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.
Sturm RT, Lang GH, Mitchell WR.The sera of 2596 thoroughbred and standardbred racehorses from Ontario were examined by hemagglutination-inhibition for antibodies to reovirus types 1, 2 and 3. The prevalence of antibodies differed between the standardbred and thoroughbred horses and varied with the age groups within the two populations. While reovirus 1 was the principal virus type infecting thoroughbreds, all three types seemed to infect standardbred horses. Differences of these findings with data from similar studies in Europe are mentioned and the epizootiological and pathological significance of these findings are discus...
Dusek J, Munk Z.The study was based on the documentation of the Napajedla Stud Farm of the English Thoroughbred horse for 1888-1972. Evaluating the effect of the age of stallions on their fertility (leaving aside the variability of the age of their mothers), such an effect was found to be significant only in four out of the 26 studs evaluated. In 65% of the selected stallions, the correlation coefficients were found to be negative, but without statistical significance. However, the objective of the study was to evaluate stallions and mares parallelly as to their age variability and fertility. The relationship...
Nickels FA, Brown CM, Breeze RG.A unilateral pulmonary granular cell tumor occurred in a Thoroughbred mare with longstanding respiratory disease wrongly attributed to chronic obstructive pulmonary disease. The clinical features, radiology and endoscopic appearance permitted an accurate diagnosis, which was supported by subsequent necropsy and histologic examination. Obstructive pulmonary disease was ruled out after measurement of arterial blood gases and maximum intrathoracic pressure changes, and after microscopic examination of the lung.
Jeffcott LB, Dalin G.The functional anatomy of the thoracolumbar (TL) spine is considered in relation to the horse's ability to perform at speed and to jump. The morphological features quite clearly show the relative inflexibility of the equine back and this was confirmed by some experimental studies. Fresh post mortem specimens from 5 Thoroughbreds were used to estimate the limits of dorsoventral movement of the TL spine from mid-thoracic to the cranial lumbar (T10-L2). The individual spinous processes could be moved a mean 1.1-6.0 mm on maximum ventroflexion and 0.8-3.8 mm on dorsiflexion. The overall flexibilit...
Rose RJ, Ilkiw JE, Arnold KS, Backhouse JW, Sampson D.Blood samples were collected from 16 Thoroughbred horses before, during and after the second day of a 3-day event. Plasma osmolality, concentrations of sodium, potassium, chloride, urea, creatinine, glucose, bilirubin, iron, total protein, albumin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, creatine kinase, calcium, inorganic phosphate, uric acid, cholesterol, triglycerides and non-esterified fatty acids were measured. Significant differences from pre-event values were found in all parameters with the greatest changes being found after the cross-country phase. ...
Allen WR, Urwin V, Simpson DJ, Greenwood RE, Crowhurst RC, Ellis DR, Ricketts SW, Hunt MD, Digby NJ.Daily oral administration of 30 mg allyl trenbolone (Regumate) for 10 to 15 days to 61 barren, maiden and lactating Thoroughbred mares which were exhibiting either deep anoestrus, shallow anoestrus, prolonged spring oestrus or lactation anoestrus, resulted in 54 mares (88 per cent) showing oestrous behaviour within 8 days, and 51 mares (84 per cent) ovulating within 18 days, after the last dose of compound. Response rate was lowest in mares in deep anoestrus. Of the 38 Regumate-treated mares which were covered during the induced oestrus, 21 (55 per cent) conceived. The practical value of this ...
Houghton E, Dumasia MC.1. The metabolism of 19-nor[4-14C]testosterone in a thoroughbred horse has been studied and neutral urinary metabolites obtained after enzyme hydrolysis have been investigated by g.l.c.-mass spectrometry. 2. 3-Hydroxyestran-17-one, 17 alpha- and 17 beta-nortestosterone, estrane-3,17-diol (two isomers), 3,16-dihydroxyestran-17-one (two isomers), 3,17-dihydroxyestran-16-one (two isomers) and estrane-3,16,17-triol were identified in the neutral urinary extracts.
Mader DR, Price EO.The discrimination learning ability of Quarter Horses and Thoroughbreds was compared by means of visual cues in a three-choice test with food as a reward. Quarter Horses learned significantly faster than Thoroughbreds, and learning progressed more rapidly for both breeds in a second discrimination task. Significant negative correlations were observed between age and rate of learning. Quarter Horses tended to be less reactive than Thoroughbreds, but individual emotional reactivity ratings and learning scores were not correlated. No correlation was found between social dominance and learning sco...
