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.
Yovich JV, Powers BE, Stashak TS.The intervertebral disks and adjacent vertebral bodies of the 2nd to 7th cervical vertebrae from 17 horses (3 months to 19 years of age) were examined grossly and by light microscopy. In each specimen, the disk tissue was fibrocartilagenous centrally and became more fibrous peripherally, but without a distinct demarcation between the nucleus pulposus and anulus fibrosus. Demarcation between the anulus fibrosus and the dorsal longitudinal ligament was not apparent. With increasing age of the horses, cellularity of the central fibrocartilagenous portion of the disk decreased. The caudal end plat...
Engelking LR, Anwer MS, Lofstedt J.Fasting is associated with unconjugated hyperbilirubinemia in several species, including the horse. Studies in ponies showed that a 3-day fast decreased plasma clearance of bilirubin, cholic acid, and sulfobromophthalein (BSP). Since these organic anions are conjugated with different substrates, it is possible that observed differences in plasma clearance result from a general decrease in hepatic conjugating capacity during the animals' fasting. To test this hypothesis, the effects of a 3-day fast on plasma clearance of IV injected BSP (4.4 to 5.1 mg/kg), which is conjugated to glutathione, an...
Woods WE, Chay S, Houston T, Blake JW, Tobin T.The efficacy of testing for illegal drugs in race horses was surveyed by evaluating 27 questionnaires received from 28 racing jurisdictions polled. Large variations in the number of samples tested and drugs detected were reported. Some jurisdictions reported only illegal medications, whereas others also reported permitted medications. To facilitate comparison, stimulants, depressants, local anesthetics, narcotic analgesics, and tranquilizers were classified as hard drugs. Other drugs, which are legal in some jurisdictions, were classified as soft. To evaluate the efficacy of testing, positive ...
Wyn-Jones G.The value of radiology as part of an examination of the equine head is emphasised and the radiological appearances of more commonly occurring conditions are described. Even the normal anatomy of this complex site is subject to great variation and the aspiring radiologist should, therefore, have a good knowledge of the possible normal variations. A flexible approach must be used rather than a limitation to one or two ritual projections. The use of contrast media, wherever it might be useful, is advocated so that the maximum amount of information may be obtained from each examination. Finally, e...
Wagner PC, Shires GM, Watrous BJ, Kaneps AJ, Schmotzer WB, Riebold TW.Fifteen horses with flexural deformity of the metacarpophalangeal joint were evaluated and their conditions were designated as mild, moderate, or severe. Evaluations were made on the basis of clinical signs and lesions seen on radiography. Horses with mild deformities were treated with corrective trimming and shoeing; those with moderate deformities were treated with desmotomy of the accessory ligament of the deep digital flexor tendon and corrective shoeing. Desmotomies of the accessory ligaments of both deep and superficial digital flexor tendons were performed on horses severely affected, f...
Essén-Gustavsson B, Lindholm A.Muscle biopsies were taken from the middle gluteus muscle of 36 Standardbred horses. Twelve of the horses were inactive, while 24 were actively trained and raced. Twelve of the trained horses were moderate performers, with a mean racing time of 1 min 21 secs per km (741 m/min) and the other 12 were excellent performers, with a mean racing time of 1 min 16 secs per km (789 m/min). The percentage and mean area of Type I fibres were similar in all three groups of horses. Marked differences were found among the subgroups of Type II fibres. The well-trained horses had a higher proportion of Type II...
Mair TS, Lane JG, Lucke VM.The clinical and post mortem features of 11 cases of lymphosarcoma involving the thoracic cavity are reviewed. The clinical findings included inappetence, weight loss, pectoral oedema, dyspnoea, pleural effusion and distension of the jugular veins. Dysphagia was present in three cases. At post mortem examination lesions were found in the abdomen as well as the chest in eight cases; clinical signs of abdominal disease were present in two cases. The features of nine other similar cases recorded in the literature are reviewed.
Brock KA.A pharyngeal performation, probably associated with endotracheal intubation, occurred in a healthy 4 1/2-month-old colt. Inhalation anesthesia was carried out for elective surgery, but acute cervical cellulitis, pleuritis, and pneumonia developed after the surgery. Antibacterial and supportive therapy was ineffective.
Thompson NE, Bergdoll MS, Pattee PA.The factor in normal sera primarily responsible for the enhancement of transfection (and transformation) of Staphylococcus aureus was identified as fibronectin. Serum samples which were depleted of fibronectin by affinity chromatography showed a marked decrease in enhancing activity. Fibronectin isolated from sera of several animal species demonstrated enhancing activity.
