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.
Belknap JK, Nickels FA.Third-degree perineal lacerations or rectovestibular fistulae in 17 mares were repaired surgically by a one-stage method. Primary healing occurred in 14 mares; there were one complete dehiscence and two partial dehiscences with fistula formation. Twelve of 13 mares that were bred became pregnant; nine carried foals to term and two are still pregnant. Two mares have each produced one unthrifty foal. One mare repeatedly aborts in the first trimester. Four mares have produced several healthy foals with no further problems. One mare suffered further perineal trauma while foaling.
Coles GC, Bauer C, Borgsteede FH, Geerts S, Klei TR, Taylor MA, Waller PJ.Methods have been described to assist in the detection of anthelmintic resistance in strongylid nematodes of ruminants, horses and pigs. Two tests are recommended, an in vivo test, the faecal egg count reduction test for use in infected animals, and an in vitro test, the egg hatch test for detection of benzimidazole resistance in nematodes that hatch shortly after embryonation. Anaerobic storage for submission of faecal samples from the field for use in the in vitro test is of value and the procedure is described. The tests should enable comparable data to be obtained in surveys in all parts o...
O'Brien MA, Holmes MA, Duffus WP.Anti-tetanus toxoid (TT) antibody (Ig) levels in the supernatant of cultured, pre-immunised equine peripheral blood mononuclear cells (PBMC) were measured by an indirect enzyme-linked immunoabsorbent assay (ELISA). Optimal anti-TT Ig production occurred at concentrations of stimulating, purified TT of between 0.001 and 0.1 micrograms ml-1, which varied depending on the cell concentration. Optimal anti-TT Ig production was most consistently produced when the cell concentration was 5 x 10(6) ml-1. At this cell concentration maximal anti-TT Ig was induced using 0.1 micrograms ml-1 TT. At a cell c...
Hance SR, Embertson RM.Colopexies were performed in 44 broodmares requiring abdominal surgery for large colon volvulus or right dorsal displacement of the large colon. Colopexies were performed by suturing the lateral bands of the left and right ventral colon to the ventral abdominal wall. Forty-seven percent of the mares in which a colopexy was performed had previous surgery for a large colon volvulus or right dorsal displacement of the large colon. Postoperative complications considered directly associated with the colopexy procedure were intermittent abdominal pain in 7, reoperation in 5, subcutaneous fistulous t...
May SA, Hooke RE, Lees P.There is increasing evidence that the chondrocyte is capable of considerable anabolic and catabolic activity. In the case of equine chondrocytes, this study demonstrates that a variety of factors involved in the pathogenesis of joint disease stimulate the production of prostaglandin E2. These include exposure to IL-1, bone fragments and LPS. In addition, an IL-1-like factor was shown to be produced by the chondrocyte itself, when stimulated by LPS, providing a possible mechanism for amplification of extra-cartilagenous signals and even autocrine control. Considered together with evidence of in...
Ronen N, van Heerden J, van Amstel SR.Three cases of horses with nutritional secondary hyperparathyroidism (NSH) are described. The horses showed typical thickening of the maxillae and mandibular bones with or without lameness. Laboratory findings included elevated concentrations of parathyroid hormone (carboxy-terminal and mid-molecule fractions), alkaline phosphatase and an increase in the fractional excretion rate of serum inorganic phosphorus.
Gibson JS, Slater JD, Field HJ.The activity of the nucleotide analogue, (S)-1-[(3-hydroxy-2-phosphonyl methoxy) propyl] cytosine (HPMPC), against equine herpesvirus-1 (EHV-1) was tested in cell culture, mice and foals. The ED50 for plaque reduction was found to be 0.07 and 0.03 microgram/ml in RK-13 and EEL cells respectively. In mice, a single administration of HPMPC (20 mg/kg, s.c.) was very effective at reducing clinical signs and virus replication if given on the day before intranasal inoculation with EHV-1. Treatment on the day of infection or day 1 p.i. was less effective, but still significantly reduced clinical sign...
