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.
Silver M, Ousey JC, Dudan FE, Fowden AL, Knox J, Cash RS, Rossdale PD.Adrenocortical and medullary function was investigated during the immediate post natal period in premature and full term foals. High plasma cortisol concentrations were characteristic of the term foals in the first 2 h after birth and these were accompanied by significant arteriovenous differences in plasma cortisol across the umbilical circulation at birth, indicating enhanced adrenal activity before delivery. No such arteriovenous differences were detected in the premature group and post natal changes in plasma cortisol were minimal. The apparent inability of the premature foal adrenal to se...
McGrath CJ.Respiratory minute volume, blood volume, RBC mass and cardiac output increase while the functional residual capacity decreases during late pregnancy. General anesthetics reach the fetus in high concentrations and tend to persist in the fetus after delivery. Use of small doses of a combination of anesthetics is recommended. Ephedrine increases vascular tone and cardiac output. Glycopyrrolate and fentanyl-droperidol are used to restrain sows for cesarean section. Morphine alone or with acepromazine works well in depressed sows. Acepromazine or xylazine, used with ketamine, is good in restraining...
Bijman J, Quinton PM.The effects of Ca2+, the cyclic nucleotides adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP), and other parameters of sweat secretion from single equine sweat glands were examined in vitro. Extracellular Ca2+, the Ca2+ ionophore A23187, and the Ca2+ channel antagonist verapamil were all without effect on sweat secretion. Prolonged rinsing of the glands in Ca2+-free Ringer solution with 5 mM ethylenediaminetetraacetic acid decreased the secretion to 30% of the control sweat rate in response to the beta-adrenergic agonist isoproterenol; the sweat respon...
Stewart JH, Rose RJ, Barko AM.Simultaneous echocardiograms, phonocardiograms and electrocardiograms were performed on 16 foals at the following times after birth: 15 mins, 60 mins, 2, 4, 12, 24, 48 h, four, seven, 14 days and four, eight and 12 weeks. Positive correlations were found between both age and body weight and the following measurements: left ventricular end-diastolic dimension, right ventricular end-diastolic dimension, left atrial dimension and aortic root dimension, posterior left ventricular wall thickness and interventricular septal thickness. Heart rate was negatively correlated with left ventricular electr...
Irvine CH.Hypothyroidism in the foal occurs as two entities because of the separate actions of thyroid hormones in regulation of metabolic rate and in cell differentiation. The hypometabolic state which results in inadequate thermogenesis and lethargy, occurs concurrently with a period when thyroid hormone secretion is inadequate. Also the severity of the concurrent symptoms is related to the degree of hormone inadequacy as measured by plasma concentrations of free T4 and T3. By contrast, the developmental lesions caused by hypothyroidism are often observed during periods when plasma thyroid hormone con...
Reinemeyer CR, Smith SA, Gabel AA, Herd RP.Fifty-five adult horses were necropsied over a 15-month period, and their worm burdens counted and speciated. Twenty-one species of Cyathostominae were recovered. Ten species: Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus, Cyathostomum coronatum, Cylicostephanus goldi, C. calicatus, C. minutus, Cylicocyclus leptostomus, C. insigne and Cyathostomum pateratum, comprised 98.9% of the total cyathostome burdens. These same 10 species also demonstrated high prevalences in 4 previous surveys. Eight of these 10 species have been shown to be resistant to benzimidazole ant...
Kitzman JV, Wilson RC, Booth NH, Hendricks HL, Bush PB.The pharmacokinetics of 4-aminopyridine (4-AP), a drug capable of antagonizing nondepolarizing neuromuscular blocking drugs, as well as several classes of injectable sedative and anesthetic agents, were studied in 6 intact, awake horses. Plasma samples were assayed for 4-AP over a frequent sampling schedule for 8 hours after IV administration. The plasma 4-AP vs time data best fit a 2-compartment pharmacokinetic model. Distribution half-life was 7.4 minutes, elimination half-life was 259 minutes, volume of the central compartment was 0.89 L/kg, volume of distribution (area) was 1.98 L/kg, volu...
