Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Greenhaff PL, Snow DH, Harris RC, Roberts CA.Two studies were undertaken in an attempt to investigate the optimal dose, route and time course required to 'bicarbonate load' the Thoroughbred. During the first study a test solution of sodium bicarbonate (NaHCO3) and a control solution of water were administered via a nasogastric tube to six horses. Blood acid-base status was determined immediately prior to and for 24 h following intubation. During the second study a standardised feed was given to four horses, with and without NaHCO3 supplementation. This was followed by a further trial involving the addition of glucose and NaHCO3 to a stan...
Seeherman HJ, Morris EA.Clinical exercise stress testing is an important diagnostic tool for evaluating exercise intolerance and degree of fitness in human athletes. The purpose of this paper was to describe the methodology necessary to perform a clinical exercise test and report the results of performance evaluations on 10 Thoroughbred racehorses using this test. The test utilised an open flow gas analysis system for ease of use with untrained horses and a fast time response lactate analyser for rapid data analysis. Exercise test measurements used to evaluate fitness included peak oxygen consumption (mean VO2peak = ...
Gatewood DM, Douglass JP, Cox JH, DeBowes RM, Kennedy GA.A 9-year-old American Saddlebred mare was referred because of abdominal distention and signs of abdominal pain. Copious peritoneal fluid obtained by abdominocentesis appeared to be frank blood. Rectal and ultrasonographic evaluation of the abdomen revealed a large mass at the distal tip of the right uterine horn. The mare was euthanatized and necropsied and the mass was determined to be a granulosa-thecal cell neoplasm. The most common clinical sign of granulosa-thecal cell neoplasm is infertility or abnormal sexual behavior. Hemoperitoneum is infrequently associated with neoplasms in horses.
Pascoe PJ, Ducharme NG, Ducharme GR, Lumsden JH.In order to determine which variables are useful and accurate in estimating prognosis in horses with abdominal pain, data were analyzed from 231 horses presented at a veterinary teaching hospital. Using multiple stepwise discriminant analysis in a recursive partition model, we obtained a decision protocol that identified survivors and nonsurvivors. The prevalence of survivors was 61% in this population. The sensitivity, specificity, and positive and negative predictive values of this model were 71, 83, 87 and 65%, respectively. This decision protocol was validated by Jackknife classification a...
Harris PA, Snow DH, Greet TR, Rossdale PD.Sixty-six Thoroughbred horses in training (2 or 3 years of age) were studied during one flat racing season, to investigate the relationship between age, sex, time of year, dietary electrolyte imbalances and plasma aspartate aminotransferase/creatine kinase (AST/CK) activities. Management and training variations were minimised. Between February to October, monthly 24 h post exercise samples were collected and analysed for AST and CK activities. Sex and/or age were shown to have a significant effect on the occurrence of high CK (> 100 iu/litre) and AST (> 300 iu/litre) activities. Fillies ...
van Weeren PR, van den Bogert AJ, Barneveld A, Hartman W, Kersjes AW.The function of the reciprocal apparatus in the hind limb of the horse was studied by kinematic gait analysis. For recording purposes a modified opto-electronic CODA-3 kinematic analysis system was used. The raw kinematic data were corrected for skin displacement artifacts by use of recently developed correction models. It was concluded that contradictory findings about the coupling of tarsal and stifle joints by the reciprocal apparatus, when comparing in vitro and in vivo studies, can be fully attributed to artifacts due to the movement of the skin markers over the underlying bony structures...
Rose RJ, Hodgson DR, Bayly WM, Gollnick PD.To determine whether maximum oxygen uptake (VO2max) in the horse in influenced by type of exercise test, five different protocols were evaluated in eight untrained Thoroughbreds exercised on a treadmill. With all protocols, horses were given a 5 min warm-up on a 10 per cent treadmill slope. Three protocols were at a 10 per cent slope and included: 1) increasing the running speed by 1 to 2 m/sec every 60 secs from 4 m/sec to a maximum of 12 m/sec; 2) running at 12 m/sec until fatigue; and 3) running for 3 to 4 mins at speeds ranging from 6 to 12 m/sec with rest pauses between exercise bouts. Th...
