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.
Norton AM, Rosanowski SM, O'Brien T.Epiglottic entrapment (EE) is a common cause of poor performance in racing standardbreds (STBs) and thoroughbreds (TBs). There is limited information published on the condition in STB racehorses and limited information on factors associated with return to racing available for either breed. Unassigned: This study investigated and compared the pre surgical findings, post-surgical complications and racing performance in STBs and TBs undergoing surgery for correction of EE. Associations between signalment and pre-surgical findings, and the presence of complications and racing post-surgery were com...
Herbst AC, Puglia AT, Malinowski K, McKeever KH.The objective of this study was to determine if calcium propionate is an alkalizing agent in exercising Standardbreds and if it alters plasma glucose and serum insulin concentrations. This study used a randomized crossover design to test the hypotheses that calcium propionate alters total CO2 (tCO), Ca, pH, strong ion difference (SID), glucose, and insulin in Standardbreds completing a simulated race test (SRT) on a high-speed equine treadmill. Blood was collected from eight horses (mean age ± SD = 16 ± 2.7 years; range = 13 - 21 years) at 10 and 5 min prior to treatment or control administr...
Galinelli NC, Bamford NJ, Erdody ML, Warnken T, de Laat MA, Sillence MN, Harris PA, Bailey SR.The role of dopamine in the regulation of insulin secretion in horses is poorly understood and requires further investigation. Pituitary pars intermedia dysfunction (PPID) is associated with decreased activity of dopaminergic neurons which normally suppress peptide hormone secretion from the pituitary pars intermedia. A high proportion of horses with PPID also have insulin dysregulation (ID), characterised by post-prandial hyperinsulinaemia and/or tissue insulin resistance, which are risk factors for the development of laminitis. The aim of this study was to investigate the effects of alpha-me...
Stutsel M, Jordan L, Smith C, Lee WY, Symonds N, Bell R, Young A.Foot-related lameness is common in Standardbred and Thoroughbred racehorses. Magnetic resonance imaging (MRI) provides information on both the soft tissue and osseous structures of the distal extremity. The aim of this study was to determine whether abnormalities identified on distal limb MRI differed between these two racehorse populations. Methods: The records of Standardbred and Thoroughbred racehorse distal extremity MRI examinations conducted at Camden Equine Centre and Ballarat Veterinary Practice between 2013 and 2023 were retrieved. Horses were included if pain causing lameness had bee...
Bertuglia A, Pallante M, Pagliara E, Valle D, Bergamini L, Bollo E, Bullone M, Riccio B.Tarsocrural osteochondrosis (OCD) is a developmental orthopedic disease commonly affecting young Standardbreds, with different fragment localization and size. Clinically, it is characterized by variable synovial effusion in the absence of lameness, whose determinants are ill-defined. We hypothesized that localization and physical characteristics of the osteochondral fragments like dimensions, multifragmentation, and instability influence joint effusion and correlate with synovial markers of cartilage degradation and inflammation. Clinical data, synovial fluid and intact osteochondral fragments...
Rodden EBK, Suthers JM, Busschers E, Burford JH, Freeman SL.Castration is the most common surgical procedure in domesticated equids; surgical techniques used and perioperative management vary considerably. Objective: To identify and chart the current evidence on perioperative complications associated with different methods of surgical castration in domesticated equids. Methods: Joanna Briggs Institute systematic scoping review. Methods: CAB Abstracts, Medline and Embase databases were searched using terms related to equine castration complications. Two authors independently and blindly screened publications against eligibility criteria. Data on study m...
Munday JS, Knight CG, Bodaan CJ, Codaccioni C, Hardcastle MR.Penile squamous cell carcinomas (SCCs) are common, potentially life-threatening neoplasms of horses. They are well-recognized to be caused by Equus caballus papillomavirus (EcPV) type 2, although EcPV2 cannot be detected in all cases. A 23-year-old standardbred gelding developed multiple penile in situ and invasive SCCs that contained histological evidence of PV infection. By using both consensus and specific PCR primers, these lesions were found to contain EcPV7 DNA, but not DNA from EcPV2 or any other PV type. To determine how frequently EcPV7 is present in equine penile SCCs, specific prime...
