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.
Perkins NR, Reid SW, Morris RS.To describe and enumerate conditions that interrupted training and racing in a population of Thoroughbred racehorses in New Zealand. Methods: A longitudinal study design was used to collect data on horses training under the care of 20 licensed racehorse trainers from venues in the mid to lower regions of the North Island between October 1997 and July 2000. Incidence rates were reported for first and second occurrences for different categories of musculoskeletal injury (MSI), and first occurrences of upper and lower respiratory tract disease, using training days as time-at-risk. The proportion ...
LeRoy BE, Knight MC, Eggleston R, Torres-Velez F, Harmon BG.A 14-year-old bay Thoroughbred gelding was presented for evaluation of a mass at the base of the tail. The mass had been present for 1 year, and recently had begun to increase in size. Additional masses were found around the eye and shoulder. A fine-needle aspirate of the tail-base mass revealed highly anaplastic round to polyhedral cells containing dark green to black cytoplasmic granules interpreted to be melanin. Histologically, the mass was composed of pleomorphic, poorly pigmented, round to polyhedral cells interpreted to be neoplastic melanocytes. With immunohistochemistry, the cells wer...
Perkins NR, Reid SW, Morris RS.To describe patterns in training, racing, and general health in a population of Thoroughbred racehorses in New Zealand. Methods: A longitudinal study was designed to collect data on horses training under the care of 20 selected trainers from 20 different stables and five regional training venues in the mid to lower regions of the North Island. Data were collected from trainers at approximately monthly intervals between October 1997 and July 2000, and electronic data containing race and trial results for all starts in New Zealand for the same time period were obtained from New Zealand Thoroughb...
Curtis RA, Kusano K, Evans DL, Lovell NH, Hodgson DR.This study investigated the reliability of measurements with a new equine ergospirometer (Quadflow). Heart rate and blood lactate responses during exercise in horses wearing the Quadflow and an open flow mask were also compared. The mean percentage error of the oxygen uptake measurements was 8.2% (range 2.1-12.5%). Percent error for peak expiratory flow rates ranged from 6.1% to 9.4 %, and for minute ventilation from 2.5% to 7.4%. The coefficients of variation of the means of four measurements in two horses exercising continuously at 9.0 m/s were <5% for variables related to pulmonary venti...
Carmalt JL, Wilson DG.To report arthroscopic debridement and lavage of a septic temporomandibular joint (TMJ) in a horse. Methods: Clinical case report. Methods: A 12-year-old Thoroughbred mare. Methods: Arthroscopic investigation of the dorsal joint pouch of the right TMJ was made through a stab incision into the dorsocaudal compartment. Mechanized resection of synovium and fibrinous debris combined with copious lavage, and intra-articular and systemic antibiotic administration was used to treat the septic TMJ. Results: Arthroscopic debridement and lavage of the TMJ, in combination with intra-articular and systemi...
Smith JJ, Embertson RM.To compare racing performance before and after sternothyroideus myotomy, staphylectomy, and oral caudal soft palate photothermoplasty in Thoroughbred racehorses with intermittent dorsal displacement of the soft palate (DDSP). Methods: Retrospective study. Methods: Thoroughbred racehorses (n=102) with DDSP. Methods: Retrieved data included signalment, primary complaint, and upper respiratory tract endoscopic finding. Lifetime race records were compared for earnings per start before and after surgery, days to 1st start, and races won postoperatively. Results: Comparing mean earnings per start fo...
Cohen ND, O'Conor MS, Chaffin MK, Martens RJ.To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. Methods: Prospective case-control study. Methods: 5230 foals on 138 breeding farms with 9136 horses. Methods: During 2003, participating veterinarians provided data from 1 or 2 farms with > or =1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis. Results: A number of variables relating to farm size and desirable management practices were significantly associated with increased od...
Derar R, Haramaki S, Hoque S, Hashizume T, Osawa T, Taya K, Watanabe G, Miyake Y.To elucidate the physiological role of insulin-like growth factor-I (IGF-I) during early pregnancy in mares, number of ovarian follicles was monitored ultrasonically during different stages of the first trimester of pregnancy in 36 thoroughbred mares. From 9 of 36 mares, blood samples were collected weekly from the mating day till the end of the first trimester of pregnancy and plasma IGF-I profiles were examined with other hormones, like follicle stimulating hormone (FSH), luteinizing hormone (LH), ir-inhibin, progesterone and estradiol-17beta. Plasma IGF-I level fluctuated throughout the stu...
