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.
Kannegieter NJ.Chronic proliferative synovitis of 27 metacarpophalangeal joints in 16 horses is described. The diagnosis was based on a history of lameness and, or, poor performance, pain on flexion of the metacarpophalangeal joint, the response to intra-articular anaesthesia, and plain and contrast radiography. Radiographic findings included concavity of the distal dorsal metacarpus proximal to the sagittal ridge, and an increase in size of the synovial tissue adjacent to the proximal, dorsal attachment of the joint capsule. Mineralisation of the synovial tissue was present in some joints, and chip fracture...
Clarke LL, Argenzio RA.In contrast to in vivo findings, the equine proximal colon fails to demonstrate significant net absorption of Na+ and Cl- under in vitro conditions. The present study was undertaken to determine if endogenous prostanoids are responsible for this apparent lack of ion transport. Proximal colonic tissues from ponies were preincubated in either normal Ringer solution or in Ringer containing 1 microM indomethacin and studied in Ussing chambers containing these solutions. Untreated colonic mucosa demonstrated negligible Na(+)-Cl- absorption in the basal state. In contrast, indomethacin-treated colon...
Porter JK, Voss KA, Bacon CW, Norred WP.Fusarium moniliforme (FM) is associated with equine leukoencephalomalacia (ELEM) and hepatotoxicities in horses and rats. The neurochemical effects of ELEM-associated corn naturally infected with FM and FM strain MRC 826 were studied in rats. Increases in brain 5-hydroxyindoleacetic acid (5-HIAA, major metabolite of serotonin, 5-HT) and 5-HIAA/5-HT ratios were observed in rats fed the ELEM-FM corn. These rats had reduced body weights (17%, P less than 0.01) and increased brain weight/body weight ratios (14%, P less than 0.01) as compared with controls that were fed commercial corn. Rats fed a ...
Carmel DK, Crisman MV, Ley WB, Irby MH, Edwards GH.We surveyed the whole blood selenium status of a randomly sampled population of horses from 4 contiguous counties in northern Maryland. Two hundred and two horses from 74 farms were sampled. Whole blood selenium levels greater than or equal to 0.100 parts per million (ppm) were considered adequate; blood levels less than 0.100 ppm were considered marginal or deficient. The average blood selenium concentration of the horses sampled was 0.137 ppm, with a standard deviation of 0.041 ppm. Blood selenium concentrations ranged from 0.050-0.266 ppm. Thirty-eight of 202 horses (18.8%) had a selenium l...
Salmon SA, Walker RD, Carleton CL, Robinson BE.A gram-variable pleomorphic bacillus was isolated from the reproductive tracts of 4 mares during routine prebreeding soundness examinations. Using a commercial bacterial identification system, these organisms were identified as Streptococcus acidominimus. However, colonial and Gram-staining characteristics did not support this identification. Subsequent testing indicated the organism was similar to Gardnerella vaginalis. Additional growth and biochemical analysis performed in our laboratory and at the Michigan Department of Public Health and by the Center for Disease Control, Atlanta, Georgia,...
Nyrop KA, DeBowes RM, Ferguson HR, Leipold HW, Wilson JW, Guffy MM.The arterial blood supply to the diaphysis of the radius, and the vascular reaction when three cerclage devices (cerclage wire, Parham-Martin band, and a partially contacting band) were applied 2 cm apart, were studied in six adult ponies. The opposite radial diaphysis served as the control. Ponies were euthanatized at weeks 4 and 8. A centrifugal blood flow pattern was demonstrated by microangiography. Larger numbers of medullary arteries exist in equine than in canine and human long bones. Changes in centrifugal blood supply were not identified beneath any of the cerclage devices.