Kähn W, Fraunholz J, Kaspar B, Pyczak T.Ultrasonography allows early and reliable pregnancy detection in several domestic animals. Transrectal sonography can be recommended in horses and cattle, transrectal or transcutaneous procedures in sheep, goats and pigs while transcutaneous ultrasound scanning is appropriate in dogs and cats. Three periods of time can be distinguished in the diagnosis of early pregnancy by ultrasound: the earliest phase, where signs of pregnancy can be found in some cases, but accuracy of diagnosis is very low; the succeeding period, where reliable diagnosis is possible, but results are often difficult to ach...
Miller PE, Pickett JP, Majors LJ.Comparisons were made of measurements obtained in horses, using 2 applanation tonometers in vivo and in vitro. In vitro comparisons indicated that although neither instrument accurately recorded intraocular pressure (IOP), compared with manometric measurements, results of both instruments indicated linear digression from manometric IOP values that could readily be corrected, thereby accurately estimating IOP in horses. For tonometer 1 (MacKay-Marg), calculated actual IOP = 1.48 - 0.9 mm of Hg; and for tonometer 2 (Tono-Pen), calculated actual IOP = 1.38 + 2.3 mm of Hg. The coefficients of dete...
Ekman S.Lesions in the cervical spine of 28 young horses (Standardbred Trotters and Swedish Warmbloods), killed because of longstanding or severe ataxia, are described. The material consists of all horses with ataxia available for necropsy and presented to the large animal clinic of the School of Veterinary Medicine, Uppsala and the Animal Hospital in Helsingborg during 1981 through 1983. After a clinical and radiographic examination, including myelography in all but 2 cases, the horses were killed and necropsy was performed. The cases were divided into three categories based on the radiographic and p...
Harkins JD, Kamerling SG, Bagwell CA, Karns PA.Eight horses with previous racing experience were used in a comparative study of training methods for Thoroughbred racehorses. They were randomly assigned to two groups of four horses each. One group was trained using an interval training method (IT) and the other using conventional training (CT) methods. Peak heart rates, heart rate recovery curves, peak plasma lactate levels, plasma lactate clearance rates and run times were used to evaluate differences in the training methods. Peak heart rates, heart rate recovery curves, and run times were not significantly different between the groups. Ho...
Firth EC, Nouws JF, Klein WR, Driessens F.A pilot study in two ponies showed that the plasma concentrations of intramuscularly administered procaine penicillin were higher if phenylbutazone was administered concurrently. In two other trials, each involving five horses, intravenous sodium penicillin was administered with and without concurrent intravenously injected phenylbutazone, and procaine penicillin was injected intramuscularly with and without oral phenylbutazone. In both cases the plasma concentrations of penicillin were higher when phenylbutazone was given. The pharmacokinetic parameters indicated that the effect was probably ...
Lord PF, Croft MA.Echocardiography may be an accurate method of measuring left ventricular (LV) volumes and mass of the horse's heart. If so, studies of the heart size and hypertrophy would be possible. This study evaluated geometric models of the external and internal LV shapes, to determine which could be applied to echocardiographic measurements. We preserved 30 horses' hearts and measured their dimensions and cross sectional areas. These measurements were entered into seven formulae representing different geometric models of the ventricle and its chamber. We derived a correction factor to estimate the long ...
Stewart-Scott IA, Pearce PD, Burkin DJ.Sex chromosome abnormalities have been detected in a further five mares with clinical histories of small ovaries and absent or irregular oestrous cycles. Three mares had 63,XO karyotypes (X monosomy) and two were sex chromosome mosaics with karyotypes of 63,XO/64,XY and 63,XO/64,XX/64,XY respectively. A sex chromosome abnormality (X monosomy) has also been found in a filly where it was suspected because of her short stature.
Barrey E.A greater knowledge of the biomechanics is necessary in equine orthopaedics, therapeutics, farriery and for the selection of athletic horses. The purpose of this study was to determine the normal distribution of the vertical component of the hoof force using a measuring boot. The measurements were carried out using 20 sound horses walking and trotting on a straight hard track. A force measuring horseshoe, attached to the foot with a boot, provided continuous recording of vertical forces at four locations on the hoof. For each measuring location, a computer program produced curves and calculate...