Nishita T, Takahasi M, Kasuya T, Matsui K, Ichihara N, Murakami M, Asari M.Equine carbonic anhydrase isozymes (CA-I and CA-II) were purified from erythrocytes by several column chromatography. Polyclonal anti-CA-I and anti-CA-II sera were produced in rabbits. Sensitive competitive enzyme-linked immunosorbent assays (ELISA) were established to determine the developmental changes in CA-I and CA-II levels in equine erythrocytes. Concentrations of CA-I and CA-II in erythrocytes from 150 clinically normal thoroughbreds (123 racehorses and 27 riding horses) were determined by ELISA. Mean (+/- SD) concentrations of CA-I and CA-II in racehorses were 1.70 +/- 0.48 and 0.94 +/...
Jenner F, Edwards RB, Voss JR, Southwood L, Markel MD, Richardson DW.To evaluate the use of hydrothermal ablation of articular cartilage for arthrodesis in horses through investigation of the effects of joint lavage with physiologic saline (0.9% NaCI) solution (80 degrees C) for various treatment times on chondrocyte viability in the articular cartilage of the metacarpophalangeal and metatarsophalangeal joints of cadaveric horse limbs. Sample Population-7 pairs of metacarpophalangeal and 8 pairs of metatarsophalangeal joints from 8 Thoroughbreds. Methods: The horses were euthanatized for reasons unrelated to musculoskeletal disease. On a random basis, 1 joint o...
de Moffarts B, Kirschvink N, Art T, Pincemail J, Lekeux P.The oxidant/antioxidant equilibrium of trained thoroughbred horses (n = 40) was assessed on three occasions during a period of three months under field conditions by blood antioxidant markers analysis, i.e. plasma ascorbic acid (AA), plasma antioxidant capacity of water-soluble components (ACW), whole blood (GSH) and oxidised (GSSG) glutathione, plasma alpha-tocopherol and beta-carotene, plasma antioxidant capacity of lipid-soluble components (ACL), red blood cell superoxide dismutase (SOD) and glutathione-peroxidase activity (GPx) and plasma trace-elements, i.e. selenium (Se), copper (Cu), zi...
Gibson VA, Stover SM, Gibeling JC, Hazelwood SJ, Martin RB.We hypothesized that recently formed, incompletely mineralized, and thus, relatively deformable osteons in the equine third metacarpus enhance in vitro load-controlled fatigue life in two ways. Macroscopically, there is a compliance effect, because reduced tissue elastic modulus diminishes the stress required to reach a given strain. Microscopically, there is a cement line effect, in which new osteons and their cement lines more effectively serve as barriers to crack propagation. We studied 18 4 x 10 x 100 mm beams from the medial, lateral, and dorsal cortices of metacarpal bones from 6 thorou...
Tozaki T, Hirota K, Hasegawa T, Tomita M, Kurosawa M.Linkage disequilibrium (LD) mapping is often used in searches for genes governing economically significant traits and diseases. The D' coefficient is a commonly used measure of the extent of LD between all possible pairs of alleles at two markers. This study aimed to test the utility of the D' coefficient for LD mapping of a trait in a thoroughbred population. Microsatellite genotype data and grey coat colour as a trait model in a thoroughbred population were used to assess the extent of LD. We demonstrated that LD mapping was a reasonable approach for initial genome-wide scans in a thoroughbr...
Davies HM, Merritt JS.Bone strains quantify skeletal effects of specific exercise and hence assist in designing training programmes to avoid bone injury. Objective: To test whether compressive strains increase on the lateral surface of the inside third metacarpal bone (McIII) and the medial surface of the outside McIII in a turn. Methods: Rosette strain gauges on dorsal, medial and lateral surfaces of the midshaft of the left McIII in 2 Thoroughbred geldings were recorded simultaneously during turning at the walk on a bitumen surface. Results: Medial surface: Compression peaks were larger in the outside limb. Tensi...
Jackson BF, Lonnell C, Verheyen KL, Dyson P, Pfeiffer DU, Price JS.Dorsal metacarpal disease (DMD) is a common problem in 2-year-old racehorses and results in loss of a significant number of days from training. Biochemical markers of bone cell activity measured early in the training season could have value for identifying 2-year-old Thoroughbred racehorses that develop DMD. Objective: To determine the association between serum concentrations of osteocalcin, the carboxyterminal propeptide of type I collagen (PICP) and the carboxyterminal cross-linked telopeptide of type I collagen (ICTP) measured early in the training season and the risk of DMD. Methods: Blood...
