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.
Bell RJ, Dart AJ, Smith CL.Ingestion of foreign bodies is uncommon in horses when compared with indiscriminate grazers such as cattle. This case report describes the diagnosis and treatment of a cervical abscess in a Thoroughbred racehorse thought to be associated with ingestion of wire. Radiographic and ultrasonographic examination provided a diagnosis, and conservative treatment of the lesion with antimicrobials initially allowed the lesion to localise closer to the skin for safer surgical exploration. Intra-operative ultrasonographic imaging facilitated surgical access, removal of the foreign body, and drainage. Whil...
Pusterla N, Wilson WD, Mapes S, Finno C, Isbell D, Arthur RM, Ferraro GL.The objective of this study was to determine viral loads, strain (neuropathogenic versus non-neuropathogenic) and state (lytic, non-replicating, latent) of equine herpesvirus-1 (EHV-1) by real-time polymerase chain reaction (PCR) in the blood and nasopharyngeal secretions of adult horses following natural exposure. The index case, a 4-year-old Thoroughbred gelding with confirmed EHV-1 myeloencephalopathy, as well as potentially exposed horses, were sampled over a period of 3 weeks. The study population comprised of 39 adult Thoroughbred horses and 35 adult "pony" and outrider horses of various...
Haase B, Brooks SA, Schlumbaum A, Azor PJ, Bailey E, Alaeddine F, Mevissen M, Burger D, Poncet PA, Rieder S, Leeb T.White coat color has been a highly valued trait in horses for at least 2,000 years. Dominant white (W) is one of several known depigmentation phenotypes in horses. It shows considerable phenotypic variation, ranging from approximately 50% depigmented areas up to a completely white coat. In the horse, the four depigmentation phenotypes roan, sabino, tobiano, and dominant white were independently mapped to a chromosomal region on ECA 3 harboring the KIT gene. KIT plays an important role in melanoblast survival during embryonic development. We determined the sequence and genomic organization of t...
Dykgraaf S, Firth EC, Rogers CW, Kawcak CE.The objective was to determine the effects of early exercise on the articular cartilage and subchondral bone at specific sites of the distal third metacarpal and metatarsal bones of 12 young Thoroughbred horses allowed free choice exercise at pasture. Six of the horses had additional controlled exercise 5 days per week from mean age of 21+/-20 days of age (range: 3-83 days) until 17.1 months of age. Confocal laser scanning microscopy was used to quantify viable and non-viable chondrocytes. Proteoglycan scoring and modified Mankin scoring was performed and subchondral bone mineral density measu...
de Mira MC, Ragle CA, Gablehouse KB, Tucker RL.A 3-year-old Thoroughbred mare was evaluated because of abnormal upper respiratory tract sounds (that had become apparent during race training) of 3 to 4 months' duration. Results: On initial physical evaluation, there were no abnormal findings. During trotting, an abnormal upper airway expiratory sound was audible. Endoscopic examination revealed a small mass protruding into the right ventral nasal meatus. Radiographic images of the skull revealed no abnormal findings. Computed tomography of the head revealed an abnormal structure in the same location as the mass that was observed during endo...
Donovan DC, Jackson CA, Colahan PT, Norton NN, Clapper JL, Moore JN, Hurley DJ.To evaluate the effects of a standardized exercise test to exhaustion in horses on leukocyte function ex vivo. Methods: 6 Thoroughbred geldings. Methods: Blood samples were obtained from each horse before exercise; at exhaustion (termed failure); and at 2, 6, 24, 48, and 72 hours after exercise to evaluate hematologic changes, rate of leukocyte apoptosis, and leukocyte production of reactive oxygen species (ROS) ex vivo. To assess leukocyte function, leukocyte ROS production in response to stimulation with lipopolysaccharide, peptidoglycan, zymosan, and phorbol myristate acetate was evaluated....
Lam KK, Parkin TD, Riggs CM, Morgan KL.To identify the risk factors for premature retirement because of tendon injury in a Thoroughbred racehorse population. Methods: 175 Thoroughbred racehorses (cases) at the Hong Kong Jockey Club that were retired from racing because of tendon injury between 1997 and 2004 and for which the last preretirement exercise was at a fast pace were each matched with 3 control horses that were randomly selected from all uninjured horses that had galloped on the same date as that last exercise episode. Methods: Training data for all horses were examined. Conditional logistic regression analyses were perfor...
