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.
Hackett ES, Embertson RM, Hopper SA, Woodie JB, Ruggles AJ.Large colon volvulus results in strangulating obstruction requiring surgical treatment. Duration of this disease prior to surgical treatment is likely to influence survival directly. Objective: The primary objective of this study was to evaluate the influence of duration of large colon volvulus on patient survival to discharge. Relationships between other factors and survival following large colon volvulus were also examined. Methods: Retrospective case analysis. Methods: Medical records of Thoroughbred mares aged ≥2 years undergoing surgical treatment for large colon volvulus between 1 Marc...
Morley PS, Bromberek JL, Saulez MN, Hinchcliff KW, Guthrie AJ.Exercise-induced pulmonary haemorrhage (EIPH) occurs commonly in Thoroughbred racehorses worldwide. While EIPH is believed to be an important cause of impaired performance in these horses, there is limited evidence from sufficiently powered studies to evaluate this association. Objective: To evaluate whether EIPH is associated with finishing position, distance finished behind race winners and differences in race earning among Thoroughbred horses racing in South Africa. Methods: Prospective cross-sectional study. Methods: One thousand Thoroughbred horses racing in South Africa were enrolled pri...
Bishop J, Heffron B, Taddei L, Benoit M, Hurt L, Costello S, Gross M, Negrusz A.Clenbuterol (CLE) is used in horses as a bronchodilator and for its anabolic steroid-like effects. CLE is a Class 3 drug according to current Association of Racing Commissioners International (ARCI) Uniform Classification Guidelines. The Racing Medication and Testing Consortium recommended a urine CLE threshold of 140 pg/mL after careful scientific review of the results of studies describing the disposition of CLE in the horse and this threshold was adopted by the ARCI. Enzyme-linked immunosorbent assay was previously used to screen samples for CLE in Illinois, but could not detect such low co...
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...
Stefaniuk M, Kaczor U, Augustyn R, Gurgul A, Kulisa M, Podstawski Z.Myostatin (GDF-8) encoded by the MSTN gene is a negative regulator of muscle growth and development and belongs to the TGF-β superfamily of secreted growth and differentiation factors. In Thoroughbred horses, an MSTN sequence polymorphism (g.66493737C>T) is associated with optimum race distance. In the present study, a genetic polymorphism of a predicted promoter of the MSTN gene was investigated in 451 horses belonging to five different breeds: Arabian, Thoroughbred, Polish Konik, Hucul and Polish Heavy Draft. Two SNPs located at g.66495826T>C and g.66495696T>C (chr;18 EquCab 2.0) s...
Umar MA, Fukui S, Kawase K, Itami T, Yamashita K.Cardiovascular effects of total intravenous anesthesia using ketamine-medetomidine-propofol drug combination (KMP-TIVA) were determined in 5 Thoroughbred horses undergoing surgery. The horses were anesthetized with intravenous administration (IV) of ketamine (2.5 mg/kg) and midazolam (0.04 mg/kg) following premedication with medetomidne (5 µg/kg, IV) and artificially ventilated. Surgical anesthesia was maintained by controlling propofol infusion rate (initially 0.20 mg/kg/min following an IV loading dose of 0.5 mg/kg) and constant rate infusions of ketamine (1 mg/kg/hr) and medetomidine (1.25...
Mirazo JE, Page P, Rubio-Martinez L, Marais HJ, Lyle C.Upper airway endoscopy at rest has been the diagnostic method of choice for equine upper respiratory tract (URT) conditions. Development of high-speed treadmill endoscopy improved the sensitivity of URT endoscopy by allowing observation of the horse's nasopharynx and larynx during exercise. However, treadmill exercise may not always accurately represent the horse's normal exercise as track surface, rider, tack and environmental variables are altered. Recently, the development of dynamic overground endoscopy (DOE) has addressed some of these shortcomings. A retrospective study was undertaken to...
Aleman M, Dimock AN, Wisner ER, Prutton JW, Madigan JE.A 2-year-old Thoroughbred gelding with clinical signs localized to the first 6 spinal cord segments (C1 to C6) had complete fusion of the atlanto-occipital bones which precluded performing a routine myelogram. An ultrasound-assisted myelogram at the intervertebral space between the atlas and axis was successfully done and identified a marked extradural compressive myelopathy at the level of the atlas and axis, and axis and third cervical vertebrae. Un hongre Thoroughbred âgé de 2 ans avec des signes cliniques localisés aux 6 premiers segments de la colonne vertébrale (C1 à C6) avait une ...