Pascoe RR.Twelve medicaments were tested for their efficacy in the treatment of Trichophyton equinum var. autotrophicum; povidone iodine, thiabendazole ointment, captan ointment and Burroughs Wellcome Ringworm Ointment gave satisfactory results but their usefulness may be limited for treatment of large numbers of horses. Aqueous washes containing 0.5% hexetidine or 0.3% chloramine-T did not prevent fungi being isolated from lesions for up to 7 days after treatment. Similarly neither etisazole nor thiabendazole suspension prevented fungi from being isolated from lesions for up to 15 days after treatment....
Eamens GJ, Macadam JF, Laing EA.Four young horses grazing pastures near industrial plants developed illthrift, lameness and skeletal abnormalities characterised by periarticular enlargement of the long bones. The clinical signs and lesions were attributed to hypocuprosis induced by an excessive intake of zinc from pasture. High pasture intakes of iron may have further compounded the problem.
Stewart DR, Kindahl H, Stabenfeldt GH, Hughes JP.Changes in plasma 15-keto-13, 14-dihydro-prostaglandin F2 alpha were monitored at frequent intervals before, during and after spontaneous deliveries (three mares) and foalings induced by oxytocin (eight mares). No evidence of increased concentrations of the prostaglandin metabolite was observed in the final 10 days of gestation. In spontaneously delivering mares, there was a marked increase from 3 ng/ml at -125 mins to 18 ng/ml at -65 mins to the highest observed value of 182 ng/ml at 20 mins pre-partum. Following delivery, concentrations declined rapidly to around 0.2 ng/ml. Further release o...
Higgins AJ, Lees P, Taylor JB.In a two part cross-over experiment, acute inflammatory exudates were induced in 7 ponies by subcutaneous implantation of 3 sterile carrageenin-soaked polyester sponge strips. Treatment comprised a single therapeutic geenin-soaked polyester sponge strips. Treatment comprised a single therapeutic dose of 4.4 mg/kg phenylbutazone (PBZ) administered intravenously at the time of sponge implantation. Exudates were harvested at 6, 12 and 24 hours and examined for leukocyte and erythrocyte numbers using the improved Neubauer technique; for eicosanoids by radioimmunoassay and by high performance liqui...
Harvey JW, Asquith RL, McNulty PK, Kivipelto J, Bauer JE.Packed cell volume, haemoglobin concentration, erythrocyte counts, erythrocyte indices, serum iron, iron binding capacities, total and differential leucocyte counts, platelet counts, total plasma protein, fibrinogen, haptoglobin and icterus index values were determined at 14 different ages in eight Thoroughbred and 14 Quarterhorse foals during the first year of life. Absolute neutrophil numbers in blood decreased and lymphocyte numbers increased during the first months. Absolute eosinophil numbers tended to increase until three months old. Haemoglobin concentration and packed cell volume decre...
Cochran JD, Amann RP, Froman DP, Pickett BW.Five experiments evaluated the effects of processing, freezing and thawing techniques on post-thaw motility of equine sperm. Post-thaw motility was similar for sperm frozen using two cooling rates. Inclusion of 4% glycerol extender was superior to 2 or 6%. Thawing in 75 degrees C water for 7 sec was superior to thawing in 37 degrees C water for 30 sec. The best procedure for concentrating sperm, based on sperm motility, was diluting semen to 50 x 10(6) sperm/ml with a citrate-based centrifugation medium at 20 degrees C and centrifuging at 400 x g for 15 min. There was no difference in sperm mo...
Orr JA, Fraser DB, Shirer HW, Wagerle LC, DeSoignie RC.Carbon dioxide concentrations were increased during expiration in the upper one-half of the trachea, pharynx, and nasal sinuses to determine if elevation of upper airway CO2 would alter breathing or arterial blood gases in the awake pony. Carbon dioxide (100%) was injected into the midcervical trachea via a chronically implanted transcutaneous cannula during the first part of the animal's expiration. This maneuver elevated upper airway expiratory CO2 concentrations but prevented any exogenous CO2 from entering the lung and being absorbed into the arterial blood. Twelve experiments were perform...
