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.
French RA, Meier WA, Zachary JF.Tissues from a 9-year-old American Standardbred gelding with a history of anorexia, mild colic, and unexpected death were submitted to the Laboratories of Veterinary Diagnostic Medicine at the University of Illinois for histopathologic examination. Microscopic diagnoses were severe subacute, diffuse eosinophilic colitis with intralesional protozoa and a subacute to chronic eosinophilic portal hepatitis with granuloma formation. Two tissue-invading, ciliated protozoa were identified in large numbers within the colonic mucosa. The ciliates were Polymorphella ampulla and Cycloposthium sp., Phylum...
Pollitt CC.Thirty-two dorsal, mid-hoof wall, lamellar sections from 8 Standardbred horses, humanely killed 48 h after the administration of an alimentary carbohydrate overload, were sectioned and examined by light microscopy. Sections were stained with the connective tissue and basement membrane stains periodic acid-Schiff (PAS), Azan and periodic acid silver methanamine (PASM) and with routine haematoxylin and eosin (H&E). Lesions of the epidermal lamellae, attributable to laminitis, were graded in order of increasing severity from Grade N (normal), Grade 1 (mild), Grade 2 (moderate) to Grade 3 (severe ...
Lindholm A, Ronéus B, Lindblad G, Jones B.The biological turnover of hyaluronan (sodium hyaluronate) of different molecular weights (0.6 x 10(6) and 2.5 x 10(6) Daltons) was studied in the synovial fluid of the middle carpal and metacarpophalangeal joints of 6 clinically healthy Standardbred horses. The hyaluronan was radioactively labelled with 14C. The biological half-life (t1/2) was calculated from repeated synovial samples after injection of the labelled hyaluronan. The mean t1/2 in the metacarpophalangeal joints was 9.7 h for low molecular weight hyaluronan and 8.9 h for high molecular weight hyaluronan and in the middle carpal j...
Moore BR, Krakowka S, Cummins JM, Robertson JT.Natural human interferon-alpha (nHuIFN alpha) was administered to actively training Standardbred racehorses with inflammatory airway disease (IAD). Inflammatory airway disease was characterized by poor exercise performance and inflammation and exudate in the upper and lower airway. Placebo, 50, 150, or 450 units(U) of nHuIFN alpha was administered orally for 5 consecutive days to eight horses per treatment group in a double-blind, randomized block design. Response to nHuIFN alpha was monitored by semiquantitative endoscopic examination score and cytologic examination of bronchoalveolar lavage ...
Dolvik NI, Klemetsdal G.The purpose of this study was to evaluate the impact of arthritis of the carpal joint on performance of Norwegian cold-blooded trotters. Two performance variables were used in the analyses. The first was the start status, for which horses that had started in one or more races within a certain age received the value 1, and horses that had not raced were correspondingly assigned the value 0. The second variable was the accumulated, transformed and standardized earnings (ATSE), which is the power transformation of earnings (earnings .2, with unraced horses assigned a value of zero) expressed as a...
Räsänen LA, Lampinen KJ, Pösö AR.To study whether end products of 2 pathways of anaerobic energy metabolism, lactate and purines, that accumulate in the blood after intense exercise indicate any relation to exercise performance. Methods: Venous blood samples were taken within 1 and 15 minutes after a trotting race of 2,100 m. Methods: 16 Clinically healthy Standardbred trotters. Methods: Blood and plasma lactate concentrations were measured by enzymatic analyzer, and purines, uric acid and allantoin, were determined by high-performance liquid chromatography. The concentrations of metabolites were then correlated to racing tim...
Art T, Votion D, Lekeux P.The purpose of this study was 1) to measure and compare some physiological parameters in horses during a standardised treadmill exercise performed either in temperate atmospheric conditions (TC) (ambient temperature: 15 degrees C; relative humidity: 55%), or in hot and humid conditions (HHC) (ambient temperature: 30 degrees C; relative humidity: 75%) and 2) to follow the recovery of the same horses during 1 h after both tests. Five healthy fit Standardbred horses were investigated twice at 8 days interval, in TC and in HHC. Some measurements were made during a standardised treadmill exercise t...