Argüelles D, Saitua A, Miraz R, Calle-González N, Requena F, Nocera I, Vitale V, Sgorbini M, Muñoz A.It has been reported that capacitive resistive electric transfer (CRET) increases blood circulation, hemoglobin oxygenation and temperature in muscles. The attributed benefits of these changes have been linked to improved athletic performance, enhanced muscle flexibility and fastening recovery from exercise-induced fatigue. For all of this, the present research aims to investigate whether the application of CRET 24 h before exercise affects the accelerometric pattern in horses during exercise. Six sound Standardbred trotters were subjected to a CRET session of 40 min of duration, applied on ...
Inflammatory myopathy and perivasculitis have been recently described in horses with chronic equine piroplasmosis (EP). These alterations may be linked to poor performances. The aims of this study were to evaluate the prevalence for EP in clinically healthy Italian Standardbred (IS) racehorses and to compare laboratory parameters and performance metrics between positive and negative horses. Real-time PCR was applied for the detection of T. equi and B. caballi positivity. Haematology parameters, blood chemistry results, subjective muscle mass scores, and performance metrics were compared betwee...
Barbazanges P, Richard EA, Lemonnier LC, Wouters CP, Toquet MP, Couroucé A.Cytology of airway samples is sensitive for diagnosis of exercise-induced pulmonary haemorrhage (EIPH), but the association between tracheal wash (TW) and bronchoalveolar lavage fluid (BALF) is unknown. The objective of this study was to determine whether diagnosis of EIPH, using haemosiderophages/macrophages (H/M) ratio, differs when based on TW or BALF. Methods: A prospective cross-sectional study was conducted on 102 standardbred horses in training. TW and BALF were collected concomitantly from all horses at rest (at least 24 hours after their last training or race), and their H/M ratios w...
Fraschetto C, Hatrisse C, Moiroud C, Beaumont A, Audigié F, Chateau H, Denoix JM, Jacquet S.To measure the trunk vertical displacement (VD) in horses trotting on a water treadmill (WT) at different water depths (WDs) and speeds. Methods: 6 sound Standardbred horses (median age 12 years [IQR:10.5-12]). Methods: The horses were trotted on a WT at 2 speeds (3.5 m/s and 5 m/s) and during 4 conditions: dry treadmill (DT), WD at mid-cannon (WD-CAN), mid-radius (WD-RAD), and shoulder (WD-SHOUL). The dorsoventral movement was obtained with accelerometers placed over the withers, thoracolumbar junction (T18), tuber sacrale (TS), and sacrum (S5). The VD was defined with the median value of the...
Jayathilake WMNK, de Laat MA, Furr M, Risco C, Lacombe VA.Hyperinsulinemia is the key feature of equine metabolic syndrome (EMS) which leads to debilitating sequelae. Hyperinsulinemia-associated laminitis (HAL) is one of the major sequelae of EMS, although the pathophysiological mechanisms are not well elucidated. Using an equine model, we hypothesized that expression of inflammatory markers would be increased in digital lamellae and striated muscle following prolonged hyperinsulinemia. Healthy Standardbred horses (5.4 ± 1.9 years) were alternately assigned to a prolonged euglycemic-hyperinsulinemic clamp (pEHC) or control group (n = 4 per group...
Hansen S, Otten ND, Nissen SD, Carstensen H, Hopster-Iversen C, Fjeldborg J, Staun SH, Fenner M, Hesselkilde EM, Buhl R.Atrial fibrillation (AF) has been proposed as a risk factor for exercise-induced pulmonary haemorrhage (EIPH) due to increased pressure in the left atrium. Objective: To evaluate if AF was associated with EIPH following a standardised exercise test (SET) to fatigue. Methods: Two-arm controlled experiment. Methods: Ten untrained Standardbred mares mean (standard deviation [SD]) age 6 (2) years performed a SET on the treadmill in sinus rhythm (SR) (SET1) and 25-44 days after induction of self-sustained AF (SET2). AF was induced by tachypacing using a pacing device. Endoscopy, including trachea...
Vidal Moreno de Vega C, Lemmens D, de Meeûs d'Argenteuil C, Boshuizen B, de Maré L, Leybaert L, Goethals K, de Oliveira JE, Hosotani G, Deforce D....Important changes in glucose transporter (GLUT) expression should be expected if the glucose influx plays a pivotal role in fuelling or connecting metabolic pathways that are upregulated in response to exercise. The aim was to assess GLUT4, 8, and 12 dynamics in response to training and acute exercise. Sixteen untrained Standardbred mares (3-4 year) performed an incremental SET at the start and end of 8 weeks harness training. M. pectoralis (PM) and M. vastus lateralis (VL) muscle biopsies were taken before and after each SET, allowing for comparing rest and acute samples in untrained (UT) ...
