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.
Tate LP, Sweeney CL, Bowman KF, Newman HC, Duckett WM.Transendoscopic neodymium:yttrium-aluminum-garnet (Nd:YAG) laser was used to treat 12 standing horses with epiglottic entrapment (EE) or dorsal displacement of the soft palate (DDSP), or both. In four horses, transendoscopic laser staphylectomy was performed. The most common presenting complaints were respiratory stridor, cough, and exercise intolerance. Ten horses with EE healed without epiglottic complications; in one horse, partial adhesion of the aryepiglottic fold to one side of the epiglottis was corrected surgically through a laryngotomy incision. One horse with DDSP had no further sign...
De Geest JP, Lauwers H, Simoens P, De Schaepdrijver L.The present investigation of 20 equine eyes shows that the iridocorneal angle of the horse is characterised by a very distinct pectinate ligament and a large ciliary cleft. The pectinate ligament consists of long and broad pigmented trabeculae which form a firm, flat and dense network that encircles the eye. On meridional sections, the ciliary cleft is visible as a wide triangular space comprising the trabecular meshwork which consists of two parts. The inner part is the larger and forms a three-dimensional network of large pigmented trabeculae with very wide intertrabecular spaces. The outer ...
Taylor PM.Doxapram, 0.05 mg/kg bodyweight/min, was infused during the second hour of 2 h halothane anaesthesia in six ponies. Two of the ponies were anaesthetised on a second occasion as controls and given 5 per cent dextrose in place of the doxapram. Respiratory depression typical of halothane anaesthesia in ponies developed in the first hour of anaesthesia and continued during the second hour in the control animals. During doxapram infusion arterial carbon dioxide tension decreased and pH increased. Arterial blood pressure increased but there was no change in pulse rate, the electrocardiogram or arter...
Donaldson WL, Zhang CH, Oriol JG, Antczak DF.Monoclonal antibodies and alloantisera were used in an indirect immunohistochemical assay to determine the expression of class I and class II Major Histocompatibility Complex (MHC) antigens by equine placental cells and the endometrial tissues at the fetal-maternal interface. MHC class I antigens were expressed at high density on the surface of the trophoblast cells of the chorionic girdle at days 32-36, just prior to their invasion of the endometrium. The mature gonadotrophin-secreting cells of the endometrial cups, which are derived from the chorionic girdle cells, had greatly reduced levels...
Sukhova GS, Ignat'ev DA, Akhremenko AK, Levashova VG, Mikhaleva II, Sviriaev VI, Anufriev AI, Ziganshin RKh, Kramarova LI, Gnutov DIu.From tissues of hibernating and active long-tailed ground squirrels and from the brain of cold-adapted Yakut horses, low molecular peptide fractions were obtained which, after injection to albino mice, decreased oxygen consumption and rectal temperature in them. The same fractions exhibited negative chrono- and inotropic effects on isolated hearts of ectothermic and endothermic animals. Fractions from the brain of ground squirrels and the brain of horse exhibited similar pattern of the activity. The activity of fractions was subjected to seasonal changes and depended on the degree of their pur...
Milne EM, Doxey DL, Gilmour JS.The analysis of peritoneal fluid is of value in the differential diagnosis of equine colic but its characteristics have not been evaluated in grass sickness. Peritoneal fluid was collected from 15 normal horses and from 11 cases of medical colic, 11 cases of surgical colic, 20 cases of acute grass sickness and 13 cases of subacute grass sickness. The fluid was analysed for its appearance, total and differential white cell count, specific gravity, total protein concentration and total and intestinal alkaline phosphatase activity. Fluid from cases of medical colic was normal in these respects. S...
Mironneau J, Martin C, Arnaudeau S, Jmari K, Rakotoarisoa L, Sayet I, Mironneau C.Saturable, high-affinity binding sites for [3H]saxitoxin were identified in equine portal vein smooth muscle membranes. These sites had a dissociation constant of 0.29 nM and a maximal binding capacity of 115 fmol.mg-1 of protein. A similar dissociation constant was obtained with cells prepared from rat portal vein. Specific binding of [3H]saxitoxin was completely displaced by unlabelled saxitoxin and tetrodotoxin, with inhibition constants of 0.42 and 2.10 nM, respectively. Tetrodotoxin blocked the fast Na+ current in single cells of rat portal vein in a concentration-dependent manner, with a...