Dusek J, Munk Z.The breeding documentation of the English Thoroughbred horse breeding farm at Napajedla was analyzed to study some effects acting upon the fertility of studs and mares and the length of gravidity. The heritability of fertility is the subject of this report. The normality of the distribution of fertility was tested by processing 300 data on fertility at the given significance level sup / Fn(xi) - F(xi) / less than or equal to Dn(a). The value of the supreme D(300) = 0.108 is lower than the critical level for alpha 0.05. The estimation of fertility heritability coefficient indicates that h2 = 0....
Guthrie GP, Cecil SG, Kotchen TA.To assess the renin-aldosterone system in a large mammal, simultaneous morning activities of plasma renin and concentrations of aldosterone and cortisol were measured in 25 thoroughbred horses. Renin was relatively low in all horses (0.16 +/- 0.02 (S.E.M.) ng angiotensin I/ml per h), levels of aldosterone in plasma were 527 +/- 130 pmol/1 and levels of cortisol in plasma were 141 +/- 11 nmol/l. Levels of aldosterone were significantly correlated with levels of renin in all horses (r = 0.62, P less than 0.001) but not with those of cortisol, and renin was negatively correlated with age in male ...
Snow DH, Guy PS.Skeletal muscle of the equine was differentiated into three fibre types according to myosin ATPase (pH 9.4) and succinic dehydrogenase activity. The percentage of these types was determined in the musculus deltoideus, m triceps brachii caput longum, m gluteus medius, m semitendinosis, m biceps femoris and m vastus lateralis of the thoroughbred, Shetland pony, pony, heavy hunter and donkey. In addition the m gluteus medius was examined in the arab and American racing quarterhorse. High myosin ATPase activity fibres varied from a mean of 93.2 per cent in the m gluteus medius of the quarterhorse ...
Simpson CF, Neal FC.Four splenectomized ponies were infected with Babesia equi. Two ponies were not treated, and two were treated with 5 mg of imidocarb/kg of body weight when 20% of their erythrocytes were parasitized. The nucleus of the parasite in erythrocytes from blood smears of nontreated ponies was roundish, deep red-staining, and usually composed two-thirds of the organism. The parasite in erythrocytes from blood smears of treated ponies was swollen and vacuolated except for an area just beneath the plasma membrane where the compressed nucleus was marginated, elongated, and clumpy. Parasites in erythrocyt...
McGuire TR, Weitkamp LR.The equine transferrin F variant is distinguishable into two types, F1 and F2, on alkaline polyacrylamide gel electrophoresis. Gene frequencies in 63 related Thoroughbreds are 0.39 and 0.19 for TfF1 and TfF2, respectively. In contrast the frequencies for these two alleles in 375 related Standardbreds is 0.00 and 0.59.
Pollitt CC, Bell K.A method of horizontal thin layer polyacrylamide gel electrophoresis at acid pH has been developed for the separation of the prealbumins in equine plasma. Using this method, it has been possible to split the S allele into two, S1 and S2, bringing the total number of prealbumin alleles in Thoroughbred horses to eight. The gene frequencies of these eight alleles in Australian Thoroughbreds are presented. All eight prealbumin types exhibit antiprotease activity and therefore, it is suggested that the name prealbumin (Pr) should be abandoned in favour of protease inhibitor (Pi) although at this st...
Bailey E.Six hundred horses were tested with lymphocytotoxic antisera derived from 550 parous mares and 58 antisera produced by alloimmunization with horse blood cells. Seven equine lymphocyte specificities were identified using correlation analysis of the test data, absorption analysis and lysostripping. These specificities are expressed on lymphocytes and platelets, but not on red blood cells (RBC). Therefore, these specificities do not appear to be products of any of the eight known blood group systems of the horse. The distribution of these specificities in 113 Thoroughbred horses and 57 Arabian ho...
Houpt KA, Wolski TR.The dominance hierarchy of a herd of 10 Thoroughbred mares was determined twice, at an interval of 18 months, using paired feeding tests. Each mare's rank was correlated significantly between the 2 tests. This indicated that the hierarchy within the herd was stable. The offspring of dominant and subordinate mares were also tested for dominance in their own age groups. The offspring of dominant mares tended to be near the top of the hierarchy while those of middle and low ranking mares were not consistently found in the middle or bottom of their own hierarchies. Paired feeding tests were carrie...