Sanada Y, Noda H, Nagahata H.A fluorometric assay was applied to evaluate blastogenesis of equine lymphocytes. Optimal culture conditions were as follows; concentrations of phytohaemagglutinin-P (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) were 1 microgram/ml, 40 micrograms/ml and 10 micrograms/ml, respectively, when 5 X 10(5) lymphocytes were incubated with culture medium containing 20% pooled horse serum (PHS) for 120 hours. The relative mean stimulation index of healthy non-pregnant mares were 5.107 +/- 0.323 (M +/- SE) with PHA, 4.019 +/- 0.183 with Con A and 3.610 +/- 0.131 with PWM. Sequentially the blas...
Johnson L, Hardy VB, Martin MT.Nomarski optics were used to identify stages of the spermatogenic cycle of seminiferous tubules in sectioned tissue or in whole dispersed tubules and to characterize the equine spermatogenic wave. Embedded tissues were sectioned at 20 microns. Whole dispersed tubules were obtained by enzymatic digestion of thin slices of fresh testis. Dispersed tubules were fixed, dehydrated in graded levels of alcohol, infiltrated with Epon, and mounted in toto on glass slides. Stages of the spermatogenic cycle could be identified under Nomarski optics in both histologic sections and tubules mounted in toto. ...
Winder NC, Grünig G, Hermann M, von Fellenberg R.The concentration of soluble fibrinogen derivatives (SFD) and protease and procoagulant activities were determined in cell-free supernatants of equine respiratory secretions obtained from horses with chronic pulmonary disease. The concentration of neutrophils was estimated from direct smears of the secretions. Lung specimens and smears of the secretions were evaluated for the presence of fibrin or fibrinogen by use of immunohistochemical methods. Thirty-five of 80 specimens tested contained SFD. Respiratory secretions from horses with moderate or severe chronic pulmonary disease contained SFD ...
Schott HC, Major MD, Grant BD, Bayly WM.Spinal cord compression by melanomas at C7-T1 is described in 2 horses. Despite similar location of the lesions, the onset of neurologic signs and clinical progression varied. Both horses were gray, but few cutaneous melanomas were found. Internal dissemination, however, was extensive in both horses. Antemortem diagnosis was made in one horse, and surgical decompression of the spinal cord was performed. Neoplasms of the vertebral canal and spinal cord are uncommon in horses. Melanoma in the spinal canal should be included in the differential diagnosis of neurologic disease, especially in matur...
Wilkie DA, Burt JK.Unilateral ocular squamous cell carcinoma in a horse was treated effectively with a combination of repeated radiofrequency hyperthermia and interstitial radiotherapy. These 2 modalities of treatment are synergistic. Interstitial irradiation was achieved, using 198Au implants to deliver a total dose of approximately 5,000 rads/implant over an area of 1 cm2. Radio frequency hyperthermia was repeated 3 times, and radiotherapy was used twice. Treatment resulted in complete regression of the tumor, and ocular complications have not been seen.
Reef VB, Johnston JK, Divers TJ, Acland H.Cholelithiasis and/or obstructive biliary tract disease was diagnosed ultrasonographically in 8 horses, 5 to 15 years old. Ultrasonographic findings revealed greater than normal amount of hepatic parenchyma in the right side of the abdomen in 8 horses and in the left side in 3 horses. The echogenicity of the liver was greater than normal, and thick distended bile ducts were seen in all horses. Choleliths were imaged ultrasonographically in 6 horses. Subsequently, postmortem findings in 6 horses revealed periportal and intralobular fibrosis, moderate bile duct dilatation, proliferation, and cho...
Erickson BK, Erickson HH, Coffman JR.This study investigated changes in packed cell volume (PCV), pulmonary artery and aortic pressures, and the interaction between oesophageal pressure and pulmonary artery and aortic pressures during strenuous exercise in the horse. It was hypothesised that oesophageal pressure changes summate with pulmonary artery and aortic pressures during exercise and contribute to exercise-induced pulmonary haemorrhage (EIPH). Acute treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate (HR) from 50 to 202 beats/min; mean pulmonary artery pressure (PAP) from 28 to 80 mmHg; mean ao...
