twenty ...
Muirhead TL, Wichtel JJ, Stryhn H, McClure JT.Serum selenium (Se), vitamin E, and resting thyroid hormone concentrations were measured in 201 horses in Prince Edward Island (PEI). Selenium concentrations were either marginal (0.0053 to 0.1200 ppm) or deficient (< 0.0053 ppm) in 79% of horses based on current reference ranges for Se in serum. Aged and young adult pleasure horses had a higher prevalence of inadequate Se concentrations compared to racehorses and broodmares (82% and 97% versus 45% and 72%, respectively). Overall, 13% of horses had inadequate (< 200 μg/dL) serum vitamin E concentrations; most of these were young pleasure hors...
Curtiss AL, Ortved KF, Dallap-Schaer B, Gouzeev S, Stefanovski D, Richardson DW, Wulster KB.Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention. Objective: To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse. Methods: Prospective cohort study. Methods: FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses...
Soroko M, Howell K, Dudek K, Henklewski R, Zielińska P.A previous thermographic study of racehorses identified 13 regions of interest (ROIs) for monitoring the impact of training. However, that investigation did not consider the influence of breed, age, gender or training intensity level on the temperature of ROIs. The present study adopted a multivariate analysis approach to determine whether the aforementioned factors, along with ambient temperature, significantly influenced ROI temperature in the key body regions. Thermography measurements were obtained from 53 racehorses of three breeds. Horses were in regular training for over 10 months, havi...
Manohar M, Hutchens E, Coney E.Exercise-induced pulmonary haemorrhage (EIPH) is a common occurrence in race horses. Although blood in cases of EIPH has been suspected to originate from the bronchial circulation, which receives approximately 1% of the left ventricular output, physiological evidence has recently emerged to indicate that the pulmonary circulation, which receives the entire output of the right ventricle, is a more likely source. High transmural pulmonary capillary pressures have been shown to cause breaks in the capillary endothelium, basement membrane as well as in the alveolar epithelium. Blood constituents e...
McIlwraith CW, Foerner JJ, Davis DM.The technique and results of arthroscopic surgery for the treatment of osteochondritis dissecans in 318 tarsocrural joints in 225 horses are reported. Of the 225 horses, 154 were racehorses or intended for racing. Arthroscopic surgery was an effective technique for treating osteochondritis dissecans of the tarsocrural joint. The overall functional ability and cosmetic appearance of the limbs were excellent. Post surgical follow-up information was obtained for 183 horses, of which 140 (76.5 per cent) raced successfully or performed their intended use following surgery. Of the remaining 43, 11 w...
McLellan J, Plevin S.Sesamoiditis is believed to be associated with injury to the suspensory branch attachment and is a common radiographic finding in yearling Thoroughbreds. No study has investigated relationships between yearling sesamoiditis and subsequent development of suspensory ligament branch injury (SLBI) in early racehorse training. Objective: To establish the prevalence of SLBI within a population of juvenile training racehorses and retrospectively investigate relationships between clinical signs of SLBI and sesamoiditis to determine if sesamoiditis is a risk factor for clinical suspensory branch injury...
Hughes KJ, Malikides N, Hodgson DR, Hodgson JL.To compare a fast Romanowsky cytological stain (Diff-Quik) and Leishman's stain for the detection of mast cells in samples from the lower airways of racehorses, and to compare the proportion of mast cells and eosinophils in the total inflammatory cells in tracheal aspirate (TA) with those in paired bronchoalveolar lavage (BAL) samples. Methods: Retrospective case series of 48 young Thoroughbred and Standardbred racehorses. Methods: Fifty-one paired TA and BAL samples were collected after treadmill exercise from 48 horses with poor racing performance. Two slides were prepared from each sample; ...
Konishi E, Shoda M, Kondo T.Japanese encephalitis virus (JEV) causes fatal diseases in equines as well as humans. In Japan, racehorses are vaccinated with inactivated JE vaccine every year and no equine JE cases have been reported since 1986. However, the current reduction in JEV activity in nature has raised an argument against the requirement of continuous vaccination. Here, we studied natural infection rates in racehorses to address the issue. To identify naturally-infected individuals from vaccinated populations, we used an immunostaining method for detecting antibodies to JEV nonstructural 1 (NS1) protein. A total o...