Eysker M, Boersema JH, Kooyman FN.Two groups of three yearling Shetland ponies were used in 1988 to study the epidemiological significance of inhibited development of the Cyathostomine nematodes. In Group 1, acquisition of infections was prevented throughout the grazing season whereas in Group 2 strongylid infections were acquired from the beginning of July until the end of September. Worm counts showed that the Cyathostomine nematode populations of Group 1 ponies mainly consisted of adult worms and those of Group 2 ponies of inhibited early third stage larvae (L3). These results indicate that a large proportion of Cyathostomi...
Schmall LM, Muir WW, Robertson JT.A comparison of the haemodynamic benefits of small volume hypertonic saline (2,400 mOsm/litre) versus isotonic saline (300 mOsm/litre) was conducted in 12 adult horses using a haemorrhagic shock model. The horses were anaesthetised and intravascular catheters placed for the measurement of haemodynamic data. Mean systemic arterial pressure was then reduced to 50 to 60 mmHg by controlled haemorrhage and maintained at that level for 40 mins. Cardiac output, stroke volume, mean systemic arterial pressure, plasma volume and urine production decreased significantly following blood loss. Hypertonic o...
Welles EG, Prasse KW, Duncan A, Morris MJ.An antigenic assay was developed for determination of protein C in horses. Protein C, a natural, vitamin K-dependent anticoagulant component in blood, was isolated from equine plasma, a specific antibody was produced in goats, and a rocket electroimmunophoresis assay was established. Tests were performed to verify the identity of the isolated protein C and to determine the purity of the antibody. Protein C antigen was measured in plasma from 34 clinically normal horses, and values were compared with amidolytic function values. The mean (+/- SD) values for the 2 test methods were similar (antig...
Carlin JI, Harris RC, Cederblad G, Constantin-Teodosiu D, Snow DH, Hultman E.Treadmill exercise of 2-min duration and increasing intensity resulted in increased formation of acetyl-CoA and acetylcarnitine in working muscle of Thoroughbred horses. At high work intensities a plateau was reached for both acetyl-CoA (approximately 50 mumols/kg dry muscle) and acetylcarnitine (approximately 20 mmol/kg dry muscle). Postexercise concentrations were significantly (P less than 0.001) correlated; [acetylcarnitine] = 349.[acetyl-CoA] + 2.4. The results indicate that approximately 350 mumols acetylcarnitine were accumulated for every 1 mumol acetyl-CoA. Under the conditions of exe...
Bertone JJ, Gossett KA, Shoemaker KE, Bertone AL, Schneiter HL.Cardiovascular responses to sublethal endotoxin infusion (Escherichia coli, 50 micrograms/ml in lactated Ringer solution at 100 ml/h until pulmonary arterial pressure increased by 10 mm of Hg) were measured 2 times in 5 standing horses. In a 2-period crossover experimental design, horses were either administered hypertonic (2,400 mosm/kg of body weight, IV) or isotonic (300 mosm/kg, IV) NaCl solution after endotoxin challenges. Each solution was administered at a dose of 5 ml/kg (infusion rate, 80 ml/min). Complete data sets (mean arterial, central venous, and pulmonary arterial pressures, pul...
Baumgärtner W, Frese K, Elmadfa I.Neuroaxonal dystrophy and minimal diffuse degenerative myelopathy was diagnosed in two female full sibling, 1- and 2-year-old, Haflinger horses. Both animals developed slowly progressive ataxia from the age of 4 months. Clinical signs, which were more prominent in the hind legs, included hypermetria and dysmetria. Histological examination revealed neuroaxonal dystrophy characterized by spheroid formation, vacuolation, astrogliosis and lipofuscin pigment deposition in macrophages and neuronal perikarya. These changes were restricted to the gracilis and cuneate nuclei, nucleus of the solitary tr...
McCabe L, Griffin LD, Kinzer A, Chandler M, Beckwith JB, McCabe ER.The lethal white foal syndrome (LWFS) is a congenital abnormality of overo spotted horses which is a model for human aganglionic megacolon or Hirschsprung disease. Foals with LWFS have an all white, or nearly all white, coat. They also present clinically with an intestinal obstruction that proves fatal within the first few days of life. The LWFS involves both melanocytes and intestinal ganglion cells, and appears to result from a genetic defect involving neural crest cells. This report describes pathologic studies of two recent cases of LWFS. Two different hypothetical models of inheritance of...