Stutsel M, Gimeno M, Young A, Bell JW, Horadagoda N.A 2-year-old Standardbred gelding was referred for a mass on the palmaromedial right front pastern which was accompanied by progressively worsening lameness. The mass was firm to palpation and covered by normal skin. Ultrasonographically, a smooth encapsulated mass was present, medial to the flexor tendons and palmar to the neurovascular bundle. Because of a poor prognosis for future athletic performance without surgical or chemotherapeutic intervention and economic constraints preventing further diagnostics and treatment, the horse was euthanised. Post-mortem magnetic resonance imaging, histo...
Tanner JC, Barrell GK.Despite being a large commercial breeding industry, there is little published data on the reproductive success of Standardbred mares. Objective: To quantify the reproductive performance of Standardbred mares under artificial breeding systems in a commercial setting and determine the incidence of early embryonic and other pre-partum losses. Methods: Retrospective cohort study. Methods: Data from four commercial farms were collected across four breeding years, and all mares were bred via artificial insemination. A total of 3995 mares contributed 7229 mare years. First-cycle pregnancy rate (FCPR)...
Jondeau C, Guyonnet A, Losada A, Laloy E, Reyes-Gomez E, Le Dudal M, Chahory S.To describe a case of lipogranulomatous conjunctivitis in a horse. Methods: A client-owned 12-year-old Standardbred gelding presenting with chronic conjunctivitis and palpebral masses. Methods: Complete ophthalmic examination, surgical excision, histopathology, and bacterial culture of biopsy samples were performed. Results: Upper and lower eyelids of both eyes were affected, with multiple yellow-to-white nodules on the palpebral conjunctiva, adjacent to the eyelid margin. Nodule removal was achieved via partial tarsal plate excision. Histopathological examination revealed granulomatous inflam...
Dementieva N, Nikitkina E, Shcherbakov Y, Nikolaeva O, Mitrofanova O, Ryabova A, Atroshchenko M, Makhmutova O, Zaitsev A.The specifics of breeding and selection significantly affect genetic diversity and variability within a breed. We present the data obtained from the genetic analysis of 21 thoroughbred and warmblood horse breeds. The most detailed information is described from the following breeds: Arabian, Trakehner, French Trotter, Standardbred, and Soviet Heavy Horse. The analysis of 509,617 SNP variants in 87 stallions from 21 populations made it possible to estimate the genetic diversity at the genome-wide level and distinguish the studied horse breeds from each other. In this study, we searched for heter...
Lagounova M, MacNicol JL, Weese JS, Pearson W.Synbiotics are often provided to horses receiving antibiotics to protect against microbiome disturbances, despite a lack of evidence for efficacy. The purpose of this study was to evaluate the effect of a synbiotic product in horses receiving antibiotics. Sixteen actively racing Standardbred horses were randomly allocated (four-way crossover) to one of four groups: antibiotics (10 days; AB), synbiotics (28 days; PROBIOPlusTM; PBP), PBP + AB, or Control. The fecal microbiome was investigated using 16S rRNA sequencing, and fecal dry matter (DM; %), pH, and scores (FS; 0-9) were measured. Data we...
Olstad K, Ekman S, Björnsdóttir S, Fjordbakk CT, Hansson K, Sigurdsson SF, Ley CJ.Recently, the central and third tarsal bones of 23 equine fetuses and foals were examined using micro-computed tomography. Radiological changes, including incomplete ossification and focal ossification defects interpreted as osteochondrosis, were detected in 16 of 23 cases. The geometry of the osteochondrosis defects suggested they were the result of vascular failure, but this requires histological confirmation. The study aim was to examine central and third tarsal bones from the 16 cases and to describe the tissues present, cartilage canals, and lesions, including suspected osteochondrosis le...
McCoy AM, Scolman KN.The aim of this study was to identify the radiographic prevalence of periarticular osteophytes of the distal tarsus in nonlame yearling Standardbred horses, and to evaluate its potential impact on race performance. Methods: Cross-sectional cohort study. Methods: Client-owned yearling Standardbred horses (n = 416). Methods: Bilateral tarsal radiographs were available from all horses for review. Osteophytes were measured on radiographs using clinical visualization software and categorized by size. Racing records were obtained from the United States Trotting Association. Regression analysis w...