Holt PE, Mair TS.Bladder paralysis and sabulous urolithiasis were diagnosed in 10 horses with urinary incontinence. Additional neurological deficits in the hindquarters were detected in five of them. Treatment by catheter drainage and bladder lavage was unsuccessful, and all the horses were destroyed within 14 months of presentation. Neuritis of the cauda equina was diagnosed post mortem in one horse, but the cause of the paralysis was not identified in the others, although radiography revealed abnormal lumbosacral vertebral angulation in one case.
Singh AK, McArdle C, Ashraf M, Granley K, Mishra U, Gordon B.Equine plasma and urine samples were analyzed by using a high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA) and particle concentration fluorescence assay (PCFIA). Although ELISA and PCFIA were rapid, simple and sensitive for the screening of furosemide, they did not give reproducible quantitative results. The HPLC method, which required relatively longer analysis time, provided simple and reproducible quantitative analysis of furosemide in plasma and urine. The performance of the three methods was compared for the quantitation of furosemide in plasma obtai...
Kohn CW, Jacobs RM, Knight D, Hueston W, Gabel AA, Reed SM.At birth, 24 Standardbred foals were assigned at random to 1 of 2 groups and were given a placebo supplement (group 1) or an iron supplement (248 mg of iron/treatment; group 2). Foals were given iron supplement or placebo 4 times during the second and third weeks after birth. Hematologic variables and general health were monitored until foals were 4 months old. Mean PCV in foals of both groups decreased during the first 2 weeks after birth, but values remained within adult horse reference ranges. During the first 6 weeks after birth, foal erythrocytes were smaller than adult horse erythrocytes...
Hamada M, Itakura C.The morphology of hypomelanosis occurring in experimentally induced equine papillomas was investigated. Histologically, dopa-positive functioning melanocytes were decreased in number from the basal layer in the epidermis. Electron-microscopically, melanogenic organelles in the melanocytes were degenerate and melanosomes were decreased in number and size. In addition, the melanocytes had some abnormal melanosomes including melanosome complexes and giant melanosomes. Some abnormal melanosomes were also present in the keratinocytes. The hypomelanosis seemed to be related to a disturbance in melan...
Lalatta Costerbosa G, Barazzoni AM, Clavenzani P, Callegari E.In this study the histochemical fiber type analysis of the articularis humeri muscle of the horse was performed. This muscle is composed of type I and type IIA fibers. A large number of spindles has been observed and the presence of these receptors could help to understand the role played by this muscle.
Cuvelliez SG, Eicker SW, McLauchlan C, Brunson DB.Anesthesia of equids is associated with pulmonary dysfunction. Cardiovascular and respiratory effects of inhalation anesthetic agents and duration of anesthesia have been studied, using oxygen as the carrier gas. To our knowledge, the effects of inspired oxygen have not been determined. We studied the cardiovascular and respiratory effects of 2 inspired oxygen fractions (0.30 and greater than 0.85) in 5 laterally recumbent, halothane-anesthetized horses. Mean systemic arterial blood pressure, cardiac output, central venous pressure, pulmonary arterial pressure, arterial pH, and arterial base e...
Lawrence LM.Substrate depletion and end product accumulation are two important factors in exercise fatigue. Fatigue during long-term exercise results from a depletion of muscle and liver glycogen and coincides with an inability to maintain blood glucose levels. During high intensity exercise, the rapid catabolism of carbohydrate and the resultant production of lactate and hydrogen ions cause a reduction in muscle pH that inhibits maximum force generation. Dietary manipulations that can influence carbohydrate status or lactate accumulation may be beneficial to performance. In human athletes, carbohydrate l...