You Y, Uboh CE, Soma LR, Guan F, Li X, Rudy JA, Chen J.A rapid and sensitive method was developed for the screening, quantification and confirmation of ethyl glucuronide (EG) and ethyl sulfate (ES) as biomarkers for alcohol administration to racehorses using liquid chromatography coupled on-line with triple quadrupole tandem mass spectrometry. Urine sample aliquots (0.1 mL) were pre-treated by protein precipitation. Separation of EG and ES was achieved on an Ultra PFP column. Isocratic elution with a flush step was performed using 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B). Analysis was performed by negative electrospra...
Schaaf KL, Kannegieter NJ, Lovell DK.Three horses, a 10-year-old Thoroughbred mare, a 9-year-old Thoroughbred gelding and a 6-year-old Arab gelding, with calcified tumours of the paranasal sinuses, are described. All horses presented with purulent nasal discharges and facial distortion. Exophthalmos, blepharospasm and ocular discharge were also a feature in individual horses. A presumptive diagnosis of a calcified tumour was made on the basis of clinical signs and radiographic and endoscopic findings. The tumours ranged from 15 to 25 cm in diameter. A large frontonasal bone flap was used to expose the tumours, which were cleaved ...
Davies Morel MC, Newcombe JR.Despite the widespread use of hCG to advance ovulation in the mare there is little information on efficacy of dose rates and any contraindications of its use. This study aims to investigate the effect of dose of hCG on ovulation within 48h and the effect of hCG on: ovulation, multiple ovulation (MO), pregnancy, multiple pregnancy (MP) rates and synchrony of MO; additionally whether any seasonal effect is evident. Sequential ultrasonic scanning was used to monitor the occurrence of ovulation, within 48h of treatment, in 1291 Thoroughbred mares treated with either 750iu hCG or 1500iu hCG s.c. Ov...
Rutherford DJ, Textor J, Fretz PB.A 4-week-old Thoroughbred filly presented with lameness of acute, severe onset of the left foreleg (LF) of 3 days' duration. Results: Diffuse swelling was present around the distal radius and carpus of the LF. Carpal varus that could be reduced manually was present. Radiographs revealed an intra- articular frontal-plane fracture in the distal radial epiphysis, which continued cranially through the distal radial physis (DRP). The lateral aspect of the DRP was wider than expected. Latero-medial carpal instability was resolved by placement of a lag screw from the dorsal midline through the epiphy...
Pacini S, Spinabella S, Trombi L, Fazzi R, Galimberti S, Dini F, Carlucci F, Petrini M.It has been proven that mesenchymal stromal cells (MSCs) can differentiate into tenocytes. Attempts to repair tendon lesions have been performed, mainly using scaffold carriers in experimental settings. In this article, we describe the clinical use of undifferentiated MSCs in racehorses. Significant clinical recovery was achieved in 9 of 11 horses evaluated using ultrasound analysis and their ability to return to racing. Our results show that the suspension of a small number of undifferentiated MSCs may be sufficient to repair damaged tendons without the use of scaffold support. Ultrasound sca...
Boden LA, Anderson GA, Charles JA, Morgan KL, Morton JM, Parkin TD, Clarke AF, Slocombe RF.Research into risk factors specific for fatality in flat racing should be focused at a regional level as the risk factors may differ among countries and even regions within countries. Objective: To identify risk factors for fatality of Thoroughbred racehorses in flat starts on all racecourses in Victoria, Australia between 1989 and 2004. Methods: Fatalities comprised all horses that died during or immediately after a flat race or official flat trial, and all horses that were subjected to euthanasia within 24 h of an event in which an injury was sustained. The retrospective study involved 283 c...
Allen WR, Brown L, Wright M, Wilsher S.Previous surveys of reproductive efficiency in British Thoroughbreds included only mares and stallions standing on studfarms in and around Newmarket. The present study was widened to compare Flatrace (FR) (Group A) and National Hunt (NH) (Group B) mares and stallions on studfarms throughout England. Objective: To assess the influences of mare type, status and age, and veterinary manipulations on reproductive efficiency parameters. To compare the inherent fertility of stallions, based on singleton and twin pregnancy rates and pregnancy loss rates, in Groups A and B Thoroughbred breeding stock. ...