Troedsson MH, Liu IK.Undiluted uterine secretion was used to determine the concentration of total protein and the accumulated volume of uterine secretion after a bacterial inoculation in mares susceptible and resistant to chronic uterine infection (CUI). The uterus of 6 susceptible and 5 resistant mares was inoculated with 5 x 10(6) Streptococcus zooepidemicus on the third day of estrus. Using a tampon inserted in the uterus, secretions were sampled at 5, 12, 24, and 36 hours after inoculation, followed by intrauterine lavage with phosphate buffered saline solution. The concentration of protein was determined in t...
Matthews HK, Andrews FM, Daniel GB, Jacobs WR, Held JP.Comparison of standard and radionuclide methods for measuring glomerular filtration rate (GFR) and effective renal blood flow (ERBF) was performed in 8 healthy female horses. Inulin and p-aminohippurate solutions were administered IV as a bolus, followed by sustained administration. Urine and plasma inulin and p-aminohippurate concentrations and urine volume were measured. Glomerular filtration rate and ERBF were calculated on the basis of these measurements. Glomerular filtration rate and ERBF were measured on the basis of plasma clearance of the radiopharmaceuticals, 99mTc-labeled diethylene...
Linford RL, McCue PM, Montavon S, Lasley BL.A cannulation technique was developed to collect blood samples from the ovarian vein of mares over an extended period. Ovarian venous cannulae placed in 4 mares remained patent for a mean (+/- SEM) duration of 36.8 (+/- 6.2) days. During mid-diestrus, concentrations of progesterone in the ovarian vein ipsilateral to the corpus luteum (1,663.8 +/- 238.8 ng/ml) were significantly (P less than 0.001) higher than concentrations measured in paired samples from the jugular vein (6.1 +/- 0.3 ng/ml). Concentration of estradiol in the ovarian vein ranged from a mean of 1,053.2 +/- 303.1 pg/ml during di...
Haugland LM, Collier MA, Panciera RJ, Bellamy J.In an attempt to prevent neuroma formation and digital reinnervation after sharp palmar digital neurectomy in 10 adult horses with navicular disease, 18,426 W/cm2 of CO2 laser energy was applied to the proximal nerve stump. Clinical follow-up was 4 to 23 months. In two horses, palmar digital nerve biopsies were taken at month 4 (four nerves) and month 7 (two nerves). Nine horses were sound immediately and at all follow-up examinations. None had clinical evidence of painful neuroma or digital reinnervation. Histologically, there was minimal scar tissue at the surgical site; axonal sprouts were ...
Sinclair R, Mumford JA.An antigen capture enzyme-linked immunosorbent assay (ELISA) was developed for the detection of equine herpesvirus type-1 (EHV-1) antigens in nasal swab specimens. The test was designed as a solid phase, amplified sandwich assay in which an EHV-1 specific monoclonal antibody was used to capture virus antigen and polyclonal antisera used to detect antigen bound to the test plates. Eight monoclonal antibodies were tested for their ability to capture virus antigen and one was selected for routine use. The sensitivity and specificity of the ELISA was compared with that of virus isolation using swa...
Madison JB, Gronwall RR.Three sets of paired circular and square full-thickness skin wounds were made on the dorsum of the metacarpus (n = 48) of 8 horses. Each wound was 6.25 cm2 in area. The wounds were treated topically with an ointment, nonadherent dressing, and bandaged with a snug elastic wrap. Wounds were photographed every other day until healing was complete. Wound areas were measured and exponential and linear wound healing models were applied to the wound healing data generated. Wound healing variables measured for each wound were: number of days to healing, maximal size attained, rate of wound contraction...
Fowden AL, Mijovic J, Ousey JC, McGladdery A, Silver M.The activities of glucose-6-phosphatase (G6P), fructose diphosphatase, phosphoenolpyruvate carboxykinase (PEPCK), aspartate and alanine transferases were measured in liver and kidney of fetal foals between 100-318 days of gestation (term approximately 335 days) and during the immediate postnatal period (0-48 h after birth). All 5 enzymes could be detected in the fetal liver and kidney at the youngest gestational age studied. Mean fetal activities were lower than those observed in their mothers and showed no change with gestational age for the majority of enzymes studied. However, renal PEPCK a...
