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Topic:Thoroughbreds
Thoroughbreds are a breed of horse known for their agility, speed, and spirit, often associated with horse racing and equestrian sports. Originating from crossbreeding native English mares with imported Arabian, Barb, and Turkoman stallions, Thoroughbreds have a well-documented pedigree that traces back to the late 17th and early 18th centuries. This breed is characterized by a refined head, deep chest, and long legs, contributing to their athletic capabilities. Thoroughbreds are primarily bred for their performance in racing but are also utilized in other equestrian disciplines. This page compiles peer-reviewed research studies and scholarly articles that explore the genetics, physiology, and performance characteristics of Thoroughbreds, as well as their management and welfare in various equine activities.
Serous cystadenoma in a normally cyclic mare with high plasma testosterone values. Serous cystadenoma was diagnosed by histologic examination of a large ovary removed from a 16-year-old Thoroughbred mare with normal estrous cycles. Palpation and ultrasound examination per rectum had revealed an excessive number of follicles in the right ovary. The ovulation fossa was palpable on the right ovary, and the left ovary appeared to have normal activity. Plasma testosterone values were high at the time of examination (0.15 ng/ml), but decreased to normal values (0.09 ng/ml) after removal of the cystadenoma.
Use of polysulphated glycosaminoglycan in equine lameness. Four cases of equine lameness were treated with intra-articular polysulphated glycosaminoglycan. Two, two-year-old flat racers were treated conservatively after traumatic injury. They subsequently became lame owing to the formation of new bone and osteophytes. Two older steeplechasers were lame owing to degenerative joint disease. The four horses were treated with intra-articular injections of polysulphated glycosaminoglycans and, after three or four injections, they became clinically sound and were able to continue racing with varying degrees of success.
Carnosine content of the middle gluteal muscle in thoroughbred horses with relation to age, sex and training. 1. Muscle biopsies were collected from 85 thoroughbred horses and analysed for carnosine content by an automated HPLC method. 2. No significant sex difference was found between colts, geldings and fillies. 3. There was a trend towards lower muscle carnosine contents with age, which was only significant between 1-year-old untrained horses and 4+ year-old horses (P less than 0.002).
[Bilateral rupture of two head flexors with synchondrolysis of the base of the skull in a horse]. Bilateral rupture of the musculus longus capitis from the tuberculum musculare of the os occipitale and of the musculus rectus capitis ventralis from the os occipitale combined with a synchondrolysis of the synchondrosis sphenooccipitalis in a 17 months old thoroughbred stallion is reported.
Some geometric properties of the third metacarpal bone: a comparison between the thoroughbred and standardbred racehorse. Geometric properties of the third metacarpal bone were compared between the young and adult Standardbred and Thoroughbred racehorse. The change in shape during growth and superimposed training was dramatic in both breeds but the Thoroughbred showed the greatest difference in the minimum moment of inertia as the animal matured. Males had larger moments of inertia throughout the length of the diaphysis than did females. The differences in geometric properties of the third metacarpal bone between the Thoroughbred and Standardbred were related to the incidence of fatigue fractures which are common...
Effect of freeze-drying on measurements of pH in biopsy samples of the middle gluteal muscle of the horse: comparison of muscle pH to the pyruvate and lactate content. Muscle biopsies taken after exercise, in comparison to those at rest, contain increased amounts of blood and this is a particular problem in studies of the horse. The inclusion of blood in muscle will introduce an upward bias in values of pH measured in muscle homogenates. In an attempt to control this, muscle biopsy samples of the middle gluteal from Thoroughbred horses were freeze-dried and dissected free of blood before determination of pH. Following exercise, muscle pH measured after freeze-drying was similar to that measured in homogenates prepared from frozen samples. In contrast, freeze...
Dermatographism in a horse. An eight-year-old Thoroughbred gelding with dermatographic urticaria is presented. Forelimb edema and generalized urticaria were the presenting clinical signs. All hematologic and serum biochemical values were normal. Immunologic and histologic evaluation failed to reveal specific abnormalities. During hospitalization, an urticarial response to mechanical pressure (dermatographism) was identified. Clinical responses to corticosteroid and antihistaminic (H1) therapy were equivocal. The condition resolved in five weeks and an etiology was not discovered. A discussion of the pathogenesis, diagnos...
Effect of phenytoin on the clinical signs and in vitro muscle twitch characteristics in horses with chronic intermittent rhabdomyolysis and myotonia. In vitro twitch characteristics of the semimembranosus muscle were evaluated in 9 clinically normal horses, in 15 horses with chronic intermittent rhabdomyolysis (CIR) and in 2 horses with myotonia. Effects of phenytoin on in vitro muscle twitch and clinical signs of CIR and myotonia were evaluated in these same horses. Times to 90% relaxation were prolonged in the horses with CIR (mean +/- SEM, 186 +/- 5.9 ms) and in 2 horses with myotonia (197 and 177 ms) compared with those in clinically normal horses (mean +/- SEM, 146 +/- 2.1 ms). Horses with CIR also had significantly (P less than 0.05) ...