Olave CJ, Ivester KM, Couetil LL, Burgess J, Park JH, Mukhopadhyay A.Racehorses commonly develop evidence of mild asthma in response to dust exposure. Diets deficient in omega-3 polyunsaturated fatty acids (Ω-3) might exacerbate this response. Objective: To compare dust exposure, bronchoalveolar lavage fluid (BALF) cytology, and plasma Ω-3 and specialized pro-resolving mediators (SPM) concentrations amongst racehorses fed dry hay, steamed hay, and haylage. Methods: Forty-three Thoroughbred racehorses. Methods: Prospective clinical trial. Horses were randomly assigned to be fed dry hay, steamed hay, or haylage for 6 weeks. Measures of exposure to dust in the...
Carvallo FR, Uzal FA, Diab SS, Hill AE, Arthur RM.Respiratory diseases have a major impact on racehorses in training and are often cited as the second most common reason of horses failing to perform. Cases were submitted by the California Horse Racing Board to the California Animal Health and Food Safety laboratory for postmortem examination between January 1, 2005 and December 31, 2014. We determined the demographics of racehorses with fatal pneumonia, characterized the pathologic findings in animals with a postmortem diagnosis of respiratory infection, and determined the most significant pathogens associated with lower respiratory tract dis...
Riggs CM.Fractures are the cause of considerable morbidity and mortality among Thoroughbred racehorses. A significant proportion of these injuries occur in the absence of any particular traumatic incident. Evidence of prefracture pathology interpreted as fatigue damage has been identified in some such cases, but the aetiology of many of these so-called 'spontaneous' fractures remains obscure. Parasagittal fractures of the third metacarpal (McIII) and third metatarsal (MtIII) bones are one of the more common fractures to affect Thoroughbred racehorses. The configuration of each of these fracture types i...
Feige K, Fürst A, Eser MW.In a random population of Swiss horses 54% suffered from a subclinical to moderate COPD. Cause of a COPD is a hypersensitivity of the respiratory tract to spores of fungi and thermophil actinomyces. Teeth problems are strongly associated with the type of diet and the feeding regime. Problems of the teeth belong to the most often treated equine diseases by large animal practitioners. Racehorses are the population of horses most often affected by gastric ulcers with an ulcer prevalence between 63 and 90%. In contrast, a much lower prevalence (37%) of stomach ulcers is seen in pleasure horses and...
Pösö AR, Viljanen-Tarifa E, Soveri T, Oksanen HE.Effects of graded intensity exercise on plasma lipids was studied in Standardbred and Finnishbred Trotters. The rate of lipolysis indicated by the elevated plasma concentrations of glycerol increased parallel with the intensity of the trot in the Standardbreds, but not as clearly in the Finnishbred trotters. During the exercise plasma triglyceride concentration increased significantly and the increase correlated with the intensity of the exercise as well as the activity of lipolysis. Together with the increase in plasma triglycerides, there was a parallel increase in the pre-beta fraction of l...
Adepu S, Ekman S, Leth J, Johansson U, Lindahl A, Skiöldebrand E.Native biglycan (BGN), which can undergo proteolytic cleavage in pathological conditions, is well known to be involved in bone formation and mineralization. This study aimed to delineate the specific cleavage fragment, a neo-epitope for BGN (BGN), in synovial fluid (SF) from young racehorses in training, osteoarthritic (OA) joints with subchondral bone sclerosis (SCBS), and chip fracture joints. A custom-made inhibition ELISA was developed to quantify BGN in SF. Cohort 1: A longitudinal study comprising 10 racehorses undergoing long-term training. Cohort 2: A cross-sectional study comprising j...
Godlewska M, Soroko M, Zielińska P.The aim of the study was to assess the influence of high-intensity laser therapy (HILT) on vein diameter and on body surface temperature changes in the tarsal joint area in a group of clinically healthy racehorses. The hypothesis of the study was that HILT increases vein diameter and body surface temperature in healthy tissue. The study involved 16 Thoroughbreds being subjected to ultrasonographic examination to assess changes of diameter of the cranial branch of the medial saphenous vein and thermographic examination to indicate temperature change of the dorsal surface of the tarsal joint, ju...