Ammar AM, Heitmann J, Kirchhoff H.After abortion sera were taken from 58 thoroughbred and other mares of the northwestern part of Germany and investigated by ELISA (enzyme linked immuno-sorbent assay) for antibodies against Mycoplasma equirhinis, M. subdolum, M. equigenitalium, M. pulmonis, M. felis, Acholeplasma laidlawii, A. hippikon, and A. equifetale. Reactions at serum dilutions of 1:32 and higher were considered as positive. At serum dilution 1:32 no antibodies were found in 11 sera. The remaining sera showed antibodies against one or more of the mycoplasma antigens investigated. The number of multiple reactions decrease...
Lumsden JH, Rowe R, Mullen K.Reference hematology and biochemistry intervals are presented for a number of variables of clinical interest determined for blood samples obtained from 60 thoroughbred mares, 12 thoroughbred foals and 50 standardbred horses in training. The observations for each variable were examined for outliers and Gaussian distribution. Parametric analysis was used where the observations were Gaussian initially or after any of four transformations, otherwise nonparametric analysis was required for estimation of the 2.5 and 97.5 percentiles. Description of the sample collection procedures, laboratory method...
Kelly DF, Pinsent PJ.A 10-month-old thoroughbred colt developed sudden complete blindness; no other neurological abnormality was detected. At necropsy 3.5 months later lesions were confined to both optic pathways in which there was extensive degeneration of axons and myelin and gliosis. The cause of the optic lesion was not determined but the lesion may be a toxic neuropathy.
Merkt H, Günzel AR.Embryonic resorption is reported as the main reason for early pregnancy losses in the West German Thoroughbred mare. An analysis of breeding records for the last 11 years showed a resorption rat of 8.4 per cent. Evidence was obtained that these early embryonic losses were associated with too early conception after foaling and with the state of lactation.
Greeves PR, Witherington DH.The difficulties that arise in filling out marking certificates for thoroughbreds are described. The description given on the certificate has to be both written and graphic. A general guide to whorl location is given.
Pascoe RR.The epidemiology of dermatomycocis due to Trichophyton equinum var autotrophicum was studied in a number of thoroughbred stables in south-east Queensland. The significant factors in the epidemiology were defined. The infection was readily transmitted, particularly by infected saddle-girths, on which the fungus could survive for 12 months. Mild abrasion from the saddle during work favoured the development of lesions and prolonged the recovery period. A pronounced age and seasonal incidence of the disease was demonstrated as young horses under the age of 3 years were most susceptible, and the ma...
Purohit RC, Nachreiner RF, Humburg JM, Norwood GL, Beckett SD.Circulating concentrations of angiotensin I and plasma renin activity (PRA) were determined in 45 Thoroughbreds before prerace medication (at rest), 1 to 1 1/2 hours before racing but after prerace medication (prerace), within 15 minutes after racing (immediately postrace), and between 1 to 2 hours after racing. Angiotensin I was measured by radioimmunoassay, and PRA was determined by the rate of generation of angiotensin I in plasma incubated at 37 C. Irrespective of prerace medication, there was a marked increase in angiotensin I (0.478 +/- 0.034 to 0.848 +/- 0.051 ng/ml) and PRA (0.191 +/- ...
Willett K, Blackmore DJ.A method is described for the measurement of haptoglobin in equine serum using the peroxidase activity of the haemoglobin-haptoglobin complex. The problems of interference with Fe2+ and Fe3+ ions are described. Normal values for haptoglobin in 629 blood samples from thoroughbreds in training are presented showing a log normal distribution with a 5 per cent to 95 per cent range of 0.42 to 1.7 g/litre. There was no consistent alteration in haptoglobin concentration throughout the season in spite of a change in red cell size and total bilirubin concentration. It is concluded that the measurement ...
Miyakoshi D, Senba H, Shikichi M, Maeda M, Shibata R, Misumi K.This study aimed to evaluate whether radiographic abnormalities at yearling sales were associated with the failure to start racing at 2-3 years of age. Radiographic abnormalities in the carpal (n=852), tarsal (n=976), metacarpophalangeal (n=1,055), and metatarsophalangeal joints (n=1,031) from 1,082 horses, recorded at yearling sale, were reviewed. Eighty-two horses (7.6%) failed to start racing. Radiographic abnormalities such as wedged or collapsed tarsal bones, irregular lucency of a sagittal ridge at the distal aspect of the distal third metatarsal bone, and proximal dorsal fragmentation o...