Boden LA, Anderson GA, Charles JA, Morgan KL, Morton JM, Parkin TD, Clarke AF, Slocombe RF.The risk of fatality is greater in jump than in flat racing in Victoria, Australia. This is the first study to identify risk factors specific to jump starts in Victoria. Objective: To identify risk factors for fatality of Thoroughbred racehorses in jump starts on all racecourses in Victoria, Australia between 1989 and 2004. Methods: Fatalities comprised all horses that died during or immediately after a jump (hurdle or steeplechase) race or official jump trial and all horses that were subjected to euthanasia within 24 h of an event in which an injury was sustained. The retrospective study invo...
Malikides N, Hughes KJ, Hodgson JL.To determine whether percentages of neutrophils in tracheal aspirate (TA) samples collected from racehorses are increased after exercise and whether interpretation of results from TA samples taken before and after exercise agree. Methods: Case series of 40 young Thoroughbred and Standardbred racehorses in race training presented for evaluation of poor performance. Methods: TA samples were collected endoscopically from racehorses presented for poor performance 24 h before and 1 to 2 h after high speed treadmill exercise testing. Aliquots of the retrieved fluid were cytocentrifuged and smears we...
Contreras M, Morales A, García-Amado MA, De Vera M, Bermúdez V, Gueneau P.To assess the presence of Helicobacter DNA in the gastric mucosa Thoroughbred horses. Results: Squamous and glandular mucosa samples were collected from 20 Thoroughbreds. None of these horses had shown any clinical symptoms of gastrointestinal disease. Necropsy tissues were analysed using histopathological techniques and a Helicobacter genus-specific PCR assay followed by sequencing of the amplicons. Seven horses were diagnosed with gastric ulceration, five with gastritis and six with both pathologies. Only two horses had a healthy gastric mucosa. Helicobacter-like DNA was detected in two out ...
Hansen M, Knorr C, Hall AJ, Broad TE, Brenig B.The solute carrier family 26, member 2 (SLC26A2) gene belongs to a family of multifunctional anion exchangers. Mutations in the human SLC26A2 gene are associated with autosomal recessively inherited chondrodysplasias. Hence, we postulate that the equine SLC26A2 could be a candidate gene for conformational traits in horses. An equine BAC clone harboring the SLC26A2 gene was isolated. The complete 142,625 bp insert sequence of this clone was determined by transposon sequencing. Together with the SLC26A2 gene the BAC clone contains four genes, i.e. the macrophage colony stimulating factor 1 recep...
Staniar WB, Kronfeld DS, Akers RM, Harris PA.The objective of this longitudinal study was to characterize growth and plasma insulin-like growth factor I (IGF-I) concentrations in pasture-raised thoroughbreds fed two sources of dietary energy. Mares and foals were randomly assigned to either a sugar and starch (SS) or fat and fibre (FF)-rich feed, and plasma IGF-I and growth were measured once a month from 1 to 16 months of age. These dependent variables were also compared with day length and ambient temperature. There was an association between plasma IGF-I concentration and average daily gain (ADG) (r = 0.32, p 0.10) in the FF group wh...
Bentley VA, Sample SJ, Livesey MA, Scollay MC, Radtke CL, Frank JD, Kalscheur VL, Muir P.Failure of functional adaptation to protect the skeleton from damage is common and is often associated with targeted remodeling of bone microdamage. Horses provide a suitable model for studying loading-related skeletal disease because horses are physically active, their exercise is usually regulated, and adaptive failure of various skeletal sites is common. We performed a histologic study of the navicular bone of three groups of horses: (1) young racing Thoroughbreds (n = 10); (2) young unshod ponies (n = 10); and (3) older horses with navicular syndrome (n = 6). Navicular syndrome is a painfu...
Hobo S, Niwa H, Anzai T.In the present study, the concentrations of serum amyloid A and surfactant protein D in sera were measured to evaluate them for identification of the clinical condition of horses with bacterial pneumonia. The study utilized 185 clinically healthy control thoroughbreds and 9 thoroughbreds for experimental infectious study with S. zooepidemicus. Blood samples were collected from the 185 healthy control thoroughbreds. The 9 thoroughbreds were experimentally infected S. zooepidemicus using an endoscopic injection to a lung lobe and were then observed of clinical conditions. Blood samples were coll...
Nakamura Y, Nishi H, Katayama Y, Niwa H, Matsumura T, Anzai T, Ohtsu Y, Tsukano K, Shimizu N, Takai S.An eight-year-old thoroughbred mare with no previous history of illness aborted a fetus at 196 days of gestation, and its internal tissues were examined immunohistologically and bacteriologically. The placenta was not examined, but specimens of the intrauterine fluids and the dam's faeces were collected four days after the abortion and examined bacteriologically. No significant histological lesions were found in the fetus but the amnion and the umbilical cord were oedematous and had petechial haemorrhages. Rhodococcus equi was isolated in pure culture from the lung, heart and stomach contents ...