The Journal of heredityJuly 1, 1990
Volume 81, Issue 4 323-331 doi: 10.1093/oxfordjournals.jhered.a110997
Sponenberg DP, Carr G, Simak E, Schwink K.The leopard complex of white spotting patterns in horses consists of the leopard, few-spot leopard, blanket, blanket with spots, varnish roan (or marble), snowflake, frosted, speckled, and mottled patterns. Horses with any of these patterns can produce the other patterns when mated to nonpatterned horses. Twenty-two horses of the Welsh Pony, Noriker, Appaloosa, and Pony of the Americas breeds produced 270 foals in a distribution consistent with a single dominant allele being responsible for the patterns. The symbol for this dominant allele, Lp, is retained from previous work on the leopard pat...
Lochner F, Sherban DG, Sangiah S, Mauromoustakos A.Using a modified bovine milk enzyme kinetic assay, xanthine oxidase activity of serum collected from 34 adult, healthy horses of both sexes was determined. Enzyme activity varied from 0 to 126 mU litre-1 with a mean of 44.95 +/- 21.05 mU litre-1. The optimal pH and temperature for maximal activity were 7.8 and 28 degrees C, respectively. Freezing the serum for four days at -70 degrees C did not destroy the enzyme activity. Various doses (25, 50 and 75 micrograms kg-1, intraperitoneally) of endotoxin (lipopolysaccharide D1 Escherichia coli O26:B6) previously known to have caused moderate to sev...
Griffin PG, Ginther OJ.Transrectal ultrasonography was used to quantitate uterine contractile activity during the estrous cycle and early pregnancy in pony mares (nonbred, n = 9; pregnant, n = 16). Continuous 1-min scans of longitudinal sections of the uterine body were videotaped, and uterine activity scores (1=minimal activity, 5=maximal activity) were assigned to each tape segment. There was a tendency (P<0.06) for a main effect of reproductive status (nonbred versus pregnant), a main effect of day (P<0.0001), and a reproductive status by day interaction (P<0.006). Uterine activity scores were higher (P&...
Meschter CL, Gilbert M, Krook L, Maylin G, Corradino R.Phenylbutazone, a non-steroidal anti-inflammatory drug known to produce intestinal erosions, was administered intravenously (13.46 mg/kg bodyweight) to 12 horses which were killed after 24, 48, 72 and 96 h. Eight untreated horses served as controls. Annular erosions in the duodenum and mucosal necrosis in the colon were seen after 48 h which progressed in severity. The erosions were characterised by sloughing of the surface epithelium, subepithelial cleft and bleb formation, necrosis of the lamina propria, degeneration of the walls of subsurface capillaries and microthrombosis. Large numbers o...
Grosenbaugh DA, Amoss MS, Hood DM, Williams JD.A heterologous radioreceptor binding assay (RRA) has been developed capable of detecting nanogram amounts of epidermal growth factor (EGF) receptor-binding activity in equine urine. The binding parameters of [125I]mEGF (murine EGF) to EGF receptors on equine plasma membranes are in good agreement with values from other EGF-RRA systems. The dissociation constant estimated from equilibrium methods (KD = 4 X 10(-10) M) is in reasonable agreement with that determined from the rate constants (KD = 6 X 10(-10) M) and is in good agreement with values determined in other species. The assay is specific...