Silberzahn P, Dehennin L, Zwain I, Reiffsteck A.Follicular fluid was obtained from equine follicles at different stages of development as determined by ultrastructural study. Gas chromatography-mass spectrometry associated with stable isotope dilution permitted the demonstration of high levels of 4-estrene-3,7-dione and 17 beta-hydroxy-4-estren-3-one, 17 beta-hydroxy-4-estren-3-one levels often being about 10 times higher than those of testosterone. These findings suggest that in the mare ovary, an aromatizing pathway may proceed using these 19-norsteroids as intermediates. As a consequence of this high level of 19-norsteroids, testosterone...
McLean RG, Frier G, Parham GL, Francy DB, Monath TP, Campos EG, Therrien A, Kerschner J, Calisher CH.A study was undertaken to investigate an increase in reported cases of clinical encephalitis due to eastern equine encephalitis (EEE) virus in horses and to determine the natural vertebrate hosts of that virus. Horses, birds, and small mammals were sampled at sites in a contiguous area in St. Joseph and Kalamazoo counties, Michigan, from 25 August to 5 September 1980. Serum samples from four horses acutely ill with encephalitis and 16 of 39 pasture mates of ill horses had neutralizing (N) antibody against EEE virus (46.5%); no viruses were isolated from these 43 sera. None of 24 draft horses f...
Trenfield K, Spradbrow PB, Vanselow B.DNA was extracted from 14 equine sarcoids, electrophoresed and hybridised with a radioactively labelled probe of bovine papillomavirus type I (BPV 1) DNA under conditions of low stringency. Twelve sarcoids contained sequences of DNA that hybridised with the probe and that comigrated with BPV 2 DNA. The viral DNAs in four of these sarcoids differed from BPV 1 and BPV 2 DNA on restriction endonuclease analysis. One of four cell lines derived from sarcoids also contained BPV 1 related DNA. The results confirm the frequent presence in equine sarcoids of unintegrated papillomaviral DNA and suggest ...
Trim CM, Colbern GT, Martin CL.Intraocular pressure was measured with a MacKay-Marg tonometer in eight horses following auriculopalpebral nerve block and topical application of lignocaine. Measurements were recorded before and after xylazine, 1.1 mg/kg intravenously, every two minutes for 16 minutes after administration of ketamine, 2.2 mg/kg intravenously, and after recovery from anaesthesia. Before xylazine, intraocular pressure was 17.1 +/- 3.9 and 18.4 +/- 2.2 mm Hg in the left and right eyes, respectively. Intraocular pressure tended to decrease after administration of xylazine and ketamine, with a significant decrease...
Pipers FS, Reef V, Wilson J.Ventricular septal defects in a foal, a 2-year-old filly, and 2 calves were demonstrated with M-mode and two-dimensional real-time echocardiography. The studies were performed with the animals unsedated, either standing or in lateral recumbency. Cardiac windows were located between the 4th and 7th intercostal spaces, approximately at the level of the olecranon. In each case, the septal defect was visualized high in the membranous portion of the interventricular septum. Defects were visualized by use of sector scanning or linear-array ultrasonic equipment, with transducer frequencies of 2.25 to...
Watney GC, Watkins SB, Hall LW.The pressure flow characteristics of a demand valve which has been suggested to be suitable for use in anaesthetised horses were determined at a range of flow rates commonly encountered in equine anaesthesia. The resistance of the valve was found to be very much greater than the resistance of normal large animal anaesthetic apparatus or the equine lower respiratory tract. The effects of the valve on pulmonary ventilation were investigated in seven anaesthetised, intubated horses. Respiratory rate and dynamic compliance were unaffected by connection of the valve but mean tidal and minute volume...
Colton SW, Downing DT.To observe the time-course of formation of sebaceous lipids in the horse, skin was pulse-labelled in vivo by intradermal injection of [1-14C]acetate and the injection sites were harvested at intervals for up to 12 days by skin punch biopsy. The distribution of radioactivity among the major neutral lipid classes and the phospholipids from these biopsies showed that, soon after pulse-labelling, the phospholipids were highly labelled followed by a long-term decrease in radioactivity. Over the same period, the low initial labelling of the dominant component, the equolides (giant ring omega-lactone...