Hoffmann KL, Wood AK, McCarthy PH.Sonographic and anatomic observations were made of the kidneys of 23 Thoroughbreds or Standardbreds. In an in vitro study of 16 horses, precise correlations were established between the gross anatomic features of the kidneys and their sonographic appearance in images obtained in dorsal, sagittal, transverse, and transverse oblique anatomic planes. The renal cortex had a uniformly mottled echogenicity, and the renal medulla was relatively hypoechogenic, compared with the cortex. Acoustic anisotropy was observed in the cortex and medulla of the cranial and caudal extremities of each kidney. The ...
Jansson A, Nyman S, Morgan K, Palmgren-Karlsson C, Lindholm A, Dahlborn K.In this study 4 Standardbred geldings (age 3-8 years, weight 431-531 kg) were used. The horses were fed a hay and oat diet and the total sodium intake was about 32 mg/kg bwt (690 mmol/day). An exercise test (ET) which contained 3 phases was performed. Phase I consisted of 23.5 min of mainly submaximal exercise, Phase 2 of 2 h of box rest and Phase 3 of 26 min of exercise including an intensive trot over 2600 m at 90% of VO2max. The ET was repeated 3 times: the first at 20 degrees C (30-40% RH), the second at 35 degrees C (30-40% RH) and the third at 35 degrees C (30-40% RH) after a nasogastric...
Nixon AJ, Pool RR.Osteochondral fragments from the axial proximoplantar/proximopalmar region of the proximal phalanx were removed from 38 joints in 30 horses. Ninety-three percent of the horses were Standardbreds, and 28 of the 30 had a low-grade lameness. All but 1 of the horses had hind limb involvement. A total of 43 fragments were removed. Most (71%) of the fragments involved the medial aspect of the joint and had to be dissected from a covering of synovial tissue. Histologically, the circumference of most fragments consisted of a transition zone at the attachment of the joint capsule, a region of nonarticu...
Lillich JD, Ruggles AJ, Gabel AA, Bramlage LR, Schneider RK.Medical records of 17 horses in which a distal sesamoid bone fracture was diagnosed between 1982 and 1992 were reviewed. There were 8 Standardbreds, 6 Quarter Horses, 2 Thoroughbreds, and 1 Arabian. Mean age was 4.7 years. A forelimb was affected in 15 horses, and a hind limb was affected in 2. All horses were lame, and most were grade III/V lame at the trot. In all horses, the diagnosis was confirmed by means of radiography. Five horses were treated with stall rest alone; 5 underwent neurectomy; 4 were treated with stall rest and corrective shoeing; and 1 was treated with stall rest and exter...
McKane SA, Rose RJ, Evans DL.Twenty-four Thoroughbred and twelve Standardbred racehorses aged between 2 and 6 years, presented for reported poor racing performance, underwent clinical exercise testing. During the last 10 s of exercise at each speed throughout an incremental speed exercise test on a treadmill inclined at a 10% slope, samples of arterial blood and expired gases were collected. Maximum oxygen uptake and the partial pressures of oxygen and carbon dioxide in arterial blood were determined. These values were compared between the two breeds of horses and also with reference to cytological findings of bronchoalve...
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...
Heath SE, Peter AT, Janovitz EB, Selvakumar R, Sandusky GE.A 2-year-old Standardbred gelding was examined because of prolapse of the third eyelid; myoclonus of the muscles of the head, neck, and forelimbs; and persistent tail swishing. The horse had a high plasma sodium concentration but was not drinking water. The hypernatremia could not be corrected by means of IV administration of fluids, and the horse became worse and, 6 days later, died. At necropsy, a tumor was found to be compressing the neurohypophysis and the area in the brain in which the thirst centers are believed to be located. It is believed that hypernatremia in this horse was a result ...