Echeverría J, Mestorino N, Turic E, Pesoa J, Errecalde JO.This research focused on studying the pharmacokinetics of a drug named Abamectin (ABM) in horses. The goal was to understand how the drug is absorbed, metabolized, and eliminated in the […]
Gallatin LL.Three of 5 horses exercising on L-NAME (NG-nitro-L-arginine methyl ester) exhibited unusual clinical signs towards the end of exercise bouts and post-exercise. L-NAME is a nitric oxide synthase inhibitor which blocks synthesis of nitric oxide from L-arginine. The induced absence of nitric oxide may have lead to the clinical signs observed.
Frerichs WM, Holbrook AA, Allen PC.Twenty Shetland ponies, 6 to 7 months old, were naturally infected with gastrointestinal nematodes and stomach bots. The ponies were allotted to 2 groups of 10 and were maintained on separate similar pastures that were free of infective larvae at the beginning of the study. The ponies in 1 group were treated monthly for 17 months with a therapeutic dose of a thiabendazole and piperazine mixture; those in the other group were not treated. During the 3rd and 5th months of the experiment, the ponies in the treated group were also given therapeutic doses of dichlorvos to remove bots. Various physi...
Poore LA, Duncan N, Williams J.A non-ossified unilateral subcutaneous fibroma was diagnosed in the distal femoral region of a 5-year-old Nooitgedacht mare. Histopathological examination of the excised mass revealed long interweaving bundles of semi-mature monotonous collagenous connective tissue with fusiform nuclei without mitotic figures. The mare made an uneventful recovery following surgical removal of the neoplasm. Subcutaneous fibromas should be considered in the differential diagnosis of skin swellings associated with the limbs of horses.
Steenkamp G, Olivier-Carstens A, van Heerden WF, Crossley DA, Boy SC.Surgical endodontic therapy is a conservative dental technique used in horses with some degree of clinical success. Failure of this procedure can partially be explained by inadequate sealing of the root apices with resultant microleakage in the periapical area. Objective: To assess and compare in vitro sealing ability of 3 different dental restorative materials used as apical sealants during equine surgical endodontics. Methods: Thirty extracted equine cheek teeth were divided randomly into 3 groups and subjected to apicoectomy and apical sealing using 3 materials: reinforced zinc oxide-eugeno...
Sams AE, Honnas CM, Sack WO, Ford TS.Elbows from cadaver limbs were evaluated to determine the presence of a communication between the ulnaris lateralis bursa (ULB) and the joint and the extent of the bursa. Thirty-two pairs of joints were studied: 12 pairs were frozen, then transversely sectioned and 20 pairs were injected with methyl methacrylate. The 12 frozen-section pairs revealed a communication between the ULB and the elbow joint in 9/24 joints (37.5%) and a true bursa (absence of communication) in 15/24 joints (62.5%). The mean bursal length in adult horses was 3.8 cm. There was no significant difference in the length of ...
McParland TJ, Horne CR, Robertson JB, Schnabel LV, Nelson NC.Limited information exists regarding associations between distal interphalangeal joint (DIPJ) abnormalities and synovial invagination changes in the distal sesamoid (navicular) bone. This retrospective, analytical study aimed to measure specific characteristics of the synovial invaginations of the navicular bone to determine whether any single characteristic was associated with abnormalities in the DIPJ or navicular apparatus (NA) using high field MRI and a sample of 200 horses' feet. The DIPJ and NA were graded independently by three scorers. The grades were averaged, creating a global pathol...
Keegan RD, Gleed RD, Sanders EA, Seaman GC, Wertz EM, Short CE.Clenbuterol (0.8 microgram/kg intravenously) was administered to 10 anesthetized horses with an abnormally low PaO2 (less than 90 mm Hg) despite controlled ventilation with an oxygen-rich gas mixture. Results were compared with those from 10 controls to which no clenbuterol was given and in which conventional methods to increase PaO2 were ongoing. Horses treated with clenbuterol had higher PaO2 values for at least 90 minutes. Clenbuterol was associated with increased heart rate and profuse sweating. Clenbuterol can be administered intravenously to increase the PaO2 of mechanically ventilated h...