Yang YJ, Cho GJ.A total of 384 Thoroughbred mares were investigated to determine and evaluate the features of early embryonic death at nine equine farms on Jeju Island, South Korea, from 2001 to 2003. Overall, 771 matings for 384 mares resulted in 376 pregnancies 15 days after ovulation. Subsequently, 12.2% (46/376) of these early conceptuses were lost within 45 days after ovulation. Furthermore, about three quarters of the 46 embryonic deaths occurred between 16 and 25 days after ovulation. The incidence of embryonic death was highest in the barren (17.2%), more than 15 years old (15.4%), and more than 10 pa...
Moorman VJ, Marshall JF, Jann HW.A 7-year-old sexually intact male Thoroughbred racehorse was evaluated because of exercise intolerance, respiratory tract noise, and coughing when eating. Results: A persistent dorsal displacement of the soft palate was identified during endoscopic examination of the upper portions of the respiratory tract. Radiography of the pharyngeal and laryngeal regions revealed a hypoplastic epiglottis that was ventral to, and not in contact with, the soft palate. The horse was anesthetized, and an oral endoscopic examination revealed a subepiglottic frenulum that had resulted in the dorsal displacement ...
Endo A, Okada S, Morita H.Diversity and compositions of the Lactobacillus, Streptococcus, and Bifidobacterium group in the feces of six healthy, actively racing horses (Thoroughbreds) were analyzed by using PCR-denaturing gradient gel electrophoresis (DGGE) and real-time PCR with primer sets specific for each group. PCR-DGGE analysis of the feces showed that Lactobacillus equi, Lactobacillus johnsonii, a phylogenetic relative of Lactobacillus salivarius, a phylogenetic relative of Lactobacillus gastricus, and Weissella confusa were predominant in almost all of the feces tested, and Streptococcus bovis/Streptococcus equ...
Catalani G, Dottavio ME, Rasia M.During acute exercise several significant cardiovascular alterations take place, along with possible physiopathological consequences, such as Exercise Inducted Pulmonary Haemorrhage (EIPH). Given the relevance of blood rheology in the determination of flow resistance and its supposed participation in the stated events, the present paper focuses on the analysis of modifications in haematocrit, blood viscosity and erythrocyte deformability in Thoroughbred horses caused by two different levels of effort (6 to 9 m/s and 13 to 16 m/s), in the same track they train in and with their own jockeys. The...
Furr M.Diagnosis of neuro-inflammatory conditions in the horse can be challenging. Current methods include evaluation of cerebrospinal fluid (CSF) for inflammation and determination of specific antibody status. The antibody index (AI) and Goldman-Witmer coefficient (C-value) can be used to aid in the interpretation. Objective: The null hypothesis to be tested was that the Al and C-values do not change in horses with neuroinflammation. Methods: Twelve horses of various ages (3-17 years) and breeds (Thoroughbred, Thoroughbred cross, draft, and Arabian) were included in the study. Methods: The study was...
Brown JA, Mapes S, Ball BA, Hodder AD, Liu IK, Pusterla N.To determine the incidence of equine herpesvirus-1 (EHV-1) infection among Thoroughbreds residing on a farm on which the virus was known to be endemic. Methods: Prospective cohort study. Methods: 10 nonpregnant mares, 8 stallions, 16 weanlings, 11 racehorses, and 30 pregnant mares and their foals born during the 2006 foaling season. Methods: Blood and nasopharygeal swab samples were collected every 3 to 5 weeks for 9 months, and placenta and colostrum samples were collected at foaling. All samples were submitted for testing for EHV-1 DNA with a PCR assay. A type-specific EHV-1 ELISA was used t...
Oki H, Kusunose R, Nakaoka H, Nishiura A, Miyake T, Sasaki Y.Genetic variation of the behaviour of racehorses is one of the major concerns for racehorse breeders. In this study, the heritabilities of behavioural responses to the inspections of conjunctiva, auscultation and blood sampling and the genetic correlations among them were estimated in the Thoroughbred racehorse. The estimation was done with Bayesian analysis with Gibbs sampling based on the univariate or bivariate threshold animal models. The behavioural responses were scored with four categories at the first entrance quarantine in Miho Training Center of Japan Racing Association from 1993 to ...