Mitten LA, Hinchcliff KW, Sams R.Evaluation of a portable blood gas analyzer, (StatPal II, Unifet, Inc, La Jolla, CA) was performed using tonometered solutions and equine blood. Samples were analyzed by the StatPal II and either an Instrument Laboratory IL1306 (Lexington, MA) or a Radiometer ABL50 blood gas analyzer (Radiometer America Inc., Westlake, OH). Comparison of the StatPal II and the IL1306 was done by analysis of 3 tonometered solutions (acidic, normal, and alkalotic) and 27 equine venous blood samples. Blood pH, PCO2, PO2, and [HCO3] values were altered by IV infusion of 5% sodium bicarbonate or exercising the hors...
Gaustad G, Larsen S.A randomised double blind and placebo controlled clinical study was carried out. Standardbred trotters (n=77), age 3-4 years) with moderate to severe lameness were grouped according to number of affected joints and, within each group, were randomised for treatment with polysulphated glycosaminoglycan (PSGAG), sodium hyaluronate (SH) or placebo for 3 weeks. The horses were inspected weekly with a final examination 2-4 weeks after the end of treatment. Mean initial lameness score was significantly reduced during treatment and at the last examination in all 3 groups (P<0.01). Additionally, the...
Kohn CW, Swardson C, Provost P, Gilbert RO, Couto CG.Myeloid and megakaryocytic bone marrow hypoplasia in association with moderate to profound neutropenia was observed in 8 young Standardbred horses sired by the same stallion; 7 horses were intermittently thrombocytopenic. Evaluation of serial neutrophil counts in 2 horses suggested that a cyclic variation in neutrophil numbers was present, that lymphocyte numbers increased when neutrophil counts decreased, and that platelet counts decreased when neutrophil counts decreased. Preliminary bone marrow cultures indicated that myeloid progenitor cells were present and that these cells were able to r...
Marr CM, Reef VB.Colour flow Doppler echocardiographic examinations were performed on 15 horses; 10 Thoroughbreds and 5 Standardbreds; 9 mares, 5 geldings and 1 stallion; mean +/- s.d. 3.4 +/- 1.1 years. Cardiac murmurs were audible in 12 horses (80%), but these had characteristics consistent with functional murmurs in all horses. A standardised two-dimensional (2-D) and M-mode echocardiographic examination was unremarkable in all horses except that aortic valve prolapse was identified in 3 horses, tricuspid valve prolapse in 2 horses and mitral valve prolapse was present in one horse. Colour flow Doppler echo...
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...
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 ...
Anderson JD, Tulleners EP, Johnston JK, Reeves MJ.The efficacy of sternothyrohyoideus myectomy (SM) and staphylectomy as treatments for intermittent dorsal displacement of the soft palate was evaluated in 209 racehorses (126 Thoroughbreds, 83 Standardbreds). The 2 most common complaints were respiratory tract noise (75% of horses) and exercise intolerance (51% of horses). Stopping, defined as the inability to finish the race at racing speed, was reported in 40% of the horses. Endoscopy at rest revealed evidence of abnormal epiglottic anatomy (hypoplasia or flaccidity) in 51% of the horses and abnormal soft palate function in 36% of the horses...
Hawkins JF, Tulleners EP, Evans LH, Orsini JA.Between 1979 and 1992, the alar folds were resected bilaterally in 22 horses and unilaterally in 2 horses. Abnormal respiratory tract noise and exercise intolerance were the primary complaints prior to surgery. Significantly (P = 0.01) more Standardbreds underwent resection of the alar folds, compared with the number of Standardbreds in the hospital population during the same period. The alar folds palpated abnormally thick in 13 horses and normal in 11 horses. Temporary dilatation of the nares with mattress sutures or clips lessened the respiratory tract noise and improved exercise tolerance ...