Halliwell RE, Hines MT.A radioimmunoassay was developed for detection of immunoglobulin in the aqueous of normal horses and horses with intraocular diseases. Levels of albumin were detected by radial immunodiffusion. Results of assays on samples from normal eyes from which aqueous was obtained by paracentesis under anesthesia were 32.10 +/- 21.50 microgram/ml for IgG, 0.05 +/- 0.01 microgram/ml for IgM, 0.04 +/- 0.02 microgram/ml for IgA and 34.0 +/- 38.0 microgram/ml for albumin. Results in 138 normal eyes sampled post mortem were 41.56 +/- 38.65 microgram/ml for IgG, 0.18 +/- 0.43 microgram/ml for IgM, 0.46 +/- 1....
Cremers HJ.The feet of horses, sheep, and goats of different breeds and from many different localities were examined for Chorioptes bovis. In horses, mites were mainly found in the Belgian and Frisian breeds (40% and 62% infected, respectively). In sheep and goats, respectively 63% and 86% were infected. In horses as well as in sheep and goats, mange-lesions were rarely seen. A number of sheep and goats were examined for mites and lesions quantitatively. In sheep all mites were restricted to the region close to the accessory digits and the claws. In goats the average number of mites was higher than in sh...
Liu IK, Pascoe DR, Chang LW, Zee YC.Serum antibody concentrations against influenza A-equi-1 virus and A-equi-2 virus were measured in a group of 18 foals from birth to 4 months of age. More than 50% of the foals were seronegative to A-equi-1 virus infection by 4 weeks of age, with titers of less than or equal to 1:16. For A-equi-2 virus, more than 50% of the foals were seronegative by 2 weeks of age, with titers of less than or equal to 1:8. Passively derived antibodies against influenza A-equi-1 virus and A-equi-2 virus in foals obtained from recently vaccinated mares and from mares not vaccinated within 6 months before foalin...
Tablin F, Weiss L.The equine bone marrow responds to blood loss by increased erythropoiesis, only releasing reticulocytes into the peripheral circulation in severe chronic anemia. We have used morphometric analysis based on electron microscopy of the equine marrow to examine the maturation and release of reticulocytes. Developing red cells in the bone marrows of normal and chronically anemic horses were divided into four stages: early, intermediate, late-stage erythroblasts, and reticulocytes. Morphometric analysis of each stage included volume density of mitochondria per micron3 of cytoplasm, surface area of t...
Muir WW, Robertson JT.The visceral analgesic, cardiorespiratory, and behavioral effects induced by xylazine, butorphanol, meperidine, and pentazocine were determined in 9 adult horses with colic. Colic was produced by inflating a balloon in the horses' cecum. Heart rate, respiratory rate, mean arterial blood pressure, and cardiac output increased after cecal balloon inflation. Xylazine and butorphanol decreased the hemodynamic response to cecal balloon inflation. Meperidine and pentazocine had minimal effects on the cardiorespiratory changes induced by cecal balloon inflation. Xylazine produced the most pronounced ...
McCraw BM, Slocombe JO.The development and pathological effects of Strongylus equinus were studied in 17 pony foals and one horse foal raised in isolation and examined at necropsy from seven days to 40 wk postinfection (PI). Following inoculation of 15000 +/- 6% or 16000 +/- 6% infective larvae by stomach tube foals were monitored for clinical signs and selected blood changes. Larvae penetrated the wall of the ileum, cecum and colon. The molt to the fourth stage occurred mostly in the wall of the ventral colon before 2 wk PI and larvae attained the liver mainly via the peritoneal cavity as early as eight days PI and...
Luckie C, Whitney C, Benoit M, Taddei L, Sukta A, Peterson J, Schwope D, Gaensslen RE, Negrusz A.Cocaine (COC) is a highly addictive plant alkaloid expressing strong psychostimulatory effect. It has no medical use in equine veterinary practice. The contamination of the environment with cocaine such as its presence on the US paper currency has been reported few times. There are anecdotal reports of low benzoylecgonine (BE) concentrations (usually much less than 100 ng/mL) being found in urine of race horses. In order to protect horsemen against harsh penalties associated with the presence of trace amounts of BE in horse urine as a result of environmental contamination, in February 2005 the...