McIlwraith CW.Tearing of the medial palmar intercarpal ligament is described in 45 intercarpal (midcarpal) joints in 42 horses (37 racehorses, 5 non-racehorses). Of the 37 racehorses, there were 20 Quarter Horses, 14 Thoroughbreds and 3 Standardbreds. The patients had been referred for arthroscopic surgery for removal of osteochondral chip fragments that had been diagnosed radiographically or diagnostic arthroscopy of a persistent carpal problem. The problem was unilateral in 39 horses and bilateral in 3. The presenting clinical signs were lameness and/or persistent synovial effusion. In one instance, the p...
Moore RM, Trims CM.Lumbosacral CSF pressure was measured in 6 horses via a catheter inserted through the lumbosacral space. Heart rate, facial artery pressure, central venous pressure, and CSF pressure were measured before IV injection of a saline solution control, for 15 minutes after saline solution injection, and for 60 minutes after the IV injection of 1.1 mg of xylazine/kg of body weight. Arterial pH and blood gases were analyzed before saline solution injection, 15 minutes after saline solution injection, and at 15, 30, and 60 minutes after xylazine injection. Constant craniocervical posture was maintained...
Berry CR, Pool RR, Stover S, O'Brien TR, Koblik PD.The source of a previously described radiolucent crescent in the flexor cortex of the distal sesamoid (navicular) bone on the palmaro45 degrees proximal-palmarodistal oblique (Pa45 degrees Pr-PaDio) clinical radiographic projection was investigated in 48 forelimb navicular bones from 24 Thoroughbreds by use of high-detail radiography and x-ray computed tomography (CT). Twenty-five of these bones also were evaluated, using microradiography and histologic examinations. Of these 25 bones, 5 had been labeled in vivo with fluorochrome markers. Tetrachrome-stained 100-microns-thick nondecalcified se...
Gaughan EM, Gift LJ, Frank RK.Tubular duplication of the cervical portion of the esophagus was diagnosed in a 10-day-old female Quarter Horse. The foal was examined because of the development of a 12- to 15-cm diameter mass at the caudal aspect of the mandible after suckling. The foal was dyspneic when in lateral recumbency. Radiography and ultrasonography revealed a fluid- and gas-filled mass. Endoscopy revealed a normal-appearing upper airway and esophagus. Complete surgical resection of the mass was successful. The mass had a 3-mm diameter communication with the esophageal lumen at the pharyngoesophageal oriface. Histol...
Mettenleiter E, Meier HP, Ueltschi G, Waibl H.The possibilities for imaging soft tissue structures, especially fluid-filled cavities such as articulations, bursae or tendon sheaths, have been improved markedly by sonography in recent years. Ultrasonic examinations were performed on the common tendon sheath of the musculus flexor hallucis longus and the musculus tibialis caudalis, from the medioplantar aspect of the tarsus, in 12 sound adult draft- and warm blood horses, and in 5 animals with a distended common sheath. The diagnostic precision of the sonographic examination of the tendon sheath is excellent and is superior to conventional ...
Ambros'eva ED, Khokhriakova ZhA, Glazko VI.The genetic structures of Orlov's and Russian trotters for 16 biochemical systems have been comparatively analyzed. Polymorphism of 6 systems of these horse groups is revealed. The main genetic differentiation between Orlov's and Russian trotters is observed on the transferrin and phosphoglucomutase loci.
Dyson SJ, Kidd L.The normal gastrocnemius tendon may contain some muscular tissue proximally. This results in a patchy echogenicity ultrasonographically where it lies caudal or lateral to the superficial digital flexor tendon (SDFT). When it has assumed a position dorsal (cranial) to the SDFT the gastrocnemius tendon has a more uniform echogenicity and its margins are well defined. Five horses had lameness associated with lesions identified ultrasonographically in the gastrocnemius tendon in the latter region. Lameness ranged from mild to severe and was characterised by reduced hock flexion, lowered arc of foo...