Moore RM, Schneider RK.Arthroscopy was performed in 1 carpal joint unilaterally in 27 horses and either in 2 carpal joints unilaterally or 1 carpal joint bilaterally in 7 horses. All horses were lame, but the cause of lameness could not be determined from radiographs. Twenty-seven carpi did not have radiographically visible abnormalities; the remaining 14 had only mild to moderate lucency or sclerosis of the radial facet of the third carpal bone. The primary abnormalities identified during arthroscopy included a crush fracture of the third carpal bone (7 carpi), an incomplete fracture of the third carpal bone in the...
Hogan PM, Bramlage LR.Medical records and lifetime race results were obtained for 61 Standardbred racehorses treated consecutively from 1985 to 1992 with transection of the accessory ligament of the superficial digital flexor tendon (AL-SDF) for tendinitis of one or both forelimbs. A clinical diagnosis of tendinitis was confirmed in all cases by ultrasonographic examination. After surgery, 50 (82%) horses raced and 42 (69%) completed 5 or more starts. Eight horses (13%) failed to start and/or complete 5 or more races due to a recurrence of tendinitis. Six (10%) horses did not start and/or complete 5 or more starts ...
Koupai-Abyazani MR, Yu N, Esaw B, Laviolette B.Urine and serum samples collected from four standard-bred mares after 30-mg intraarticular administrations of triamcinolone acetonide were analyzed using combined high-performance liquid chromatography-atmospheric pressure ionization mass spectrometry. Maximum triamcinolone acetonide concentrations of 32.3, 14.8, 24.3, and 29.4 ng/mL in the urine and 2.7, 1.9, 2.3, and 2.5 ng/mL in the serum samples were observed. The peak concentrations of the drug were detected approximately 22 h (urine) and 12 h (serum) after administration. The drug elimination profiles for both urine and serum are present...
Gottlieb-Vedi M, Persson S, Erickson H, Korbutiak E.The purpose of this study was to determine if training with short intervals at the velocity producing a lactate level of 4 mmol/l (VLA4) is sufficient to induce adaptations and better exercise tolerance. Five Standardbred mares (4-8 years) were interval trained on a treadmill 3 days a week for 12 weeks and subsequently detrained for 4 weeks. Standardized exercise tests were performed before, during and after the training period and muscle biopsies were taken. Measurements were made of heart rate, oxygen consumption, stride frequency, blood volume and blood lactate. Plasma volume was reduced af...
Moore BR, Krakowka S, Robertson JT, Cummins JM.Cytologic examination of bronchoalveolar lavage fluid (BALF), including phenotypic analysis of lymphocytes, was performed on 32 Standardbreds with poor race performance and endoscopic examination findings characteristic of inflammatory airway disease (IAD). Nucleated cell counts in BALF from IAD-affected horses were higher than those in control horses; the cytologic profile of BALF in affected horses included mixed inflammation, characterized by mild neutrophilia, lymphocytosis, and monocytosis. Eosinophil and mast cell counts were not higher in the IAD-affected group, compared with those in t...
Kokkonen UM, Hackzell M, Räsänen LA.To study the exercise-induced changes in atrial natriuretic peptide (ANP), a hormone with cardiovascular and renal effects, an incremental submaximal exercise test on a high-speed treadmill was carried out with Standardbred and Finnhorse trotters, the former bred for speed and the latter originally for heavy work. Standardbreds performed the 2 min exercise intervals at speeds of 6, 7, 8, 9 m s-1 and Finnhorses, according to their training status, at 5, 6, 7, 8 m s-1, 4, 5, 6, 7 m s-1 or 5, 6, 7 m s-1. Steady-state heart rate (HR) was reached within each 2 min interval. The increase in HR was l...
Guhl A, Lindner A, von Wittke P.Eight thoroughbred horses, trained for racing competition, were subjected to a standardised incremental speed test to determine the relationship between their blood lactate concentrations and running speed. Between 14 days before and 14 days after completing the standardised exercise test, the horses were timed for runs of 2000 to 6000 m. The blood lactate concentration after each run was measured and compared with the blood lactate concentration predicted from the individual horse's blood lactate-running speed relationship curve determined from the standardised exercise test. The relationship...
