Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Racehorses
Racehorses are a distinct category of horses bred and trained for competitive racing events, characterized by their speed, agility, and stamina. These horses are primarily Thoroughbreds, Standardbreds, or Quarter Horses, each with specific attributes suited to different types of racing. The physiology and management of racehorses focus on optimizing performance through training, nutrition, and veterinary care. Research in this area often explores aspects such as biomechanics, cardiovascular health, and injury prevention. This page gathers peer-reviewed research studies and scholarly articles that investigate the physiology, training methodologies, and health management practices associated with racehorses, providing insights into the factors influencing their performance and welfare.
Diagnostic approach to exercise intolerance in racehorses. The diagnostic approach to the exercise intolerant racehorse depends on sound, fundamental steps to allow complete examination of the entire horse in a logical, time-efficient fashion. Availability of referral diagnostic modalities should not overshadow the need for collecting a clinical history or performing a complete physical examination. The diagnostic approach to exercise intolerance can be divided into a few basic steps. The first step, conducted without the horse, is a thorough discussion about the horse with the trainer and/or owner. Many clinical histories are complex and therefore fo...
Oblique views of the ilium and the scintigraphic appearance of stress fractures of the ilium. The research article discusses a study on the use of oblique dorsal views in detecting stress fractures in horses who participate in races. The aim of the researchers was to [...]
Effect of a warm-up on energy supply during high intensity exercise in horses. The VO2(max) in racehorses is approximately double that of elite human athletes and the rate of increase in VO2 at the onset of high intensity exercise is much greater than in man. The kinetics of gas exchange are affected by a warm-up prior to exercise in humans, there being a greater aerobic contribution to high intensity exercise after warm-up. Our hypothesis was that a warm-up would increase aerobic energy delivery in racehorses during high intensity exercise. Thirteen fit Standardbred racehorses ran to fatigue at 115% of VO2(max) on a treadmill at 10% slope. Prior to acceleration, horses ...
Effects of hematocrit and erythrocyte deformability on pulmonary vascular pressures in perfused pony lungs. To evaluate the contribution of hematocrit and RBC deformability to pulmonary vascular pressures of racehorses. Methods: Pony lungs were isolated and right and left lungs were perfused separately with blood. The effects of changing hematocrit and of pentoxifylline treatment were evaluated. Methods: 11 healthy mixed-breed ponies. Methods: Ponies were anesthesized, blood was collected, and lungs were removed and perfused with blood at constant flow rate. Results: Increasing the hematocrit from 35% to 65% resulted in increases in pulmonary arterial pressure (53%, 45%), capillary shear stress (45%...
Effects of exercise on plasma concentrations of caffeine and its metabolites in horses. The effects of exercise on the metabolism of caffeine (CA) were studied 3h after administration of the drug to race horses which then underwent exercise sets (1000-m gallop). Analysis was made of pharmacokinetics of CA, changes in its plasma concentrations, its metabolites, i.e., theophylline (TP), theobromine (TB) and paraxanthine (PX), and the molar concentration ratios of CA to these metabolites. After exercise, AUC and t1/2 tended to decrease, and the concentration of CA decreased, while the concentrations of TP and TB significantly increased. The TP/CA ratio and TB/CA ratio significantly ...
Sternothyrohyoideus myectomy or staphylectomy for treatment of intermittent dorsal displacement of the soft palate in racehorses: 209 cases (1986-1991). 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...
Arthroscopic findings in the carpal joints of lame horses without radiographically visible abnormalities: 41 cases (1986-1991). 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...
Prevalence of upper respiratory tract disorders detected with a flexible videoendoscope in thoroughbred racehorses. A total of 350 thoroughbred racehorses found clinically as having coughs or abnormal breath sounds underwent endoscopic examination of the upper respiratory tract at rest. As a result, abnormal endoscopic findings were obtained in all horses, demonstrating that thoroughbred racehorses with a clinical abnormality in the respiratory system necessarily had disorders in the upper respiratory tract. Whereas 11 types of disorder were observed, a combination of three different types of disorder were found in the highest frequencies in 3-, 4- and 5-year-old horses (27.8%, 29.2% and 29.7%, respectively...