Swanstrom MD, Zarucco L, Stover SM, Hubbard M, Hawkins DA, Driessen B, Steffey EP.The superficial (SDF) and deep digital flexor (DDF) muscles are critical for equine forelimb locomotion. Knowledge of their mechanical properties will enhance our understanding of limb biomechanics. Muscle contractile properties derived from architectural-based algorithms may overestimate real forces and underestimate shortening capacity because of simplistic assumptions regarding muscle architecture. Therefore, passive and active (=total - passive) force-length properties of the SDF and DDF muscles were measured directly in vivo. Muscles from the right forelimbs of four Thoroughbred horses we...
Fortier LA, Kornatowski MA, Mohammed HO, Jordan MT, O'Cain LC, Stevens WB.Structural changes in articular cartilage associated with the ageing process require definition for investigators performing developmental and age-related studies, for which information is lacking. Objective: To 1) determine the onset and end of puberty as defined by serum insulin like growth factor (IGF-I) and IGF-binding protein-3 (IGFBP-3) concentrations and 2) correlate articular-epiphyseal cartilage complex structural changes with the onset and end of puberty. Methods: IGF-I and IGFBP-3 were measured in serum samples from normal female and male horses age 9-715 days to determine peak and ...
Archer DC, Proudman CJ, Pinchbeck G, Smith JE, French NP, Edwards GB.The clinical features of 71 cases in 70 horses in which part of the small intestine became entrapped in the epiploic foramen are described. The horses' sex, age and breed, the month during which they were affected, and whether they exhibited stereotypic behaviour were compared with the same variables in 1279 horses which suffered other types of surgical colic during the same period. Thoroughbred and thoroughbred cross horses were over-represented among the 70 affected horses. There was no age or sex predilection. Fifty-five (77.5 per cent) of the cases occurred between October and March and 15...
Wood JL, Newton JR, Chanter N, Mumford JA.Respiratory disease is important in horses, particularly in young Thoroughbred racehorses, and inflammation that is detected in the trachea and bronchi (termed inflammatory airway disease [IAD]) is more significant in this population in terms of impact and frequency than other presentations of respiratory disease. IAD, which is characterized by neutrophilic inflammation, mild clinical signs, and accumulation of mucus in the trachea, may be multifactorial, possibly involving infections and environmental and immunological factors, and its etiology remains unclear. This 3-year longitudinal study ...
Gross DK, Stover SM, Hill AE, Gardner IA.To assess the accuracy and reliability of a visual method of evaluating horseshoe characteristics. Methods: 1,199 Thoroughbred racehorses. Methods: Characteristics of 1 forelimb horseshoe were visually assessed on horses immediately prior to racing by 5 field observers at 5 major racetracks in California. Characteristics evaluated included horseshoe type; toe grab height; and the presence of a rim, pad, and heel traction devices. Sensitivity and specificity for observer assessment of horseshoe characteristics were calculated by comparing observer assessments to a postmortem laboratory standard...
Hosaka Y, Sakamoto Y, Kirisawa R, Watanabe T, Ueda H, Takehana K, Yamaguchi M.Although tumor necrosis factor (TNF) alpha is an important key factor in degeneration of equine superficial digital flexor tendon (SDFT), the dynamism of TNF receptors and associated factors on tendinocytes has not been elucidated. To reveal signaling events mediated by TNF-receptors (TNF-Rs) in tendinocytes, we focused on four signaling factors, TNF-R1, TNF-R2, TNF-R-associated factor 2 (TRAF2) and nuclear factor-kappa B (NF-kappaB), and investigated the distribution and production of these factors. Cultured tendinocytes were obtained from SDFTs of thoroughbred horses. The tendinocytes were t...
Matthee S, McGeoch MA.The current level of anthelmintic resistance in the horse-breeding industry is extremely high and therefore more emphasis is being placed on studies that focus on the judicious use of anthelmintic products. The aims of the study were to: 1) establish if there is variation in the egg excretion pattern of strongyles between the different age classes of Thoroughbred horses in the Western Cape Province (WCP), 2) test if a selective treatment approach successfully reduces the number of anthelmintic treatments and maintains acceptably low helminth burdens in adult Thoroughbred horses, and 3) evaluat...
Morel MC, Newcombe JR, Swindlehurst JC.Numerous and conflicting reports exist regarding factors that may effect mare reproductive performance, in particular multiple ovulation (MO) and its consequences. Sequential ultrasonic examination was used to monitor 3075 ovulations in 1581 mainly Thoroughbred mares to ascertain: whether increasing age is associated with an increase in MO; whether this is counteracted by an increase in embryo mortality (EM) prior to Day 13; and whether this embryonic loss may be associated with small-for-age embryonic vesicles (Days 13/14). Overall ovulation rate was 1.31, MO occurring in 29.3% of cycles. MO ...