Bürki F, Rossmanith E.Selected sets of serum samples of horses were tested blindly in a comparative investigation for antibodies against Equine Infectious Anemia (EIA) virus. Three commercial kits were used, a well-established agar-gel immuno-diffusion kit which our laboratory has been using routinely for 14 years on one hand, a competitive ELISA kit (CELISA) and a non-competitive ELISA kit on the other hand. The American EIA Reference Laboratory in Ames cotested 56 serum samples with the same 3 products, with highest-level correlation, thereby ascertaining full dependability of our own results. Five EIA experts su...
Ekfalck A, Appelgren LE, Funkquist B, Jones B, Obel N.The distribution of 35-S-labelled cysteine and methionine in the epidermis of the equine hoof following 2 hours of intra-arterial injection was studied by microautoradiography. Material for autoradiography was obtained by biopsy about 1 hour after termination of the intra-arterial injection and also 10 and 40 days later. In the specimens obtained one hour after the injection of labelled cysteine and methionine, the amount of radioactivity in the matrix and in the most proximal part of the laminar layer was very high. There was a clear difference between the distribution of the two labelled ami...
Clarke LL, Roberts MC, Argenzio RA.The association of feeding practices with the development of digestive disorders in horses has long been recognized, although the underlying mechanisms had been barely considered. The physiologic consequences of meal frequency may help to explain the relationship and prove to be of major significance in the induction of many conditions. Many Equidae kept for performance and leisure activities are fed high-energy, low-forage rations twice daily, with limited access to hay or grazing. Rapid ingestion of such meals stimulates a copious outpouring of upper alimentary secretions and results in tran...
Jasko DJ, Lein DH, Foote RH.The analysis of breeding records and sperm morphologic classifications from ejaculated semen during 99 stallion seasons, over a 2-year period, revealed a significant correlation (r = 0.34, P less than 0.01) between the percentage of morphologically normal sperm in ejaculates and the per cycle fertility estimate of the stallions studied. In addition, the percentage of sperm classified as having major defects (abnormal heads, proximal droplets, and abnormal midpieces) was significantly inversely correlated (r = -0.36, P less than 0.01) with the same fertility estimates. Multiple variable regress...
Houpt KA.In summary, horses spend 60% or more of their time eating when grazing or when feed is available free choice. Grasses are their preferred food, but they supplement the grass with herbs and woody plants. Sweetened mixtures of oats and corn are the most preferred concentrate. Horses can increase or decrease the time spent eating and amount eaten to maintain caloric intake. Their intake is stimulated by drugs such as diazepam and by the presence of other horses. Horses stop eating when gastric osmolality increases; increases in plasma osmolality, protein, and glucose accompany digestion. Foals ea...
Donoghue S, Meacham TN, Kronfeld DS.Cumulative nutritional demands on good brood mares are unrivalled among domestic livestock, but little attention has been given to the influence of nutrition on their reproductive performance and efficiency. We suggest that part of the decline in racing performance of progeny of mares over 10 years of age may be caused by suboptimal nutrition. This article contrasts the concepts of minimal and optimal nutrient requirements, revives Hammond's concept of nutrient partitioning to the conceptus and mammary gland, and discusses energy and nutrient requirements during gestation and lactation. Furthe...
Schryver HF.Horses are subject to poisoning from many sources. This article considers poisonings from minerals and vitamins of nutritional significance and from minerals as environmental contaminants.
Szczerba-Turek A, Bancerz-Kisiel A, Lipczyńska K, Siemionek J, Raś A, Platt-Samoraj A, Szweda W.The aim of the study was to evaluate a novel diagnostic scheme which combines quantitative PCR and High-Resolution Melting (qPCR-HRM) curve analysis for rapid differentiation based on E5 partial CDS of bovine papillomavirus type 1 or 2 (BPV-1 or BPV-2), and to perform a phylogenetic analysis of the complete CDS of the E5 gene of BPV detected in equine sarcoids. Samples of 38 skin lesions obtained from 27 horses were collected for molecular examinations. All lesions were clinically diagnosed as sarcoids, but results of histopathological examinations did not always corroborate the clinical diagn...
