Standardbred horses are a breed known for their performance in harness racing, characterized by their ability to trot or pace at high speeds. This breed is distinguished by its well-muscled build, strong legs, and calm temperament. Standardbreds are primarily used in racing but are also versatile in other equestrian activities, including riding and driving. Their genetic lineage can be traced back to the late 18th century, with the establishment of the breed registry in the United States. This page compiles peer-reviewed research studies and scholarly articles that explore the genetics, physiology, and performance characteristics of Standardbred horses, as well as their management and health considerations in various equine disciplines.
Ter Woort F, Caswell JL, Arroyo LG, Viel L.OBJECTIVE To describe histologic findings in the small airways during postmortem examination of actively racing horses and to quantify the degree of airway inflammation by use of a semiquantitative scoring system. SAMPLE Lung tissues obtained from 95 horses (Thoroughbreds, Standardbreds, and Quarter Horses) that had been actively racing or training. PROCEDURES 10 standardized lung sections were obtained during postmortem examination of 37 horses that had been actively racing or training, and 2 histologic sections of the caudodorsal lung lobes previously collected from each of 58 horses that di...
Moulin N, François I, Coté N, Alford C, Cleary O, Desjardins MR.Despite the recommendation of plate fixation for propagating condylar fractures of the third metacarpal (McIII) or third metatarsal bone (MtIII), lag screw fixation can be a viable surgical option. Objective: To evaluate short-term outcome and long-term racing performance of horses that underwent lag screw fixation of long condylar fractures of the McIII/MtIII. Methods: Retrospective case series. Methods: Medical records, post-surgical racing performance and outcome of 26 horses with propagating fractures of the medial and/or lateral condyle of McIII/MtIII were reviewed. Medical information in...
Connysson M, Muhonen S, Jansson A.This study investigated the effects of transport and diet on metabolic response during a subsequent race-like test in Standardbred horses in training fed a forage-only diet and a 50:50 forage:oats diet. Six trained and raced Standardbred trotter mares were used. Two diets, 1 forage-only diet (FONLY) and 1 diet with 50% of DM intake from forage and 50% from oats (FOATS), were fed for two 29-d periods in a crossover design. At Day 21, the horses were subjected to transport for 100 km before and after they performed an exercise test (transport test [TT]). At Day 26, the horses performed a control...
Burns TA, Dembek KA, Kamr A, Dooley SB, Dunbar LK, Aarnes TK, Bednarski LS, O'Brien C, Lakritz J, Byrum B, Wade A, Farmer R, Tan S, Toribio RE.Cobalt chloride (CoCl ) is administered to racehorses to enhance performance. The purpose of this study was to evaluate the clinical, cardiovascular, and endocrine effects of parenterally administered CoCl . Objective: To describe the effects of weekly intravenous doses of CoCl on Standardbred horses. Methods: Five, healthy Standardbred mares. Methods: Prospective, randomized, experimental dose-escalation pilot. Five Standardbred mares were assigned to receive 1 of 5 doses of CoCl (4, 2, 1, 0.5, or 0.25 mg/kg) weekly IV for 5 weeks. Physical examination, blood pressure, cardiac output, and e...
Dern K, van Eps A, Wittum T, Watts M, Pollitt C, Belknap J.Although continuous digital hypothermia (CDH) protects lamellae from injury in the oligofructose (OF) model of sepsis-related laminitis (SRL), conflicting results exist from these studies regarding effects of CDH on lamellar inflammatory events. Objective: To determine the effect of CDH on lamellar inflammatory events in normal and OF-treated horses when instituted at a clinically relevant time point (onset of clinical signs of sepsis in this model). Methods: Standardbred geldings (n = 15) aged 3-11 years were used. Methods: In a randomized, controlled discovery study, animals were administ...
Jacob SI, Geor RJ, Weber PSD, Harris PA, McCue ME.Diagnosis of equine pituitary pars intermedia dysfunction (PPID) remains a challenge as multiple factors (stress, exercise, and time of year) influence ACTH and cortisol concentrations. To assess endocrine status in a study designed to evaluate the effects of age and diet on glucose and insulin dynamics, we performed thyrotropin-releasing hormone (TRH) stimulation tests and overnight dexamethasone suppression tests in March, May, August, and October on 16 healthy Thoroughbred and Standardbred mares and geldings. Horses were grouped by age: adult (mean ± SD; 8.8 ± 2.9 yr; n = 8) and aged (20...
