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Topic:Standardbred Horses
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.
Nerve block and intra-articular anaesthesia of the forelimb in the sound horse. Nerve blocks and intra-articular anaesthesia are used extensively as routine methods in lameness evaluation. The method is based on the assumption that the technique itself does not change the movement pattern. The aim of this study was to carry out a quantitative kinematic study to confirm or reject the hypothesis that high palmar digital nerve block (HPDN) and intra-articular fetlock joint anaesthesia (IAF) influence significantly the movement pattern of the horse. Seven Standardbred horses trotting at 4.5 m/s were recorded at 240 Hz on a treadmill before and after anaesthesia by use of a Pr...
Exercise that induces substantial muscle glycogen depletion impairs subsequent anaerobic capacity. The purpose of this study was to develop a model of muscle glycogen depletion and to study the effect of this model on aerobic and anaerobic capacity of horses. The maximal rate of oxygen consumption (VO2max), maximal accumulated oxygen deficit (MAOD), muscle glycogen concentration and blood lactate concentration of 6 fit Standardbred horses were measured on 3 occasions 7 days apart (Trials 1, 2 and 3). Between Trials 2 and 3, strenuous exercise intended to deplete muscle glycogen was performed by exercising horses on the treadmill on 3 consecutive days. Strenuous exercise resulted in reductio...
Standardisation of muscular biopsy of gluteus medius in French trotters. Morphometric measurements were taken from 41 French trotters of various ages and both sexes. Biopsy location was determined for the dorsal compartment as being one-third of the distance from the tuber sacrale to the tuber coxae and for the ventral compartment as being one-third of the distance from the tuber coxae to the caudal Cd1-Cd2 intervertebral joint. Ten horses were biopsied at these 2 sites at a sampling depth equal to half the total depth of the compartment as measured by ultrasonography. The percentage of slow and fast myosin heavy chain fibres was measured by using an immunoenzymati...
Racing performance in red blood cell hypervolaemic standardbred trotters. The association between red blood cell hypervolaemia (RCHV) and racing performance was examined in 116 Standardbred trotters referred to the clinic during a 5 year period with histories of impaired racing performance. Red cell hypervolaemia was the only significant abnormality detected in a thorough clinical examination, cell volumes ranging 116-178% of the predicted normal values. They were also compared with the performance traits of the contemporary Swedish Standardbred trotter population (n = 58,058). The performance traits were based on earnings per year and start, best annual racing time...
Blood gas, plasma lactate and bronchoalveolar lavage cytology analyses in racehorses with respiratory disease. The purpose of this study was to evaluate the relationship between bronchoalveolar lavage (BAL) cytology, arterial blood gases and plasma lactate concentration during a standardised treadmill test (STT) in racehorses with small-airway inflammation (SAI), or exercise-induced pulmonary haemorrhage (EIPH). Sixteen Thoroughbred and 20 Standardbred actively racing racehorses, were divided into a control group (n = 10), EIPH group (n = 13) and SAI group (n = 13). Each STT consisted of a 2 min trot at 4 m/s followed by 5 x 1 min, incremental speed steps (6, 8, 10, 11 and 12 m/s) at 10% incline for Th...
The kinematics of loading and fatigue in the standardbred trotter. The Standardbred trotter must pull a considerable load when racing and, consequently, draught loading is a common method of training in the Standardbred and the effects of loading and fatigue due to loading on the locomotor pattern was the purpose of this investigation. Four mature healthy Standardbred horses trotted with and without a horizontal-pulling loading of 34 kg until the horses were no longer willing to keep pace with the treadmill despite encouragement. Heart rate was monitored every min using a bipolar electrocardiogram. The kinematics for 5 consecutive strides were filmed. Horses ...
Plasma cortisol and beta-endorphin concentrations in trained and over-trained standardbred racehorses. The effects of training and over-training on plasma cortisol and beta-endorphin (betaEP) concentrations at rest and after standardised exercise tests and the cortisol responses to adrenocorticotropin (ACTH) administration were investigated in standardbred horses. Twelve horses were divided randomly into control and over-trained (OT) groups after 17 weeks slow- and moderate-intensity treadmill training. The standardised treadmill exercise test consisted of 2 min at velocities corresponding to 30, 50, 70 and 100% of maximum O2 consumption. Over-training, defined as a significant decrease in body...