De Bastiani G, La Côrte FD, Azevedo MDS, Jacobsen TK, Kommers GD.Articular degeneration can be characterized by fibrillation and eburnation of the articular layers of the metacarpophalangeal (MP) joint. Structural changes within the articular joint predispose the development of osteophytes, enthesophytes and, in many cases is associated with changes the collateral ligaments of the MP joint. The aim of the present study was to investigate the relationship between degenerative processes of the articular cartilage and the enthesopathies of collateral ligaments (superficial or deep portion) of the equine MP joint, using radiographic, ultrasonographic and anatom...
Frayne J, Stokes CR.The quantity and distribution of MHC Class II positive cells and T cells in the equine endometrium was investigated throughout the oestrous cycle. Significantly more MHC Class II positive cells were detected in the stratum compactum and stratum spongiosum of endometria from naturally cycling mares during the follicular than during the luteal phase of the oestrous cycle. Significantly more T cells were also detected in the stratum compactum, but not stratum spongiosum, of these mares during the follicular phase. Furthermore, there was a marked increase in the number of MHC Class II positive cel...
Allen WE, Ayliffe TR.Endometrial concentrations of sodium benzylpenicillin were determined in biopsy samples from anoestrous pony mares after intramuscular administration of the penicillin at 22,000 iu/kg. Serum samples, collected at the same time as biopsies, were also assayed for their penicillin content. In experiment 1 a single pair of blood and tissue samples was taken from each mare between five and 360 minutes after injection. In experiment 2 each mare was sampled consecutively six times (between five and 300 minutes) after injection. Both serum and endometrial concentration reached a peak between 15 and 30...
Lettry V, Sumie Y, Mitsuda K, Tagami M, Hosoya K, Takagi S, Okumura M.The objective of this study was to investigate the changes in synovial fluid concentration of collagen type II cleavage site (C2C) and procollagen II C-propeptide (CPII), markers of joint cartilage degeneration and synthesis, respectively, in horses with intraarticular fracture or osteochondrosis dissecans (OCD), and to examine the relationship between arthroscopic findings and these biomarker levels. Synovial fluid was collected from 36 joints in 18 horses (6 fractures and 12 OCDs). Samples from contralateral normal joints, when available, served as controls (n = 12). Concentrations of C2C an...
Andraus MH, Siqueira ME.An analytical procedure to screen butorphanol in horse race urine using ELISA kits and its confirmation by GC-MS is described. Urine samples (5 ml) were subjected to enzymatic hydrolysis and extracted by solid-phase extraction. The residues were then evaporated, derivatized and injected into the GC-MS system. The ELISA test (20 microl of sample) was able to detect butorphanol up to 104 h after the intramuscular administration of 8 mg of Torbugesic, and the GC-MS method detected the drug up to 24 h in FULL SCAN or 31 h in the SIM mode. Validation of the GC-MS method in the SIM mode using nalbup...
Kuchembuck NL, Colahan PT, Zientek KD, Pirman DA, Wegner K, Cole CA.To determine the durations of the local anesthetic effect and plasma procaine concentrations associated with 5- and 10-mg doses of procaine hydrochloride (with or without 100 microg of epinephrine) administered SC over the lateral palmar digital nerves of horses. Methods: 6 healthy adult horses. Methods: The hoof withdrawal reflex latency (HWRL) period was determined by use of a focused heat lamp before and after administration of procaine with and without epinephrine. Blood samples were collected immediately before determination of each HWRL period to assess plasma concentrations of procaine ...
Meredith TB, Dobrinski I.To determine whether thyroid function was associated with pregnancy status in broodmares. Methods: Prospective study. Methods: 79 Thoroughbred and Standardbred broodmares between 2 and 22 years old. Methods: Serum triiodothyronine (T3) concentration was measured before and 2 hours after i.v. administration of thyrotropin releasing hormone (TRH), and serum thyroxine (T4) concentration was measured before and 4 hours after TRH administration. Pregnancy status was monitored by means of transrectal ultrasonography beginning 16 days after ovulation. Results: Baseline T3 and T4 concentrations varied...