Outbreak of equine influenza among horses in Hong Kong during 1992. Equine-2 influenza virus A (H3N8) infection occurred among vaccinated thoroughbred horses in Hong Kong during November and December 1992. The outbreak was unique in that it occurred among a large population stabled under intensive conditions. It resulted in the postponement of seven race meetings over a period of 32 days. The outbreak originated after the importation of horses 25 to 32 days before any clinical signs were reported. Vaccination did not prevent 75 per cent of the population from becoming infected, and half the infected horses developed clinical signs. Vaccination did, however, co...
Lag screw fixation of noncomminuted sagittal fractures of the proximal phalanx in racehorses: 59 cases (1973-1991). Medical records of 59 racehorses with noncomminuted midsagittal proximal phalanx fractures repaired by means of lag screw fixation between 1973 and 1991 were reviewed. Fractures were classified as short incomplete fractures (7), long incomplete fractures (32), complete fractures extending into the proximal interphalangeal joint (13), and complete fractures extending through the lateral cortex of the proximal phalanx (7). Time from fracture repair to first race following fracture repair, number of racing starts, and fastest race times before and after surgery were obtained from race records and...
Arthroscopic removal of axial osteochondral fragments of the plantar/palmar proximal aspect of the proximal phalanx in horses: 119 cases (1988-1992). Medical records from 119 horses that had undergone arthroscopic surgery for removal of axial osteochondral fragments of the palmar/plantar proximal aspect of the proximal phalanx were reviewed. Standardbred racehorses represented 109 (92%) of those affected. Ninety-three (78%) of the horses were < 3 years old. Gender distribution was consistent with that of the equine hospital population. Fragments most commonly were observed in the hind limbs (155/164; 95%), specifically, on the medial aspect of the left hind limb (72/164; 44%). Bilateral fragmentation occurred in 21 of 119 (18%) horses, a...
Observations on the anatomy and pathology of the palmar intercarpal ligaments in the middle carpal joints of thoroughbred racehorses. Ten carpi from juvenile Thoroughbred horses were dissected in detail to record the anatomy of the palmar intercarpal ligaments (PICLs). These were found not to be substantially attached to the palmar carpal ligament. The lateral PICL was sited at the convergence of the palmar aspects of the third, fourth, intermediate and ulnar carpal bones and aligned predominantly in a proximodistal direction. The medial PICL had a large origin distally on the lateral aspect of the radial carpal bone (Cr) and attached to third (C3) and second (C2) carpal bones with apparently separate fibre orientations. Fib...
Proximodorsal first phalanx osteochondral chip fragmentation in 336 horses. The results of arthroscopic surgery in the treatment of osteochondral fragmentation of the proximodorsal aspect of the first phalanx and the influence of other fetlock joint lesions on prognosis were evaluated in 336 horses. Horses were classified as: 1) returning to previous use at the same or higher class of performance; 2) returning to previous use (regardless of class of performance); or 3) failing to return to previous use. Ninety-six horses (29%) had fragmentation alone; 140 horses (42%) had fragmentation and additional fetlock lesions, and 100 horses (29%) underwent concurrent carpal ar...
Effect of sodium cromoglycate on light racehorses with elevated metachromatic cell numbers on bronchoalveolar lavage and reduced exercise tolerance. Some young horses with clinical signs of small airway disease demonstrate increased metachromatic cell numbers on bronchoalveolar lavage. The purpose of this study was to determine the effect of sodium cromoglycate treatment on clinical signs, bronchoalveolar lavage cytology and bronchoalveolar lavage histamine parameters in these horses. Twelve racehorses (age: 3.4 +/- 1.6 years) with a history of respiratory embarrassment at exercise, clinical signs of obstructive airway disease and bronchoalveolar lavage metachromatic cell differential greater than 2% were selected. Horses were randomly ass...
Prolonged presence of isoxsuprine in equine serum after oral administration. 1. Isoxsuprine [1-(4-hydroxyphenyl)-2-(1-methyl-2-phenoxyethylamino)-1- propanol] serum concentrations after single- and multiple-dose administration to horse were investigated using immunoenzymatic ELISA, HPLC-UV and thermospray HPLC-MS methods. 2. Using HPLC-MS, isoxsuprine was detected up to 72 h after a single administration (1.2 mg/kg by gastric probe) and up to 96 h after the end of serial administration (1.2 mg/kg every 12 h for 7 days). 3. ELISA detected the drug up to 96 h after a single dose and up to 6 days after the end of prolonged administration. 4. Isoxsuprine is present in hors...