Lo Feudo CM, Stancari G, Collavo F, Stucchi L, Conturba B, Zucca E, Ferrucci F.Dynamic upper airway obstructions (DUAO) are common in racehorses, but their pathogenetic mechanisms have not been completely clarified yet. Multiple studies suggest that alterations of the pharyngo-laryngeal region visible at resting endoscopy may be predictive of the onset of DUAO, and the development of DUAO may be associated with pharyngeal lymphoid hyperplasia (PLH), lower airway inflammation (LAI) and exercise-induced pulmonary hemorrhage (EIPH). The present study aims to investigate the possible relationship between the findings of a complete resting evaluation of the upper and lower ai...
Hare JE, Viel L, O'Byrne PM, Conlon PD.Some young horses with clinical signs of small airway disease demonstrate increased metachromatic cell numbers on bronchoalveolar lavage. The purpose of this study was to determine the effect of sodium cromoglycate treatment on clinical signs, bronchoalveolar lavage cytology and bronchoalveolar lavage histamine parameters in these horses. Twelve racehorses (age: 3.4 +/- 1.6 years) with a history of respiratory embarrassment at exercise, clinical signs of obstructive airway disease and bronchoalveolar lavage metachromatic cell differential greater than 2% were selected. Horses were randomly ass...
Lucassen A, Hankel J, Finkler-Schade C, Osbelt L, Strowig T, Visscher C, Schuberth HJ.Feed supplements such as fermentation products (SCFP) alter immune responses in horses. The purpose of this study was to analyze whether a prebiotic activity of the SCFP alters the gut microbiome in horses. Racehorses were fed either SCFP (Olimond BB, OLI, = 6) or placebo pellets (PLA, = 5) for 43 days. Fecal microbiota analysis was performed using 16S rRNA gene sequencing. The numbers and function of circulating immune cell subpopulations were analyzed by flow cytometry. SCFP supplementation resulted in non-consistent differences in fecal microbiota between the PLA and OLI during the feedi...
Ciamillo SA, Wulster KB, Gassert TM, Richardson DW, Brown KA, Stefanovski D, Ortved KF.Catastrophic injuries of the fetlock joints occur in Thoroughbred racehorses and are preceded by stress-induced bone injury. Early detection of subchondral bone injury is essential to prevent irreversible damage or bone failure. Objective: To investigate the use of standing, robotic cone-beam computed tomography (CBCT) for assessing longitudinal changes in subchondral bone morphology and pathology of the fetlock joints associated with race training in young Thoroughbreds. Methods: Observational cohort study. Methods: Forty-one 2-year-old Thoroughbred racehorses were recruited prior to the star...
Collery A, Browne JA, O'Brien C, Sheridan JT, Murphy BA.Hair follicles (HF) represent a useful tissue for monitoring the circadian clock in mammals. Irregular light exposure causes circadian disruption and represents a welfare concern for stabled horses. We aimed to evaluate the impact of two stable lighting regimes on circadian clock gene rhythmicity in HF from racehorses. Two groups of five Thoroughbred racehorses in training at a commercial racehorse yard were exposed to standard incandescent light or a customized LED lighting system. The control group received light from incandescent bulbs used according to standard yard practice. The treatment...
Konishi E, Shoda M, Kondo T.Recent reductions in numbers of human and equine Japanese encephalitis (JE) cases in Japan have seen calls to end JE vaccination. Here, we analyzed yearly variations of natural JE virus activity, using sera collected serially in 1998-2003 from racehorses residing in Ibaraki and Shiga prefectures, both located in central Japan. A total of 208 sera from 24 individuals in Ibaraki and 259 from 27 in Shiga were examined for antibodies to JE virus nonstructural 1 (NS1) protein, a marker of natural infection. The natural infection rate in epizootic seasons, which was determined by a significant incre...