Clark L, Bradley EJ, Mackechnie-Guire R, Taylor A, Ling J.Asymmetry of horses and humans is widely acknowledged, but the influence of one upon the other during horse riding is poorly understood. Riding simulators are popular for education of beginners and analysis of rider biomechanics. This study compares trunk kinematics and saddle forces of 10 experienced riders (ER) and 10 novice riders (NR) performing rising trot on a simulator. Markers were placed on the 4th lumbar (L4) and 7th cervical (C7) spinous processes, and both acromion processes. Displacements in three axes of motion were tracked using 10 high-speed video cameras sampling at 240 Hz. Di...
Del Prete C, Lanci A, Cocchia N, Freccero F, Di Maio C, Castagnetti C, Mariella J, Micieli F.Blood collection by indwelling intravenous catheter (IVC) avoids repeated venipuncture, which could cause thrombophlebitis risk, anxiety and pain in patients. Objective: To compare blood gas parameters, electrolytes, glucose, lactate and haematocrit concentration obtained from venous blood samples collected via a jugular IVC by push-pull (PP) technique to those obtained by venipuncture in hospitalised foals, at the time of catheter placement (T0) and 24 hours after the beginning of intravenous therapy (T24). Methods: Prospective observational study. Methods: Paired blood samples were drawn fr...
Anna M, Łukasz M, Adam O, Chełmońska-Soyta A.The aim of the study was to investigate the mechanisms leading to immunization through the use of a multicomponent bacterial immunomodulator and to find out the relationship between the TLR 4 receptor with selected parameters of innate immunity and to acquire immunity. The study was conducted on 18 Polish Pony Horses foals divided into two study groups: control (n = 9) and experimental (n = 9). Foals from the experimental group received intramuscular duplicate injection of 5 ml of multi-component bacterial immunomodular at 35 and 40 days of age. RNA isolated from venous blood was use...
Dusek J, Skalický J.Changes have been observed in nine foals, six months of age, after weaning for the time of three days, namely in the intake of drinking water, hematocrit, sedimentation of erythrocytes and three minerals Na+, K+ and Cl-. Foals respond to weaning immediately, lowering significantly their consumption of drinking water and increasing high significance of Na+ and Cl-. Changes of level K+, hematocrit and sedimentation don't show any significant variations. The results reached are to be considered as an introductory information for further inquiry on the more extensive methodical basis.
Gebhart W, Niebauer GW.The morphological substrates of pigmented and depigmented skin as well as the structural characteristics of spontaneously developing melanomas were revealed by clinical, light- and electron microscopic methods in gray horses (Lipizzaner breed) from the Vienna Spanish Riding School. On clinical investigations in a group of 31 older horses (more than 10 years old) 20 exhibited melanomas, whereas 23 younger animals (less than 10 years of age) had no evidence for visuable melanotic tumors. Concomitantly with the progressive graying of the hair a depigmentation of the skin was frequently observed. ...
Dumasia MC.The in vivo biotransformation of metoprolol tartrate in the thoroughbred racehorse was studied after administration of a single oral dose. Metoprolol and its basic and bifunctional phase I metabolites were isolated from urine and plasma using mixed mode solid phase extraction (SPE) cartridges. The isolates were derivatised as trimethylsilyl ethers and analysed by capillary column gas chromatography--positive ion electron ionisation and ammonia chemical ionisation mass spectrometry. Metabolism was primarily confined to the oxidative transformations of the p-(2-methoxy)ethyl substituent. Metopro...
Johnson SE, Barshick MR, Gonzalez ML, Riley JW, Pelletier ME, Castanho BC, Ealy EN.Strenuous exercise can cause tissue damage, leading to an extended recovery period. To counteract delayed post-exercise recovery, a commercial product containing L-carnitine (AID) was tested in adult horses performing consecutive exercise tests to exhaustion. Fit Thoroughbreds were administered an oral bolus of placebo (CON) or AID prior to performing an exercise test to exhaustion (D1). The heart rate (HR) and fetlock kinematics were captured throughout the exercise test. Blood was collected before, 10 min and 1, 4 and 6 h relative to exercise for the quantification of cytokine (1, 8, 10, ) g...
Ras-Noryńska M, Sokół R.Infections caused by nematodes of the subfamily Cyathostominae affect nearly 100% of pastured horses. Despite of an absence of pronounced symptoms, cyathostominosis can have very serious health consequences. The aim of this study was to monitor changes in total protein levels and concentrations of selected microelements and macroelements in the blood of horses before and after ivermectin treatment. In healthy horses infected by the studied parasites, total blood protein levels were below the physiological norm, but iron (Fe), magnesium (Mg), calcium (Ca) and phosphorus (P) concentrations were ...