Crevier-Denoix N, Audigié F, Emond AL, Dupays AG, Pourcelot P, Desquilbet L, Chateau H, Denoix JM.OBJECTIVE To evaluate the effect of track surface firmness on the development of musculoskeletal injuries in French Trotters during 4 months of race training. ANIMALS 12 healthy 3-year-old French Trotters. PROCEDURES Horses were paired on the basis of sex and body mass. Horses within each pair were randomly assigned to either a hard-track or soft-track group. The counterclockwise training protocol was the same for both groups. Surface firmness of each track was monitored throughout the training period. Radiography, ultrasonography, MRI, and scintigraphy were performed on all 4 limbs of each ho...
Al-Haidar A, Moula N, Leroux A, Farnir F, Deleuze S, Sandersen C, Amory H.The aim of this study was to establish echocardiographic reference values for the equine species using allometric regression equations based on body weight (BW) and thoracic circumference (TC). Methods: A total of 239 horses or ponies were studied, including 65 warmbloods, 33 Standardbreds, 41 Thoroughbreds, 32 Arabian horses, 28 draft horses, and 40 ponies aged from 1 day to 30 years, weighing from 18 to 890 kg, with no evidence of cardiac disease. Methods: For each horse or pony, a two-dimensional and M-mode echocardiography was performed. Within each breed, the relationships between BW or ...
Jacob SI, Geor RJ, Weber PSD, Harris PA, McCue ME.Glucose and insulin dynamics may be different in adult and aged horses. Objective: To determine the effects of age and dietary carbohydrates on glucose and insulin dynamics in healthy horses. Methods: Balanced Latin square with four isocaloric diets: CONTROL (hay plus restricted-starch-and-sugar fortified pellets), STARCH (control plus kibbled corn), FIBER (control plus unmolassed sugar beet pulp/soybean hull pellets) and SUGAR (control plus dextrose powder). Methods: A total of 16 healthy Thoroughbreds and Standardbreds divided into two age groups: ADULT (8.8 ± 2.9 years; n = 8) and AGE...
Huxford KE, Dart AJ, Perkins NR, Bell R, Jeffcott LB.AIMS To compare the efficacy of an enteric coated esomeprazole paste with an enteric coated omeprazole paste to increase gastric pH after oral administration in horses. METHODS Nine adult Standardbred horses were randomly assigned to three groups, each containing three horses, for a study comprising three phases of 10 days, with an 18-day washout period between each phase. In each phase, three horses received either 0.5 mg/kg esomeprazole, 1 mg/kg omeprazole or a placebo, as an oral paste, once daily for 10 days (Days 0-9). Over the course of study all horses received all three treatments....
Romagnoli N, Al-Qudah KM, Armorini S, Lambertini C, Zaghini A, Spadari A, Roncada P.The aims of this study were to assess the plasma concentrations of romifidine in horses after intravenous injection, to evaluate the red blood cell (RBC) partitioning of the anaesthetic drug, and to improve knowledge regarding its sedative effect in horses describing the pharmacokinetic model. Eight adult Standardbred horses received a single bolus of romifidine at a dosage of 100 g/kg. Blood samples (5 mL) were collected immediately before romifidine administration (), and at 2, 5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 90, 105, 120, 150 and 180 min after injection. A sedation score was recor...
Tsang AS, Dart AJ, Sole-Guitart A, Dart CM, Perkins NR, Jeffcott LB.To compare the effect of application of manuka honey with unique manuka factor (UMF) 5 or 20 with a generic multifloral honey on equine wound healing variables. Methods: Two full-thickness skin wounds (2.5 × 2.5 cm) were created on the metatarsus of both hindlimbs of eight Standardbred horses. The wounds on each horse were assigned to 1 of 4 treatments: UMF20 (UMF20) and UMF5 (UMF5) manuka honey; generic multifloral honey (GH); and a saline control. Bandages were changed daily for 12 days, after which treatment was stopped and the bandages were removed. Wound area was measured on day ...
Carmalt JL, Johansson BC, Zetterström SM, McOnie RC.OBJECTIVE To determine factors affecting race speed in Swedish Standardbred horses undergoing surgery of the carpal flexor sheath (CFS), to investigate whether preoperative racing speed was associated with specific intraoperative findings and whether horses returned to racing, and to compare the performance of horses undergoing surgery of the CFS with that of age- and sex-matched control horses. ANIMALS 149 Swedish Standardbred trotters undergoing surgery of the CFS and 274 age- and sex-matched control horses. PROCEDURES Medical records of CFS horses were examined. Racing data for CFS and cont...
Verdegaal EJMM, Delesalle C, Caraguel CGB, Folwell LE, McWhorter TJ, Howarth GS, Franklin SH.OBJECTIVE To evaluate use of a telemetric gastrointestinal (GI) pill to continuously monitor GI temperature in horses at rest and during exercise and to compare time profiles of GI temperature and rectal temperature. ANIMALS 8 Standardbred horses. PROCEDURES Accuracy and precision of the GI pill and a rectal probe were determined in vitro by comparing temperature measurements with values obtained by a certified resistance temperature detector (RTD) in water baths at various temperatures (37°, 39°, and 41°C). Subsequently, both GI and rectal temperature were recorded in vivo in 8 horses over...