Lanyon LE.The skeleton consists of a series of elements with a variety of functions. In locations such as the skull, where shape or protection are of prime importance, the bone's architecture is achieved during growth under predominant genetic control. In locations such as the limbs, where the ability to withstand repetitive loading is important, only the general form of the bone will be achieved as a result of growth alone, the remaining characteristics resulting from an adaptive response to functional load bearing. In the horse, this functional load-bearing will be provided by the animal's natural act...
Tajima M, Fujinaga T, Mizuno S, Otomo K.The distributions of phytohemagglutinin-P (PHA) and concanavalin A (ConA) binding sites were investigated for equine, bovine and canine peripheral blood lymphocytes (PBL). Non-B lymphocytes were collected from each PBL using a fluorescence-activated cell sorter (FACS), and the numbers of PHA and ConA binding sites on their surfaces were counted. Most PHA binding sites on PBL of the three species were shown on the surfaces of non-B lymphocytes. On the other hand, the ConA binding sites on equine and canine PBL existed mainly on the surfaces of non-B lymphocytes, but B lymphocytes of these two s...
Adolf GR, Traxler E, Maurer-Fogy I.Equine interferon-beta 1 (EqIFN-beta 1) was purified from extracts of recombinant Escherichia coli by sequential chromatography on hydroxylapatite, anion-, and cation-exchangers. The resulting protein was greater than 98% pure as determined by sodium dodecylsulfate gel electrophoresis, gel permeation HPLC, and reverse-phase HPLC. Amino-terminal amino acid sequencing revealed that essentially all molecules contained an additional amino-terminal methionine. The specific antiviral activity of EqIFN-beta 1 determined on equine dermal fibroblasts challenged with vesicular stomatitis virus (VSV) was...
Yadernuk LM.A 13-year-old broodmare was referred for weight loss and left facial nerve paralysis. Bilateral temporohyoid osteoarthropathy was diagnosed based on proliferation of the temporohyoid joints and stylohyoid bones on radiographs and guttural pouch endoscopy. The left side was more severely affected. Treatment resulted in little or no improvement.
McClure SR, Hillberry BM, Fisher KE.To evaluate in vitro holding power and associated microstructural and thermal damage from placement of positive-profile transfixation pins in the diaphysis and metaphysis of the equine third metacarpal bone. Methods: Third metacarpal bones from 30 pairs of adult equine cadavers. Methods: Centrally threaded positive-profile transfixation pins were placed in the diaphysis of 1 metacarpal bone and the metaphysis of the opposite metacarpal bone of 15 pairs of bones. Tensile force at failure for axial extraction was measured with a materials testing system. An additional 15 pairs of metacarpal bone...
Lemonnier LC, Wolfsdorf KE, Kreutzfeldt N, Fedorka C, Chigerwe M, Bozorgmanesh R.Prognosis for life and future fertility in broodmares following hydrops is reportedly good, but evidence to support these reports is limited. The objective of this case series was to describe the prognosis for survival and fertility in mares presented to a referral hospital following diagnosis of hydrops. Medical records were reviewed to identify mares diagnosed with hydrops. Data collected included history (gestation, sire of the foal), clinical findings at presentation and throughout hospitalization (complications, treatments, survival to discharge) and future foaling rates. Thirty mares wer...
Padjasek M, Cisło-Sankowska A, Lis-Bartos A, Qasem B, Marycz K.The purpose of this study was to describe the use of PLDLA/TPU matrix enriched with cyclosporine A (CsA) as a therapeutic platform in horses with immune-mediated keratitis (IMMK) with an in vitro evaluation CsA release and degradation of the blend as well as determination of the safety and efficacy of that platform used in the animal model. The kinetics of the CsA release from matrices constructed of thermoplastic polyurethane (TPU) polymer and a copolymer of L-lactide with DL-lactide (PLDLA) (80:20) in the TPU (10%) and a PLDL (90%) polymer blend were studied. Moreover, we used the STF (Simul...