Pál Z, Bodó G.Allograft arthroplasty is a promising cartilage-resurfacing technique. A 14-year-old horse was diagnosed with a medial femoral condyle subchondral bone cyst. Allografts were harvested from a young donor animal and implanted to fill the cyst cavity. A visual assessment of the surgical site was possible during follow-up arthroscopy. In addition to a desirable gliding surface and a good adaptation of the grafts, fibrillation of the cranial ligament of the medial meniscus was noted and debrided. The recipient horse became sound four months after follow-up surgery with a high level of owner satisfa...
Oheida AH, Shalgum AA, Alrtib AM, Booker AO, Ben-Naser KM, Davies HMS.Carpal conformation is an important factor in relation to joint soundness. The equine carpometacarpal joint (CMCJ) was reported to have variations in its three palmaromedial articulations. Lacking one or more of these articulations has not been radiographically evaluated in Thoroughbred (TB) and Standardbred (SB) racehorses. The study aimed to identify the prevalence of the variation in the palmaromedial articulation of the carpometacarpal joint (PM-CMCJ) in TB and SB horses. Additionally, to detect the probability of having each of the three articulations within and between the breeds. Finall...
Lo Feudo CM, Stucchi L, Conturba B, Stancari G, Zucca E, Ferrucci F.Poor performance is a multifactorial syndrome of racehorses, commonly associated with subclinical disorders, which can be diagnosed by exercise testing. Objective: Describe the prevalence of medical causes of poor performance in Standardbreds unassociated with lameness, and evaluate their relationships with fitness variables measured by exercise treadmill test. Methods: Hospital population of 259 nonlame Standardbred trotters referred for poor performance. Methods: The horses' medical records were retrospectively reviewed. Horses underwent a diagnostic protocol including resting examination, p...
Steel C, Ahern B, Zedler S, Vallance S, Galuppo L, Richardson J, Whitton C, Young A.Radiographs underestimate the extent of bone injury in horses with third carpal bone (C3) fractures (Fx). We aimed to describe bone pathologies identified using computed tomography (CT) and compare the diagnostic value of digital radiography (DR) and CT in horses with C3 Fx. CT images of 15 racehorses with C3 Fx and 10 controls were reviewed (Part 1) then DR and CT images of 26 racehorses (24 Thoroughbred, 2 Standardbred) with C3 Fx (Part 2) were evaluated. Agreement on fracture geometry and concomitant bone lesions was tested between DR and CT using the kappa statistic (Part 2). For agreement...
Zetterberg E, Leclercq A, Persson-Sjodin E, Lundblad J, Haubro Andersen P, Hernlund E, Rhodin M.Many horses, just before and during their athletic career, show vertical movement asymmetries, to the same degree as clinically lame horses. It is unknown whether these asymmetries are caused by pain or have alternative explanations, such as inherent biological variation. In the latter case, movement asymmetries would be expected to be present at a very young age. This study aimed to investigate the prevalence of movement asymmetries in foals. Motion analysis, using an inertial measurement unit-based system (Equinosis), was performed on 54 foals (31 Swedish Warmbloods, 23 Standardbreds) during...
Carstensen H, Nissen SD, Saljic A, Hesselkilde EM, van Hunnik A, Hohl M, Sattler SM, Fløgstad C, Hopster-Iversen C, Verheule S, Böhm M, Schotten U....Atrial fibrillation (AF) is more prevalent in athletes, and currently, the mechanisms are not fully understood. Atrial fibrillation inducibility and stability was investigated in trained and untrained Standardbred racehorses. The horses underwent echocardiography for evaluation of atrial size. High-density mapping during AF was performed, and the presence of structural remodeling, as well as the expression of inflammatory and pro-inflammatory markers in the atria, was studied. Atrial fibrillation sustained significantly longer after tachypacing in the trained horses, whereas no difference in A...
White R, Nath L, Hebart M, Franklin S.P wave indices are used as non-invasive electrocardiographic markers of atrial remodelling in humans. Few studies have investigated their use in animals. The aim of this study was to measure P wave duration and P wave dispersion (Pd) in healthy standardbred horses and investigate variables that might influence these measurements. A 12-lead electrocardiogram was recorded at rest and P wave indices were calculated in 53 horses. A general linear model was used to investigate the main effects: age, bodyweight, sex, resting heart rate, presence of a murmur, exercise status and the number of years r...