Wong JKY, Kwok WH, Chan GHM, Choi TLS, Ho ENM, Jaubert M, Bailly-Chouriberry L, Bonnaire Y, Cawley A, Ming Williams H, Keledjian J, Brooks L....Acadesine, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, commonly known as AICAR, is a naturally occurring adenosine monophosphate-activated protein kinase (AMPK) activator in many mammals, including humans and horses. AICAR has attracted considerable attention recently in the field of doping control because of a study showing the enhancement of endurance performance in unexercised or untrained mice, resulting in the term 'exercise pill'. Its use has been classified as gene doping by the World Anti-Doping Agency (WADA), and since it is endogenous, it may only be possible to control del...
Olive J, Serraud N, Vila T, Germain JP.The metacarpal condyle has received extensive attention as a predominant site of overload arthropathy in racehorses. However, detailed descriptions of MRI lesion patterns for the metacarpophalangeal joint and comparisons between types of racing horses are currently lacking. Aims of this retrospective, cross-sectional study were to describe and compare standing low-field magnetic resonance findings in the metacarpophalangeal joints for groups of Standardbreds and Thoroughbreds using systematic semiquantitative scores. Data archives at the Clinique Vétérinaire Equine de Chantilly and Imavet we...
Kraus M, Physick-Sheard PW, Brito LF, Schenkel FS.The number of Standardbred racehorses admitted to the Ontario Veterinary College Teaching Hospital (Guelph, Canada) for treatment of atrial fibrillation (AF) has been on the rise since the early 1990s. A small number of sires have been contributing to a large proportion of cases, indicating there may be a genetic predisposition to the arrhythmia in this breed. Objective: The objectives of this study were to determine the heritability of AF in Standardbred horses and whether heritability of the arrhythmia differs across gaits and/or sexes. Methods: Heritability study based on retrospective revi...
Ahern BJ, Van Eps AW, Boston RC, Franklin SH.To determine the degree and ease of arytenoid abduction achieved with abaxial placement of a FASTak II suture anchor compared to 2 suture patterns with different directions of insertion-caudomedial to craniolateral and medial to lateral. Methods: Ex vivo experimental. Methods: Cadaveric larynges from 10 Standardbred racehorses. Methods: Each larynx was sequentially instrumented with all 3 arytenoid suture attachment in random order: (1) abaxial placement of a FASTak II suture, (2) caudomedial to craniolateral suture, and (3) medial to lateral suture placement. Each construct was abducted at 5N...
DeLay J.Postmortem lesions and cause of death were evaluated retrospectively for 963 horses examined as part of the Ontario Racing Commission Death Registry over a 13-y period. The Death Registry was established in 2003 to identify factors leading to death or euthanasia of racehorses in this Canadian province. Postmortem examination was carried out on 56% of horses reported to the Death Registry and included Standardbred, Thoroughbred, and American Quarter Horses. Musculoskeletal injury was the most common reason for death associated with racing or training among all racehorses and involved 68% of hor...
Ringmark S, Revold T, Jansson A.This study examined feed intake, growth, body condition, muscle glycogen content and nutrition-related health in 16 Standardbred horses fed a high-energy, forage-only diet ad libitum and allocated to either a control training programme (C-group) or a training programme with the high-intensity training distance reduced by 30% (R-group), from January as 2-year olds until December as 3-year olds. Feed intake was recorded on 10 occasions during 3 consecutive days. Body weight was recorded once in a week and height, body condition score (BCS), rump fat thickness and thickness of the m. longissimus ...
Baskerville CL, Bamford NJ, Harris PA, Bailey SR.Insulin-like growth factor-1 (IGF-1) plays several important physiological roles, and IGF-related pathways have been implicated in developmental osteochondral disease and endocrinopathic laminitis. This factor is also a downstream marker of growth hormone activity and its peptide mimetics. Unfortunately, previously used assays for measuring equine IGF-1 (radioimmunoassays and ELISAs) are no longer commercially available, and many of the kits on the market give poor results when used on horse samples. The aim of the present study was to compare three different ELISA assays (two human and one ho...
Lane HE, Burns TA, Hegedus OC, Watts MR, Weber PS, Woltman KA, Geor RJ, McCutcheon LJ, Eades SC, Mathes LE, Belknap JK.Insulin dysregulation, obesity, and exposure to high-nonstructural carbohydrate (NSC) forage are risk factors for equine metabolic syndrome-associated laminitis (EMSAL); high systemic insulin concentrations in EMSAL are proposed to induce cellular dysregulation in the digital lamellae through activation of the insulin-like growth factor-1 receptor. Objective: To use a dietary challenge model (DCM) and a euglycaemic-hyperinsulinaemic clamp (EHC) model to assess lamellar growth factor-related signalling. Methods: Lamellar phospho (P)-protein concentrations of signalling proteins important in gro...