Stewart JH, Rose RJ, Barko AM.Respiratory measurements and blood-gas and acid-base values are reported in nine term induced foals. Measurements were performed at 2, 15, 30 and 60 mins, 4, 12, 24 and 48 h, and four and seven days after birth. Minute respiratory volume was significantly lower at birth than values from 12 h old. Tidal volume peaked at 60 mins old, while respiration rate decreased significantly at 15 mins after birth. Oxygen consumption was high at birth and decreased to its lowest values at 24 and 48 h. The respiratory exchange ratio and ventilatory equivalent showed few significant changes to seven days, as ...
Brown MP, Gronwall R, Kroll WR, Beal C.Five foals from two to three days old were given a single oral dose of ampicillin trihydrate (20 mg/kg bodyweight [bwt]). Serum ampicillin concentrations were measured serially over a 24 h period. The study was repeated in the same foals at 16 to 21 days old. The mean peak serum ampicillin concentration at two to three days old was 5.0 micrograms/ml at 1 h after treatment; the mean peak serum concentration at 16 to 21 days old was 2.7 micrograms/ml at 2 h. The concentrations steadily declined and ampicillin was not detected in the serum from any of the foals by 24 h. Serum clearance averaged 1...
Spehar AM, Hill MR, Mayhew IG, Hendeles L.Pharmacokinetic characteristics of the anticonvulsant phenobarbital were studied in seven pony and two Thoroughbred foals aged between four and 10 days. A single, 20 mg/kg bodyweight (bwt) dose of phenobarbital was given intravenously over 25 mins and the serum concentrations of the drug were measured using an EMIT AED assay (coefficient of variation 1.37 per cent at 30 micrograms/ml, n = 7). Phenobarbital elimination was found to follow first order kinetics. The mean (+/- sd) peak phenobarbital serum concentration was 18.6 +/- 2.1 micrograms/ml at 1 h after initiation of infusion with a mean ...
Beech J.Data were collected from 37 horses with a neurologic disability and compared to a group of 34 normal horses. Affected horses had neuroaxonal dystrophy, gliosis, vacuoles, and sometimes pigment localized to the accessory cuneate nuclei with minimal or no changes in the spinal cord and no changes in the proximal peripheral nerves. The focal nature of the change and usual absence of significant light microscopic spinal cord or peripheral nerve changes are different than previously described equine neuropathologic conditions.
Leadon DP, Jeffcott LB, Rossdale PD.Total calcium, total protein, albumin and globulin content were determined in 49 samples of mammary secretions from 37 crossbred and Thoroughbred mares. The mares were divided into three categories: Group 1--post partum samples from spontaneous full term Thoroughbred deliveries (n = 20); Group 2--pre- and post partum samples from spontaneous full term Thoroughbred deliveries (n = 6); Group 3--pre- and post partum samples from induced premature deliveries in crossbred mares (n = 11). Calcium concentrations of the mammary secretions proved useful in predicting full term and also in assessment of...
Bartels JE, Beckett SD, Brown BG.Serial arteriography was used to determine the vascular pattern and blood flow in the penis of the pony stallion. Ponies were anesthetized with pentobarbital sodium, and catheters were surgically introduced into the internal pudendal and obturator arteries. The vascular anatomy was visualized by angiography via image-intensified fluoroscopy and was recorded on 70-mm film at 3 frames/s or by direct radiography. Blood flow into the corpus cavernosum penis (CCP) was limited during quiescence because the blood was immediately shunted into the venous system. After vasodilation with mild stimulation...
Kosch PC, Koterba AM, Coons TJ, Webb AI.Developments in evaluation of newborn foals with respiratory distress are discussed. Major causes of respiratory distress are outlined and discussed in terms of the similar respiratory signs exhibited by foals with this clinical syndrome. History, physical examination, clinical pathology, chest radiography and blood gas analyses are discussed as important elements of the evaluation of the condition of these foals. Foals with respiratory disease are grouped into three major categories on the basis of clinical signs and arterial blood gas profiles. The evaluation of foals with respiratory distre...