Young DR, Nunamaker DM, Markel MD.Eight untrained 2-year-old Thoroughbred horses were used in a study of the remodeling response of the proximal sesamoid bone (PSB) to training-related stimuli. Two horses each were assigned to 1 of 4 groups: group 1, untrained, pasture turnout (control); group 2, modified-classically trained, dirt track; group 3, classically trained, dirt track; and group 4, classically trained, wood chip track. Horses were given fluorochromic bone labels every 28 days during training. All horses were euthanatized after 5 months of training, and the proximal sesamoid bones (PSB) were removed. A midsagittal sec...
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...
Yokomori T, Tozaki T, Mita H, Miyake T, Kakoi H, Kobayashi Y, Kusano K, Itou T.According to oral traditions of horse caretakers and trainers, the differences in the position and number of facial hair whorls may be associated with temperamental traits. Elucidating genetic background of facial hair whorls and its relationship to temperamental traits may promote more efficient breeding and maintenance of racehorses. In this study, we estimated heritabilities of the position and number of facial hair whorls in Japanese Thoroughbred horses. Results: The number of facial hair whorls varied from one to four and heritability estimate in 4024 Thoroughbred horses was low (h2= 0....
Williams CA, Kronfeld DS, Staniar WB, Harris PA.Plasma concentrations of glucose and insulin following a meal were compared in twelve Thoroughbred mares fed a pelleted concentrate (PC), a traditional sweet feed high in sugar and starch (SS), or a feed high in fat and fiber (FF). The feeds had similar DE and CP but differed in fat (19, 32, and 166 g/kg DM, respectively), NDF (199, 185, and 369 g/kg DM, respectively) and nonstructural carbohydrates (574, 645, and 247 g/kg, respectively). Mares were randomly assigned to two groups balanced for foaling date and weight. All mares received PC in late gestation; then, after foaling, one group was ...
Wilson G, Lucas D, Hambly C, Speakman JR, Morton JP, Close GL.To formulate individualized dietary strategies for jockeys, it is vital that energy requirements are quantified. We measured total energy expenditure (TEE) over two separate weeks in spring and summer using doubly labelled water in a group of male flat jockeys (n = 8, 36.9 ± 5.7 years, 164 ± 8 cm, 54.6 ± 2.5 kg). Total energy intake (TEI) was self-recorded, as were all riding and structured exercise activity. Mean daily TEE was 10.83 (±2.3) and 10.66 (±1.76) MJ, (p = .61) respectively. Self-reported TEI were 6.03 (±1.7) and 5.37 (±1.1) MJ (p = .40), respectiv...
Campbell TE, Doughty H, Harris PA, de Laat MA, Sillence MN.The rapid intake of high-cereal, low-roughage meals may cause gastrointestinal and behavioral disorders. We investigated some of the factors that can affect the rate of intake (ROI) in four separate studies. Study 1 investigated the effect of chaff length and addition rate on the ROI of oats. The ROI decreased as more chaff was added to the diet, attaining significance (P < .05, n = 6) at levels above 15% addition and reaching a plateau at ∼50%. This was independent of stalk length (1.4 cm vs. 4.1 cm). Study 2 showed that meal size (varying from 0.5 to 4 g/kg BW) did not affect the RO...
Hale J, Hughes K, Hall S, Labens R.Autologous conditioned serum (ACS) is a common intra-articular treatment for osteoarthritis in horses. The objective of this study was to investigate the influence of ACS preparation method on product contamination and concentrations of relevant cytokines and the influence of multiple freeze/thaw cycles. Blood was obtained from 10 healthy Thoroughbred horses and processed in parallel using a commercial and a non-commercial method to obtain ACS. Fluorescent microsphere immunoassay (FMIA) analysis was performed to quantify Interleukin 1 receptor antagonist (IL-1Ra), Interleukin-10 (IL-10), Inter...
Ousey JC, Dudan F, Rossdale PD.The status of the mare and foetus in relation to readiness for birth was assessed by measurement of the electrolytes sodium, potassium and calcium in mammary secretions pre-partum. Sixteen Thoroughbred mares were allowed to foal spontaneously and the ionic status of their mammary secretions was measured over three to five weeks pre-partum. From these measurements, a scoring system was developed where an ionic score of 35 points or more suggested that the mare was within 24 h of foaling. On the basis of this ionic score, 10 pony mares were induced with either oxytocin or fluprostenol and assess...