Gardner AK, van Eps AW, Watts MR, Burns TA, Belknap JK.Supporting limb laminitis (SLL) is a devastating sequela to severe unilateral lameness in equine patients. The manifestation of SLL, which usually only affects one limb, is unpredictable and the etiology is unknown. A novel, non-painful preferential weight bearing model designed to mimic the effects of severe unilateral forelimb lameness was developed to assess lamellar signaling events in the supporting limb (SL). A custom v-shaped insert was attached to the shoe of one forelimb to prevent normal weight bearing and redistribute weight onto the SL. Testing of the insert using a custom scale pl...
Schutten KJ.A 12-year-old Standardbred mare was diagnosed with a ruptured prepubic tendon 1 month prepartum. The mare was treated with analgesia, stall rest, and an abdominal support wrap that was tightened daily. Both a live foal born 1 month later and the mare are doing well. Poulinage réussi par une jument Standardbred ayant une rupture du tendon prépubien. Un mois avant la parturition, une rupture du tendon prépubien a été diagnostiquée chez une jument Standardbred âgée de 12 ans. La jument a été traitée à l’aide d’analgésiques, d’un repos en stalles et d’un pansement de soutien r...
Doubli-Bounoua N, Richard EA, Léon A, Pitel PH, Pronost S, Fortier G.The potential involvement of viruses in inflammatory airway disease (IAD) was previously investigated through either serology or PCR from nasopharyngeal swabs (NS). The aims of this study were to determine the prevalence and incidence of viral genome detection by qPCR in the equine airways, and their association with respiratory clinical signs. Both NS and tracheal washes (TW) were collected monthly on 52 Standardbred racehorses at training, over 27 consecutive months (581 samples). Equid herpesviruses (EHV)-1, -4, -2 and -5, equine rhinitis virus-A and -B (ERBV), equine adenovirus-1 and -2, e...
Flethøj M, Kanters JK, Pedersen PJ, Haugaard MM, Carstensen H, Olsen LH, Buhl R.Although premature beats are a matter of concern in horses, the interpretation of equine ECG recordings is complicated by a lack of standardized analysis criteria and a limited knowledge of the normal beat-to-beat variation of equine cardiac rhythm. The purpose of this study was to determine the appropriate threshold levels of maximum acceptable deviation of RR intervals in equine ECG analysis, and to evaluate a novel two-step timing algorithm by quantifying the frequency of arrhythmias in a cohort of healthy adult endurance horses. Results: Beat-to-beat variation differed considerably with he...
Tapio H, Argüelles D, Gracia-Calvo LA, Raekallio M.To describe a modified technique for permanent translocation of the common carotid artery (CCA) to a subcutaneous position in standing horses. Methods: Experimental study. Methods: Healthy adult Standardbred and Warmblood horses (n = 8). Methods: Surgery was performed with the horses standing under sedation and with local anesthesia. A combination of previously described techniques was used modifying the approach and closure of the incision. The right CCA was approached through a linear skin incision dorsal and parallel to the jugular vein and through the brachiocephalicus and omohyoideus ...
Heinonen E, Hedenstierna G, Meriläinen P, Högman M, Nyman G.To study the effect of the pulsed delivery of nitric oxide (NO) on pulmonary gas exchange in the anaesthetized horses. Design Prospective, controlled randomized. Methods: Five healthy Standardbred trotters, three geldings and two mares. Methods: The horses were anaesthetized with thiopentone and isoflurane and positioned in dorsal recumbency. Nitric oxide was added as a pulse to the inspired gas during the first half of each inspiration. In three horses the effect of NO on the ventilation-perfusion distribution was also investigated using the multiple inert gas elimination technique. Data w...
Bertuglia A, Pagliara E, Grego E, Ricci A, Brkljaca-Bottegaro N.Joint impact injuries initiate a progressive articular damage finally leading to post-traumatic osteoarthritis (PTOA). Racehorses represent an ideal, naturally available, animal model of the disease. Standardbred racehorses developing traumatic osteoarthritis of the fetlock joint during the first year of their career were enrolled in our study. Age-matched controls were contemporarily included. Biomarker levels of equine osteoarthritis were measured in serum and synovial fluid (SF) at baseline, and repeated yearly over the next 4 years of training (from T1 to T4). The effect of time and disea...