Hultgren BD, Pearson EG, Lassen ED, Watrous BJ, Hedstrom OR.A conifer twig was responsible for severe fibrinopyogranulomatous adhesive pleuritis and pneumonia in a horse. At necropsy, the twig was found in a terminal bronchus and extended into the lung parenchyma, through the pleura, and into the accumulated exudate. Inhalation of plant material may be a more common cause of pleuritis than previously recognized. Meticulous examination at necropsy would be necessary to make the diagnosis.
Aldrich ED, Earnest J, Moorman VJ.To compare a 2-layer closure with suture line reversal for a pelvic flexure enterotomy to 1-layer and traditional 2-layer hand sewn closures. Methods: Ex vivo, simple randomized study. Methods: Large colon segments from adult horses (n = 18). Methods: Pelvic flexures were harvested from 18 horses and randomly assigned to 1 of 3 closure techniques (n = 6 per technique). A 10-cm enterotomy was made in each pelvic flexure and closed with the assigned technique. Closure time, luminal diameter via contrast radiographs, and bursting pressure were recorded for each specimen and compared betwe...
Kenney RM, Kent MG, Garcia MC, Hurtgen JP.A total of 174 stallions were subjected to a standard fertility examination and classified as fertile, subfertile or sterile. All stallions were phenotypical males involved in breeding programmes with no detectable abnormalities in their reproductive organs. Fertile stallions had no history of any breeding problem. Subfertile stallions were referred with a history of a breeding problem that was subsequently determined not to be attributable to the mares or infectious diseases. They were divided into chromosomally normal and abnormal groups on the basis of karyotype. The relative DNA content of...
Wood TC, White KL, Thompson DL, Garza F.This experiment was designed (1) to determine if H-Y antigen is expressed on the cell surface of pre-implantation equine blastocyst stage embryos, (2) if so, to identify differences in expression on inner cell mass (ICM) verses trophectoderm cells and (3) to evaluate whether the detection of this glycoprotein would aid in the identification of equine embryonic sex. A total of 33 blastocyst stage horse embryos were collected 6-7 days post-ovulation by trans-cervical flush and were immediately evaluated for the presence of H-Y antigen. Additionally, 17 embryos, collected at similar stages and cu...
Fadok VA.This article discusses some new thoughts on the pathogenesis of four unusual equine dermatoses: reticulated leukotrichia, hyper-esthetic leukotrichia, mane and tail dystrophy, and linear alopecia of the Quarter Horse. Although many of the thoughts contained herein are speculative, it is hoped that they stimulate discussion among those of us interested in the wonderful world of equine dermatology. More importantly, it is hoped that they stimulate further investigation and research. These diseases represent only the tip of the iceberg pf what we don't know about equine skin diseases!
Slovis N, Irvin L.Colic is a common presenting complaint in foals. Unfortunately, evaluation of foals with colic can be difficult due to the common clinical presentation of acute abdominal pain attributable to a wide variety of disorders and a broad range of etiologies. Similar to foals, colic is one of the most common diseases of pregnant and periparturient mares. Several conditions are unique or occur more commonly in broodmares. This article reviews the most commonly encountered types of colic events in neonatal foals and periparturient mares, how to correctly diagnose these conditions, as well as details co...
Fitzgerald BP, Peterson KD, Silvia PJ.During the breeding season, the effect of constant administration of an agonist analog of gonadotropin-releasing hormone (GnRH; goserelin acetate) on reproductive activity of mares was determined. Twenty-four mares undergoing estrous cycles were allocated at random to 6 groups (n = 4/group) and, on May 29 (day 0), received no treatment (group 1, controls), 120 micrograms (group 2), 360 micrograms (group 3), 600 micrograms (group 4), or 1,200 micrograms (group 5) of GnRH agonist/d for 28 days via a depot implanted subcutaneously. The final group of mares (group 6) was treated with 120 microgram...