Burns TA, Watts MR, Belknap JK, van Eps AW.Supporting limb laminitis (SLL) is a complication of severe orthopedic disease in horses and is often life-limiting, yet the pathophysiology remains obscure. Objective: To investigate the role of digital lamellar inflammatory signaling in the pathophysiology of SLL using a model of unilateral weight bearing, hypothesizing that there would be evidence of lamellar inflammation in limbs subjected to the model. Methods: Thirteen healthy adult Standardbred horses were used for this study (11 geldings, 2 mares; mean age 6.5 ± 2.5 years; mean body weight 458.3 ± 32.8 kg). Methods: Randomized...
Marzok M, Kandeel M, Babiker H, Alkhodair KM, Farag A, Ibrahim H, El-Ashker M, Alghuwainem Y, El-Khodery S.The purpose of this study was to provide a systematic meta-analysis on echocardiographic measurements in normal Thoroughbred and Standardbred horses. The current systematic meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). All the available published papers on the reference values of echocardiographic assessment via M-mode echocardiography were searched, and fifteen studies were finally selected for analysis. In both fixed and random effect, the confidence interval (CI) for the interventricular septum (IVS) was 2.8-3.1 and 4.7-7.5; for the ...
Jonsson H, Egenvall A.There is little information about the prevalence of gastric ulcers in Standardbred trotters and potential correlations between ulcers and various traits, e.g. age, sex, performance, temperament and feeding regimens, need further elucidation. Objective: The prevalence of ulcers in the gastric squamous mucosa of Swedish Standardbreds was estimated and the associations between ulcer score and age, sex, performance, temperament and feeding regimens were determined. Methods: Eighty Swedish Standardbreds in active race training, trained by 9 different trainers, underwent gastroscopy. Information on ...
Thomson PC, Hayek AR, Jones B, Evans DL, McGreevy PD.Significant proportions of horses leave the Australian Thoroughbred and Standardbred racing industries, which has ramifications for both the economic sustainability and the public perception of racing. The aim of this study was to quantify potential horse wastage, describe the destinations of exiting horses and identify risk factors for horses going to these destinations. Methods: Questionnaires were sent to 1258 selected Thoroughbred and 981 Standardbred trainers, with response rates of 30% and 32%, respectively. The survey investigated the role of various risk factors for wastage, including ...
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...
Klein DJ, McKeever KH, Mirek ET, Anthony TG.The athletic horse, despite being over 50% muscle mass, remains understudied with regard to the effects of exercise and training on skeletal muscle metabolism. To begin to address this knowledge gap, we employed an untargeted metabolomics approach to characterize the exercise-induced and fitness-related changes in the skeletal muscle of eight unconditioned Standardbred horses (four male, four female) before and after a 12-week training period. Before training, unconditioned horses showed a high degree of individual variation in the skeletal muscle metabolome, resulting in very few differences ...
Malikides N, Hughes KJ, Hodgson DR, Hodgson JL.To determine whether diagnosis of airway inflammation, using cut-off percentages for neutrophils, differs when based on samples from tracheal aspirate (TA) and bronchoalveolar lavage (BAL) collected concomitantly from the same racehorse. Methods: Retrospective case series of 48 young Thoroughbred and Standardbred racehorses in race training, but showing poor performance. PROCEDURE TA and BAL samples were collected from all horses 1 to 2 h after high-speed treadmill exercise. Aliquots of the retrieved fluid were cytocentrifuged and smears stained with Diff-Quik. The mean percentage of neutrophi...
MacNamara B, Bauer S, Iafe J.Endoscopic examinations were performed on 965 Standardbred racehorses competing at Yonkers Raceway between June 16 and Aug 3, 1988, to demonstrate an association between exercise-induced pulmonary hemorrhage or chronic obstructive pulmonary disease and poor racing performance. Findings suggested that both exercise-induced pulmonary hemorrhage and chronic obstructive pulmonary disease adversely affect performance, whereas a combination of the 2 conditions more severely affects racing performance than do either of the conditions individually.
de Laat MA, Sillence MN, McGowan CM, Pollitt CC.Endocrinopathic laminitis is frequently associated with hyperinsulinaemia but the role of glucose in the pathogenesis of the disease has not been fully investigated. This study aimed to determine the endogenous insulin response to a quantity of glucose equivalent to that administered during a laminitis-inducing, euglycaemic, hyperinsulinaemic clamp, over 48 h in insulin-sensitive Standardbred racehorses. In addition, the study investigated whether glucose infusion, in the absence of exogenous insulin administration, would result in the development of clinical and histopathological evidence of ...