Staniar WB, Kronfeld DS, Wilson JA, Lawrence LA, Cooper WL, Harris PA.Growth and protein status were examined in Thoroughbred foals and yearlings offered pasture supplements with different crude protein contents and amino acid compositions. Both supplements contained 3.0 Mcal/kg DM, 10% corn oil, 1.4% calcium, and three sources of fiber. The control supplement contained 14% CP and 22% soybean meal, whereas the experimental supplement contained 9% CP and 3% soybean meal and was fortified with 0.6% lysine and 0.4% threonine. Mares and foals were fed twice daily (0700 and 1400) and kept on 12.14-hectare pastures (mixed grass and ladino clover) until weaning (6 mo)....
Wright IM, Minshall GJ.Osteochondritis dissecans (OCD) of the distal sagittal ridge of the third metacarpal bone (McIII) has not previously been described in the literature. Objective: To describe the clinical, radiological and arthroscopic features of OCD of the distal sagittal ridge of the McIII and to report outcome in a series of cases. Methods: Retrospective case series. Methods: Case records and images of horses with OCD of the distal sagittal ridge of the McIII admitted to a single referral centre between February 2006 and February 2013 were reviewed. Follow-up information was obtained by telephone questionna...
Swanstrom MD, Zarucco L, Stover SM, Hubbard M, Hawkins DA, Driessen B, Steffey EP.The superficial (SDF) and deep digital flexor (DDF) muscles are critical for equine forelimb locomotion. Knowledge of their mechanical properties will enhance our understanding of limb biomechanics. Muscle contractile properties derived from architectural-based algorithms may overestimate real forces and underestimate shortening capacity because of simplistic assumptions regarding muscle architecture. Therefore, passive and active (=total - passive) force-length properties of the SDF and DDF muscles were measured directly in vivo. Muscles from the right forelimbs of four Thoroughbred horses we...
Preston SA, Trumble TN, Zimmel DN, Chmielewski TL, Brown MP, Hernandez JA.To characterize lameness during training and compare exercise variables and financial returns among yearling Thoroughbreds that were bought for the purpose of resale for profit. Methods: 40 yearling Thoroughbreds. Methods: Prospective study. Methods: Horses purchased at yearling sales (summer 2004) were trained prior to resale at 2-year-olds in training sales (spring 2005). Horses were monitored daily for diagnosis and treatment of lameness during training. Selected variables, including sex, age, purchase price, lameness, distance (No. of furlongs) galloped during training, and financial retur...
Ginther OJ, Douglas RH, Lawrence JR.Responses of 22 veterinarians to a questionnaire and the records of three brood-mare farms were examined to obtain information on twinning. The incidence rates of multiple ovulations on the three farms were 9%, 11%, and 22%. The multiple ovulation rate was reduced 42-67% in foaling mares compared to barren and maiden mares. Multiple ovulations were significantly more frequent in Thoroughbreds (19%) than in Quarter Horses (9%) and Appaloosas (8%). Both the questionnaire and the farm records indicated a high degree of repeatability of multiple ovulations and twin pregnancies within mares and wit...
Dunowska M, Howe L, Hanlon D, Stevenson M.The significance of infection with Equid herpesvirus 2 (EHV-2) remains unresolved, mainly due to its widespread distribution, and frequent isolation of the virus not only from diseased animals, but also from clinically normal horses. It has been suggested that EHV-2 exerts its effects on the host indirectly, through predisposition to secondary infections. The aim of this study was to determine kinetics of EHV-2 infection among foals and to investigate the role that EHV-2 may play in development of Rhodococcus equi pneumonia on one farm. Serial blood samples were collected from 43 foals over a ...
Bowers K, Weinhandl JT, Anderson DE.Equine tibial fractures are relatively infrequent in racing and non-racing sport horses, but limitations in successful treatment of tibial fractures in adult horses result in relatively high mortality compared with other musculoskeletal injuries. The aetiology of tibial fracture can be classified into two general categories: traumatic impact or fatigue failure. Tibial stress fractures, also known as fatigue fractures, are often rated as the second most common stress fracture in racing Thoroughbreds; young age, early stage in race training, and initiation of training after a period of rest are ...