Comparison of some responses to exercise on the track and the treadmill in French trotters: determination of the optimal treadmill incline. The purpose of this study was to determine the optimal treadmill slope for trotters to produce the same heart rate and blood lactate responses as on the track during a standardized exercise test. Nine 2-year-old French trotters performed exercise tests on a training track and on a treadmill set at an incline of 0, 2 or 4%. For all horses, track testing was performed on day 1 and then on the treadmill according to a Latin-square design. The track test utilized three steps each of 3 min at speeds of 470, 530, 590 m/min and the same speeds were used on the treadmill. Derived physiological variabl...
Equine viral arteritis: further characterization of the carrier state in stallions. Further characterization of the carrier state in stallions infected with equine arteritis virus revealed that there is considerable variation in the frequency of its occurrence among breeds. The frequency ranged from 12.5% (Holsteiner stallions) to 72.7% (Dutch Warmblood stallions), with a mean occurrence of 40.8% in the seropositive stallions (n=561) examined. More than 70% of the virus shedders were Standardbred stallions. The carrier state was not confirmed in any of the stallions that had been vaccinated against equine viral arteritis nor was there any evidence of intermittent virus sheddi...
Retrospective study of subchondral sclerosis and lucency in the third carpal bone of Standardbred trotters. The aim was to investigate radiographic findings of subchondral sclerosis and subchondral lucency in the dorsoproximal-dorsodistal (DPr-DDi) projection of the third carpal bone (C3) in relation to clinical appearance and to prognosis for racing. In a retrospective study, case records of 89 Standardbred trotters diagnosed with traumatic carpitis confirmed with intra-articular anaesthesia were examined. Records included data on degree of lameness at presentation and after flexion tests and a radiographic examination of the carpus, including a DPr-DDi projection of the C3. Subchondral lucency was...
The confirmation and control of metabolic caffeine in standardbred horses after administration of theophylline. The origin of caffeine detections in equine serum and urine after theophylline administrations was examined. Three different preparations containing theophylline were administered to standardbred mares. Both blood and urine samples were collected. Caffeine was detected and quantified in theophylline administration samples by high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS-MS). Further in vitro analysis showed that caffeine metabolites were not detected when caffeine, or caffeine-containing products, were added to urine. Data derived from ...
Outcome and racing performance after internal fixation of third and central tarsal bone slab fractures in horses. A review of 20 cases. Twenty horses with central and third tarsal bone slab fractures, were treated internal fixation. Eighteen of the 20 cases were Standardbred trotters, one was a Thoroughbred racehorse and one a Swedish Warmblood. The central tarsal bone (CT) was involved in 12 cases and the third tarsal bone (T3) in 8 cases. The fractures were treated by lag screw fixation with one (18 cases) or two (2 cases) 3.5 or 4.5 mm cortical screws. Horses were confined to stall rest for one month and then put on a gradually increasing exercise programme. Convalescence time was 3-8 months until the fracture had healed an...
Serological surveillance of equine viral arteritis in the United Kingdom since the outbreak in 1993. Serological analysis of blood samples submitted to the Animal Health Trust showed that during 1995, 185 of 9203 unvaccinated horses (2.0 per cent) tested positive for antibodies to equine arteritis virus (EAV), and that during 1996, 46 of 8851 unvaccinated horses (0.52 per cent) tested positive. During both years thoroughbreds were the predominant breed tested and only a small proportion of these (<0.3 per cent), consisting predominantly of imported mares, were seropositive. In contrast, among standardbred horses, from which samples were actively solicited in 1995, 84 of 454 (18.5 per cent) we...
Effects of prior exercise on muscle metabolism during sprint exercise in horses. The effect of warm-up exercise on energy metabolism and muscle glycogenolysis during sprint exercise (Spr) was examined in six fit Standardbred horses exercised at 115% of maximal O(2) consumption (VO(2 max)) until fatigued, 5 min after each of three protocols: 1) no warm-up (NWU); 2) 10 min at 50% of VO(2 max) [low-intensity warm-up (LWU)]; and 3) 7 min at 50% VO(2 max) followed by 45-s intervals at 80, 90, and 100% VO(2 max) [high-intensity warm-up (HWU)]. Warm-up increased (P < 0.0001) muscle temperature (T(m)) at the onset of Spr in LWU (38.3 +/- 0.2 degrees C) and HWU (40.0 +/- 0. 3 de...
Results of bone scintigraphy in racing standardbred horses: 64 cases (1992-1994). To document anatomic patterns of scintigraphic uptake and related orthopedic disease associated with racing activity in Standardbred horses. Methods: Retrospective study. Methods: 64 Standardbred horses evaluated for lameness. Methods: Medical records at the time of discharge were reviewed, and information regarding signalment; history; results of lameness examination, scintigraphy, and radiography; diagnosis; and treatment were obtained. Results: 274 areas of increased radiopharmaceutical uptake were identified. Scintigrams of 218 limbs (106 forelimbs, 112 hind limbs) were available for revie...