Jansson A, Lindberg JE.Most athletic horses are fed a high-starch diet despite the risk of health problems. Replacing starch concentrate with high-energy forage would alleviate these health problems, but could result in a shift in major substrates for muscle energy supply from glucose to short-chain fatty acids (SCFA) due to more hindgut fermentation of fibre. Dietary fat inclusion has previously been shown to promote aerobic energy supply during exercise, but the contribution of SCFA to exercise metabolism has received little attention. This study compared metabolic response with exercise and lactate threshold (VLa...
Armstrong RB, Essén-Gustavsson B, Hoppeler H, Jones JH, Kayar SR, Laughlin MH, Lindholm A, Longworth KE, Taylor CR, Weibel ER.The purpose of this study was to describe the relationships between 16 physiological, biochemical, and morphological variables presumed to relate to the oxidative capacity in quadriceps muscles or muscle parts in Standardbred horses. The variables included O2 delivery (blood flow) and mean capillary transit time (MTT) during treadmill locomotion at whole animal maximal O2 consumption (VO2max, 134 +/- 2 ml.min-1 x kg-1), capillary density and capillary-to-fiber ratio, myoglobin concentration, oxidative enzyme activities, glycolytic enzyme activities, fiber type populations, and fiber size. Thes...
Jäderkvist K, Andersson LS, Johansson AM, Árnason T, Mikko S, Eriksson S, Andersson L, Lindgren G.In a previous study it was shown that a nonsense mutation in the DMRT3 gene alters the pattern of locomotion in horses and that this mutation has a strong positive impact on trotting performance of Standardbreds. One aim of this study was to test if racing performance and trotting technique in the Nordic (Coldblood) trotters are also influenced by the DMRT3 genotype. Another aim was to further investigate the effect of the mutation on performance in Standardbreds, by using a within-family analysis and genotype-phenotype correlations in a larger horse material than in the previous study. We gen...
Slack J, Boston RC, Soma LR, Reef VB.Cardiac arrhythmias are a recognised but poorly characterised problem in the Standardbred racehorse. Frequency data could aid the development of cardiac arrhythmia screening programmes. Objective: To characterise the occurrence of cardiac arrhythmias in Standardbreds prior to racing and in the late post race period using a handheld, noncontinuous recording device. Methods: Prospective, observational study, convenience sampling. Methods: Noncontinuous electrocardiographic recordings were obtained over a 12 week period from Standardbred horses competing at a single racetrack. Electrocardiograms ...
Jeffcott LB, Field JR, McLean JG, O'Dea K.The existence of an innate insulin insensitivity in ponies was investigated and compared with the situation in larger breeds of horse. Ponies that were fat or had previously suffered laminitis were found to be far more intolerant to oral glucose loading (1 g/kg bodyweight [bwt]) than normal ponies or Standardbreds. These ponies also exhibited a far greater response in plasma insulin levels after glucose loading. Insulin response tests (0.4 iu/kg bwt insulin intravenously) showed only a minimal and very protracted response in both the fat and laminitic groups. The relevance of these findings in...
van de Goor LH, van Haeringen WA, Lenstra JA.As a consequence of the close integration of horses into human society, equine DNA analysis has become relevant for forensic purposes. However, the information content of the equine Short Tandem Repeat (STR) loci commonly used for the identification or paternity testing has so far not been fully characterized. Population studies were performed for 17 polymorphic STR loci (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG6, HTG7, HTG10, LEX3 and VHL20) including 8641 horses representing 35 populations. The power of parental exclusion, polymorphic information content...
Bamford NJ, Baskerville CL, Harris PA, Bailey SR.The enteroinsular axis is a complex system that includes the release of incretin hormones from the gut to promote the absorption and utilization of glucose after a meal. The insulinogenic effect of incretin hormones such as glucagon-like peptide-1 (GLP-1) remains poorly characterized in the horse. The aim of this study was to compare postprandial glucose, insulin, and GLP-1 responses of different equine breeds adapted to twice-daily meals containing micronized maize. Four Standardbred horses, 4 mixed-breed ponies, and 4 Andalusian cross horses in moderate BCS (5.5 ± 0.2 out of 9) were fed mea...