Mespoulhès-Rivière C, Brandenberger O, Rossignol F, Robert C, Perkins JD, Marie JP, Ducharme N.OBJECTIVE To develop and assess the feasibility, repeatability, and safety of an ultrasound-guided technique to stimulate the first cervical nerve (FCN) at the level of the alar foramen of the atlas of horses. ANIMALS 4 equine cadavers and 6 clinically normal Standardbreds. PROCEDURES In each cadaver, the FCN pathway was determined by dissection, and any anastomosis between the first and second cervical nerves was identified. Subsequently, each of 6 live horses underwent a bilateral ultrasound-guided stimulation of the FCN at the alar foramen 3 times at 3-week intervals. After each procedure, ...
Tuomola K, Mäki-Kihniä N, Valros A, Mykkänen A, Kujala-Wirth M.Bit-related lesions in competition horses have been documented, but little evidence exists concerning their potential risk factors. Objective: To explore potential risk factors for oral lesions in Finnish trotters. Methods: Cross-sectional study. Methods: The rostral part of the mouth of 261 horses (151 Standardbreds, 78 Finnhorses and 32 ponies) was examined after a harness race. Information on bit type, equipment and race performance was collected. Results: A multivariable logistic regression model of Standardbreds and Finnhorses showed a higher risk of moderate or severe oral lesion stat...
de Laat MA, Patterson-Kane JC, Pollitt CC, Sillence MN, McGowan CM.Lamellar pathology in experimentally-induced equine laminitis associated with euglycaemic hyperinsulinaemia is substantial by the acute, clinical phase (∼48h post-induction). However, lamellar pathology of the developmental, pre-clinical phase requires evaluation. The aim of this study was to analyse lamellar lesions both qualitatively and quantitatively, 6, 12 and 24h after the commencement of hyperinsulinaemia. Histological and histomorphometrical analyses of lamellar pathology at each time-point included assessment of lamellar length and width, epidermal cell proliferation and death, base...
Ringmark S, Lindholm A, Hedenström U, Lindinger M, Dahlborn K, Kvart C, Jansson A.Training of Standardbred race horses aims to improve cardiovascular and metabolic functions but studies on the effects of different training strategies from breaking till racing are lacking. Sixteen horses with the goal to race as 3-year-olds were studied from breaking (1-year-olds) to December as 3-year-olds. Horses were allocated to either a control (C) or reduced (R) training program from 2 years of age. The aim was to evaluate the effect of reducing the distance of high intensity exercise by 30% with respect to velocity at lactate concentration 4 mmol/l (VLa4), blood lactate and cardiovasc...
Van de Water E, Oosterlinck M, Korthagen NM, Duchateau L, Dumoulin M, van Weeren PR, Olijve J, van Doorn DA, Pille F.An established lipopolysaccharide (LPS) model previously described in Warmbloods, was inconsistent in Standardbred horses, where lameness was not detected despite the presence of synovitis. The present study aimed to determine the dose of LPS from E. coli O55:B5 required to induce mild to moderate lameness following middle carpal joint injection in Standardbred horses and to quantitate the induced lameness over time, with and without anti-inflammatory pre-treatment. In a baseline trial, eight healthy, clinically sound Standardbred horses were used in a rule-based dose-escalation design trial, ...
Ringmark S, Roepstorff L, Essén-Gustavsson B, Revold T, Lindholm A, Hedenström U, Rundgren M, Ogren G, Jansson A.The aim of this study was to, from a holistic perspective, describe the effects of a forage-only feeding system and a conventional training program on young Standardbred horses and compare data with similar observations from the literature. Sixteen Standardbred colts fed a forage-only diet for 4 months from breaking (August to December) and with the goal to vigorously trot 5 to 7 km at a speed of 5.6 m/s (3 min/km) were studied. The horses were fed grass haylage (56 to 61% dry matter (DM), 2.80 to 3.02 Mcal DE/kg DM and 130 to 152 g CP/kg DM) ad libitum, 1 kg of a lucerne product and minerals....
Art T, Lekeux P.Five healthy, fit Standardbreds (mean +/- SEM, 490.4 +/- 15.0 kg, 4.0 +/- 0.5 years) were studied during a standardized test carried out on a treadmill. The test consisted of an 8-minute warm-up and a 9-minute exercise period (1 minute at 1.7, 4, 7, 8, 9, and 10 m/s; 2 minutes at 4 m/s; and a 1-minute walk at a 6% slope). Respiratory airflow, tidal volume (V(T)), and respiratory frequency (f) were continuously recorded, using 2 ultrasonic pneumotachographs connected to a face mask and mass spectrometer. Oxygen uptake, carbon dioxide output, and expired minute volume (V(E)) were obtained on a b...