DRUDGE JH, LELAND SE, WYANT ZN, ELAM GW, HUTZLER LB.In five horses dosed with polymethylenepiperazine at dose levels of 21, 51 or 106 mg. per Ib. body-weight clearance of ascarids was obtained with all dosages. The effect against oxyurids was much less marked and large numbers of immature worms were found at autopsy four days after treatment. About 85% of small strongyles were removed at dosages of 21 mg. per Ib. and above and about 50% of Strongylus vulgaris were removed at dosages of 51 mg. per Ib. and above. The drug was inactive against S. edentatus, Trichostrongylus axei, Habronema muscae and Strongyloides westeri. In another eight horses ...
Villasmil DP, De Siger J, Barrientos MP, Mussgay M, Mackenzie RB.
Summary
Seven donkeys were immunized with a Venezuelan equine encephalitis virus vaccine which had been prepared by inactivation of the virus with formalin and Tween-80-Tri(n-butyl)phosphate and addition of saponin. Fourteen days later they, and four non-vaccinated controls, each received 50,000 suckling mouse intraperitoneal LD50 units of challenge virus. None of the seven immunized donkeys demonstrated signs of clinical illness or viremia. Of the four non-vaccinated controls, all became ill and one died. These results suggest that more extensive experiments might well be carried out on ...
Mathison PT.This article describes the etiology, clinical signs, diagnosis, and treatment of various equine nodular diseases. Although of different etiologies, this group of diseases shares a common histologic reaction pattern characterized by infiltration of eosinophils and collagen degeneration. Collagenolytic granuloma, axillary nodular necrosis, unilateral papular dermatosis/eosinophilic folliculitis, amyloidosis, habronemiasis, and mast cell tumors are discussed.
Smanik LE, Selberg KT, Mason GL, Brock M, Stewart HL, Goodrich LR, Kawcak CE.To perform a pilot study with the intent of assessing the feasibility of a modified subchondroplasty (mSCP) technique in a validated preclinical equine model of full-thickness articular cartilage loss and evaluate the short-term patient response to the injected materials. Methods: 3 adult horses. Methods: Two 15-mm-diameter full-thickness cartilage defects were created on the medial trochlear ridge of each femur. Defects were treated with microfracture and then filled by 1 of 4 techniques: (1) autologous fibrin graft (FG) via subchondral injection of fibrin glue (FG), (2) autologous fibrin gra...
ROBERTS SR.The research article explores the origin or causation (etiology) of an ancient horse disease known as equine periodic ophthalmia, where clinical and pathological investigations have yet to yield conclusive results. […]
Tomlinson F, Terschuur J, Henson F.Soft tissue injuries and joint disease are the predominate causes of lameness in the equine athlete and these pathologies carry a guarded prognosis for a return to previous performance. Recently the use of autologous products has become more widespread as a treatment in equine sports medicine. However, the efficacy of these products is yet to be fully established. To evaluate the current published evidence base regarding the efficacy of autologous products in soft tissue injuries and joint disease. A systematic review of English articles using MEDLINE, EMBASE and Web of Science databases from ...
The study investigates the case of an Australian Quarter Horse suffering from Polysaccharide Storage Myopathy (PSSM), a muscular disease commonly seen in Quarter Horse breeds, Warmbloods, and draft horses. This […]
Hopper SA, Schneider RK, Johnson CH, Ratzlaff MH, White KK.To compare transfixation and standard full-limb casts for prevention of in vitro displacement of a mid-diaphyseal third metacarpal osteotomy site in horses. Methods: 6 forelimbs from 6 horses euthanatized for reasons not related to the musculoskeletal system. Methods: A 30 degrees osteotomy was performed in the mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the osteotomy site to maintain alignment during casting. Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the radius. A full-limb cast that inc...
McCarthy PH.A detailed description is given of the methods to locate and palpate a subcutaneous part of the zygomatic branch of the auriculopalpebral nerve in 9 out of 10 adult horses examined. This permits the exact placing of local anaesthetic along the nerve branch at the described site, resulting in the akinesis of the m orbicularis oculi and the elimination of the blink reflex. This facilitates ophthalmologic examination and possible treatment of some eye conditions.