Lumsden JH, Rowe R, Mullen K.Reference hematology and biochemistry intervals are presented for a number of variables of clinical interest determined for blood samples obtained from 60 thoroughbred mares, 12 thoroughbred foals and 50 standardbred horses in training. The observations for each variable were examined for outliers and Gaussian distribution. Parametric analysis was used where the observations were Gaussian initially or after any of four transformations, otherwise nonparametric analysis was required for estimation of the 2.5 and 97.5 percentiles. Description of the sample collection procedures, laboratory method...
Bell RJ, Kingston JK, Mogg TD, Perkins NR.To establish the prevalence and factors influencing the prevalence and severity of gastric ulceration in racehorses in New Zealand. Methods: Horses (n=171) in active training for racing by trainers (n=24) located throughout New Zealand were examined using gastroscopy during 2003 and 2004. Images of the examination were recorded and reviewed, and an ordinal grade based on the severity of gastric ulceration present was assigned, using the grading system proposed by the Equine Gastric Ulcer Council (EGUC). Information about the horses such as age, breed, sex, stabling, time at pasture, pasture qu...
Nath LC, Anderson GA, McKinnon AO.To evaluate the reproductive efficiency of horse farms in north-east Victoria and identify aspects of management to be targeted for improving reproductive efficiency. Methods: Retrospective study. Methods: Records from seven Thoroughbred (TB) and four Standardbred (STB) studs in north-east Victoria from 1990 to 2001 were reviewed; 8813 cycles in 4455 mares were analysed. TB mares were inseminated by natural mating, whereas STB mares (89%) were artificially inseminated. Results: The overall early pregnancy rate per cycle was 68.8% for TB mares and for STB mares, 68.3%. Multiple pregnancy per cy...
Leleu C, Cotrel C, Courouce-Malblanc A.The relationships between V4 (the velocity for a blood lactate concentration of 4 mmol/litre) and V200 (the velocity for a heart rate of 200 bpm) and the performance indices of 223 healthy French trotters were analysed. They were divided into four age groups of three, four, five and six years and over, and into three performance groups (good, intermediate and poor performers) defined by the index of trot (ITR), an annual index of performance calculated by the national stud. V4 and V200 were assessed during the performance of a three-step standardised field exercise test, and four performance i...
Grøndahl AM, Dolvik NI.Radiography of the tibiotarsal and metacarpo- and metatarsophalangeal joints was performed on 753 Standardbred trotters (6 to 21 months old) born in 1988. The surveyed population was drawn at random from all parts of Norway and represented about 60% of Standardbred trotters born the same year. Osteochondrosis in the tibiotarsal joint was diagnosed in 108 (14.3%) horses, and the prevalence of disease in progeny groups > 10 ranged from 0 to 69%. Bony fragments in the palmar/plantar portion of the metacarpo- and metatarsophalangeal joints were diagnosed in 89 (11.8%) horses, and the prevalence of...
Cocchia N, Paciello O, Auletta L, Uccello V, Silvestro L, Mallardo K, Paraggio G, Pasolini MP.Endometritis is the most important cause of infertility in barren mares. The quick method of endometrial cytology (EC) has a relatively high reliability in diagnosing endometrial inflammation in the mare. For reliable cytological results, a collection technique that yields many well-preserved cells representative of a large uterine surface area without causing harm to the reproductive tract is required. The aim of the study was to compare three usually employed techniques for collection of endometrial and inflammatory cells (guarded cotton swab, uterine lavage, and cytobrush) in chronically in...
Nissen SD, Weis R, Krag-Andersen EK, Hesselkilde EM, Isaksen JL, Carstensen H, Kanters JK, Linz D, Sanders P, Hopster-Iversen C, Jespersen T....Long-term exercise induces cardiac remodeling that potentially influences the electrical properties of the heart. Objective: We assessed whether training alters cardiac conduction in Standardbred racehorses. Methods: Two hundred one trained and 52 untrained Standardbred horses. Methods: Cross-sectional study. Resting ECG recordings were analyzed to assess heart rate (HR) along with standard ECG parameters and for identification of atrial and ventricular arrhythmias. An electrophysiological study was performed in 13 horses assessing the effect of training on sinoatrial (SA) and atrioventricular...
Austin SM, Foreman JH, Hungerford LL.Risk factors for development of pleuropneumonia were determined by reviewing medical records of 45 horses with pleuropneumonia and 180 control horses examined between Jan 1, 1980 and Jan 1, 1990. Factors considered included age, breed, sex, occupation, transport farther than 500 miles within the previous week, racing within the previous 48 hours, viral respiratory tract infection or exposure to horses with viral respiratory tract disease within the previous 2 weeks, and vaccination against influenza or rhinopneumonitis within the previous 6 months. Results indicated that Thoroughbreds were at ...