McCutcheon LJ, Geor RJ, Hinchcliff KW.This study examined changes in skeletal muscle GLUT4 content and glucose transport in isolated muscle membranes (GT) from horses before and 2 min after standardised submaximal exercise tests (SET) prior to and after completion of 6 weeks of training. Seven horses, age 3-9 years, body mass mean +/- s.e. 530 +/- 19 kg, and sedentary for at least 4 months, completed 6 weeks of training on a treadmill. An initial SET (UT) was performed on a 4 degree incline at a speed equivalent to 55% of pretraining VO2max and was repeated post-training at the same absolute workload (ABS). A third SET (REL) was p...
Mohammed HO, Rebhun WC, Antczak DF.A retrospective case-control study was conducted to identify risk factors in horses associated with the development of the common skin tumours known as sarcoids. The study involved 503 sarcoid cases diagnosed (January 1980-December 1989) at New York State College of Veterinary Medicine and a similar number of controls (non-sarcoid cases). Data on age, breed and sex of cases and controls were obtained from computerised records. Multiple logistic regression analysis was used to identify risk factors. Separate data were obtained for the same 10-year period from the Veterinary Medical Data Program...
Reef VB.Ventricular septal defects (VSDs) were diagnosed in 27 horses; in 26 affected horses systolic murmurs were detected over both sides of the chest. Holodiastolic decrescendo murmurs were also detected in 5 horses. Standardbreds and Arabian horses were over-represented, while Thoroughbred horses were under-represented, when compared to the hospital population (P < 0.0001). Five horses had previously raced successfully, one 2-year-old was training successfully and close to racing, and 4 horses had competed successfully in other types of competition. Eleven horses had a history of exercise intolera...
Ronéus M, Essén-Gustavsson B, Lindholm A, Persson SG.Muscle biopsies were taken from the middle gluteal muscle of 28 Standardbred trotters, 3-4 years of age. The 13 horses in Group T were trained consistently from 18 months of age, whereas the 15 horses in Group UT were not exposed to any systematic training before 3 years of age. Group T horses had a lower percentage of Type IIB fibres (31%) than did Group UT horses (39%). Citrate synthase (CS) activity, representing oxidative capacity, was higher in Group T (72 mmol kg-1 min-1) than in Group UT (47 mmol kg-1 min-1). Biopsies were taken from 4 horses in each group when they were foals and then ...
Osteochondrosis (OC) develops in growing horses due to disturbed differentiation and maturation of cartilage, particularly at the predilection sites of the fetlock, hock and stifle joints. Horses with osteochondrotic lesions are at a high risk of developing orthopaedic problems later in life. This article briefly reviews the published heritability estimates for OC and offers perspectives for selection in the horse industry. Heritabilities for OC in Warmblood and Standardbred horses have been estimated at 0.1-0.4 in animal threshold models. Whole genome scans using microsatellites have identifi...
Malinowski K, Shock EJ, Rochelle P, Kearns CF, Guirnalda PD, McKeever KH.Ageing appears to affect immune and neuroendocirne function in horses and response to acute exercise. No studies have examined the combined effects of training and ageing on immune and neuroendocirne function in horses. Objective: To ascertain whether training and age would affect the plasma beta-endorphin (BE) and cortisol (C) as well as immune function responses to acute exercise in Standardbred mares. Methods: Graded exercise tests (GXT) and simulated race tests (SRT) were performed before and after 12 weeks training at 60 % HRmax. BE and C were measured at rest and at 5, 10, 20, 40, 60 and...
Buhl R, Ersbøll AK, Eriksen L, Koch J.The purpose of this study was to assess the intraobserver variation of various echocardiographic measures in standardbred trotters. Serial echocardiographic examinations were carried out on eight standardbred mares by one ultrasonographer for 5 separate days. During each examination, five nonconsecutive cardiac cycles (frames) were recorded and an average obtained for each individual measure. Various echocardiographic measures were obtained by use of two-dimensional (2-D), M-mode, color flow Doppler and pulsed wave Doppler echocardiography. The total variation in the echocardiographic measurem...
De Maré L, Boshuizen B, Vidal Moreno de Vega C, de Meeûs C, Plancke L, Gansemans Y, Van Nieuwerburgh F, Deforce D, de Oliveira JE, Hosotani G....There is a great need for objective external training load prescription and performance capacity evaluation in equestrian disciplines. Therefore, reliable standardised exercise tests (SETs) are needed. Classic SETs require maximum intensities with associated risks to deduce training loads from pre-described cut-off values. The lactate minimum speed (LMS) test could be a valuable alternative. Our aim was to compare new performance parameters of a modified LMS-test with those of an incremental SET, to assess the effect of training on LMS-test parameters and curve-shape, and to identify the optim...