Moeller BC, Stanley SD.A method for the detection and quantitation of 35 endogenous steroids in equine serum was developed and validated. Androgens, estrogens, progestins and their metabolites potentially present in serum were simultaneously monitored in one method using on-line sample extraction by turbulent flow chromatography (TFC) on a 2-dimensional liquid chromatography system and detected on a triple-stage quadrupole mass spectrometer by electrospray ionization. Analytes were detected and quantitated by single-reaction monitoring or selected-ion monitoring. Limits of detection (range 0.025-10 ng mL(-1)) and qu...
Ishii H, Shibuya M, So YM, Wong JKY, Ho ENM, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Yamada M, Leung GN.IOX4, a hypoxia-inducible factor stabilizer, is classified as a banned substance for horses in both horse racing and equestrian sports. We recently reported the pharmacokinetic profiles of IOX4 in horse plasma and urine and also identified potential monitoring targets for the doping control purpose. In this study, a long-term longitudinal analysis of IOX4 in horse hair after a nasoesophageal administration of IOX4 (500 mg/day for 3 days) to three thoroughbred mares is presented for the first time for controlling the abuse/misuse of IOX4. Six bunches of mane hair were collected at 0 (pre), ...
Kuhnke S, König von Borstel U.The present study aimed to assess an agreement between established and novel methods to determine laterality and to identify the distribution of laterality in warmbloods and Thoroughbreds. Nine different methods to investigate a horses' laterality outside a riding context and during riding were compared across two groups of horses (sample A: 67 warmblood- type horses, sample B: 61 Thoroughbreds). Agreement between any two methods was assessed by calculating Cohen's kappa with McNemar's test or Bowker's Test of Symmetry, and the deviation from equal distributions was assessed with chi2-tests. C...
Manohar M, Goetz TE, Hassan AS, Depuy T, Humphrey S.In view of the suggestion that pulmonary injury-induced release of histamine and/or other chemical mediators from airway inflammatory and mast cells contribute to the exercise-induced arterial hypoxemia (EIAH) in human athletes, we examined the effects of pretreatment with a potent anti-inflammatory agent, dexamethasone, on EIAH and desaturation of hemoglobin in horses. Seven healthy, sound, exercise-trained Thoroughbreds were studied in the control (no medications) experiments, followed in 7 days by intravenous dexamethasone (0.11 mg.kg(-1).day(-1) for 3 consecutive days) studies. Blood-gas m...
Kelly G, Lumsden JM, Dunkerly G, Williams T, Hutchins DR.Mucosal ulcers and, occasionally, small granulomas on the axial surface of one or both arytenoid cartilages have been found in TB yearlings presented for post sale endoscopic examination. Objective: To determine the incidence, endoscopic characteristics and outcome of a group of Thoroughbred yearlings affected with mucosal ulcers and granulomas of the arytenoid cartilage. Objective: The incidence of mucosal ulceration of the arytenoid cartilages of yearling Thoroughbreds is relatively high compared to other upper airway abnormalities; and that the majority of mucosal ulcers heal uneventfully, ...
Whitton RC, Jackson MA, Campbell AJ, Anderson GA, Parkin TD, Morton JM, Boden LA.A retrospective cohort study was performed to compare the rates of musculoskeletal injury (MSI) in horses receiving local corticosteroid injection (LCI) with those that were untreated and those prior to treatment. Of the 1911 study horses, 392 had been treated. A LCI was defined as any injection of corticosteroid into or adjacent to a synovial structure, muscle, or tendon/ligament. A MSI was defined as any limb injury identified by a veterinarian, following which the horse did not race for at least 6 months, or was retired. Hazard ratios (HR) comparing hazard of injury following injection to t...
Ishii H, Obara T, Kusano K, Kijima-Suda I.Paracetamol is commonly used as an over-the-counter analgesic and antipyretic medication for humans, but not sold as a legitimate therapeutic medication for horses in Japan. However, paracetamol is commonly found in horses together with its two isomers, metacetamol and orthocetamol. We previously reported that paracetamol and orthocetamol were both present in selected feed consumed by Japanese racehorses. For the purpose of the doping control of paracetamol in local Japanese horses, we proposed establishing residue limits (Japanese residue limits, JRLs) to minimize the risk of reporting parace...