Górecka A, Jezierski TA, Słoniewski K.Weak or equivocal expression of oestrous behaviour, related to different level of mares' reactivity, may cause problems in oestrus detection and thus influence the reproductive efficiency. The aim of the study was to test whether a breed characterised by low pregnancy rate and high emotional reactivity (Thoroughbreds) differs in oestrous behaviour from a primitive breed with higher reproductive efficiency (Koniks). Additionally, the follicle size was examined to determine how it influences the intensity of oestrus and uterine ultrasonic image and whether the pregnancy rate differs in relation ...
Boyde A, Firth EC.We describe morphological aspects of the articular calcified cartilage mineralizing front 'tidemark' in the distal joint surface of the third metacarpal bone from 14 horses. Compositional backscattered electron scanning electron microscopy and confocal scanning light microscopy were conducted on polymethylmethacrylate (PMMA)-embedded medio-lateral slices. After maceration, scanning electron microscopy (SEM) was used to study the calcified cartilage surface in the 'wedges' intervening between the slices. An anatomically reproducible clustering of canals in the calcified cartilage was found at o...
Skiöldebrand E, Heinegård D, Eloranta ML, Nilsson G, Dudhia J, Sandgren B, Ekman S.The aim of the present study was to correlate the levels of COMP and aggrecan as indicators of tissue damage, in synovial fluid (sf) from carpal joints of acutely lame racehorses, with macroscopical lesions of articular cartilage (OA), osteochondral fractures and ligament tears found at arthroscopy. Sixty-three lame horses [49 Standardbred trotters (STB) and 14 Thoroughbreds (TB)] in conventional training and racing that underwent arthroscopy of their middle carpal or radiocarpal joints were included in the study. Intact as well as fragmented COMP and aggrecan released into the synovial fluid ...
Burn JF, Portus B, Brockington C.The equine carpus has a well-defined limit to joint extension at approximately 180 degrees . During locomotion however, the carpus hyperextends during stance phase. Hyperextension is resisted by the carpal bones and ligaments, and it has been proposed that large increased hyperextension might relate to potentially damaging stress levels in the carpus. The aim of this study was to investigate the relationship between peak hyperextension of the carpus (PCE) and speed during locomotion on the level and on an incline. Five Thoroughbred horses were exercised on a treadmill at speeds between 1.8 and...
Ohta M, Oku K, Mukai K, Akiyama K, Mizuno Y.To assess the clinical usability of propofol-ketamine anesthesia for internal fixation of fractures in racehorses, hemodynamics, blood pH and gases, and vital responses to the continuous intravenous anesthesia in 7 surgical cases were analyzed. The quality of induction with propofol was variable for individual horses. The vital signs reflecting circulation, breath, and anesthetic depth were kept good without any troubles throughout the surgery. Mean time from the end of anesthesia to standing up was prolonged, however recovery from anesthesia was calm and smooth in all cases. Propofol-ketamine...
Ousey JC, Rossdale PD, Fowden AL, Palmer L, Turnbull C, Allen WR.Intrauterine growth retardation (IUGR) impairs post natal adaptive responses and is associated with increased adrenocortical activity in many species. Objective: To determine whether a restricted or enhanced intrauterine environment affects neonatal adaptation and adrenocortical function in horses. Methods: Embryos from large (577 kg) Thoroughbred (TB) mares were transferred to smaller (343 kg) pony (P) mares and vice versa, to create a restricted (TB-in-P, n = 11) or enhanced (P-in-TB, n = 8) intrauterine environment. Control groups (TB-in-TB, n = 8; P-in-P, n = 7) were also included. Results...
Giannitti F, Petrov R, Parker J, Booth M, Anderson M.A 9-year-old Thoroughbred gelding presented with a 97-day history of poor performance and intermittent fever. Clinicopathologic changes included increased serum activity of γ-glutamyltransferase and alkaline phosphatase, mild hyperbilirubinemia, and leukocytosis with neutrophilia and lymphopenia. Abdominal ultrasound revealed hepatomegaly with hyperechoic hepatic parenchyma and biliary distention. Pathologic findings included marked hepatomegaly (liver 3.6% of body weight), firm hepatic consistency with a diffuse enhanced reticular pattern, severe portal bridging and sinusoidal fibrosis, oval...