Kirschvink N, Art T, de Moffarts B, Smith N, Marlin D, Roberts C, Lekeux P.Exercise-induced oxidative stress is investigated as a potential performance-limiting factor in human sports medicine. Therefore, the present study aimed to assess whether physiological variables that change with exercise intensity were correlated with blood oxidant markers in healthy and heaves-affected horses. Seven healthy horses, 8 heaves-affected in remission and 7 heaves-affected in crisis performed a standardised exercise test (SET) of stepwise increasing intensity. Variables monitored during exercise were heart rate (HR), venous plasma lactate (LA), packed cell volume (PCV) and arteria...
Johnstone IB, Viel L, Crane S, Whiting T.The purpose of this study was to determine whether a defect in hemostasis might be a factor in the etiology of exercise-induced pulmonary hemorrhage (EIPH). Hemostatic parameters were evaluated in 22 EIPH-positive and ten EIPH-negative racing horses while in a rested state. Nineteen EIPH-positive and ten EIPH-negative horses were further evaluated just before and immediately after a 15 min exercise period on a 260 m oval track. When EIPH-positive and EIPH-negative horses were compared at rest, there was no significant difference in any of the coagulation and fibrinolytic parameters studied. Th...
Perkins GA, Viel L, Wagner B, Hoffman A, Erb HN, Ainsworth DM.In diagnosing inflammatory airway disease (IAD) in performance horses, a histamine bronchoprovocation (HBP) test is often performed. In previously published studies, HBP is usually undertaken prior to cytological examination of the bronchoalveolar lavage (BAL) cells. The purpose of this study was to determine if HBP alters (1) the total nucleated cell numbers and distribution in BAL fluid (BALF) and (2) the mRNA and protein concentrations of selected cytokines in BAL cells and BALF, respectively. BALF was initially collected endoscopically from the right middle or diaphragmatic lung lobe in ei...
Buhl R, Nissen SD, Winther MLK, Poulsen SK, Hopster-Iversen C, Jespersen T, Sanders P, Carstensen H, Hesselkilde EM.Limited information is available on paroxysmal atrial fibrillation (PAF) in the horse. Indeed, undiagnosed PAF could result in poor performance. Due to the intermittent occurrence, PAF is difficult to diagnose. However, implanting a small ECG device (implantable loop recorder, ILR) subcutaneously, allows the continuous and automatic detection of PAF. Objective: The aim was to investigate the potential of ILRs as a tool for diagnosing PAF in horses with poor performance. Methods: Prospective field study. Methods: Twelve racing Standardbred trotters with intermittent reduced performance (mean ag...
Leleu C, Bariller F, Cotrel C, Barrey E.Locomotion analysis is increasingly used to assess the gait of horses in the selection and training of equine athletes. We have developed a specific locomotor test for fast trotting harnessed horses that uses an accelerometric device. We describe here the reproducibility of the locomotor test and the validation of its use to analyse trotters on the racetrack. We measured the performance of eight horses under the same conditions three times in a single week. We then tested the influence of five tracks on the variables measured using eight different trotters every two days. The horses trotted at...
McCoy AM, Beeson SK, Rubin CJ, Andersson L, Caputo P, Lykkjen S, Moore A, Piercy RJ, Mickelson JR, McCue ME.Several horse breeds have been specifically selected for the ability to exhibit alternative patterns of locomotion, or gaits. A premature stop codon in the gene DMRT3 is permissive for "gaitedness" across breeds. However, this mutation is nearly fixed in both American Standardbred trotters and pacers, which perform a diagonal and lateral gait, respectively, during harness racing. This suggests that modifying alleles must influence the preferred gait at racing speeds in these populations. A genome-wide association analysis for the ability to pace was performed in 542 Standardbred horses (n = 17...
Cothran EG, MacCluer JW, Weitkamp LR, Bailey E.American Standardbred horses are divided into two groups based upon gait: the trot and the pace. The tendency to trot (diagonally opposite legs moving forward together) or pace (the two legs on the same side of the body moving forward together) appears to be genetically determined, although no formal genetic analysis has been undertaken. There is nearly complete assortative mating for gait; however, about 20% of the offspring sired by trotters are registered as pacers, while fewer than 1% of those sired by pacers are registered as trotters. Electrophoretically detectable genic variation at 13 ...
Lapointe JM, Laverty S, Lavoie JP.Case histories, results of synovial fluid analyses, treatment regimens and outcome are described for 15 adult Standardbred horses with confirmed post-injection septic arthritis. Joint sepsis followed injection of corticosteroids, hyaluronic acid, polysulphated glycosaminoglycan, or local anaesthetic. The median interval from injection to appearance of clinical signs was 2.5 days, and median interval from injection to referral was 9 days. The median initial synovial leucocyte count on admission was 57 x 10(9)/litre, but there was a wide range of values (18-258 x 10(9)/litre). The median synovia...