Raidal SL, Hughes KJ, Eastwell B, Noble N, Lievaart J.There is little information on foal mortality and the epidemiology of diseases in the neonatal period in Australian equine breeding enterprises. Methods: This was a prospective cohort study of 1219 foals on 15 breeding farms in south-eastern Australia to identify the proportion of foals recognised on farm as abnormal at birth or within the first 48 h postpartum, determine the prevalence and risk factors for neonatal disease and assess the subsequent performance of foals in the study population. Results: Overall, 27 foals died within 6 weeks of birth in the study population (2.2%), 142 foal...
Khalesi H, Sakha M, Veshkini A, Rezakhani A.Heart murmurs and valvular regurgitation are common in horses and often have no effect on their performance. However, when structural changes occur in the heart size, they can affect performance adversely. This study aimed to examine the correlation between cardiac valves disease and poor performance in athletic horses. A total of 300 athletic Thoroughbred and mix-breed horses including 164 mares and 136 stallions, with a history of poor performance, were selected. Horses with cardiac murmurs were identified and further cardiac examination including precise auscultation, base-apex electrocardi...
Shepard MK, Lee WL, Eggleston RB.A 21-year-old Thoroughbred gelding with a history of equine pituitary pars intermedia dysfunction (PPID) presented with priapism of 2 days' duration. The horse received a caudal morphine epidural and then underwent corpus cavernosum lavage and phallectomy under general anesthesia. The patient's recovery featured multiple unsuccessful attempts to stand and his respiratory distress persisted for several hours until he acutely developed severe colic and was euthanized. Necropsy findings revealed a pituitary adenoma of the pars intermedia, bilateral adrenal cortical hyperplasia, and diaphragmatic ...
Bracher V, Mathias S, Allen WR.Placentation between 80 and 220 days of gestation was studied by measurement of fetal dimensions and gross, light and transmission and scanning electron microscopic examinations of the allantochorion and endometrium from 4 fertile mares with no, or very mild, endometrial histopathology and 6 subfertile Thoroughbred mares suffering varying degrees of age-related chronic degenerative endometritis (endometrosis). Spontaneously occurring twin gestation was observed in 3 animals. Several of the subfertile mares had endometrial cysts which showed 2 distinct features during pregnancy: those located n...
Wilson KE, Bogers SH, Council-Troche RM, Davis JL.To determine the effects of general anesthesia on the safety and efficacy of co-administered potassium penicillin G (PEN) and gentamicin (GENT) in horses. Methods: Nonrandomized crossover. Methods: Six adult, Thoroughbred horses. Methods: Horses were administered PEN (22 000 IU/kg IV) and GENT (6.6 mg/kg IV). Plasma samples were collected over a 6 h period and synovial fluid was collected at 30 min and 6 h respectively. Drug administration and sample collection protocols were repeated after at least a 48 hour washout period and induction of anesthesia using xylazine/ketamine and main...
Kusano K, Minamijima Y, Mashita S, Kunii H, Yamashita S, Nagata S.Repeated topical application of indomethacin is common in Japanese racehorses, despite the lack of pharmacokinetic data. Objective: To determine the concentrations of indomethacin and its metabolite, desmethylindomethacin, in plasma and urine of Thoroughbreds topically treated repeatedly with indomethacin. Methods: In vivo experimental. Methods: Seven female Thoroughbreds were topically treated with 50 g of 1% indomethacin cream per horse to the back and hips (500 mg of indomethacin/head/2400 cm , 0.21 g/cm ) for 3 consecutive days. Samples were pretreated by protein precipitation for plas...
Murphy DJ, Kö-Peternelj V, Aleri JW.Superficial digital flexor tendon (SDFT) injury is common in racehorses and a significant cause of lost training days and wastage in the industry. Objective: To compare the post-injury performance of Thoroughbred and Standardbred racehorses diagnosed with SDFT tendonitis treated with intralesional bone marrow and superior check desmotomy or managed conservatively and further to compare this performance with that of uninjured racehorses. Methods: Retrospective and case-controlled. Methods: Medical and race records of racehorses treated surgically or managed conservatively for SDFT tendonitis we...
Parkin TD, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL.The risk of fatal distal limb fractures in thoroughbreds racing in the UK was calculated and shown to vary considerably between the different types of race. Flat turf racing was associated with the lowest risk (0.4 per 1000 starts) and national hunt flat racing was associated with the highest risk (2.2 per 1000 starts). The types of fracture were classified by detailed radiographic and postmortem examinations of all the cases recorded over two years, and the distribution of the different types of fracture in the five main types of racing was examined. Overall, lateral condylar fractures of the...