Leon PM, Campos VF, Thurow HS, Hartwig FP, Selau LP, Dellagostin OA, Neto JB, Deschamps JC, Seixas FK, Collares T.Single nucleotide polymorphisms (SNPs) in the p53 gene have been studied extensively in humans. The aims of this study were to determine the frequency of the Arg/Pro SNP in p53 in Thoroughbred mares on one stud in Brazil and to correlate p53 genotypes with reproductive performance. SNPs were detected by PCR-restriction fragment length polymorphism in blood samples from 105 horses and confirmed by sequencing. The allele frequency in Thoroughbred mares at codon 72 in exon 4 was 73.3% Arg/Pro, 17.1% Arg/Arg and 9.6% Pro/Pro. The presence of Arg/Pro was significantly associated with abortion (P=0....
Helal IE, Misumi K, Tateno O, Kodama T, Ishimaru M, Yamamoto J, Miyakoshi D, Fujiki M.To evaluate changes in serum cartilage oligomeric matrix protein (COMP) concentrations in response to exercise in horses. Methods: 15 horses in experiment 1 and 27 horses in experiment 2. Methods: In experiment 1, 15 Thoroughbreds free of orthopedic disease underwent a standardized exercise protocol. Running velocity and heart rate (HR) were recorded, and blood samples were collected immediately before (baseline) and 1, 5, and 24 hours after a single episode of exercise. In experiment 2, 27 horses underwent 9 stages of a training program in which each stage consisted of 4 to 8 consecutive dail...
Kingston JK, Geor RJ, McCutcheon LJ.To compare dew-point hygrometry, direct sweat collection, and measurement of body water loss as methods for determination of sweating rate (SR) in exercising horses. Methods: 6 exercise-trained Thoroughbreds. Methods: SR was measured in 6 horses exercising at 40% of the speed that elicited maximum oxygen consumption for 45 km, with a 15-minute rest at the end of each 15-km phase. Each horse completed 2 exercise trials. Dew-point hygrometry, as a method of local SR determination, was validated in vitro by measurement of rate of evaporative water loss. During exercise, local SR was determined ev...
Snow DH, Martin V.To investigate the claim that equine erythrocytes released from the spleen are older cells than those found at rest in the circulation, the 2,3, diphosphoglycerate (2,3 DPG), adenosine triphosphate (ATP) and creatine concentration of erythrocytes before and following splenic emptying were examined. Normal values for thoroughbreds (43) and ponies (10) at rest were established. Following either exercise or intravenous injection of adrenaline in six thoroughbreds, there was an increase in erythrocyte creatine content and a decrease in ATP concentration. Exercise produced a slight increase in 2,3 ...
Brooks DE, Plummer CE, Mangan BG, Ben-Shlomo G.To describe clinical findings in equine subepithelial keratomycosis (SEK). Methods: Retrospective medical records study. Methods: Medical records of horses that had subepithelial keratomycosis (SEK) at the University of Florida Veterinary Medical Center from 2007 to 2011 were reviewed. Methods: Data collected from the medical records included signalment, clinical descriptions of ocular lesions, diagnostic techniques, and therapeutic outcomes. Results: Twenty-one horses, consisting of three Quarter horse geldings, two Morgan geldings, one Morgan mare, two Arabian mares, three Arabian geldings, ...
McGlinchey L, Hurley MJ, Riggs CM, Rosanowski SM.Few studies have described incidences of proximal limb and pelvic fracture (PLPF) in Thoroughbred racehorses occurring on race day and during training. Information regarding clinical presentations and future racing careers in cases of PLPF is limited. Objective: To describe the incidence, clinical presentation and outcome of PLPF sustained by horses in racing and training at the Hong Kong Jockey Club (HKJC) between 2003 and 2014. Methods: Retrospective cohort study. Methods: Horses with PLPF confirmed by nuclear scintigraphy, ultrasonography, radiography or post-mortem examination were identif...
Bohák Z, Szenci O, Harnos A, Kutasi O, Kovács L.Temperament has not been taken into account in previous studies evaluating the stress response to exercise in horses. The aim of the present study was to investigate the cortisol response in Thoroughbred racehorses to a single exercise bout, and to analyse the results based on the basic personality of the horse examined. Twenty healthy Thoroughbred horses were selected for the study based on a 25-item rating questionnaire survey used for characterising equine temperament. Eight temperamental and twelve calm horses took part in the experiment. The horses trotted as a warm-up activity, and then ...