Velie BD, Hamilton NA, Wade CM.Performance data for 164,046 Thoroughbreds entered in a race or official barrier trial in Australia were provided by Racing Information Services Australia. Analyses estimating the heritability for a range of racing performance traits using a single-trait animal model were performed using ASREML-R. Log of cumulative earnings (LCE; 0.19 ± 0.01), log of earnings per race start (0.23 ± 0.02) and best race distance (0.61 ± 0.03) were all significantly heritable. Fixed effects for sex were significant (P < 0.001) for all performance traits aside from LCE (P = 0.382). With the exception of annual ...
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...
Ramzan PH, Palmer L, Powell SE.Fracture of the metacarpal/tarsal condyle is usually preceded by prodromal pathology. Early recognition of injury is desirable to minimise the risk of serious breakdown; however, the clinical and diagnostic characteristics of unicortical condylar fractures have been poorly documented to date. Objective: To describe the clinical, imaging and outcome features of racehorses in first opinion practice diagnosed with short unicortical fracture of the metacarpal/tarsal condyle. Methods: Retrospective case series. Methods: All flat racehorses sustaining a unicortical condylar fracture while under the ...
Cullinane M, O'Sullivan E, Collins DM, Byrne AW, More SJ.Recently, considerable international attention has been paid to the problem of unwanted horses. In Ireland, stray horses, particularly in urban areas, are a further problem. The Control of Horses Act 1996 was enacted in response to an ongoing problem of uncontrolled horses in public places. As yet, no research work has been conducted focusing on stray horses in Ireland. This paper describes horses impounded under the Act in the Munster region of Ireland during 2005-2012 and the factors influencing decisions regarding their disposal. A logistic regression model was developed to investigate fact...
Endo Y, Tsuchiya T, Omura T, Nakai K, Korosue K, Ishimaru M, Ishikawa Y, Hobo S.The present study evaluated the effects of single-dose marbofloxacin in protecting horses against fever associated with transportation using 48 healthy Thoroughbreds. All horses were premedicated with interferon-α (0.5 U/kg, sublingually, every 24 hr) for 2 days before transportation and on the day of transportation. Horses were randomly assigned to receive marbofloxacin (2 mg/kg, IV, once; MRFX group), enrofloxacin (5 mg/kg, IV, once; ERFX group) or saline (0.9% NaCl) solution (10 ml, IV, once; control group) ≤1 hr before being transportation. Each group contained 16 horses (8 males, 8 fem...
Ghosh S, Qu Z, Das PJ, Fang E, Juras R, Cothran EG, McDonell S, Kenney DG, Lear TL, Adelson DL, Chowdhary BP, Raudsepp T.We constructed a 400K WG tiling oligoarray for the horse and applied it for the discovery of copy number variations (CNVs) in 38 normal horses of 16 diverse breeds, and the Przewalski horse. Probes on the array represented 18,763 autosomal and X-linked genes, and intergenic, sub-telomeric and chrY sequences. We identified 258 CNV regions (CNVRs) across all autosomes, chrX and chrUn, but not in chrY. CNVs comprised 1.3% of the horse genome with chr12 being most enriched. American Miniature horses had the highest and American Quarter Horses the lowest number of CNVs in relation to Thoroughbred r...
Leutton JL, Lumsden JM.To investigate laryngeal function in cases of recurrent laryngeal neuropathy pre- and post laryngoplasty (LP) using dynamic respiratory endoscopy (DRE). Objective: To compare the rima glottidis area during DRE pre- and post LP; document all forms of dynamic upper airway obstruction (DUAO) pre- and post LP and investigate the relationship between post operative abduction at rest and exercise. Methods: Prospective case series. Methods: Thoroughbred racehorses with pre- and post LP DRE were included. Left-to-right arytenoid cartilage angle ratios and rima glottidis area ratios were used to quanti...
Ahern BJ, Boston RC, Ross MW.To evaluate equids with enostosis-like lesions (ELLs) and document the clinical and epidemiological features of this disease. Methods: Retrospective case series. Methods: 79 equids with a scintigraphic diagnosis of at least 1 ELL on ≥ 1 occasion. Methods: Medical records of 4,992 equids that underwent bone scintigraphy between March 1997 and March 2009 were reviewed; 78 horses and 1 pony had a scintigraphic diagnosis of an ELL. For those equids, signalment; physical, scintigraphic, radiographic, and lameness examination results; and outcome were reviewed. Results: Of the 79 equids, 4 (5.1%) ...