Rojas-Núñez I, Gomez AM, Selland EK, Oduol T, Wolf S, Palmer S, Mohammed HO.Neurofilaments heavy chain proteins (pNF-H) have been identified as useful serum biomarkers for humans and animals with neurologic conditions, some of which can lead to poor performance, and athletic injuries. However, there are no published reports that describe a reference range for serum pNF-H levels in healthy racehorses. This cross-sectional study was carried out to determine the serum concentration of pNF-H in 1,349 samples collected from 1,291 clinically healthy standardbred (SB) racehorses. Data on age, time of sampling (pre-race or post-race), and finishing position during a race were...
Stewart GA, Fulton LJ, McKellar CD.Atrial fibrillation is described in a champion pacer which earlier had been named Australian Harness Horse of the Year as a 3-year-old in 1986-87. Prior to conversion atrial fibrillation had been present for at least 6 weeks, during which the horse had not raced. Successful treatment was achieved with two 10g doses of quinidine sulphate per oesophageal tube, after slow digitalisation with intravenous digoxin over 4d. Four hours after commencement of quinidine therapy the arrhythmia had regressed to atrial flutter and converted to sinus rhythm 10 min later. Considering his age, standard of raci...
Kraus BM, Ross MW, Boston RC.To compare results (ie, return to racing and earnings per race start) of surgical versus nonsurgical management of sagittal slab fractures of the third carpal bone in racehorses. Methods: Retrospective study. Methods: 32 racehorses (19 Thoroughbreds, 11 Standardbreds, and 2 Arabians). Methods: Medical records and radiographs were reviewed to obtain information regarding signalment and treatment. Follow-up information was obtained from race records. Robust regression analysis was performed to evaluate earnings per start in horses that raced at least once before and after injury. Results: 22 (69...
Rose RJ, Davis PE.Three young Standardbred pacers with atrial fibrillation were treated with quinidine sulphate (QS) by stomach tube. They were given 10g QS every 2 hours until cardioversion was achieved. Total doses varied between 20 and 30 g. No premedication was given nor any follow up treatment after return to sinus rhythm. All horses were given 3 months rest after the treatment, and when electrocardiographed then, and at 6 months, showed normal sinus rhythm. As all 3 horses won races after cardioversion and showed subsequent normal electrocardiograms it seems likely that atrial fibrillation can occur witho...
Littlejohn A, Bowles F.Radiometer Blood Micro-system 2 was used in studies designed to, (a) compare the mean blood gas and acid-base values of 38 normal horses and 20 horses with chronic obstructive pulmonary disease (COPD), (b) determine the means and standard deviations of blood gas and acid-base values of Thoroughbred horses in training, and (c) investigate the relationships between clinical data, blood gas values, intracardiac and pulmonary arterial pressures in subjects with COPD. There were significant differences between the mean values for partial pressure of arterial oxygen (PaO2), arterial carbon dioxide (...
Tunón AM, Rodríguez-Martínez H, Hultén C, Nummijärvi A, Magnusson U.Undiluted uterine fluid from 20 Warmblood/Standardbred mares (5 to 14 yr old) was recovered by absorption to an intrauterine tampon. The mares were considered gynecologically healthy based on a clinical examination including uterine swabs for cytology and bacteriology as well as endometrial biopsy examinations. The protein profiles (SDS-PAGE) and concentrations of total protein, albumin, and immunoglobulins (Ig) A and G in the uterine fluid were examined and compared with the same proteins in serum. Major peaks were identified on the obtained protein profiles, and there was a clear similarity ...