Preston SA, Zimmel DN, Chmielewski TL, Trumble TN, Brown MP, Boneau JC, Hernandez JA.To estimate prevalences of various presale radiographic findings and of presale arthroscopy in horses offered for sale at the 2006 Keeneland September yearling sale and to compare sales prices between yearlings with and without various presale radiographic findings or a history of arthroscopy. Methods: 397 Thoroughbred yearlings. Methods: Cross-sectional study. Methods: Presale radiographs and health records were examined to estimate prevalences of various radiographic findings and presale arthroscopy. Sales price records were used to compare sales prices between yearlings with and without var...
Hollinshead FK, Mehegan MK, Gunn A, Nett T, Bruemmer JE, Hanlon DW.The aim of this project was to test the hypothesis that progesterone concentration 5 days after ovulation did not differ between pregnant and nonpregnant Thoroughbred mares on stud farms located in the Waikato region of New Zealand. A prospective cohort study was performed involving five stud farms in the Waikato region of New Zealand during the 2018 breeding season. A total of 275 mares were enrolled in the study. Mares were served by 34 individual stallions. Blood samples were taken from each mare 5 days after ovulation (D0) and measured for progesterone concentration. Early pregnancy was co...
Birks EK, Ohmura H, Jones JH.Measurements of gas exchange while breathing gases of different O concentrations are useful in respiratory and exercise physiology. High bias flows required in flow-through indirect calorimetry systems for large animals like exercising horses necessitate the use of inconveniently large reservoirs of mixed gases for making such measurements and can limit the amount of equilibration time that is adequate for steady-state measurements. We obviated the need to use a pre-mixed reservoir of gas in a semi-open flow-through indirect calorimeter by dynamically mixing gases and verified the theoretical ...
Breuhaus BA.Certain breeds of horses may be genetically predisposed to developing insulin dysregulation, which is a risk factor for development of endocrinopathic laminitis in horses. This study was performed to test the hypotheses that Paso Fino horses exhibit evidence of insulin dysregulation compared with Thoroughbred horses and that obesity exaggerates the insulin dysregulation. Intravenous glucose tolerance tests were performed in 14 moderate-weight Thoroughbreds, 12 moderate-weight Paso Finos, and 12 overweight Paso Finos. Moderate Paso Finos had greater baseline serum insulin concentrations, area u...
Staniar WB, Kronfeld DS, Hoffman RM, Wilson JA, Harris PA.Monitoring weight of foals is a useful management practice to aid in maximising athletic potential while minimising risks associated with deviations from normal growth. Objective: To develop predictive equations for weight, based on linear measurements of growing Thoroughbreds (TBs). Methods: Morphometric equations predicting weight from measurements of the trunk and legs were developed from data of 153 foals. The accuracy, precision and bias of the best fitting equation were compared to published equations using a naive data set of 22 foals. Results: Accuracy and precision were maximised with...
Edens LM, Taylor DD, Murray MJ, Spurlock GH, Anver MR.A large fibrotic mass originating from the cecal base was discovered upon surgical exploration of the abdomen in a Thoroughbred mare with a history of chronic colic and weight loss. The mass protruded intraluminally resulting in partial obstruction. Surgical excision was not feasible due to the location of the mass and the inability to exteriorize it adequately from the abdominal cavity. The mass was fibrous with a shiny, gelatinous material present throughout the neoplasm. Histologically, large confluent spaces filled with mucopolysaccharides were identified by staining with Alcian blue. The ...
Habershon-Butcher J, Bowen M, Hallowell G.A reliable method for obtaining renal ultrasonographic measurements in the horse is important for diagnosis and monitoring of clinical renal disease. The aims of this prospective study were to develop and validate a novel translumbar ultrasound technique for measuring renal dimensions in horses. Six Thoroughbred or Thoroughbred part bred horses were recruited. All horses were scheduled for euthanasia due to reasons unrelated to the kidneys. Two observers recorded renal length, width, and depth; and dimensions of the cortex, medulla, pyramids, and pelvis for both kidneys in each horse using nov...
Turco S, Gabbianelli F, Mavian CN, Pietrucci D, De Paolis L, Gialletti R, Mechelli L, De Ciucis CG, Cappelli K, Dell'Anno F, Mecocci S, Donato GG....Papillomaviruses (PVs) are small, non-enveloped viruses, ubiquitous across the animal kingdom. PVs induce diverse forms of infection, such as cutaneous papillomas, genital papillomatosis, and carcinomas. During a survey on the fertility status of a mare, a novel PV (EcPV) has been identified using Next Generation Sequencing, and it was further confirmed with genome-walking PCR and Sanger sequencing. The complete circular genome 7607 bp long shares 67% average percentage of identity with EcPV9, EcPV2, EcPV1, and EcPV6, justifying a new classification as PV 10 (EcPV10). All EcPV genes are cons...