Factors affecting the circadian rhythm in plasma cortisol concentrations in the horse. In horses, a circadian rhythm in plasma cortisol concentrations has been reported in some but not all studies. When a rhythm occurred, horses were accustomed to a management routine, comprising stabling, feeding and sometimes exercise, which may entrain a circadian pattern. In this work, we monitored plasma cortisol by collecting jugular blood through indwelling cannulae from four groups: 1): 10 untrained, unperturbed mares grazing excess pasture, bled hourly for 26 hr; 2) 4 mares housed in a barn for 48 hr before sampling every 15 min for 20-24 hr; 3) 5 mares placed in an outdoor yard for sam...
Glucose transport and glycolytic enzyme activities in erythrocytes of two-year-old thoroughbreds undergoing training exercise. D-Glucose transport and cytosolic enzyme activities were measured in erythrocytes from 2-year-old thoroughbreds under continuous training exercise (race horses) and compared with those from untrained horses of various ages (sires, mares and untrained 2-year-old thoroughbreds). The activities of the glucose transport and glycolytic enzymes, hexokinase and pyruvate kinase, in the race horses' erythrocytes were elevated to 2-3.5 times above those of untrained horses. There were no significant differences in plasma glucose, triglyceride or IRI concentrations between the horses in training and untr...
Kinetics and haematological effects of erythropoietin in horses. A plasma kinetic study of erythropoietin (EPO) was carried out in 4 horses after subcutaneous administration (30 IU/kg bwt) of recombinant human erythropoietin (rhEPO). At standardized intervals for 48 h before injection and for 60 h post-administration, the EPO plasma levels were determined with an immunoradiometric assay based on a sandwich technique. The peak plasma concentration (30-113 mIU/ml) was observed after a delay ranging from 6 to 9 h post-administration and the drug levels reached a physiological value around 60 h following rhEPO injection. Moreover, reference values for plasma EP...
Survey of selected design and ventilation characteristics of racehorse stables in the Pretoria, Witwatersrand, Vereeniging area of South Africa. Stables housing more than 20 horses in training were surveyed in the Pretoria, Witwatersrand, Vereeniging area of South Africa. Most racehorses were kept in loose boxes, bedded on straw or sawdust and remained indoors while the stables were cleaned. The average floor area was 13 m2 and airspace was 55 m3 per animal. The average predicted minimum air change rate by natural convection in calm winds was 7.0 air changes per hour, which was reduced to 2.2 when the doors and shutters were closed. The survey showed that many of the stables had been built without due consideration to factors that migh...
Pulmonary haemodynamics in the exercising horse and their relationship to exercise-induced pulmonary haemorrhage. Exercise-induced pulmonary haemorrhage (EIPH) is a common occurrence in race horses. Although blood in cases of EIPH has been suspected to originate from the bronchial circulation, which receives approximately 1% of the left ventricular output, physiological evidence has recently emerged to indicate that the pulmonary circulation, which receives the entire output of the right ventricle, is a more likely source. High transmural pulmonary capillary pressures have been shown to cause breaks in the capillary endothelium, basement membrane as well as in the alveolar epithelium. Blood constituents e...
Streptococci and Pasteurella spp. associated with disease of the equine lower respiratory tract. The likelihood of finding evidence of inflammation in 551 tracheal washes collected endoscopically from 278 Thoroughbred racehorses increased with the number of bacterial colony forming units (cfu) per ml of wash (P < 0.001). The aerobic bacteria Streptococcus zooepidemicus, Pasteurella/Actinobacillus-like species and Streptococcus pneumoniae were significantly associated with lower airway inflammation whereas coagulase-negative Staphylococcus spp., alpha-haemolytic Streptococcus spp., Acinetobacter spp., Bacillus spp., Escherichia coli, Pseudomonas aeruginosa, non-haemolytic Streptococcus ...
An occurrence of equine transport pneumonia caused by mixed infection with Pasteurella caballi, Streptococcus suis and Streptococcus zooepidemicus. An acute death occurred in a racehorse with pneumonia after long-distance transportation in December, 1990. Pasteurella caballi, Streptococcus suis and Streptococcus zooepidemicus were isolated from the lung at high rate. Specific antigens of these bacteria were also demonstrated immunohistologically in the pneumonic lesion. These findings indicated that the disease is equine transport pneumonia caused by a mixed infection of the three bacterial species. This is the first report on the isolation of P. caballi and S. suis from a racehorse in Japan.