Cortical somatosensory-evoked potentials in the horse. Cortical somatosensory-evoked potentials (SEP) were recorded from thoracic and pelvic limbs in 15 horses (13 Thoroughbreds and 2 Quarter Horses). Ulnar nerve SEP were evoked by electrical stimulation of the lateral palmar branch of the ulnar nerve at the level of the metacarpophalangeal joint. Recordings were taken between electrodes at 2 cm lateral to the vertex (contralateral to the stimulated limb) and the midpoint of the interorbital line. Four peaks were found in all recordings: N1, P1, N2, and P2. Latencies to the peaks were 39.0 +/- 2.7, 45.5 +/- 5.3, 50.4 +/- 5.2, and 62.3 +/- 3.7 ms (...
Micronema deletrix-induced granulomatous osteoarthritis in a lame horse. Necropsy of a chronically lame 16-year-old thoroughbred gelding revealed granulomatous osteomyelitis and polyarthritis due to a widely disseminated infection by Micronema deletrix. Diagnosis was based upon the nematode's morphology with its characteristic rhabditiform oesophagus. Granulomata, often containing one or more centrally located M. deletrix, were observed histologically in sections prepared from femur, kidney, stomach, lung, adrenal gland and sublumbar lymph nodes. Neither verminous meningo-encephalitis nor cephalic granulomata, which are the more commonly described lesions, was foun...
Efficacy of water vapor-saturated air in the treatment of exercise-induced pulmonary hemorrhage in Thoroughbred racehorses. The efficacy of water vapor-saturated air as a treatment for horses with exercise-induced pulmonary hemorrhage (EIPH) was studied. Horses selected for study (n = 14) had grade 1 or greater hemorrhage in the trachea after a minimum of 4 breezes between 0.8 and 1 km, as determined by endoscopy. Nine horses were treated with water vapor-saturated air; 5 horses were not treated. When the mean and maximal EIPH scores from the pretreatment period were compared with the mean and maximal EIPH scores from the treatment period in both treated and nontreated groups, there was no significant difference be...
Assessment of copper and zinc status of farm horses and training thoroughbreds in south-east Queensland. The copper and zinc concentrations in the blood of stabled thoroughbred horses and in Australian Stock Horses mares at pasture, either late pregnant or lactating were determined by an atomic absorption spectroscopic method. The plasma concentration of the trace elements in these apparently normal horses were generally below the "normal" range. The plasma copper, caeruloplasmin copper, whole blood copper and plasma zinc concentrations in the stabled thoroughbreds were 0.76 +/- 0.19 micrograms/ml (n = 82), 0.56 +/- 0.14 micrograms/ml (n = 83), 0.75 +/- 0.18 micrograms/ml (n = 82) and 0.47 +/- 0....
Treatment of Fasciola hepatica infection in horses with triclabendazole. Thirteen thoroughbred foals with an adult infection and a presumed immature infection with Fasciola hepatica were treated with 12 mg triclabendazole/kg bodyweight. The absence of eggs from samples of faeces examined at intervals up to 110 days after treatment showed that all the animals were cured. In a second trial the same dose of triclabendazole cured 11 of 12 foals whereas nitroxynil at 7 mg/kg cured only six of 12 foals. No side effects were observed after treatment.
Pulmonary micro-embolism following orthopaedic surgery in a Thoroughbred gelding. A NUMBER of post general anaesthetic complications are
known to occur in the horse and are well documented (Heath
1981). These include post anaesthetic forelimb lameness o r
ischaemic myopathy (so-called 'radial paralysis') (Trim and
Mason 1974) and spinal cord degeneration (Brearley, Jones,
Kelly and Cox 1986). The only postoperative respiratory
complication which has been documented in the horse is
postoperative hypoxaemia (Gillespie, Hall and 3 1 e r 1969;
Waterman, Jones and Richards 1982).
In a report of the post mortem examinations of 185 injured
human patients who died followi...
The use of radionuclide bone scanning in the diagnosis of tibial ‘stress’ fractures in the horse: a review of five cases. Five horses, all two year old Thoroughbreds, presented with acute onset hindlimb lameness following moderate to fast exercise. The use of a hand-held scintillation detector after Tc99 MDP injection greatly aided the diagnosis of tibial stress fractures in these horses. Radiological findings were subtle, involving only periosteal new bone and callus at the fracture site. In two cases this took several weeks to develop but in three others was present at the onset of lameness, indicating insidious pre-fracture bone pathology. The site of the most obvious radiological signs was constant in all fiv...
Incidence, location and classification of 371 third carpal bone fractures in 313 horses. The medical records and radiographs of all horses with a third carpal bone fracture admitted to The Ohio State University Veterinary Hospital from 1979 to 1987 were reviewed. Three hundred and seventy-one fractures were found in 313 horses; 57 percent were Standardbreds, 41 per cent were Thoroughbreds, and only 1.6 per cent were Quarterhorses. All were young racehorses (average age = 3.1 years). Third carpal fractures occurred more frequently in the right limb (60 percent) than the left limb (40 percent); Thoroughbreds had a greater right-left disparity (67.5 percent R, 27.1 per cent L). Fract...