Weller D, Franklin S, White P, Shea G, Fenner K, Wilson B, Wilkins C, McGreevy P.This article reports on the results of a survey of racehorse trainers (n = 112) outlining the reasons for tongue-tie (TT) and noseband (NB) use by Thoroughbred trainers (TBTs) (n = 72) and Standardbred trainers (SBTs) (n = 40). The study also investigated the reported effectiveness of TTs and possible complications arising from their use. Tongue-tie use was reported by 62.5% (n = 70) of racehorse trainers. The reasons for TT use varied between TBTs and SBTs. For TBTs, the most common reason for TT use was to prevent or reduce airway obstruction (72.3%, n = 34), followed closely by to prevent o...
Mann S, Abuelo A, Stokol T, Wakshlag JJ, Bayly W, Reed S, Gandy J, Ramsay JD, Divers TJ.High serum γ-glutamyl-transferase (GGT) activity syndrome in racehorses has been associated with maladaption to exercise. Investigation of affected horses before and immediately after standard exercise may provide critical insight into the syndrome's pathophysiology. Objective: To investigate blood biomarker changes in actively competing racehorses with high GGT activity associated with an exercise challenge. Methods: Case-control study. Methods: High GGT case (age: 2-3 years) and normal GGT control (age: 2-7 years) pairs (3 Thoroughbred, 4 Standardbred pairs) at least 3 months into thei...
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 ...
Gibson MJ, Legg KA, Gee EK, Rogers CW.After establishing a baseline of stipendiary stewards' reporting using the paper-based system in the 2015/16 and 2016/17 seasons of harness racing, it is important to examine if the implementation of an online system has altered frequency and descriptors used for clinical outcomes. The objective of this study was to describe the race level injury and reporting outcomes, and horse- and race-level variables associated with the rate of the reporting of these outcomes during the 2019/20 and2020/21 harness racing seasons in New Zealand. The introduction of the online system was associated with few ...
Stevenson AJ, Weber MP, Todi F, Mendonca M, Fenwick JD, Kwong E, Young L, Leavitt R, Nespolo R, Beaumier P.A study of the effects of intravenous administration of either 150 mg or 250 mg of furosemide to standardbred mares pre-treated with other drugs was undertaken to determine whether a unique pattern of drug elimination into urine and from plasma for each compound occurred. Furosemide significantly reduced the plasma concentrations of codeine compared to control 2-6 h after furosemide administration. In contrast, the plasma concentrations of theophylline, phenylbutazone, pentazocine, guaifenesin and flunixin were not markedly altered by furosemide. In the case of acepromazine, clenbuterol and fe...
Micklethwaite L, Wood AK, Sehgal CM, Polansky M, Dowling BA, Dart AJ, Rose RJ, Hodgson DR.To determine whether quantitative analysis of sonographic brightness could be used to detect healing of an induced injury of the superficial digital flexor tendon in horses and whether rate of healing was influenced by equine recombinant growth hormone. Methods: 8 clinically normal Standardbreds. Methods: A localized injury was created in the left and right superficial digital flexor tendons of each horse by injection of 2,000 units of collagenase. After injury, 4 horses received equine recombinant growth hormone, a possible promoter of tendon healing. Sonographic images (7.5 MHz) of the flexo...
Jaggard G.The major problems of racing in the United States at the present time are caused by too much racing. This has led to too few horses and small fields. Consequently many owners and trainers are trying to enter their horses too frequently and to race them when they are not really fit to run. The desire to race horses as frequently as possible has led to constant pressure from horsemen through their organizations for so called "permissive medication". Started in the state of Colorado approximately ten years ago this has grown until finally there are only a few states, notably New York and New Jers...
Ward JL, Fubini SL.Cecocolic intussusception was detected in a 2-year-old male Standardbred horse with a 3-day history of signs of intermittent colic. The entire cecum, which was located within the lumen of the right ventral colon, was edematous and necrotic, and could not be manually reduced. A colotomy was made, and partial typhlectomy was performed. An ileocolostomy also was performed. To prevent eversion of the cecal base, the site of invagination into the colon was oversewn. Several postoperative complications were treated, including peritonitis, thrombophlebitis, anemia, and hypoproteinemia, and 1 year aft...