Natalini CC, Robinson EP.To evaluate the effects of long duration subarachnoid catheterization in horses on cerebrospinal fluid (CSF) cellularity and bacteriology, arterial blood pressure, heart rate, respiratory rate, rectal body temperature, and spontaneous locomotor activity. Methods: Prospective experimental study. Methods: Five clinically normal healthy adults horses weighing 511 +/- 47 kg. Methods: Subarachnoid catheters were placed using sedation and local anesthesia and maintained for 48 hours in standing horses. Cerebrospinal fluid samples were tested for cellularity and bacteria growth. Heart rate, respirato...
Shepherd GE, Findlay JK, Cooper MJ, Allen WR.A clinical trial involving 359 mares was conducted to ascertain the clinical value of a synthetic prostaglandin analogue (fluprostenol, ICI-81,008) structurally related to PGF2oc for treating mares in prolonged dioestrus. Some 263 mares (73.3%) displayed oestrus within 5 days of a first intramuscular injection of 250 mug fluprostenol and, of those mares later examined for pregnancy, 108 (40%) were found to have conceived during the first induced oestrus. A further 21 mares (8%) cycled normally and conceived to services during the second oestrus. Most (80.3%) of the plasma samples obtained from...
Thornton JR.In the athletic horse, an exercise test may be required to measure the adaptation of the animal to a specific training program; to modify the training program in response to the progress achieved; to investigate the reasons for failure to perform at the expected level; and to form part of an overall clinical examination of a horse with a specific disability. This article includes information on the scope and form of an exercise test, the parameters measured during the test and their interpretation, treadmill and track tests, and the clinical applications of exercise tests.
Schnorr B, Wille KH.Summary. The activities and localization of a lysosomal acid phosphatase and of a Mg++- and Ca++-activated ATPase were shown in the pars proventricularis epithelium of the horse stomach using cytochemical methods and the light and electron microscopes. Activity of the non-specific alkaline phosphatase was exclusively demonstrated on the subepithelial vessel loops of the papillae occultae.
The activityof ATPases gradually decreased from the stratum basale to the stratum super- ficiale. Reaction intensity was optimal after 45 rain and did not increase further. An increase of the Mg++-activated ...
Lewis D, Scott M, Fischer CD, Bond SL, Léguillette R.Desmitis of the collateral ligament of the distal interphalangeal joint is a cause of lameness in performance horses. The objective of this prospective, experimental, ex vivo feasibility study was to evaluate the success of ultrasound-guided injection of the collateral ligaments of the distal interphalangeal joint in the equine forelimb. Seventy-six ultrasound-guided dye injections of the collateral ligament of the distal interphalangeal joint were performed on horses' cadaver limbs. The hooves were sectioned transversely to verify the location of the dye relative to the collateral ligaments a...
Lees P, Dawson J, Sedgwick AD.The research article investigates the role of chemicals called eicosanoids, particularly prostaglandin E2 (PGE2) and leukotriene B4 (LTB4), in the movement of certain cells, polymorphonuclear and mononuclear leucocytes, during inflammation […]
Shideler RK, Squires EL, Pickett BW, Anderson EW.Twenty-three geldings were used to determine changes in seminal characteristics following castration and the effect of frequency of ejaculation on these seminal characteristics. In Exp. 1, semen was collected from 8 geldings every other day after castration until the number of spermatozoa per ejaculate was below 1% of the precastration value. An average of 3 ejaculates was required to reduce the number of spermatozoa below this level. In Exp. 2, 15 stallions were castrated and each stallion was assigned to 1 of 3 groups for seminal collection at 7, 14 or 21 days post-castration. The ejaculates...
Coffman JR, Mussman HC, Cawley LP.The study investigates the potential for lactic dehydrogenase isoenzymes to be a useful diagnostic tool for equine infectious anemia, a disease that shows similarities to infectious mononucleosis in humans. Background […]
Julien R, Bechis G, Gregoire J, Rathelot J, Rochat H, Sarda L.The N-terminal amino acid sequences of two forms of colipase isolated from horse pancreas have been compared. Four sequence differences were found in the first 51 amino acids. This lead us to conclude that there are two distinct colipases in the horse pancreas.