Radiological measurements from the feet of normal horses with relevance to laminitis. Lateromedial radiographic projections were made from the feet of 25 normal horses and 3 angles and 3 distances were measured. From these, normal ranges of calculated variables were obtained. The width and length of each foot and the height of the horse at the withers was also measured. In view of its possible importance in clinical laminitis, particular attention was paid to 'founder' distance (D). This is the vertical distance between the proximal limit of the dorsal hoof wall and the proximal limit of the extensor process of the distal phalanx. There were significant differences between bree...
Nonsurgical management of type II fractures of the distal phalanx in 48 standardbred horses. To evaluate nonsurgical management of type II fractures of the distal phalanx in Standardbred horses. Methods: Retrospective study of 48 affected horses. Results: Most fractures occurred on the lateral palmar process of the left forelimb or the medial palmar process of the right forelimb; 81% of horses were considered sound enough to return to training and 63% raced. Of those returning to racing, 41% competed in > 10 races, 37% in 2 to 10 races and 22% in only 1 race. There was no difference in performance before and after fracture. Twenty-four of 25 horses had a bar shoe fitted for > 50...
Comparison of intra-articular injection of 2 ml of 0.9% NaCl solution with rest alone for treatment of horses with traumatic arthritis. To compare effects of intra-articular injection of 2 ml of 0.9% NaCl solution with rest alone for treatment of horses with traumatic arthritis. Methods: 38 Standardbred horses with moderate to severe lameness that resulted from traumatic arthritis. Methods: Horses were stratified on the basis of number of affected joints. In each stratum, horses were allocated randomly to treatment groups (intraarticular injection of 2 ml of 0.9% NaCl solution vs rest only). Treatment was for a period of 3 weeks. Horses were inspected weekly with a final examination 2 to 4 weeks after completion of treatment. ...
A cross-sectional study on compulsive behaviour (stable vices) in horses. A researcher-administered survey study was performed involving 769 horses from 32 Thoroughbred, Standardbred, and pleasure horse stables in southwestern Ontario. Data were gathered on individuals (breed, age, and sex) and at the stable level (housing, management). The effects of these factors on cribbing, stall-walking, weaving, stall-kicking, tongue playing, and pawing were assessed by unconditional analysis (Chi-square, t test) and conditionally using stepwise logistic regression. Individual level factors had significant effects on most compulsive behaviours. Some stable level factors, in mo...
Attenuation by phenylbutazone of the renal effects and excretion of frusemide in horses. The objectives of this study were to determine the effect of phenylbutazone premedication on the pharmacokinetics and urinary excretion of frusemide in horses; and on frusemide-induced changes in urinary electrolyte excretion. Six Standardbred mares were used in a 3-way crossover design. The pharmacokinetics and renal effects of frusemide (1 mg/kg bwt i.v.) were studied with and without phenylbutazone premedication (8.8 mg/kg bwt per os 24 h before, followed by 4.4 mg/kg bwt i.v. 30 min before frusemide administration). A control (saline) treatment was also studied. Administration of frusemide...
The elimination profiles of tenoxicam and hydroxytenoxicam in equine urine and serum after a 200-mg oral dose. Tenoxicam (Mobiflex) was administered orally to four standardbred mares at a dose of 200 mg. Elimination profiles of tenoxicam and hydroxytenoxicam were generated based on quantitation of these analytes in urine and serum by liquid chromatography (LC) with ultraviolet detection. Tenoxicam was confirmed by LC-tandem mass spectrometry daughter ion mass spectra in the last postadministration sample in which tenoxicam was detected. The tenoxicam and hydroxytenoxicam urinary elimination profiles had the same shape for the same horse; however, each horse was significantly different from the others. ...
The relationship between mechanical work and energy expenditure of locomotion in horses. Three-dimensional motion capture and metabolic assessment were performed on four standardbred horses while walking, trotting and galloping on a motorized treadmill at different speeds. The mechanical work was partitioned into the internal work (W(INT)), due to the speed changes of body segments with respect to the body centre of mass, and the external work (W(EXT)), due to the position and speed changes of the body centre of mass with respect to the environment. The estimated total mechanical work (W(TOT)=W(INT)+W(EXT)) increased with speed, while metabolic work (C) remained rather constant. A...