Coleridge MO, DiGiovanni DL, Rodgerson DH, Spirito MA.To describe the use of a wire snare technique for epiglottic entrapment. Methods: Case series. Methods: Eight adult horses. Methods: Under general anesthesia, a modified mouth gag was placed in the oropharynx. An endoscope was passed through the gag until there was adequate visualization of the entrapped epiglottis. The entrapping mucosa was grasped with bronchoesophageal forceps and pulled rostrally, releasing the epiglottis. A custom snare was passed down the bronchoesophageal forceps to encircle the redundant subepiglottic mucosa. Tension was applied to the entrapping mucosa via the forceps...
Sato F, Shibata R, Shikichi M, Ito K, Murase H, Ueno T, Furuoka H, Yamada K.Rupture of the gastrocnemius muscle is occasionally found in neonatal foals associated with dystocia and assisted delivery. In this report, 3 cases of gastrocnemius muscle disruption in newborn Thoroughbred foals (6, 5 and 2 days old) are reported. In all cases, the foals were presented with inability to rise unassisted postpartum, a dropped tarsus and swelling in the caudal aspect of the thigh accompanied by a hematoma. Ultrasonography, radiography, computerized tomography (CT) and subsequent autopsy were performed to confirm the clinical and pathological features of these cases.
Dall'Olio S, Scotti E, Fontanesi L, Tassinari M.The myostatin (MSTN) gene encodes a protein known to be a negative regulator of muscle mass in mammalian species. Different polymorphisms of the horse (Equus caballus) MSTN gene have been identified, including single nucleotide polymorphisms and a short interspersed nuclear element (SINE) insertion of 227 bp within the promoter of the gene. The SINE insertion has been associated with performance traits in Thoroughbred racehorses and it was proposed as a predictor of optimum racing distance. The aims of this study were to perform in silico analysis to identify putative gains or abrogation of tr...
Proudman CJ, Hunter JO, Darby AC, Escalona EE, Batty C, Turner C.The intestinal bacterial community of the horse is a key determinant of intestinal and whole body health. Understanding the bacterial community structure and function is an important foundation for studies of intestinal health and disease. Objective: To describe the faecal bacterial community and volatile organic compounds (VOCs) of the faecal metabolome of healthy Thoroughbred racehorses and to characterise responses to dietary supplementation with amylase-rich malt extract. Methods: Intervention study. Methods: Faecal samples were collected noninvasively before and 6 weeks after supplementat...
Wylie CE, Newton JR, Bathe AP, Payne RJ.The electronic patient records of all equine patients of Rossdales Equine Practice between January 1, 2005 and November 1, 2013 were reviewed to determine the number of cases of supporting limb laminitis (SLL) in a large equine practice and referral hospital setting in the UK and to discuss the implications for future epidemiological studies. The clinical notes were searched electronically for a combination of 'laminitis AND (contralateral OR supporting OR overload OR weight bearing)'. The prevalence of SLL within each identified denominator population and the corresponding 95% CI were calcu...
Clarke KL, Reardon R, Russell T.To determine if arthroscopic surgery performed on weanlings/yearlings with trochlear ridge OCD of the femur (stifle OCD), or intermediate ridge of the tibia (tarsal OCD) detected on routine presale radiographs affects future racing performance. Methods: Retrospective case control study. Methods: Thoroughbred weanlings and yearlings. Methods: Stifle (N = 37; 22 male, 15 female) and tarsal (N = 35; 22 male, 13 female) OCD cases were identified. Outcome measures relating to racing performance (number of race starts, wins, places, and prize money earned, from races in their 2- and 3-year-old racin...
Holmes JM, Mirams M, Mackie EJ, Whitton RC.Bone is repaired by remodelling, a process influenced by its loading environment. The aim of this study was to investigate the effect of a change in loading environment on bone remodelling by quantifying bone resorption and formation activity in the metacarpal subchondral bone in Thoroughbred racehorses. Sections of the palmar metacarpal condyles of horses in race training (n = 24) or resting from training (n = 24) were examined with light microscopy and back scattered scanning electron microscopy (BSEM). Bone area fraction, osteoid perimeter and eroded bone surface were measured withi...