O'Brien RT, Biller DS.Radiography continues to be the initial test of choice in equine dental imaging for reasons of availability and ability to detect bone and tooth changes. Contrast radiography may be useful to characterize dental involvement in cases with draining tracts. For radiographically occult lesions, other modalities are useful. CT is better than plain radiography due to the inherent avoidance of superimposition of the opposite dental arcade, excellent bone density characterization, and good spatial resolution. Nuclear medicine may be useful to verify bone involvement in the dental region in cases in wh...
Hughes KJ, Hodgson DR.The research article discusses the case of a 7-year-old Thoroughbred stallion presenting symptoms such as ataxia, a leftward head tilt and a cloudy left eye, revealing a diagnosis of temporohyoid […]
Okamura K, Sasaki N, Fukunaka M, Yamada H, Inokuma H.The purpose of this study was to determine the pharmacokinetics and dose proportionality of mosapride citrate, a selective 5-HT4 agonist, after oral administration in horses. Seven healthy Thoroughbreds were dosed with distilled water and 0.5, 1.0, or 1.5 mg/kg mosapride citrate through a nasogastric tube. Serum mosapride concentrations were measured by a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method. Mosapride showed the Cmaxs of 31, 60, and 104 ng/g and AUCs of 178, 357, and 566 ng.hr/g at doses of 0.5, 1.0, 1.5 mg/kg, respectively. The Cmaxs and AUCs increased in proporti...
Brown JA, Derksen FJ, Stick JA, Hartmann WM, Robinson NE.To report the effect of unilateral laser vocal cordectomy on respiratory noise and airway function in horses with experimentally induced laryngeal hemiplegia (LH). Methods: Experimental study. Methods: Six Standardbred horses without upper airway abnormalities at rest or during high-speed treadmill exercise. Methods: Respiratory sounds and inspiratory trans-upper airway pressure (P(Ui)) were measured before (baseline) and 14 days after induction of LH by left recurrent laryngeal neurectomy, and again 30, 60, 90, and 120 days after endoscopically assisted laser cordectomy of the left vocal cord...
König HE, Amselgruber W.The microscopic structure of the arteries was investigated in the gastro-intestinal tract of the horse. The median artery was also studied for comparative purposes. The adventitia is responsible for the holding and suspension of the visceral arteries. Disturbances in this system are considered to be a prime factor leading to chronically deficient blood flow. This is associated with pain which is generally classified as colics.
Norby MA, Link RP.Thirty horses were anaesthetized with halothane and thiopental sodium. To determine the hepatotoxic effect of halothane, bromsulphalein (BSP) tests for liver function were made immediately before and 24 hours after anaesthesia and surgery. The periods of anaesthesia varied from 35 minutes to 3 1/2 hours. Results of these tests indicated no significant impairment of liver function 24 hours after anaesthesia, the time at which liver damage due to chloroform, which has a molecular structure similar to that of halothane, has reached its peak
McManamny LF.This research argues for the veterinarians leading the planning and enforcement of disease control measures in thoroughbred stud farms, emphasizing their expertise and knowledge in disease diagnosis and management. Collaboration […]
Carnevale EM, Maclellan LJ, Coutinho da Silva MA, Checura CM, Scoggin CF, Squires EL.Insemination of recipients for oocyte transfer and gamete intrafallopian transfer (GIFT) in five experiments were reviewed, and factors that affected pregnancy rates were ascertained. Oocytes were transferred into recipients that were (1) cyclic and ovulated at the approximate time of oocyte transfer, (2) cyclic with aspiration of the preovulatory follicle, and (3) noncyclic and treated with hormones. Recipients were inseminated before, after, or before and after transfer. Intrauterine and intraoviductal inseminations were done. Pregnancy rates were not different between cyclic and noncyclic r...
Vos NJ, Vos A.A salivary duct fistula in a horse was repaired surgically without using a stent. Seventeen months after the operation the skin incision had healed without complications and the fistula had not recurred.