Adams R, Mayhew IG.Behaviour and response to neurological testing of apparently healthy newborn foals differed significantly from the adult in several ways. Foals responded to external stimulation with exaggerated movements although they tended to sink into a relaxed state when restrained. They had a more angular head position and assumed a base wide stance. The menace reflex developed during the first two weeks post partum. In general, the foals' gait was choppy or dysmetric. In lateral recumbency the foals had increased extensor tone, hyperreflexive tendon reflexes, crossed extensor reflexes as well as recumbe...
Sloet van Oldruitenborgh-Oosterbaan MM, Kalsbeek HC.A 14-year-old Friesian breeding mare had strangury, depression, inappetence, neutrophilia and uraemia. Its urine had a low specific gravity and contained protein, blood cells and bacteria. Rectal examination showed that both kidneys and ureters were enlarged. Post mortem examination confirmed the diagnosis of pyelonephritis and revealed that small tumours in the vulva were probably the cause of the uropathy.
Baird AN, Freeman DE.Rectal tears have important medicolegal implications, and severe tears have a poor prognosis. Prompt diagnosis, immediate application of first aid measures, early referral, use of appropriate definitive treatments, and aggressive aftercare will improve the prognosis. The grade of rectal injury will determine the definitive treatment, but there are few guidelines to determine which treatment is best in each case. Bypass procedures, such as colostomy and indwelling rectal liner, have their own advantages and disadvantages, but can facilitate healing and prevent life-threatening complications if ...
Gulevsky AK, Grischenko VI, Tereschenko OS, Shchenyavcky IJ.The experimental data presented in the work testify to the cytostatic activity of 1-10 kD polypeptide fractions from brains of the hibernating ground squirrel and the Yakut horse towards Ehrlich ascitic carcinoma (EAC) cells. The experiments on the investigation of the inhibiting influence of 1-10 kD fractions from tissues of the hibernating and cold-adapted animals on protein-synthesizing system of EAC cells allow us to conclude that the cytostatic effect of the fractions is effected at the genetic level in the tumor cells.
Correa WM.Smears and imprints were made from the liver of 27 equine fetuses, believed to have aborted as a result of Equine Virus Abortion (EVA) infection. Several different fixatives and staining techniques were employed for the demonstration of typical intra-nuclear inclusion bodies in these preparations, and the following conclusions were reached. Methanol proved to be the best fixative and Pappenheim's panoptic method was the best staining technique, giving good contrast and definition of the inclusion bodies. Cytological methods provided a simple and rapid means of diagnosis, but histological secti...
Parkes RD, Colles CM.Fetal electrocardiography (FECG) in the mare has been investigated by several workers (Holmes and Darke 1968, Kanagawa and others 1967). This short paper seeks to evaluate previous work, present new findings, and provide a practical technique enabling veterinary surgeons to diagnose singleton and twin pregnancies in the latter part of pregnancy.
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.
Ellis PM.An accurate modified auscultatory technique for the indirect measurement of arterial pressure in the horse is described. Limitations of the method were sensitivity to external motion in nervous, conscious horses, and the failure to detect Korotkoff sounds in shocked, anaesthetized surgical cases. The apparatus required for the method is expensive and is probably impractical for routine monitoring during anaesthesia.
May SA, Hooke RE, Lees P.The presence, in equine synovial fluid, of inhibitors of interleukin-1 (IL-1) activity has been investigated by means of an assay involving IL-1-mediated production of PGE2 by synovial cells. Inhibitors of IL-1 alpha and IL-1 beta were identified in normal synovial fluid and synovial fluid from two horses with early joint disease. Inhibitors of IL-1 alpha were also present in synovial fluid from two horses with long-standing joint disease. However, IL-1 beta inhibitory activity was not present in fluid from the horses with more chronic joint disease. The effect appeared to be specific for IL-1...
Cook G, Papich MG, Roberts MC, Bowman KF.To determine the i.v. pharmacokinetics of cisapride and measure systemic absorption after rectal administration. Methods: 5 healthy adult mares (380 to 610 kg). Methods: Cisapride was administered, i.v., at a dosage of 0.1 mg/kg of body weight. In the same horses, after a 1-week washout period, cisapride was administered rectally at a dosage of 1 mg/kg by mixing crushed tablets with propylene glycol and administering the mixture into the rectum. After each drug administration, a series of blood samples were collected. Plasma was obtained and analyzed by high-performance liquid chromatography t...