Knych HK, Arthur RM, Stanley SD, McKemie DS.In order to ensure the welfare of performance horses and riders as well as the integrity of the sport, the use of both therapeutic and illegal agents in horse racing is tightly regulated. While Dehydroepiandrosterone (DHEA) is not specifically banned from administration to racehorses in the United States and no screening limit or threshold concentration exists, the metabolic conversion of DHEA to testosterone make its presence in nutritional supplements a regulatory concern. The recommended regulatory threshold for total testosterone in urine is 55 and 20 ng/mL for mares and geldings, respec...
Nielsen MK, Wang J, Davis R, Bellaw JL, Lyons ET, Lear TL, Goday C.The equine ascarid parasite Parascaris equorum is well known as a ubiquitous parasite infecting foals. A sibling species, Parascaris univalens, was first described over 130 years ago, but very little attention has been given to its existence and possible implications for anthelmintic resistance, clinical disease, or host age spectrum. P. univalens only possesses one germ line chromosome pair as opposed to two for P. equorum, but the two species are otherwise considered morphologically identical. For the present study, live worms obtained from the University of Kentucky parasitology horse herd ...
Wieder ME, Paine SW, Hincks PR, Pearce CM, Scarth J, Hillyer L.Salbutamol sulphate (Ventolin Evohaler) was administrated via the inhalation route to six horses at a dose of 0.5 mg every 4 h during the day for 2 days (total dose 4 mg). Urine and blood samples were taken up to 92 h postadministration. Hydrolyzed plasma and urine were extracted using solid phase extraction (SPE). A sensitive tandem mass spectrometric method was developed in this study, achieving a lower limit of quantification (LLOQ) for salbutamol of 10 pg/mL in plasma and urine. The parent drug was identified using UPLC-MS/MS. Most of the determined salbutamol plasma concentrations, post l...
Preston SA, Riggs CM, Singleton MD, Troedsson MH.Exercise-induced pulmonary haemorrhage (EIPH) is reported as a performance limiting condition in racehorses, yet few longitudinal studies characterising EIPH have been reported. Objective: To characterise EIPH during training and racing in the absence of prophylactic medication with furosemide among horses imported to Hong Kong during 2007-2012. Methods: Retrospective descriptive study of clinical endoscopy, EIPH status, and racing records. Methods: Thoroughbred geldings (n = 822) imported from New Zealand between 2007 and 2012 were retrospectively assigned to 4 groups: diagnosed with EIPH via...
Heffron B, Benoit M, Bishop J, Costello S, Hurt L, Simpson L, Taddei L, Kline K, Negrusz A.During prolonged strenuous exercise, racehorses can experience acidemia. To counteract this phenomenon, trainers can administer blood alkalizing agents that raise the plasma pH and total carbon dioxide (TCO2) concentration. In Illinois, the administrative threshold for TCO2 in plasma is 37.0 mmol/L. Because accuracy in the reported measurement of TCO2 must be ensured, uncertainty measurements are often issued alongside the reported concentrations. We report a validated method for measuring TCO2 levels in equine plasma using the Beckman UniCel DxC 600. A six-point calibration curve ranging from...
Trope GD, Ghasem-Zadeh A, Anderson GA, Mackie EJ, Whitton RC.High-resolution 3D imaging may improve the prediction and/or early identification of condylar fractures of the distal metacarpus/tarsus and reduce the frequency of breakdown injury in racehorses. Objective: To test the hypotheses that horses suffering condylar fractures have higher bone volume fraction (BV/TV) of the distal metacarpal epiphysis, greater subchondral bone thickness at the fracture site and higher second moment of inertia in the metacarpal midshaft as identified with high-resolution 3D imaging. Methods: Cross-sectional study using cadaver material. Methods: Thoroughbreds that die...
Matthee S.Anthelmintic products form the basis of helminth control practices on horse stud farms at present. Regular evaluation of the efficacy of these products is advisable, as it will provide information on the worm egg reappearance period and the resistance status in the worm population. The aim of this study was to evaluate the efficacy of doramectin, pyrantel pamoate, ivermectin and moxidectin on a Thoroughbred stud farm in the Western Cape Province, South Africa. The study also compared the anthelmintic efficacy of two moxidectin formulations administered at their recommended dosages (an injectab...