Becht JL, Page EH, Morter RL, Boon GD, Thacker HL.Serological evidence with or without clinical signs of neonatal isoerythrolysis was experimentally produced in 6 of 8 foals born to mares allo-immunized with washed erythrocytes from the stallion. Blood group antigens were determined in all mares, stallions and foals, and the incompatible antigenic factor(s) responsible for the disease were defined. In 5 of 8 foals born to alloimmunized mares, a single antigenic factor difference accounted for the erythrocyte incompatibility between mare and foal. The erythrocyte antigen suspected as the most responsible for isoerythrolysis observed was A1. Ag...
Raeside JI, Gofton N, Liptrap RM, Milne FJ.Direct connection of the artery of a fetal ovary to the carotid artery of the mare allowed collection of a large volume of blood over a 30-min period. Extraction of steroids and their fractionation was followed by separation of the steroids by alumina adsorption chromatography, and Sephadex LH-20 and Celite partition chromatography. Further resolution of the material by HPLC led to the identification of dehydroepiandrosterone (DHA) by nuclear magnetic resonance and mass spectrometry. Other compounds were isolated, which remain to be identified fully, but in the 8th month of pregnancy the princ...
Harkins JD, Robinson NE, Woods WE, Lehner AF, Smith MD, Gates RS, Fisher M, Tobin T.Clenbuterol, a beta2 agonist/antagonist, is the only bronchodilator approved by the US Food and Drug Administration for use in horses. The Association of Racing Commissioners International classifies clenbuterol as a class 3 agent, and, as such, its identification in post-race samples may lead to sanctions. Anecdotal reports suggest that clenbuterol may have been administered by intratracheal (IT) injection to obtain beneficial effects and avoid post-race detection. The objectives of this study were (1) to measure the pharmacological efficacy of IT dose of clenbuterol and (2) to determine the ...
Chatfield JA, Dewell R, Miranda AJ, Wilcox S, Vannieuwenhoven TJ.To describe on-site veterinary medical care for working dogs and horses deployed for the 2012 Republican National Convention (RNC) in Tampa, Fla, August 24 to 30, 2012. Methods: Retrospective case series. Methods: 130 dogs and 45 horses. Methods: Data collected included breed, age, history, task assignment, reason for evaluation, and physical examination findings. A patient encounter report was recorded each time an animal was seen by veterinary staff for a physical evaluation. Results: 46 of the 130 (35%) dogs and all 45 (100%) horses underwent at least 1 on-site veterinary evaluation, for a ...
Atwill ER, Mohammed HO, Lopez JW, McCulloch CE, Dubovi EJ.To locate counties within New York state with a high seroprevalence among the equine population, to determine host, management, and environmental factors that were associated with seropositivity to Ehrlichia risticii, and to determine evidence for arthropod- or helminth-mediated transmission of E risticii to horses. Methods: Cross-sectional study. Methods: A random sample of 3,000 of the 39,000 equine operations in New York state was selected, and 2,587 horses from 511 operations were tested. Methods: Blood samples were collected from horses and tested for seropositivity, using the indirect fl...
Irvine CH, Turner JE, Alexander SL, Shand N, van Noordt S.In mares, dioestrous FSH profiles based on once-a-day sampling are variable; however, the pulsatility of plasma FSH, which has been suggested by limited windows of intensive sampling, may contribute to this variability. Jugular blood from six mares was sampled at 4 h intervals throughout an ovulatory cycle to determine cyclic FSH and LH patterns more accurately and to measure gonadotrophin pulse frequency during dioestrus. Synchronous pulses of FSH and LH occurred regularly in all mares between day 4 and day 12 (ovulation = day 0) with a mean (+/- SEM) frequency of 1.9 +/- 0.1 (FSH) or 1.6 +/-...
Turna Yilmaz O, Gunduz MC, Evkuran Dal G, Kurban I, Erzengin OM, Ucmak M.Doppler ultrasonography is a noninvasive technique which enables us to follow the physiologic and physiopathologic changes in blood flow in tissues. It is becoming an essential tool in veterinary medicine, especially in theriogenology. Twenty-seven Arabian mares were grouped by age ('young', 3-10 y, n=15; 'old', 19-23 y, n=12). The uterine arteries of the mares were examined using Doppler ultrasonography when an ovarian follicle ≥35mm was visible (Day -1). After these measurements, human chorionic gonadotropin (hCG; 2500IU) was administered to 14 mares selected randomly. One day later (Day 0...