Sullivan SL, Whittem T, Morley PS, Hinchcliff KW.Furosemide is the most commonly used medication for exercise-induced pulmonary haemorrhage (EIPH); however, critical evaluation of the strength of evidence for efficacy of furosemide is lacking and is warranted so that evidence-based treatment decisions can be made. Objective: To evaluate the efficacy of furosemide to reduce the severity or frequency of detection of EIPH in Thoroughbred and Standardbred racehorses. Methods: Systematic review with meta-analyses. Methods: Primary studies were identified via searches of electronic databases, relevant texts and reference lists of published article...
Ishida N, Hobo S, Takahashi T, Nanbo Y, Sato F, Hasegawa T, Mukoyama H.It has been suggested that a variety of stresses on animals may accelerate their production of superoxide. Racehorses are considered to be exposed to substantial oxide stress due to transport and exercise for training and racing. To determine the effect of exercise and transport on racehorses in terms of superoxide and antioxidative ability, changes in the superoxide-scavenging ability of equine serum were observed using electron spin resonance (ESR). Changes in the concentration of lipid peroxide, which is produced in equine serum by superoxide, were also examined. The analysis revealed that ...
Sugiura T, Matsumura T, Fukunaga Y, Hirasawa K.A sero-epizootiological study was conducted on horses which showed clinical pyrexia at two training centers, each of which maintained 1, 200 to 2, 100 racehorses for training, of the Japan Racing Association. It continued from 1980 to 1985 to clarify the cause of pyrexia, so that measures might be considered for the prevention of infectious disease. A total of 3, 849 horses were found to be affected with pyrexia for the 6 years. Of them, 2, 852 horses were tested to equine herpesvirus type 1 (EHV-1), equine rhinovirus type 1 (ERhV-1), rotavirus and equine adenovirus (EAdV) by collecting paired...
Ryan M, Gildea S, Walsh C, Cullinane A.More knowledge of equine influenza (EI) vaccine usage in training yards and the factors that influence serological response to vaccination are required to determine evidence-based vaccination strategies. Objective: The aim of this study was to ascertain the vaccination history of a population of Thoroughbred racehorses and identify factors that impacted on their antibody titres against EI. Methods: Observational field study. Methods: The study population consisted of 102 vaccinated Thoroughbred horses in training on a single premises. The vaccination histories recorded in their official passpo...
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....
Ohta M, Wakuno A, Okada J, Kodaira K, Nagata S, Ito M, Oku K.To evaluate the effects of IV fentanyl administration on the end-tidal sevoflurane concentration (ET(SEVO)) in thoroughbred racehorses, the ET(SEVO) required for internal fixation of longitudinal fractures was compared between horses anesthetized with sevoflurane-fentanyl (Group SF; n=9) and those anesthetized with sevoflurane alone (Group S; n=9). The loading dose of fentanyl (5.0 µg/kg) was administered over 15 min followed by a maintenance dose of fentanyl (0.1 µg/kg/min) throughout the operation in Group SF. The mean ET(SEVO) during the operation in Group SF (2.6 ± 0.2%) was significant...
Olive J, D'Anjou MA, Girard C, Laverty S, Theoret C.The purpose was to evaluate the capacity of 1.5 T magnetic resonance (MR) imaging to assess articular cartilage in racehorses with naturally occurring metacarpophalangeal joint osteoarthritis. A sagittal, three-dimensional spoiled gradient-recalled echo (SPGR) with fat saturation (FS) sequence was acquired ex vivo on 20 joints. Following joint dissection, specific areas on the third metacarpal condyle were designated for subsequent sampling for histologic cartilage thickness measurement and modified Mankin scoring. Cartilage thickness was measured and cartilage signal intensity was also graded...
Rey AI, Segura J, Arandilla E, López-Bote CJ.This study tested the effect of micellized vitamin E (D-α-tocopherol; 1,400 IU/d) administered 12 and 1 h orally before training for 1 d (ST-VitE) or 8 d (LT-VitE) compared with an unsupplemented control (CONTROL) on plasma α-tocopherol, thiobarbithuric acid-reactive substances (TBARS), total glutathione (GSHt), and trolox equivalent antioxidant capacity (TEAC) in 10 race horses. Different sampling times [immediately before training (BEF) and after intense training (END) or 8 h after recovery (+8h)] were investigated. Plasma α-tocopherol concentration was greater in the ST-VitE group than t...