Tangyuenyong S, Sato F, Nambo Y, Murase H, Endo Y, Tanaka T, Nagaoka K, Watanabe G.This study aimed to compare body growth, metabolic, and reproductive hormonal changes in trained Thoroughbred yearling horses under different climate conditions with and without light supplementation (LS). Thoroughbred yearlings raised at research centers of the Japan Racing Association in Hokkaido (north) or Miyazaki (south) were divided into control and LS groups. In the LS groups, 44 colts and 47 fillies from Hokkaido and 11 colts and 11 fillies from Miyazaki were exposed to LS with an extended photoperiod of 14.5 hr of daylight and 9.5 hr of darkness. One week before and once a month after...
Musiał AD, Ropka-Molik K, Piórkowska K, Jaworska J, Stefaniuk-Szmukier M.In horses, the identification of the genetic background of phenotypic variation, especially with regard to performance characteristics and predisposition to effort, has been extensively studied. As α-actinin-3 function is related to the regulation of muscle contraction and cell metabolism, the ACTN3 gene is considered one of the main genetic factors determining muscle strength. The aim of the present study was to assess the genotype distribution of two SNP variants within the equine ACTN3 gene (g.1104G > A and c.2334C > T) across different utility types and horse breeds. The ana...
Manohar M, Goetz TE.The present study examined whether Thoroughbred horses performing strenuous exercise exhibit intrapulmonary arteriovenous shunting that may contribute to the observed arterial hypoxemia. Experiments were carried out on seven healthy, exercise-trained Thoroughbreds at rest, maximal exercise (galloping at 14 m/s on a 3.5% uphill grade for 120 s), and submaximal exertion (8 m/s on a 3.5% uphill grade for 150 s). Along with blood gas/hemodynamic parameters, intrapulmonary arteriovenous shunting was studied by injecting 15-microm-diameter microspheres, labeled with different stable isotopes, into t...
Guo X, Sugita S.Topography of ganglion cells in the retina of the horse (Thoroughbred) was analyzed in the wholemount retina stained with cresyl violet, and a total number of ganglion cells were estimated. Sizes of ganglion cells were also measured and size spectra were analysed. The main results showed that: (1) a common point in 4 wholemount retinae, based on cell densities and retinal locations, was that a retina could be divided into 5 regions, namely visual streak, nasal, temporal, dorsal and ventral region to the visual streak. A maximum cell density of 4,000 cells/mm2 was found in the visual streak. An...
Lee SK, Lee JK, Lee I.Equus caballus papillomavirus type 2 (EcPV-2) is implicated in genital neoplasms in horses, including equine penile papillomas, penile intraepithelial neoplasia, and squamous cell carcinoma (SCC). This virus seldom regresses spontaneously and can result in the development of SCC, which may result in significant clinical damage and economic cost. However, the prevalence of this virus is unknown in clinically unaffected horses. The aim of this study was to determine the prevalence of EcPV-2 DNA in genital swabs from healthy horses in the Republic of Korea and to investigate genetic variability w...
Tully LJ, Murphy AM, Smith RK, Hulin-Curtis SL, Verheyen KL, Price JS.To explore whether genetic susceptibility is a potential risk factor for superficial digital flexor (SDF) tendinopathy in Thoroughbred (TB) racehorses. Objective: To identify informative single nucleotide polymorphisms (SNPs) that capture genetic diversity across a range of candidate genes and to investigate, in a case-control study, their association with SDF tendinopathy in UK National Hunt TB racehorses in training. Methods: Case-control candidate gene association study. Methods: This study used in silico gene assembly and DNA sequencing to screen candidate genes for SNPs. Seven candidate g...
Graham RJTY, Anderson JR, Phelan MM, Cillan-Garcia E, Bladon BM, Taylor SE.Palmar osteochondral disease (POD) is a common cause of lameness in competition horses. Magnetic resonance imaging (MRI) is the most sensitive diagnostic modality currently available, however it may not be financially or logistically practical for routine screening of POD. There is increasing interest in the use of metabolomics for diagnosis prior to progression to irreversible damage. Objective: To determine metabolite levels in synovial fluid (SF) of horses with a clinical diagnosis of POD based on diagnostic analgesia and MRI, with the hypothesis that metabolomic profiles differ between dis...
Baker B, Gaffin SL, Wells M, Wessels BC, Brock-Utne JG.Endotoxins (lipopolysaccharides-LPS) and anti-endotoxin IgG antibodies were measured in racehorses before and after races of 1,000, 2,000 and 2,800 m. Results show that the mean plasma concentration of endotoxin increased significantly (p less than 0.02) while the anti-LPS IgG concentration decreased significantly (p less than 0.005) in all horses following the races. Pre-race and post-race anti-LPS IgG levels in racing-fit racehorses were significantly higher than in untrained horses (p less than 0.05). The possibility therefore exists that training-induced stress leads to leakage of LPS into...