Martinez Zuviria S, Ciurkiewicz M, Wohlsein P, Madariaga G, Zuccolilli G.Cystic hygroma (hygroma cysticum) is a malformation that has not yet been described as a cause of early pregnancy loss in equines. The condition is a congenital anomaly occurring during embryogenesis due to a failure in which the primitive lymphatic sac does not reach the venous system at the jugular vein, resulting in a lymphatic stasis that starts in the neck region and continues to the rest of the body. From 2015 to 2020, a total of 5,730 ultrasound examinations were performed in mares from 43 different horse farms and embryo transfer farms when sexing pregnancies. In 12 pregnant mares, a s...
Wellcome open researchOctober 17, 2017
Volume 2 60 doi: 10.12688/wellcomeopenres.12176.2
Wardle R, Pullman JA, Haldenby S, Ressel L, Pope M, Clegg PD, Radford A, Stewart JP, Al-Saadi M, Dyer P, Peffers MJ. Incidental findings of virus-like particles were identified following electron microscopy of tissue-engineered tendon constructs (TETC) derived from equine tenocytes. We set out to determine the nature of these particles, as there are few studies which identify virus in tendons , and their presence could have implications for tissue-engineering using allogenic grafts. Virus particles were identified in electron microscopy of TETCs. Virion morphology was used to initially hypothesise the virus identity. Next generation sequencing was implemented to identify the virus. A pan herpesvirus PCR ...
Johns IC, Miles A.Ultrasound is widely used for evaluating horses with suspected liver dysfunction. Although a change in size is considered suggestive of pathology, no clear guidelines exist to define the hepatic ultrasonographically visible locations (HUVL) in horses. The aim of the study was to describe the HUVL in normal horses and determine whether this is altered by signalment, height, weight and body condition score (BCS). Methods: Prospective observational study. Methods: Bilateral ultrasonographic evaluation was performed in 58 clinically normal horses with no history of hepatic disease. The most crania...
Kasper C, Doran R.A 2-year-old horse with signs of colic, reflux on nasogastric intubation, and large colon distention on transrectal palpation was found to have a leiomyoma involving the duodenum. The mass was excised without penetration of the lumen of the small intestine, and the horse recovered without complications.
Kambayashi Y, Tsuzuki N, Tokushige H, Kusano K.It is desirable to reduce surgery-induced oxidative stress (OS) because it can cause immune suppression and delayed wound healing. Propofol is known to have antioxidant potential and to reduce OS in humans, but there have been no studies of this issue in horses. This study was conducted to evaluate OS under three different propofol administration protocols in Thoroughbred racehorses undergoing arthroscopic surgery with sevoflurane anesthesia. Blood oxidative stress (bOS) and blood antioxidant power (bAP) were used as OS biomarkers. Both bOS and bAP significantly decreased after surgery in all ...
Hinrichs K, Watson ED.Twelve horse mares were used to investigate the effect of phenylbutazone or progesterone administration on uterine tubal motility, as reflected by embryo recovery from the uterus on day 5 after ovulation. Four treatment groups were used: group A (controls), in which uterine flush was performed 7 to 11 days after ovulation; group B (5-day controls), in which uterine flush was performed 5 days after ovulation; group C, in which uterine flush was performed 5 days after ovulation following administration of phenylbutazone (2 g, IV) on day 3; and group D, in which uterine flush was performed 5 days...
Adeyefa CA, Tomori O, Akpavie SO, Awoseyi OA.Thirteen cases of a disease with a low morbidity and very high mortality in horses in Nigeria are described; the disease is characterised by fever (rectal temperature > or = 40 degrees C), generalised muscle spasms, ataxia, increased respiratory and heart rates and terminal lateral recumbency. The illness generally lasts three to five days but durations of 12 to 30 hours have been observed. Laboratory investigations, including histopathology and serology suggest a viral aetiology, possibly an alphavirus of the equine encephalitis group.
Keegan RD, Greene SA, Brown JA, Weil AB, Bayly WM.Six horses were randomly assigned to receive either frusemide (F) (0.5 mg/kg i.v.) or an equivalent volume of saline (S) i.v., 4 h prior to treadmill exercise. Horses were instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP), and diastolic (DAP) carotid arterial pressures, pulmonary artery pressure (PAP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), blood gases, and cardiac output (CO). Plasma (PV) and blood volumes (BV) were measured using 2 injections of Evan's Blue dye. Baseline parameters were recorded while the horse stood quietly. Hor...