Ultrasonic transmission velocity and single photon absorptiometric measurement of metacarpal bone strength: an in vitro study in the horse. Ten pairs of third metacarpal bones from Thoroughbred horses aged two to 12 years were used to estimate bone strength. Measurements of transverse cortical ultrasound velocity, cortical cross sectional area and bone mineral content were made using ultrasonic transmission velocity and single photon absorptiometry. These data were used to determine bone mineral density, compact bone density and modulus of elasticity. The results were compared with those measured by direct means or chemical analysis and satisfactory correlations were obtained between estimated and measured values. Single photon ab...
Dose-related effects of detomidine on autonomic responses in the horse. 1. Detomidine is a novel veterinary sedative analgesic which is thought to act by stimulation of alpha 2 adrenoreceptors. The present study was undertaken to determine the direction, time course, and dose-response relationship of detomidine on specific autonomic responses in the unanaesthetized horse. 2. Detomidine was administered intravenously to eight adult thoroughbred racehorses at doses of 0.010-0.040 mg kg-1, according to a double-blind Latin square crossover design. Cardiac and respiratory rates, pupil diameter and rectal temperature were monitored for 180 min postinjection. 3. Detomid...
Slab fractures of the third carpal bone in standardbreds and thoroughbreds: 155 cases (1977-1984). Case records and radiographs of 155 horses with third carpal bone (C3) slab fractures were reviewed. Of these cases, race records were obtained for 72 Thoroughbreds and 61 Standardbreds. Three performance criteria were examined: ability to make 1 start, ability to make 10 starts or earn $2,000 (within 1 year of first start after the fracture), and earnings per start. Treatment distribution (lag screw fixation, fragment excision, or rest) was similar in both breeds. Significant differences between breeds were identified in age and sex distributions, fracture displacement, and postinjury perform...
Diagnosis and correction of twin pregnancy in the mare. Reproductive Physiology 1. Twin pregnancies result in high rates of abortion, stillbirth, and neonatal mortality. 2. Twins develop subsequent to multiple ovulations. Multiple ovulations are related to breed, parity, and mare history. Multiple ovulations are most frequently seen in Thoroughbred and Draft mares. Multiple ovulations are more common in barren and perhaps maiden mares than in lactating mares, and they are more common in certain individual mares. 3. Equine embryos are motile in the uterus from the time of first detection (Days 9 to 10) until fixation (Day 16). They are frequently lo...
Corynebacterium folliculitis in a horse. A 7-year-old Thoroughbred was examined for evaluation of mildly pruritic multiple skin lesions that had progressed from nodules to alopecia and crusts. Folliculitis caused by Corynebacterium pseudotuberculosis was diagnosed by bacterial culture. Oral treatment with a trimethoprimsulfadiazine paste resulted in resolution of all lesions, with normal hair regrowth.
Verification of ineffectual activity of ivermectin against adult Onchocerca spp in the ligamentum nuchae of horses. Ivermectin paste formulation (200 micrograms/kg) was administered orally to 27 horses (13 Thoroughbreds and 14 of mixed breeding) to evaluate activity against adult Onchocerca spp in the ligamentum nuchae. Ages, known or estimated, of the horses ranged from 1 to 22 years. Single or multiple doses (1 to 5) of the drug were given to each horse. When multiple doses were administered, the intervals between treatments ranged from 7 to 92 days. At 27 to 171 days after initial treatment (single dose or first of multiple doses), the horses were killed. Some of the horses treated more than once were ki...
Y chromosome length variation and its significance in the horse. The results of Y chromosome measurements in 31 horses are presented. The Y chromosome was identified using G-, R-, and C-banding techniques. From G-banded metaphase spreads, total X and Y chromosome and separate proximal (P) and distal (D) Y-band measurements were made. Within this group, the Y/X ratio (%) for each animal varied from 18.93 to 43.95, with an overall mean of 34.85 and a coefficient of variation (CV) of 16.12. The overall mean P/X ratio (%) was 23.57 with a CV of 20.57, compared with an overall mean D/X ratio (%) of 11.26 with a CV of 15.18. The group studied included 27 Thorough...
Piperazine resistance in population-B equine strongyles: a study of selection in Thoroughbreds in Kentucky from 1966 through 1983. Observations were completed over an 18-year period (1966 through 1983) in Thoroughbred mares (15/year) and yearlings (11 to 24/year) on a farm where benzimidazole-resistant small strongyles had emerged previously (1962 to 1965). This farm was operated as a closed, nonboarding type, which included a racing stable for its home-bred foals. At 2-week intervals, counts of worm eggs per gram of feces (EPG) and larvae per gram of feces were done to monitor strongyle infections and efficacies of bimonthly (every 8 weeks) antiparasitic treatments that were administered by stomach tube or were fed (dich...