Weideman H, Schoeman SJ, Jordaan GF, Kidd M.This study investigated if environmental factors had an effect on the incidence of epistaxis related to exercise-induced pulmonary haemorrhage (EIPH) among racehorses in southern Africa. Data covering the period 1986-2001 and involving 778 532 race runs were analysed. This included the following information: date of race, age, sex, name of breeder, trainer, distance, jockey, state of going, weight carried, racing centre and altitude. Veterinarians employed by the Jockey Club suspended officially entered horses that presented with epistaxis (frank bleeding from the nostrils) after racing. On-co...
Drudge JH, Lyons ET, Tolliver SC, Lowry SR, Fallon EH.Observations were completed over an 18-year period (1966 through 1983) in Thoroughbred mares (15/year) and yearlings (11 to 24/year) on a farm where benzimidazole-resistant small strongyles had emerged previously (1962 to 1965). This farm was operated as a closed, nonboarding type, which included a racing stable for its home-bred foals. At 2-week intervals, counts of worm eggs per gram of feces (EPG) and larvae per gram of feces were done to monitor strongyle infections and efficacies of bimonthly (every 8 weeks) antiparasitic treatments that were administered by stomach tube or were fed (dich...
Gilkerson J, Jorm LR, Love DN, Lawrence GL, Whalley JM.Equid herpesvirus-4 (EHV-4) was detected in nasal swabs taken from foals using a PCR based test and this information used to study the epidemiology of EHV-4 disease on three Australian Thoroughbred stud farms in NSW in 1992. There was a very high level of agreement (kappa value of 0.84) between the PCR results and virus isolation using cell culture techniques. There was a strong seasonal distribution of EHV-4 shedding. Twenty-five of 26 positive samples were collected in January and March with the remaining positive sample collected in February. Foals with clinical signs of upper respiratory t...
Arai K, Tagami M, Hatazoe T, Nishimatsu E, Shimizu Y, Fujiki M, Misumi K.We investigated the relationship between cartilage oligomeric matrix protein (COMP) levels in synovial fluid (SF), serum and urine and the development of osteochondral damage and osteophyte (OP) formation following intraarticular fractures of the carpus in racehorses in order to assess the clinical usefulness of COMP as a diagnostic biomarker of developmental osteoarthritis (OA). Two monoclonal antibodies (mAb clones 2A11 and 3C8) raised against equine COMP were shown to be capable of detecting the molecule in serum and urine as well as SF. Fifty-one samples were obtained from 26 OP-positive (...
Nixon AJ, Fortier LA, Goodrich LR, Ducharme NG.Debridement of osteochondritis dissecans (OCD) cartilage lesions results in fibrocartilage and imperfect hyaline repair tissue, and forms a permanent irregularity to the subchondral bone plate. Objective: To evaluate the clinical, radiographic and outcome effects of OCD cartilage flap reattachment for select lesions as an alternative to OCD debridement. Objective: Separated cartilage flaps resulting from OCD lesions may be re-incorporated into the hyaline cartilage surface by reattachment rather than debridement and removal. Methods: Resorbable polydioxanone pins were used to reattach OCD flap...
Marenzoni ML, Passamonti F, Cappelli K, Veronesi F, Capomaccio S, Supplizi AV, Valente C, Autorino G, Coletti M.Fifteen unweaned thoroughbred foals, born on a stud farm to vaccinated mares, were clinically monitored during their first six months of life and repeatedly tested for equine herpesvirus type 1 (EHV-1) and equine herpesvirus type 4 (EHV-4). Nasopharyngeal swabs and blood samples were collected and screened respectively by PCR and seroneutralisation to detect the presence of the virus, explore its role as a possible cause of respiratory disease, and to assess the efficiency of the pcr for the diagnosis of this disease. The foals were divided into three groups on the basis of their clinical sign...
Sharma S, Dhaliwal GS, Dadarwal D.Service records of 253 mares (1181 mare-years) spanning over 7 consecutive years, from nine organized Thoroughbred stud farms, situated in the subtropical northwestern India were retrospectively analyzed to assess their reproductive performance. The overall per cycle pregnancy rate at Day 16 and overall foaling rates were 50.30% and 68.95%, respectively, and were significantly higher in mares aged 3-7 years than > or =18 years old mares. The late embryonic losses (9.86%) that occurred between Days 16 and 39 post-ovulation contributed more than 50% of the overall detected pregnancy losses (19.1...