Olenchock SA, Murphy SA, Mull JC, Lewis DM.Various work environments in agriculture naturally contain gram-negative bacteria and their endotoxins, which are heat stable, lipopolysaccharide-protein complexes that are integral parts of the outer membrane of gram-negative bacteria (1). Respiratory exposure to endotoxin-containing dusts has been associated with both an acute decline in pulmonary function (2) and chronic lung disease (3) in cotton dust-exposed subjects. Endotoxins can profoundly affect both humoral and cellular mediation systems in humans and experimental animals (4). One biologically active humoral system that is associate...
Rugh KS, Jiang B, Hatfield DG, Garner HE, Hahn AW.Using a recently developed nonlinear algorithm which identifies reference points on left ventricular pressure waveforms and other waveforms, we analyzed heart rate recovery in ponies after strenuous treadmill exercise. Each pony performed exercise tests with and without premedication with atropine methyl nitrate. Resting and exercise heart rates were 54 +/- 3 and 209 +/- 6 beats/min, respectively, without premedication and 85 +/- 8 and 212 +/- 5 beats/min, respectively, following atropine premedication. Post-exercise heart rate recovery without premedication was best described by a biexponenti...
Dyke TM, Sams RA, Thompson KG, Ashcraft SM.To compare pharmacokinetics of eltenac after first and last IV administrations (0.5 mg/kg), using a multiple dosing schedule. Methods: 6 adult mares. Methods: Eltenac (50 mg/ml) was administered IV at a dosage of 0.5 mg/kg of body weight every 24 hours for days 0 through 4. On days 0 and 4, blood samples were collected before, then periodically for 8 hours after eltanac administration. Concentration of eltenac in plasma samples was determined by use of high-performance liquid chromatography. Results: On day 0, median area under the plasma eltenac concentration versus time curve (AUC) was 6.77 ...
Seki N, Tochinai R, Sekizawa SI, Márquez MA, Fukuda K, Ohmura H, Kuwahara M.The Criollo is an Argentine horse breed with a calm temperament. Although its temperament is considered to be related to its neurophysiological characteristics, the details of this are unknown. Therefore, we analyzed the heart rate variability in Criollos as a preliminary study to deepen the neurophysiological understanding of their autonomic function. Electrocardiograms were recorded from Criollos and Thoroughbreds, and the power spectrum of heart rate variability was analyzed. Compared with Thoroughbreds, Criollos showed (i) a significantly higher high-frequency component, which is an index ...
Aceto H, Parente EJ.To validate and then use quarterly earnings to assess racing performance of Thoroughbreds after modified laryngoplasty for treatment of recurrent laryngeal neuropathy Methods: Retrospective cohort study. Methods: Thoroughbred racehorses after modified laryngoplasty (N = 70), and untreated cohorts (N = 210). Methods: Medical (2005-2008) and race records of 70 Thoroughbred racehorses treated by modified laryngoplasty were reviewed. Postsurgery data were collated as the number of starts and the dollar race winnings for each quarter after the date of surgery. Comparisons were made to an untreated ...
McClure SR, Schumacher J, Snyder JR.Three horses were found to have an extensive nasopharyngeal cicatrix that was responsible for respiratory impairment. The cicatrization was diagnosed by use of endoscopy during evaluations of the horses for inspiratory stridor. All 3 horses were treated by endoscope-guided transnasal incision of the cicatrix and were able to resume their previous activities.
Lanz S, Howard J, Gerber V, Peters LM.Little is known about the clinical usefulness in horses of the 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase assay, a biomarker used in other species for the detection of pancreatitis. The main objectives of this study were to evaluate the prevalence of increased DGGR-lipase activity in horses with signs of colic and investigate its association with, and validity to diagnose, underlying gastrointestinal diseases, treatment method (medical or surgical), and outcome (survival or non-survival). Clinical data from 192 horses presented for colic to a teaching h...