Lawless SP, Werner LA, Baker WT, Hunt RJ, Cohen ND.To describe short-term and long-term survival of horses with duodenojejunal mesenteric rents, and to examine the association of selected preoperative, intraoperative, and postoperative factors with survival or colic after discharge, in horses with duodenojejunal mesenteric rents. Methods: Retrospective case series. Methods: Horses undergoing surgery for correction of small intestinal lesions secondary to duodenojejunal mesenteric rents (n = 38). Methods: Medical records (2006-2014) of horses admitted to a referral hospital in Kentucky were reviewed. Data for preoperative and intraoperative...
Tsuchiya T, Noda R, Ikeda H, Maeda M, Sato F.Pituitary pars intermedia dysfunction (PPID) is an endocrine disorder the clinical signs of which include infertility, but few reports have examined the relationship between PPID and reproductive performance in broodmares. Objective: Broodmares with infertility of unknown etiology were screened for PPID using baseline endogenous plasma ACTH concentrations, and its relationship with subsequent reproductive performance was analyzed. Methods: Sixty-seven Thoroughbred broodmares. Methods: Adrenocorticotropic hormone concentrations were measured in autumn. The broodmares were divided into 3 groups ...
Jacobs RD, Gordon MBE, Vineyard KR, Keowen ML, Garza F, Andrews FM.Low gastric pH for extended periods of time can increase the risk of gastric ulceration in horses. Therefore, nutritional interventions that buffer stomach acid may be helpful to decrease ulcer risk. The objective of this trial was to evaluate whether the incorporation of calcified Lithothamnion corallioides and Phymatolithon calcareum (Calmin; Celtic Sea Minerals, Cork, Ireland) into an equine ration would buffer equine gastric juice. Nine mature, Thoroughbred-cross horses, including 6 geldings and 3 mares (524 ± 49 kg) were housed in stalls and fed 2 kg/day of a texturized concentrate (Pu...
Hackett RP, Ducharme NG, Gleed RD, Mitchell L, Soderholm LV, Erickson BK, Erb HN.To test the hypothesis that the pulmonary vascular pressures of Thoroughbred and Standardbred horses behave similarly during exertion. Measurements were made on 5 Thoroughbred and 5 Standardbred horses on a treadmill at rest and during 3-minute exercise intervals at speeds predicted to produce 75%, 90%, and 100% maximal heart rate. Left forelimb acceleration, heart rate, esophageal pressure, and pulmonary artery pressure were measured continuously. Pulmonary capillary and wedge pressures were measured during intermittent occlusion of the pulmonary artery. Breathing rate and gait frequency were...
Curtiss AL, Aceto H, Embertson RM.Epiglottic entrapment can occur in yearling Thoroughbreds (TB); however, race performance following surgical correction is unknown. Objective: To determine the race performance of horses treated surgically for epiglottic entrapment as yearlings as compared to an untreated cohort. A second objective was to identify risk factors for treated horses not racing post-operatively. Methods: Retrospective cohort and case-control studies. Methods: Medical (1989-2014) and race records of 66 treated TB racehorses were reviewed. Observed abnormalities on pre- and post-operative endoscopic images and surgic...
Posukonis MN, Daglish J, Wright IM, Kawcak CE.To evaluate bone mineral content patterns between fracture configurations using novel CT image analysis. Methods: CT images from 97 Thoroughbred racehorses with third metacarpal/tarsal condyle fractures provide the case population for analysis. Methods: Fractures were grouped by radiographic appearance. Image analysis objectively measured area of highly attenuating pixels (aHAP), areal density of highly attenuating pixels (dHAP) utilizing novel convex hull analysis, and subjective assessment of apparent attenuation intensity ranking (AAIR) for each fracture. Differences between fracture config...
Jackson BF, Lonnell C, Verheyen K, Wood JL, Pfeiffert DU, Price JS.Injuries to the skeleton are a major cause of morbidity and mortality in racehorses and age, gender and season have all been shown to influence risk of injury. Objective: To use biochemical markers of bone cell activity to establish to whether cellular processes in bone underlie these described effects. Methods: Blood samples were collected monthly from 2-year-old horses in race training between November 1998 and September 1999. Mean age at the start of the study was 20 months (range 18-23 months), with no significant difference in average age between colts (n = 84) and fillies (n = 63). Three...