Knych HK, Arthur RM, McKemie DS, Baden RW, Seminoff K, Kass PH.Flunixin meglumine (FM) and phenylbutazone (PBZ) are potent anti-inflammatory agents and as such their potential to mask injuries that would otherwise keep a horse from training or racing is concerning. A common practice in racetrack medicine in the USA is to administer the two drugs within close proximity (24 hours apart) of each other, raising the concern of pharmacokinetic interactions and enhanced anti-inflammatory effects. Objective: Describe the pharmacokinetics and effects of PBZ on the clearance of FM when administered in close proximity as well as effects on inflammatory mediators. M...
Umar MA, Yamashita K, Kushiro T, Muir WW.To evaluate the cardiovascular effects of total IV anesthesia with propofol (P-TIVA) or ketamine-medetomidine-propofol (KMP-TIVA) in horses. Methods: 5 Thoroughbreds. Methods: Horses were anesthetized twice for 4 hours, once with P-TIVA and once with KMP-TIVA. Horses were medicated with medetomidine (0.005 mg/kg, IV) and anesthetized with ketamine (2.5 mg/kg, IV) and midazolam (0.04 mg/kg, IV). After receiving a loading dose of propofol (0.5 mg/kg, IV), anesthesia was maintained with a constant rate infusion of propofol (0.22 mg/kg/min) for P-TIVA or with a constant rate infusion of propofol (...
Gutierrez J, Eisenberg RL, Koval NJ, Armstrong ER, Tharappel J, Hughes CG, Tobin T.Pemoline is a central nervous system stimulant that has been used to treat attention-deficit hyperactivity disorder and narcolepsy in humans; its identification in horses could be considered evidence of attempts to influence performance. Two recent pemoline 'positives' in English racehorses led us to review the chemical relationships between tetramisole, levamisole, aminorex and pemoline. Pemoline is a simple oxidation product of aminorex, which has been shown in the United States and elsewhere to be an equine metabolite of levamisole. Based on the clear structural relationships between aminor...
Rosales C, Krekeler N, Tennent-Brown B, Stevenson MA, Hanlon D.To describe selected periparturient variables in a sample of Thoroughbred mares and their foals on a commercial stud farm in New Zealand. Methods: Data were collected for 969 foaling records, from 592 mares, by foaling attendants from one Thoroughbred stud farm in the Waikato region of New Zealand for the breeding seasons 2008-2013, inclusive, and collated retrospectively. The associations between mare- and foal-level variables and gestation length, time of birth (expressed as the number of hours after midday), fetal membrane retention time, time for the foal to stand and suckle after birth, a...
Ellegren H, Andersson L, Johansson M, Sandberg K.A synthetic polynucleotide (TG)n was hybridized to equine DNA digested with HinfI and hypervariable hybridization patterns were obtained. Mendelian inheritance of these DNA fingerprinting patterns was confirmed by pedigree analysis. Estimates of the probabilities of identical band patterns in unrelated individuals of different breeds (Swedish Trotters, North Swedish Trotters, Thoroughbreds and Arabians) were in the range 1 x 10(-4) - 7 x 10(-6). The variability derived with the (TG)n probe in horses was higher than what we obtained with several other commonly used probes for DNA fingerprinting...
Lyons ET, Tolliver SC, Kuzmina TA.A parasite study was done in 1,300 horse mares on 26 farms in Central Kentucky over a 5-month period in 2010 and 2011. The mares included 1,114 Thoroughbreds (TB) on 24 farms, 64 Standardbreds (SB) on 1 farm, and 122 mixed light horse types (MLH) on 1 farm. The objective of this research was to determine strongyle eggs per gram of feces (EPG) counts for evaluation by known age, number positive, and level of egg shedding by the mares. This was done to establish strongyle EPG profiles for the mares to aid in determining whether antiparasitic treatment was necessary. Eggs found were considered th...
Malekipour F, Whitton CR, Lee PV.Subchondral bone injury due to high magnitude and repetition of compressive loading is common in humans and athletic animals such as Thoroughbred racehorses. Repeated loading of the joint surface may alter the subchondral bone microstructure and initiate microdamage in the bone adjacent to the articular cartilage. Understanding the relationship between microdamage, microstructure and mechanical properties of the subchondral bone adjacent to the articular cartilage is, therefore, essential in understanding the mechanism of subchondral bone injury. In this study, we used high-resolution µCT sca...