Gilbert RO, Marlow CH.Records of 1,009 pregnancies in 574 foaling, barren and maiden Thoroughbred mares on a single stud farm, over a period of 12 years were examined. The farm is situated in the eastern Cape Province of South Africa, at an elevation of 1,800 m, and in an area of climatic extremes. Records of 604 pregnancies in 249 foaling Thoroughbred mares were examined. For these purposes, those pregnancies in which a mare conceived in the same breeding season during which she had foaled were considered as pregnancies in foaling mares. Pregnancy was confirmed by rectal palpation by a single experienced practitio...
Vergara-Hernandez FB, Nielsen BD, Robison CI, Fabus TA, Kompare JL, LeCompte Lazić RA, Colbath AC.The main factors influencing speed in athletes are stride length (SL) and stride rate (SR). However, conflict remains whether SL or SR is the key determinant of higher speeds. Quarter Horses (QH) generally reach higher speeds in their races than do Thoroughbreds (TB). However, the influence of SL and SR on this greater speed is unclear. Therefore, the main objective of this study was to compare SL and SR in QH and TB raced in short (sprint) and long (classic) distances. We hypothesized that QH have a higher SR in comparison to TB, and SR decreases as distance increases. Two race distances were...
Seeherman HJ, Morris EA.The purpose of this study was to compare exercise measurements in yearling, two-year-old and adult Thoroughbreds using a standardised treadmill incremental exercise test. Peak oxygen consumption (VO2 peak: 128.0 +/- 2.1, 140.0 +/- 2.1, 163.7 +/- 3.4; ml/kg/min +/- se, P less than 0.05), peak packed cell volume (PCV peak: 0.50 +/- 0.01, 0.58 +/- 0.01, 0.64 +/- 0.01 litres/litre +/- se, P less than 0.05) and the maximum number of steps completed in the exercise test (STEPmax: 7.7 +/- 0.1, 8.1 +/- 0.1, 8.6 +/- 0.1; steps +/- se, P less than 0.05) increased with age and degree of physical activity...
Newton JR, Wood JL, Castillo-Olivares FJ, Mumford JA.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...
Urquieta B, Durán MC, Coloma I, Parraguez VH.Our aim was to compare Corpus luteum (CL) development and blood plasma concentration of progesterone ([P4]) in thoroughbred mares after spontaneous ( Methods: C) or human chorionic gonadotrophin (hCG)-induced ovulation. Lactating mares (C=12; hCG=21) were daily teased and mated during second oestrus post-partum. Treated mares received 2500 IU hCG i.v. at first day of behavioural oestrus when dominant follicular size was >35, or=45 mm. Dominant follicle before ovulation, CL and gestational sac were measured by ultrasound and [P4] by radioimmunoassay (RIA). Blood sampling and ultrasound CL ex...
Kurosawa M, Nagata S, Takeda F, Mima K, Hiraga A, Kai M, Taya K.Our aim was to investigate plasma catecholamine responses to so-called 'doping' drugs and exercise in Thoroughbreds. Plasma adrenaline (Ad) and noradrenaline (NA) were determined after the administration of caffeine and promazine hydrochloride (PRZ) using a high performance liquid chromatographic method. Caffeine or PRZ was administered i.m. to Thoroughbreds and its effects on plasma catecholamines at rest and during exercise were compared with the saline control. The treadmill exercise was performed 1 h after administration. A dose of 5.0 mg/kg bwt caffeine was found to significantly increase...
Viljanto M, Cutler C, Taylor P, Habershon-Butcher J, Gray B.MK-0677 (ibutamoren) is an orally active non-peptide growth hormone secretagogue that binds to the ghrelin receptor stimulating the secretion of endogenous growth hormone. It is one of the most prevalent performance-enhancing compounds currently available online and is potentially subject to abuse both in human and equine sports. The aim of the current study was to investigate whether it could be detected in equine hair following oral administration of MK-0677 mesylate to a Thoroughbred racehorse. MK-0677 and its O-dealkylated metabolite were extracted using an existing method for prohibited s...