Pihl TH, Jacobsen S, Olsen DT, Højrup P, Grosche A, Freeman DE, Andersen PH, Houen G.OBJECTIVE To purify and characterize equine vitamin D-binding protein (VDBP) from equine serum and to evaluate plasma concentrations of VDBP in healthy horses and horses with gastrointestinal injury or disease. ANIMALS 13 healthy laboratory animals (8 mice and 5 rabbits), 61 healthy horses, 12 horses with experimentally induced intestinal ischemia and reperfusion (IR), and 59 horses with acute gastrointestinal diseases. PROCEDURES VDBP was purified from serum of 2 healthy horses, and recombinant equine VDBP was obtained through a commercial service. Equine VDBP was characterized by mass spectr...
Suarez-Fuentes DG, Caston SS, Tatarniuk DM, Kersh KD, Ferrero NR.Contaminated or septic navicular bursitis has been reported to have a guarded prognosis after surgical treatment with navicular bursotomy only. In our experience, the use of navicular bursotomy for the treatment of this disease in combination with systemic and local delivery of antimicrobials can provide a good prognosis, even in horses with chronic disease. Objective: To report the outcome of horses undergoing navicular bursotomy for the treatment of contaminated or septic navicular bursitis. Methods: Descriptive case series. Methods: Navicular bursotomy was performed in combination with syst...
Liggett AD, Weiss R, Blue JL.Myospherulosis was diagnosed in a mature pony. Several parent bodies containing many spherules were observed microscopically in biopsy material from an area of cellulitis. The spherules are altered red blood cells that form as the result of prolonged contact with necrotic fat or petrolatum-based ointments. These structures must be differentiated from fungal elements. The recommended treatment is surgical excision.
Vermedal H, Strand E.To report dynamic laryngeal collapse (DLC) associated with poll flexion as a potential complication of the laryngeal tie-forward procedure (LTFP) in harness racehorses. Methods: Short case series. Methods: Three harness racehorses. Methods: Preoperative and postoperative medical records of all harness racehorses that underwent the LTFP were reviewed, as were high-speed treadmill videoendoscopy recordings of 35 horses that returned for upper airway evaluation postoperatively. Results: One standardbred and two Norwegian coldblooded trotters in which dorsal displacement of the soft palate had bee...
Martin GS, Strand E, Kearney MT.To determine the relationship between prediction errors of a regression model of racing finish times and earnings or finish position; the relationship between standardized finish times, determined by use of this model, and earnings or finish position; and whether this model was valid when applied to data for horses that underwent surgical treatment. Methods: Survey. Methods: Records of 6,700 healthy Thoroughbreds racing in Louisiana and of 31 Thoroughbreds with idiopathic left laryngeal hemiplegia that underwent surgical treatment. Methods: Predicted and standardized finish times were calculat...
Barber SM, Panizzi L, Lang HM.To evaluate arthrodesis as a treatment for carpometacarpal joint osteoarthritis (CMC-OA). Methods: Case series. Methods: Horses (n=12) with CMC-OA. Methods: Arthrodesis was facilitated by insertion and fanning of a drill bit into the CMC joint at several (3-5) locations in 15 limbs. Follow-up radiographs were obtained for 7 horses (9 limbs). Outcome was determined by telephone survey of owners based on postoperative pain, return to use, appearance of the limb, and success of treatment. Results: Postoperative pain was slight or moderate in 10 of 12 (83%) horses during the first 30 days, and 11 ...
Timoney PJ.The usefulness of the double immunodiffusion test for the diagnosis of louping ill infection was investigated. Whereas louping ill viral antigen was not detected in brain material from field cases of the infection, its presence was readily confirmed in suckling mouse brain isolates of the virus. The double immunodiffusion test was found to be unreliable as a serological test for the retrospective diagnosis of louping ill infection in the horse.