Trommershausen Bowling A, Clark RS.Gene frequencies at 20 blood group and protein polymorphism loci (A, C, D, K, P, Q, U, Al, Tf, Pi, Xk, Es, Gc, PGD, CA, Cat, PGM, AP, Hb and PHI) are given for seven horse breeds in the United States (Thoroughbred, Arabian, Standardbred, Morgan, Quarter Horse, Paso Fino and Peruvian Paso). These data are used to calculate that the battery of tests is at least 96% effective for recognizing incorrect paternity in these breeds. In addition to paternity testing, these tests can be applied to studies of breed relationships.
Richard EA, Pitel PH, Christmann U, Lekeux P, Fortier G, Pronost S.Surfactant protein D (SP-D), mainly synthesised by alveolar type II cells and nonciliated bronchiolar cells, is one important component of innate pulmonary immunity. In man, circulating concentrations of SP-D are routinely used as biomarkers for pulmonary injury. To date, serum SP-D levels have only been investigated in horses in an experimental model of bacterial airway infection. Objective: To compare serum SP-D concentrations at rest and after exercise in horses with and without inflammatory airway disease (IAD). Methods: Venous blood samples were collected from 42 Standardbred racehorses a...
Boy MG, Galligan DT, Divers TJ.Medical records of 82 horses with clinical signs of neurologic disease and histologic lesions suggestive of protozoal encephalomyelitis were reviewed. The presence of a protozoan parasite in the CNS was not influenced by prior treatment of the horse with corticosteroids. Prior treatment of horses with trimethoprim-sulfonamide alone or in combination with pyrimethamine resulted in a decreased number of horses in which a protozoan parasite was detected in the CNS at necropsy. The mean age of affected horses was 3.62 +/- 2.78 years, with male and Standardbred horses being overrepresented, compare...
Bailey E.The sera of 390 pregnant Standardbred mares and 409 pregnant Thoroughbred mares were tested for anti-red blood cell (RBC) antibodies. Of the Standardbred mares and Thoroughbred mares, 20% and 10%, respectively, had anti-RBC antibodies detectable in hemolytic or saline agglutination tests. Most of the antibodies were specific for the CA blood-group antigen of horses. Other antibodies were specific for the Aa, Ab, Aa, Ab, Da, Df, Ka, Ua, or Qa blood-group antigens. The occurrence of these antibodies in the serum and colostrum was compared for 268 mares. With 3 exceptions, whenever antibodies wer...
Wilson DA, Baker GJ, Pijanowski GJ, Boero MJ, Badertscher RR.Suspensory ligaments (SL) from 32 Thoroughbreds and 32 Standardbreds were collected to evaluate the variation in muscle content with respect to age, breed, sex, limb, and use. Six transverse sections, each 3 to 5 mm thick, were obtained from each SL. Four sections were taken from the body of the SL and 1 from the midportion of each branch. Sections were stained with van Gieson picric acid-fuchsin solution, then photographed, and black-and-white slides were made from the processed negatives. The transverse-sectional area of the SL and the contained muscle were determined by use of a computer wi...
Huntington PJ, Forman AJ, Ellis PM.This paper reports the first isolation of equine arteritis virus (EAV) in Australia and serological evidence of exposure to EAV in Australian horses. Twelve Standardbred stallions imported from North America were found to shed EAV in semen. One hundred and seven stallions were tested for serum antibodies to EAV and 73% of Standardbred stallions tested were seropositive as compared to 8% of Thoroughbred stallions. Serum antibody was detected in 71% of Standardbred mares, 6% of Standardbred racehorses and 1% of Thoroughbred mares and racehorses. Examination of stored serums demonstrated that EAV...
Nunamaker DM, Butterweck DM, Provost MT.Geometric properties of the third metacarpal bone were compared between the young and adult Standardbred and Thoroughbred racehorse. The change in shape during growth and superimposed training was dramatic in both breeds but the Thoroughbred showed the greatest difference in the minimum moment of inertia as the animal matured. Males had larger moments of inertia throughout the length of the diaphysis than did females. The differences in geometric properties of the third metacarpal bone between the Thoroughbred and Standardbred were related to the incidence of fatigue fractures which are common...
Kinnunen S, Hyyppä S, Oksala N, Laaksonen DE, Hannila ML, Sen CK, Atalay M.Heat shock protein (HSP) expression is an adaptive mechanism against the disruption of cell homeostasis during exercise. Several antioxidant supplementation strategies have been used to enhance tissue protection. In this study, we examined the effects of a redox modulator, alpha-lipoic acid (LA) on HSP responses in six standardbred trotters following intense aerobic exercise. DL-LA supplementation (25 mg kg(-1) d(-1)) for five weeks increased the resting levels of HSP90 (1.02+/-0.155 in control and 1.26+/-0.090 after supplementation in arbitrary units) and the recovery levels of inducible HSP7...