Kingston JK, Bayly WM, Sellon DC, Meyers KM, Wardrop KJ.To investigate the effects of formaldehyde fixation on equine platelets using flow cytometric methods to evaluate markers of platelet activation. Methods: Blood samples from 6 Thoroughbreds. Methods: The degree of fluorescence associated with binding of fluorescein isothiocyanate (FITC)-conjugated anti-human fibrinogen antibody and FITC-annexin V in unactivated and adenosine diphosphate (ADP)-, platelet activating factor (PAF)-, and A23187-activated platelet samples in unfixed and 0.5, 1.0, and 2.0% formaldehyde-fixed samples was assessed by use of flow cytometry. Results: In samples incubated...
Smyth GB, Dagley K.To obtain information on the types of Australian horses, how they are kept and their activities. Methods: An invitation to participate in an opt-in, internet-based survey was sent to 7000 people who had registered an email address to receive information from the Australian Horse Industry Council Inc. Results: There were 3377 (48%) useable responses from owners of 26,548 horses. Most horses were kept on small properties (usually 2-8 ha) in paddocks in rural areas of Queensland, New South Wales and Victoria. Most horses were female or geldings and the most common of 54 different activities was...
Korosue K, Murase H, Sato F, Ishimaru M, Kotoyori Y, Tsujimura K, Nambo Y.To test the usefulness of measuring pH and refractometry index, compared with measuring calcium carbonate concentration, of preparturient mammary gland secretions for predicting parturition in mares. Methods: Evaluation study. Methods: 27 pregnant Thoroughbred mares. Methods: Preparturient mammary gland secretion samples were obtained once or twice daily 10 days prior to foaling until parturition. The samples were analyzed for calcium carbonate concentration with a water hardness kit (151 samples), pH with pH test paper (222 samples), and refractometry index with a Brix refractometer (214 samp...
Blissitt KJ, Bonagura JD.Colour flow Doppler echocardiography is a technique that is used with two-dimensional (2-D) echocardiography to study blood flow patterns in the heart and blood vessels. This method was used to define normal flow patterns and to evaluate valvular function in 40 clinically normal Thoroughbred and Thoroughbred cross horses. Flow patterns from 10 standardised echocardiographic images were described in relation to anatomic landmarks and timing during the cardiac cycle. Consistent intracardiac flow patterns were identified in the normal horses. High velocity flow signals or regurgitant jets were re...
Bayly WM, Redman MJ, Sides RH.It has been postulated that the hypoxaemia and hypercapnoea that characterize strenuous equine exercise are partly due to flow limitations imposed by high breathing frequencies (fb), and that gas exchange would be improved if fb could be lowered. To evaluate this possibility, 6 Thoroughbred horses underwent 4 incremental treadmill exercise tests at inclines of 0, 5, 10 and 25%, respectively. In the test, horses were given a warm-up for 2 min, then ran sequentially for 1 min each at 60, 100 and 115% VO2max. Oxygen consumption (VO2), blood gas tensions (PaO2, PaCO2), fb, tidal volume (VT), minut...
Barakzai SZ, Boden LA, Dixon PM.To (1) assess the degree of arytenoid cartilage abduction lost after laryngoplasty (LP) in Thoroughbred National Hunt racehorses and (2) to correlate postoperative racing performance with degree of arytenoid abduction after LP. Methods: Case series. Methods: National Hunt Thoroughbred racehorses (n=68). Methods: Grade of postoperative arytenoid abduction for National Hunt racehorses that had LP with ventriculocordectomy was assessed at 1 day, 6 days, and 6 weeks after LP. Race records were analyzed to ascertain if there was correlation between the degree of arytenoid cartilage abduction and va...
Goetz TE, Holland CJ, Dawson JE, Ristic M, Skibbe K, Keegan KG, Johnson PJ, Schaeffer DJ, Baker GJ.The seroprevalence and seasonal trend of antibody titers against equine monocytic ehrlichiosis (Potomac horse fever) were determined in apparently healthy horses in selected areas of Illinois in 1986. Sera from 1,367 horses (6 months to 29 years old) were evaluated for the presence of antibodies against Ehrlichia risticii with indirect immunofluorescence. The majority (88%) of the horses were Thoroughbred or Standardbred racehorses. The number of horses with antibodies against E risticii was 229/1,367 (16.75%). The titers in these horses ranged from 1:10 to 1:640. As the year progressed, the n...