Kobayashi M, Kuribara K, Amada A.The purpose of this investigation was to study, under field conditions, the usefulness of an incremental exercise test to measure V200 (running velocity [V] at heart rate HR[ of 200 beats/min) for evaluation of training effects in the young Thoroughbred. Five to 112 two-year-old Thoroughbreds were used over 4 years to investigate the correlation between HR and V, the influence of the track and rider's weight to V200, reproducibility of V200 and the changes of V200 as training progresses. The high correlation coefficient between HR and V, and V200 were obtained in horses that exercised smoothly...
Knych HK, Arthur RM, McKemie DS, Chapman N.Flunixin meglumine is commonly used in horses for the treatment of musculoskeletal injuries. The current ARCI threshold recommendation is 20 ng/mL when administered at least 24 h prior to race time. In light of samples exceeding the regulatory threshold at 24 h postadministration, the primary goal of the study reported here was to update the pharmacokinetics of flunixin following intravenous administration, utilizing a highly sensitive liquid chromatography-mass spectrometry (LC-MS). An additional objective was to characterize the effects of flunixin on COX-1 and COX-2 inhibition when drug con...
Kushiro T, Yamashita K, Umar MA, Maehara S, Wakaiki S, Abe R, Seno T, Tsuzuki K, Izumisawa Y, Muir WW.The anesthetic sparring and cardiovascular effects produced by midazolam 0.8 mg/ml-ketamine 40 mg/ml-medetomidine 0.05 mg/ml (0.025 ml/kg/hr) drug infusion during sevoflurane in oxygen (MKM-OS) anesthesia was determined in healthy horses. The anesthetic sparring effects of MKM-OS were assessed in 6 healthy thoroughbred horses in which the right carotid artery was surgically relocated to a subcutaneous position. All horses were intubated and ventilated with oxygen using intermittent positive pressure ventilation (IPPV). The end-tidal concentration of sevoflurane (ET(SEV)) required to maintain s...
Flunker JC, Clouser JM, Swanberg JE.Thoroughbred horse farm workers self-report a high frequency of work-related injuries and pain. However, an analysis of Thoroughbred horse farm workers' compensation injury claims is absent from the literature, yet may benefit worker safety. We analyzed workers' compensation insurance firm data containing 2276 claims filed between 2008 and 2015. Injury frequency, cost, and lost time per cause, nature, and body part injured were examined qualitatively and via univariate tests. Factors associated with high cost and high duration lost time claims were modeled via multivariable logistic regression...
Smith S, Marr CM, Dunnett C, Menzies-Gow NJ.Birthweight of Thoroughbred foals has increased in recent years. It is unknown whether this is associated with increased broodmare obesity or endocrine dysfunction. Objective: To determine insulin, leptin and triglyceride concentrations in Thoroughbred mares throughout gestation and investigate their association with obesity and foal birthweight. Methods: Cohort study. Methods: A total of 66 mares were included from 40 days post-breeding. Body condition score (BCS), weight and blood samples were obtained every 60 days throughout gestation. Serum/plasma insulin, leptin and triglyceride concentr...
Whittaker S, Sullivan S, Auen S, Parkin TD, Marr CM.Although low birthweight is a risk factor for neonatal illness, the impact of high birthweight on the health of foals and mares, and on the foals' long-term athletic capability, is unknown. Objective: To investigate whether: 1) foals that are excessively heavy are associated with an increased prevalence of maternal illness in the first month post partum and reproductive dysfunction in the following season; 2) excessively light or heavy foals are at an increased risk of illness in the first month of life; and 3) birthweight is associated with racing success. Methods: Veterinary records from 230...
Le Jeune SS, Macdonald MH, Stover SM, Taylor KT, Gerdes M.Objective-To determine whether partial transection of the medial branch of the suspensory ligament (MBSL) alters equine third metacarpal bone (MC3) condylar surface strains and forelimb, distal joint angles in a manner consistent with promotion of lateral condylar fracture. Study Design-In vitro biomechanical experiment. Sample Population-Right forelimbs from 7 Thoroughbred horse cadavers. Methods-Lateral and medial MC3 condylar, dorsal and abaxial, bone surface strains and distal joint angles were measured both before and after partial transection of the MBSL during in vitro axial limb compre...