Slocombe JO, de Gannes RV, Lake MC.The aims of studies in 2002 and 2003 on three farms with 76 foals naturally infected with Parascaris equorum were to (i) identify if the nematode was resistant to ivermectin and moxidectin, and (ii) confirm the effectiveness of fenbendazole and pyrantel pamoate for the parasite. Twelve clinical trials, each with a Fecal Egg Count Reduction Test, were conducted on two Thoroughbred and one Standardbred farms in southwestern Ontario, Canada. In each trial, Parascaris eggs/g feces were estimated for each foal pre- and post-treatment using the Cornell-Wisconsin double flotation and Cornell-McMaster...
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...
Schwarzwald CC, Schober KE, Bonagura JD.Noninvasive assessment of left ventricular (LV) function is incompletely studied in horses. Objective: The goals of this study were to investigate the feasibility, techniques, and reliability of tissue Doppler imaging (TDI) for characterization of LV radial wall motion in healthy horses. Methods: Three Standardbreds, 3 Thoroughbreds; age 8-14 years; body weight 517-606 kg. Methods: Repeated echocardiographic examinations were performed by 2 observers in unsedated horses using TDI. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and b...
Padalino B, Davis GL, Raidal SL.Transportation has been suggested as a risk factor for gastric ulceration in horses, but limited evidence supports this assumption. Methods: Twenty-six Standardbred, Thoroughbred, and Warmblood mares from a university teaching herd. Methods: Twelve mares were confined for 12 hours, overnight, in reproductive stocks with indwelling nasogastric tubes (NGTs) to assess pH of gastric fluid (GF). Gastric ulceration was assessed endoscopically before and after confinement. Subsequently, 26 horses were transported for 12 hours, overnight, in 2 consignments. During transportation, GF was aspirated ...
McGurrin MK, Physick-Sheard PW, Kenney DG.Transvenous electrical cardioversion (TVEC) has been developed for treatment of atrial fibrillation (AF) in horses. The relationship among patient variables, treatment response, and outcome in a typical referral population has not been evaluated. Objective: Patient variables such as age, sex, weight, and duration of arrhythmia affect prognosis for response to treatment and the energy level at which cardioversion occurs. Methods: TVEC was applied to 72 episodes of lone AF in 63 client-owned performance horses, with the majority (54) being Standardbred racehorses. Methods: Catheterization of the...
Richard EA, Fortier GD, Pitel PH, Dupuis MC, Valette JP, Art T, Denoix JM, Lekeux PM, Erck EV.The objectives of this study were to determine the prevalence of sub-clinical diseases in poorly-performing Standardbred horses, compare their physiological response to exercise with control horses, and identify predictive parameters of poor-performance. Fifty horses underwent thorough clinical and ancillary examinations, including haematological and biochemical evaluation, Doppler echocardiography, standardised exercise tests (SETs) on both treadmill and racetrack, treadmill video-endoscopy and collection of respiratory fluids. Most of the poorly-performing horses exhibited many concomitant d...
Olstad K, Cnudde V, Masschaele B, Thomassen R, Dolvik NI.Osteochondrosis (OC) is an important developmental orthopedic disease of human and equine patients. The disease is defined as a focal disturbance in enchondral ossification. In horses, the disturbance can occur secondary to failure of the blood supply to growth cartilage. Diagnosis of the early, subclinical stages that can clarify the etiology is currently confined to cross-sectional histological examination. The potential for micro-computed tomography (micro-CT) with angiography to detect early lesions of OC has not yet been investigated. Methods: Nine Standardbred foals bred from parents wit...
Naccache F, Metzger J, Distl O.Osteochondrosis (OC) is an injury to cartilage canals with a following necrosis in the growth cartilage, from there it can develop to osteochondrosis dissecans (OCD). Due to its high impact in the equine industry, new insights into predisposing factors and potential high-risk genetic variants are warranted. This article reviews advancements in quantitative and molecular genetics in refining estimation of genetic parameters and identifying predisposing genetic loci. Heritabilities were highest for hock OC with estimates at 0.29-0.46 in Hanoverian warmblood and Norwegian trotters, whereas in Tho...