Use of electrocautery probes in arthroscopic removal of apical sesamoid fracture fragments in 18 Standardbred horses. To develop a technique for arthroscopic excision of apical sesamoid fracture fragments using electrocautery probes. Methods: A total of 18 Standardbred horses. Methods: Arthroscopic removal of apical sesamoid fracture fragments using both hook and loop electrocautery probes was performed on 18 Standardbred horses. The fracture fragments were approached using either an ipsilateral (3) or contralateral (15) arthroscopic triangulation technique. Distension of the metacarpo- (metatarso)-phalangeal joints was achieved using a 1.5% glycine solution. Under arthroscopic guidance, both the suspensory a...
A comparison of the ultrastructure and metabolic response of the skeletal muscle of horses performing intense treadmill exercise at 20 and 35 degrees C. The aim of this study was to determine whether the metabolic response and ultrastructure of muscle differed when horses performed intense exercise at different ambient temperatures. Four Standardbred geldings performed treadmill exercise, including an intensive trot of 2600 m on two different occasions, either at a high ambient temperature of 35 degrees C or at a temperature of 20 degrees C. The horses had a warm-up period of 23.5 min of submaximal exercise, followed by 2 h of box rest before the intensive exercise. Muscle biopsy data of adenine nucleotides, creatine phosphate, lactate and gly...
Apical fracture of the proximal sesamoid bone in standardbred horses: 43 cases (1990-1996). To determine whether fracture fragment dimensions, suspensory ligament damage, and racing status at the time of injury were associated with outcome in Standardbred horses with apical fracture of the proximal sesamoid bone. Methods: Retrospective study. Methods: 43 Standardbred racehorses. Methods: Medical records, racing records, and radiographs were reviewed, and ultrasonographic findings were scored. Measurements of the fractured portion of the proximal sesamoid bone were made. Results: Seventy-four percent (32/43) of horses were pacers, and 26% (11/43) were trotters. Statistical differences...
Muscle characteristics and plasma lactate and ammonia response after racing in Standardbred trotters: relation to performance. Blood samples from the jugular vein and muscle biopsies (gluteus medius) in 25 Standardbred trotters were obtained 5-10 min after racing. The biopsies were analysed for fibre type composition and enzymatic profile and blood samples for plasma lactate and ammonia concentrations. Muscle characteristics, plasma lactate and ammonia concentrations after racing were compared with each horse's individual performance index (IPI). The IPI is calculated annually from the individual horse's racing performance (% placing 1, 2 or 3, total annual earnings, average earning per start, and best racing record),...
Field exercise testing for assessing fitness in French standardbred trotters. This review considers standardized exercise testing which is, routinely used for French Trotters in the field. Track testing provides a more limited range of measurements than treadmill testing, but has the advantage of being performed in the horse's natural environment. Various measurements such as heart rate during exercise and blood lactate concentration after exercise may be measured on the track and lead to the calculation of physiological variables such as V200 (velocity corresponding to a 200 bpm heart rate) and V4 (velocity corresponding to a 4 mmol/L blood lactate concentration). V4 i...
Post operative performance of racing Standardbreds treated arthroscopically for carpal chip fractures: 176 cases (1986-1993). A retrospective study of 176 Standardbred horses that had arthroscopic surgery for carpal chip fractures over a 7 year period was done in order to determine fracture location and post operative performance. Chip fractures of the proximal third carpal bone and the distal radiocarpal bone occurred with equal frequency (49.2 and 49.6% respectively), and chip fractures involving the antebrachiocarpal joint were rare. Trotters had significantly more third carpal bone lesions than radiocarpal bone lesions when compared to pacers (P = 0.0304). Seventy-four per cent of horses made at least one start f...
Equine laminitis: its development coincides with increased sublamellar blood flow. The effect of alimentary carbohydrate overload on hoof temperature was investigated to determine the state of the sublamellar vasculature preceding the onset of equine laminitis. Hoof, core and ambient temperatures and heart rate were logged continuously in 21 mature Standardbred horses kept in an environmental chamber set at 10 degrees C. Recording hoof temperature was a successful, noninvasive, method to measure indirectly, shifts in digital blood flow against a background of cold induced, physiological, vasoconstriction. High hoof temperatures were assumed to indicate digital vasodilation a...
Evaluation of enterolithiasis in equids: 900 cases (1973-1996). To identify breed, age, sex, physical findings, history, and outcome of treatment in horses and other equids with enterolithiasis. Methods: Retrospective study. Methods: 900 equids with enterolithiasis. Methods: Medical records from equids with enterolithiasis admitted between 1973 and 1996 were reviewed. Data on signalment, history, physical examination and clinicopathologic findings, surgical findings, and outcome were compiled from records and from telephone interviews with owners. Sex and breed predilections were determined by comparison of the study population with the general hospital po...