Love S, Duncan JL.Groups of animals of different ages and experience of previous parasite exposure were allowed to graze a single pasture for 5 weeks in autumn (7 October to 11 November). There was evidence that previous exposure modified cyathostome development, as acquired burdens in foals which had previously grazed were smaller and developed more slowly than those of helminth-naive animals of the same age. The burdens acquired by yearling and adult ponies were of a similar size to those of the previously grazed foals, but the incidence of arrested development was higher in the younger groups of foals and ye...
Souillard A, Audran M, Bressolle F, Jaussaud P, Gareau R.The pharmacokinetics of recombinant human Epo (rHuEpo) were investigated after subcutaneous administration to horses. Four horses received a single 30IU kg-1 dose of rHuEpo. One horse received three repeated doses of 120 IU kg-1 at 48 h intervals. Plasma erythropoietin (Epo) was measured by radioimmunoassay. In both cases pharmacokinetic parameters were evaluated using a one-compartment open model and first-order input and output rates. The mean values (+/-SD) for elimination half-life, CL/F, and Vd/F after a single dose were 12.9 +/- 3.34 h, 11.8 +/- 4.96 L h-1, and 233 +/- 126 L, respectivel...
Zicker SC, Marty GD, Carlson GP, Madigan JE, Smith JM, Goetzman BW.Bilateral renal dysplasia and nephron hypoplasia was diagnosed in a Quarter Horse foal with clinical signs of lethargy, convulsions, and diarrhea. Laboratory evaluation revealed anemia, hypoproteinemia, leukopenia, hyponatremia, hypochloremia, and hyposmolality. The foal also had high concentrations of serum creatinine, BUN, and phosphorus. Evaluation of urinary indices revealed a high ratio of urinary gamma-glutamyl-transferase activity to concentration of creatinine, as well as a high fractional clearance ratio of sodium and potassium. Intravenous treatment with saline solution (0.9% NaCl) a...
Guzeloglu A, Atli MO, Kurar E, Kayis SA, Handler J, Semacan A, Aslan S.The aims of the present study were to elucidate the expression profiles of leukotriene (LT) pathway mRNA transcription and to determine the possible interaction of LT and prostaglandin (PTG) pathways genes in equine endometrium during the estrous cycle and early pregnancy. Endometrial biopsies were obtained from mares on the day of ovulation (d0), at late diestrous (LD, n = 4), and after luteolysis in the estrus phase (AL, n = 4) of the cycle. Biopsies were also taken on Days 14 (P14; n = 4), 18 (P18, n = 4), and 22 (P22, n = 4) during early pregnancy that were comparable days to cyclic sampli...
Anderson K, Morrice-West AV, Walmsley EA, Fisher AD, Whitton RC, Hitchens PL.Musculoskeletal injuries are observed in Thoroughbred racehorses and may become catastrophic. Currently, there are limited methods for early detection of such injuries. Most injuries develop gradually due to accumulated damage, providing the opportunity for early detection. Horses experiencing pain or lameness may exhibit changes in behaviour so the development of an objective, real-time system monitoring horse behaviour may enable detection of bone injuries before catastrophic failure. Objective: To determine whether intensive observational methods of assessing horse behaviour can be replaced...
Walter KM, Moore CE, Bozorgmanesh R, Magdesian KG, Woods LW, Puschner B.Two horses were referred for methemoglobinemia and hemolytic anemia following 5 acute deaths in their herd from an unidentified toxin source. Horses have a greater risk than other mammalian species of developing methemoglobinemia and hemolytic anemia following ingestion of oxidizing toxins, due to deficiencies in the mechanisms that protect against oxidative damage in erythrocytes. Their susceptibility to oxidative erythrocyte damage is evident in the numerous cases of red maple (Acer rubrum) toxicosis. The suspected toxins causing A. rubrum toxicosis are tannic acid, gallic acid, and a metabo...