Uhlhorn H, Ekman S, Haglund A, Carlsten J.Thirty-five carpal joints from 20 standardbred trotters, age 1 to 7 years, all euthanized for nonorthopedic reasons, were examined to investigate the correlation between assessments of subchondral bone sclerosis in the third carpal bone from radiographs in the dorsoproximal-dorsodistal (DPr-DDi) projection and histomorphometric bone volume density measurements. The agreement between assessments of sclerosis from antemortem versus postmortem radiographs was also evaluated. Bones graded as sclerotic in the DPr-DDi projection had significantly higher bone volume density values for all areas of me...
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...
Warm-season grasses (WSG) incorporated into traditional cool-season rotational grazing systems to increase summer yields are typically established in monoculture in separate pasture areas. Few studies have evaluated alternative interseeded establishment of WSG, despite potential benefits for improving biodiversity and land-use efficiency. The objective of this study was to determine the impact of establishment method (monoculture vs. interseeded) on crabgrass pasture forage yield, nutritive value, and preference under equine grazing. Three adult standardbred mares grazed two main plots on two ...
Goodrich LR, Nixon AJ, Conway JD, Morley PS, Bladon BM, Hogan PM.An in-depth review of dynamic compression plate (DCP) fixation of propagating medial condyle fractures of the third metacarpus or metatarsus has not been previously reported. Objective: To describe the technique, evaluate short-term outcome and long-term race performance of racehorses that underwent DCP fixation for repair of propagating or spiralling medial condylar fractures of the third metacarpal (McIII) or metatarsal (MtIII) bone. Methods: Retrospective case series. Methods: The surgical case records of 30 horses with propagating fractures of the medial condyle of McIII or MtIII were revi...
Wilson DG.A 3-year-old Standardbred gelding was referred for evaluation of a fluctuant swelling that developed over the dorsum of the carpus subsequent to arthroscopic surgery on that carpus. A synovial hernia was diagnosed and surgically repaired. Although complications secondary to arthroscopy are rare, synovial herniation can develop after arthroscopic surgery. The condition must be differentiated from the more common true bursitis or false bursitis that is commonly referred to as a hygroma.
Machin J, Duer W, Maylin G, Fenger C, Wilson D, Ivey M, Berthold B, Allison S, Tobin T.Methylprednisolone (MP) acetate is a commonly used corticosteroid for suppression of inflammation in synovial structures in horses. Its use is often regulated in equine sports by plasma MP concentrations. Objective: To describe variability in MP plasma concentrations after MP acetate injection in different synovial structures and with co-administration with hyaluronic acid (HA). Methods: Field study in actively racing horses in three disciplines (Thoroughbred, Standardbred and Quarter Horse). Methods: Seventy-six horses (15 Thoroughbreds, 20 Standardbreds and 41 Quarter Horses) were included i...
McKane SA, Rose RJ, Evans DL.Twenty-four Thoroughbred and twelve Standardbred racehorses aged between 2 and 6 years, presented for reported poor racing performance, underwent clinical exercise testing. During the last 10 s of exercise at each speed throughout an incremental speed exercise test on a treadmill inclined at a 10% slope, samples of arterial blood and expired gases were collected. Maximum oxygen uptake and the partial pressures of oxygen and carbon dioxide in arterial blood were determined. These values were compared between the two breeds of horses and also with reference to cytological findings of bronchoalve...
Bos A, Compagnie E, Lindner A.Blood is collected for hematologic and biochemical analyses when racehorses perform poorly. However, racing affects most analyte levels; therefore, the timing of blood sampling can affect analyte levels and interpretations. Objective: This study aimed to determine if the blood variable levels returned to pre-racing levels 2 and 3 days post-racing. Methods: Blood was sampled from 17 healthy racehorses pre- and post-racing. The variables measured from plasma were albumin, cholesterol, creatinine, calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), creatine phosphokinase (C...