Edwards SH, Khalfan SA, Jacobson GA, Pirie AD, Raidal SL.OBJECTIVE To determine plasma drug concentrations after IV administration of a bolus followed by continuous rate infusion (CRI) of sodium benzylpenicillin and ceftiofur sodium to healthy adult horses. ANIMALS 6 Thoroughbred mares (3 to 9 years old; mean ± SD body weight, 544 ± 55 kg) with no history of recent antimicrobial treatment. PROCEDURES Horses were used in 2 experiments conducted 14 days apart. For each experiment, horses were housed individually in stables, and catheters were placed bilaterally in both jugular veins for drug administration by CRI (left catheter) and for intermittent...
Toombs-Ruane LJ, Riley CB, Rosanowski SM, Kendall AT, Benschop J.Decreased efficacy of veterinary antimicrobials and increased prevalence of multi-drug resistance (MDR) is of concern, but little is known of antimicrobial resistance encompassing the New Zealand (NZ) equine population. Recent concerns have arisen over the emergence of multi-resistant bacteria [1], especially on NZ stud farms where antibiotics are frequently used for respiratory disease without veterinary input [2]. Objective: To describe bacterial culture and antimicrobial sensitivity results from respiratory samples submitted of young horses (4 weeks to 3 years old). Methods: Retrospective s...
You Y, Uboh CE, Soma LR, Guan F, Li X, Rudy JA, Chen J.A rapid and sensitive method was developed for the screening, quantification and confirmation of ethyl glucuronide (EG) and ethyl sulfate (ES) as biomarkers for alcohol administration to racehorses using liquid chromatography coupled on-line with triple quadrupole tandem mass spectrometry. Urine sample aliquots (0.1 mL) were pre-treated by protein precipitation. Separation of EG and ES was achieved on an Ultra PFP column. Isocratic elution with a flush step was performed using 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B). Analysis was performed by negative electrospra...
Spiegel IB, White SD, Foley JE, Drazenovich NL, Ihrke PJ, Affolter VK.Nine horses from ages 5 to 21 years were diagnosed with cutaneous equine sarcoidosis (ES) over an 18-year period. In addition to skin, the lungs were frequently involved, with other organ systems affected less commonly. A predisposition for thoroughbreds and geldings was noted. Cutaneous lesions and signs included crusts, scales, alopecia and pruritus. These were found at various sites, particularly the legs/thighs/elbows, thorax, neck, face and ventral abdomen. Three horses were euthanized shortly after hospitalization; others survived as long as 12 years. Histopathologic stains, immunohistoc...
Wen X, Luo S, Lv D, Jia C, Zhou X, Zhai Q, Xi L, Yang C.The horse gut is colonized by a rich and complex microbial community that has important roles in horse physiology, metabolism, nutrition, and immune functions. Fewer across-breed variations in horse gut microbial diversity have been illustrated. In this article, the gut microbiota of Thoroughbred, Mongolian, and Hybrid horses [first filial generation (F1) of Mongolian (maternal) and Thoroughbred (paternal)] were studied by second-generation high-throughput sequencing technology. Differences in gut microbiota composition and function between breeds were determined using diversity and functional...
Kim YM, Ha SJ, Seong HS, Choi JY, Baek HJ, Yang BC, Choi JW, Kim NY.In this study, genome-wide CNVs were identified using a total of 469 horses from four horse populations (Jeju horses, Thoroughbreds, Jeju riding horses, and Hanla horses). We detected a total of 843 CNVRs throughout all autosomes: 281, 30, 301, and 310 CNVRs for Jeju horses, Thoroughbreds, Jeju riding horses, and Hanla horses, respectively. Of the total CNVRs, copy number losses were found to be the most abundant (48.99%), while gains and mixed CNVRs accounted for 41.04% and 9.96% of the total CNVRs, respectively. The length of the CNVRs ranged from 0.39 kb to 2.8 Mb, while approximately 7.2% ...
Kalashnikov VV, Zajcev AM, Atroshchenko MM, Miroshnikov SA, Zavyalov OA, Frolov AN, Skalny AV.The objective of the present study was assessment of gender differences in hair trace element content in English Thoroughbred horses (North Caucasus, Russia) using ICP-DRC-MS and calculation of the reference values. Trace element content in mane hair of 190 stallions and 94 mares (3-7 years old) bred in North Caucasus (Russia) was assessed using inductively coupled plasma mass spectrometry. Mane hair Co, Cr, Mn, Li, Si, and Sr levels in mares exceeded those in stallions by 77%, 63%, 64%, 42%, 39%, and 64%, respectively. Hair Fe and Si content was nearly twofold higher in female horses as comp...