Arango-Sabogal JC, Mouncey R, de Mestre AM, Verheyen K.Thoroughbred breeders aim to have foals born early in the season, but scientific evidence on the advantages for race performance is scarce and contradictory. Unassigned: The association between date of birth and purchase price as foal/yearling, with race performance by the end of the second and third years of life of Thoroughbreds racing in flat races in the United Kingdom (UK) and Ireland (IRE) was assessed using negative binomial and zero-inflated negative binomial models on the entire 2014-2015 UK/IRE foal crops ( = 28,282). Unassigned: In total, 6666 and 9456 horses raced in UK/IRE flat r...
Wilson AJ, Rambaut A.Horse racing is a multi-million pound industry, in which genetic information is increasingly used to optimize breeding programmes. To maximize the probability of producing a successful offspring, the owner of a mare should mate her with a high-quality stallion. However, stallions with big reputations command higher stud fees and paying these is only a sensible strategy if, (i) there is a genetic variation for success on the racecourse and (ii) stud fees are an honest signal of a stallion's genetic quality. Using data on thoroughbred racehorses, and lifetime earnings from prize money (LE) as a ...
Jensen RC, Fischer JH, Cwik MJ.The effect of age and training status on the pharmacokinetics of flunixin meglumine was evaluated in 16 Thoroughbreds. Horses were assigned to 1 of 3 groups on the basis of age and training status: group A (n = 6), horses in active training and less than or equal to 5 years old; group B (n = 5), horses out of training for a minimum of 6 weeks and less than or equal to 5 years old; and group C (n = 5), horses out of training for at least 2 years and greater than or equal to 9 years old. After administration of 500 mg of flunixin meglumine IV, multiple serum and urine samples were obtained over ...
Whitton RC, Rose RJ.To determine the relative contributions of the palmar intercarpal ligaments in the midcarpal joint to the restraint of dorsal displacement of the proximal row of carpal bones. Methods: A biomechanical study of cadaver equine carpi. Methods: Eight equine forelimbs from six thoroughbred horses. Methods: With joints in full extension, the radius was dorsally displaced while midcarpal joint displacement was measured. The restraining force at a joint displacement of 1.5 mm was determined from the load-displacement curve. A ligament or pair of ligaments was then cut and the testing procedure repeate...
Moiroud CH, Coudry V, Denoix JM. The aim of this study was to analyse the pelvic fracture distribution and location in a referral centre caseload. Methods: Medical records of 6,717 horses examined in a referral centre over a 7-year period were reviewed to identify all horses diagnosed with a pelvic fracture. Eighty-six horses were identified and divided into three disciplines, namely Thoroughbred racehorses (TBR), Standardbred trotter racehorses (STR) and non-racing sport horses (NRSH). Results: A pelvic fracture was diagnosed in 1.3% of the cases examined during the study period. Prevalence was significantly higher ...
Hawkins JF, Tulleners EP.Epiglottitis was diagnosed and treated in 20 horses (13 Thoroughbreds and 7 Standardbreds) over a 5-year period. Eighteen horses were used for racing, and 2 Standardbreds were broodmares. Primary clinical signs were exercise intolerance, respiratory noise, and coughing. The most common endoscopic diagnosis made by referring veterinarians was epiglottic entrapment (11 horses). In 19 horses, endoscopic evaluation at admission revealed mucosal ulceration and thickening of the lingual surface of the epiglottis. Other endoscopic findings included dorsal displacement of the soft palate (14 horses), ...
Strand E, Össurardóttir S, Wettre KB, Fjordbakk CT.To report clinical findings and performance in horses in which alar fold collapse (AFC) had been diagnosed and surgically treated and to assess form and degree of respiratory obstruction. Methods: Retrospective case series. Methods: Twenty-one standardbreds, 2 coldblooded trotter racehorses, 1 thoroughbred, and 1 Icelandic horse. Methods: Alar fold collapse was diagnosed on the basis of continuous abnormal expiratory flutter noise coinciding with filling of the false nostrils during exercise on a high-speed treadmill that was alleviated by suturing the alar folds (AF) temporarily in a dorsal p...
Hübers E, Bauer N, Fey K, Moritz A, Roscher K.The retrospective study aimed to evaluate the prevalence of true thrombocytopenia and ethylenediaminetetraacetic acid (EDTA)-induced pseudothrombocytopenia in horses and ponies and to assess the diagnostic and prognostic utility of true thrombocytopenia. Methods: In 3592 patients (2008-2015) hematological data (ADVIA® 2120, Siemens) were reviewed. Inclusion criteria were platelet counts < 90 x 109/l (EDTA-blood) and/or < 84 x 109/l (citrate blood). Thrombocytopenia was classified as true, EDTA-induced, and questionable. Patients with true thrombocytopenia were assigned to nine groups ac...