Geor RJ, Stewart-Hunt L, McCutcheon LJ.There is limited information about factors regulating glucose utilisation post exercise in horses. Objective: To determine the effects of a single bout of moderate intensity exercise on measures of insulin-mediated (IMGU) and noninsulin-mediated (NIMGU) glucose uptake during a hyperglycaemic clamp (HC). Methods: Hyperglycaemic clamps were administered in random order to 8 Standardbreds under 4 conditions: 1) rest, insulinopenia (R-L); 2) rest, hyperinsulinaemia (R-H); 3) post exercise (45 min at ∼ 50% VO2peak), insulinopenia (Ex-L) and 4) post exercise, hyperinsulinaemia (Ex-H). In the R-L a...
Pleasant RS, Baker GJ, Muhlbauer MC, Foreman JH, Boero MJ.The case records, radiographs, and nuclear bone scans of 58 horses with stress reactions or stress fractures of the proximal palmar aspect of the third metacarpal bone (MC3) were reviewed. There were 47 Standardbreds, 4 Quarter Horses, 3 Thoroughbreds, 2 Arabians, 1 Oldenburg, and 1 Pony of America. Fifty-six of the horses were racehorses or performance horses. The mean and median ages of affected horses were 4 and 3 years, respectively. Lameness ranged from mild to severe. Physical findings were usually subtle and included signs of pain on deep palpation of the proximal palmar aspect of MC3 a...
Koho NM, Mykkänen AK, Reeben M, Raekallio MR, Ilves M, Pösö AR.MCT1-CD147 complex is the prime lactate transporter in mammalian plasma membranes. In equine red blood cells (RBCs), activity of the complex and expression of MCT1 and CD147 is bimodal; high in 70% and low in 30%. We studied whether sequence variations contribute to the bimodal expression of MCT1 and CD147. Samples of blood and cremaster muscle were collected in connection of castration from 24 horses. Additional gluteus muscle samples were collected from 15 Standardbreds of which seven were known to express low amounts of CD147 in RBCs. The cDNA of MCT1 and CD147 together with a promoter regi...
Gottlieb-Vedi M, Essén-Gustavsson B, Lindholm A.Five Standardbred trotters performed treadmill exercise with incrementally increasing trotting velocities for 2 min intervals in three different tests until fatigue. Each test was performed with draught loads of either 10, 20 or 30 kilopond (kp). Each trotting interval was followed by 2 min periods at a walk without draught load. Recordings were made of heart rate (HR), respiratory rate (RR), plasma lactate (PLA) and stride frequency (SF) at the end of each trotting interval. The HR increased to average values of 191 +/- 10,203 +/- 10 and 214 +/- 7 bpm and PLA increased to 3.8 +/- 0.7, 7.3 +/-...
François I, Lalèyê FX, Micat M, Benredouane K, Portier K.Some controversy exists over whether or not horses' recovery and cardiopulmonary function are affected by suspension in slings. Objective: To measure arterial oxygen tension and pulmonary ventilation in anaesthetised horses placed in a standing position in an Anderson Sling (AS) after a period of right lateral recumbency (RLR). Methods: Randomised crossover experimental study. Methods: Six Standardbred horses were anaesthetised twice. Catheters were inserted into the right jugular vein and the left carotid artery. After premedication with romifidine, anaesthesia was induced with diazepam and k...
Denham J, Hulme A.Sodium bicarbonate administration in the hours prior to exercise has been used as a performance-enhancing substance in horses since the late 1980s. Although sodium bicarbonate administration to racehorses 24 hours before racing is a banned practice in most racing industries, whether or not it improves running performance in racehorses is currently unclear. The aim of this systematic review and meta-analysis was to establish whether or not acute sodium bicarbonate administration improves running performance in trained Standardbred and Thoroughbred horses. Seven randomized controlled trials, in...
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, ...