Factors affecting the clinical outcome of injuries to the superficial digital flexor tendon in National Hunt and point-to-point racehorses. Ultrasonographic examination was used to define the severity of injuries to the superficial digital flexor tendon in 73 National Hunt or point-to-point racehorses and the factors influencing the outcome of the cases were examined. Thirty-four of the horses (46 per cent) returned to work with an average time out of training of 13.5 months. The rate of recurrence of the injury was 35 per cent. The severity of the lesions was related to the outcome; all the mildly affected horses returned to work, with 63 per cent of them racing and an average time out of training of 10.2 months; 50 per cent of t...
Excision of intralaryngeal granulation tissue in 25 horses using a neodymium:YAG laser (1986 to 1991). Granulation tissue masses arising from the axial surface of the arytenoid cartilage in 25 horses were excised using a contact neodymium:yttrium aluminum garnet laser. A technique that eliminated the need for general anesthesia or laryngotomy was developed for transen-doscopic removal of the masses in standing horses. Nineteen racehorses made abnormal upper respiratory tract noises or their performance was decreased, whereas six horses not used for racing had a history of stertor (five horses) or epistaxis after nasogastric intubation (one horse). Thoroughbreds were significantly (p = .0126) ov...
Functional significance of the morphology and micromechanics of collagen fibres in relation to partial rupture of the superficial digital flexor tendon in racehorses. The high incidence of partial rupture of the superficial digital flexor tendor in the equine athlete represents a major cause for concern in the racing industry. Frequently, the lesion is localised to the central core of the tendon. This study tested the hypothesis that the site specific structural failure results from differences in the collagen fibre morphology and associated micromechanics between central and peripheral regions of the tendon. Bundles of collagen fibres were dissected from central and peripheral sites in the mid-metacarpal region of the tendon. Crimp morphology was quantifie...
Tearing of the medial palmar intercarpal ligament in the equine midcarpal joint. Tearing of the medial palmar intercarpal ligament is described in 45 intercarpal (midcarpal) joints in 42 horses (37 racehorses, 5 non-racehorses). Of the 37 racehorses, there were 20 Quarter Horses, 14 Thoroughbreds and 3 Standardbreds. The patients had been referred for arthroscopic surgery for removal of osteochondral chip fragments that had been diagnosed radiographically or diagnostic arthroscopy of a persistent carpal problem. The problem was unilateral in 39 horses and bilateral in 3. The presenting clinical signs were lameness and/or persistent synovial effusion. In one instance, the p...
[Blood lactate in the steeplechase horse: triangular and rectangular series of steps during short duration races]. Five steeplechase race horses were observed during incremental and constant-load exercises with the aim of separating effects of work rate and time on blood lactate. Each independent exercise (an incremental and three constant load tests) was a sequence of three two-minute runs, separated by two one-minute rest intervals for jugular blood sampling. The following observations were made: 1. During constant load exercises, in the five horses, blood lactate stabilized below 4 mmol.l-1: lactatemia critical velocity (LVC) = 3.33 +/- 0.16 mmol.l-1. Nevertheless, VCL, critical lactate velocity inducin...
Can a pelvic fracture in a horse be detected by probe scintigraphy? Pelvic fracture is a relatively common spontaneous fracture in thoroughbred racehorses. Its diagnosis can be difficult, and radiography in the acute phase carries the risks associated with anaesthesia and recumbency. This paper describes the use of a hand-held probe for point counting after the injection of technetium-99m in the investigation of four cases of pelvic fracture. The level of increased uptake of radioactivity was lower (40 to 61 per cent increase) than for distal limb bone fractures.
An association between complete and incomplete stress fractures of the humerus in racehorses. Twenty-one horses had a complete unilateral humeral fracture during race training or racing at a California racetrack during the period 24 February 1990 to 10 July 1991. Fractures occurred approximately equally in left and right limbs, and in males and females. Most fractures occurred during training, and in 2- and 3-year-old horses. Only 5 of 16 Thoroughbred horses with known racing records had previously raced more than once, and their mean time between races was less than the time between their last race and fracture (P = 0.07). Ten of 13 humeri studied further had gross evidence of periost...