Dranchak PK, Valberg SJ, Onan GW, Gallant EM, Binns MM, Swinburne JE, Mickelson JR.To determine whether there was genetic linkage between the recurrent exertional rhabdomyolysis (RER) trait in Thoroughbred horse pedigrees and DNA markers in genes (the sarcoplasmic reticulum calcium release channel [RYR1] gene, the sarcoplasmic reticulum calcium ATPase [ATP2A1] gene, and the transverse tubule dihydropyridine receptor-voltage sensor [CACNA1S] gene) that are important in myoplasmic calcium regulation. Methods: 34 horses in the University of Minnesota RER resource herd and 62 Thoroughbreds from 3 families of Thoroughbreds outside of the university in which RER-affected status wa...
Lyons ET, Tolliver SC, Drudge JH, Granstrom DE, Collins SS.During the period 28 February-1 July 1992, fecal samples were collected and examined for eggs of Strongyloides westeri once from each of 382 horse foals (364 Thoroughbreds, 16 Standardbreds, one Lippizaner, and one draft-type horse) in central Kentucky. Ages of the foals at the time of sampling ranged from 7 to 63 days (mean 22 days). The nine farms in the study were considered to have overall excellent deworming programs. None of the foals had been treated with an antiparasitic compound before the study. Eggs of S. westeri were found in 6% (22 of 382) of the foals on 78% (7 of 9) of the farms...
Wilkes EJA, Heller J, Raidal SL, Woodgate RG, Hughes KJ.Information regarding parasite control practices currently used on Thoroughbred and Standardbred studs in Australia is lacking. Anthelmintic resistance (AR) is a global problem which has implications for equine health and welfare. Objective: To identify parasite control practices currently used on horse studs in Australia and investigate the frequency of use of management factors that have been associated with the likelihood of promoting or delaying AR. Methods: Questionnaire study of equine parasite control on Thoroughbred and Standardbred studs in Australia. Methods: An online questionnaire ...
Ramzan PH, Parkin TD, Shepherd MC.There has been much research directed at potential causative agents and the epidemiology of lower respiratory tract disease (LRTD), but few reports of the clinical progression and outcome. Objective: To define clinical features of LRTD in racehorses, including association with age and average duration of disease, through the analysis of endoscopic data. Methods: A retrospective analysis of records from a single training yard of endoscopic examinations undertaken over a 2-year period was performed. Horses were subjected to regular endoscopic examination for a variety of reasons, and all horses ...
Johns I, Stephen JO, Del Piero F, Richardson DW, Wilkins PA.Hemangiosarcoma is a rare neoplasm of horses and hemangiosarcoma in young horses might behave differently than in mature horses. The purpose of this study was to identify the characteristics of hemangiosarcoma occurring in horses < or = 3 years of age. Medical records from 1982 to 2004 were searched for horses < or = 3 years of age with a histopathologic diagnosis of hemangiosarcoma. Eleven records were identified. Thoroughbred and Thoroughbred crosses predominated. Age ranged from 9 days to 3 years. All horses presented with cutaneous or leg swellings or joint effusion. Physical examina...
Fazio F, Casella S, Giannetto C, Caola G, Piccione G.The aim of the present work was to evaluate the influence of exercise on serum homocysteine and oxidative stress in Thoroughbreds during official races. For our study, ten Thoroughbred mares, 5 years old and clinically healthy, were used. The horses were trained to take part in an official 2100 meter race. Reactive oxygen species (dROMs), antioxidant barrier (Oxy-adsorbent), thiol antioxidant barrier (SHp) and homocysteine (sHcy) were investigated. Blood samples, collected from each horse at rest, immediately after the race, and 30 and 180 min after the end of the race, were collected by jugul...
Bellezzo F, Hunt RJ, Provost R, Bain FT, Kirker-Head C.Fractured ribs are encountered quite frequently in newborn Thoroughbred foals, often with fatal outcome. Surgical repair of fractures therefore requires consideration as a means of reducing mortality. Objective: To evaluate the repair of rib fractures using internal fixation techniques in foals at 2 different equine hospitals following similar diagnostics and case selection. Methods: The records of 14 foals that underwent internal fixation of fracture ribs were reviewed. Subject details, clinical presentation, diagnosis, surgical technique, post operative care and complications were recorded. ...