Sertich PL, Reef VB, Oristaglio-Turner RM, Habecker PL, Maxson AD.A multiparous pregnant Welsh Pony mare was examined because of anorexia, dyspnea, and a large abdomen. Ultrasonography of the uterus revealed an excessive amount of amniotic fluid surrounding the fetus. Transabdominal ultrasonography permitted differentiation of hydrops amnii from hydrops allantois. The mare aborted a 7-month-old fetus with brachygnathia and a large, edematous umbilical cord. Hydrops amnii, an excessive accumulation of amniotic fluid in the amniotic cavity, is most commonly reported in cattle and sheep.
Benamou AE, Marlin DJ, Lekeux P.Based on previous in vitro studies, we hypothesised that endothelin (ET) would induce vasoconstriction in the pulmonary circululation of the horse and that this action would be mediated via ET(A) receptors. Pulmonary and systemic haemodynamic responses to endothelin-1 (ET-1), a potent vasoactive endogenous peptide, were investigated in 6 conscious, nonsedated horses at rest. Bolus i.v. injections of exogenous ET-1 (0.1, 0.2 and 0.4 microg/kg bwt) caused significant increases in pulmonary (PAP) and carotid (CAP) artery pressures, with peak increases of 79% and 51% for mean PAP and CAP, respecti...
Bell K, Pollitt CC, Patterson SD.Subdivision of equine TfH into two variants, designated H1 (faster) and H2 (slower), has been accomplished by high voltage, thin layer polyacrylamide gel electrophoresis at pH 7.9. Transferrin H1 and H2 have been shown to be controlled by codominant alleles and gene frequencies of the Tf alleles have been determined in the Australian Thoroughbred, Standardbred. Quarter Horse and Arabian Horse breeds.
Divers TJ, Byars TD, Spirito M.Bilateral ureteral defects were diagnosed as the cause of depression and azotemia in an 8-day-old Thoroughbred filly. The azotemia resulted from accumulation of urine in the retroperitoneal area. A ventral midline laparotomy was performed, and defects found in both the left and right ureter were repaired. Uroperitoneum and abdominal distention, presumably from urine leakage at the left ureteral surgery site, were detected on the fourth postoperative day and necessitated abdominal drainage. Thirty-six hours later, the leakage stopped spontaneously, and the foal recovered normally. This report s...
Hammer EJ, Chope K, Lemire TD, Reef VB.This report describes the identification and surgical removal of a lipoma from the extensor tendon sheaths of a horse. To the authors' knowledge, this is the first report of a lipoma of the extensor tendon sheaths of a horse. Ultrasonographic evaluation was crucial to patient management, providing information regarding the soft tissue mass characteristics, tumor margins and synovial involvement prior to surgical exploration. Surgical removal was performed and was curative.
Conturba B, Lo Feudo CM, Stucchi L, Stancari G, Olivieri L, Ferrucci F.The aim of the present work was to describe a case of recurrent capillary haemangioma at the coronary border of the left front limb in a 6-month-old thoroughbred filly successfully treated with diode laser ablation and adjunctive laser photocoagulation therapy. Le but de cette étude était de décrire un cas d’hémangione capillaire récidivant du bord coronaire du membre antérieur gauche chez un cheval de race de 6 mois traité avec succès par une ablation au laser diode et traitement adjuvant de photo-coagulation au laser. El objetivo del presente trabajo fue describir un caso de hemang...
Kamali MF, Wilson AC, Acquisto NM, Spillane L, Schneider SM.Flunexin is a nonsteroidal anti-inflammatory drug approved for veterinary use in horses and cattle. Acepromazine is a phenothiazine derivative used in horses, dogs, and cats. Human exposure to these substances is rare. Methods: We report a case of a human injection of two equine medications, flunixin and acepromazine, which resulted in altered mental status, respiratory alkalosis, gastrointestinal bleeding, and elevation of liver transaminases in a 43-year-old woman who worked as a horse trainer. The patient intentionally self-injected these medications and subsequently presented to the Emerge...
Gould JC, Rossano MG, Lawrence LM, Burk SV, Ennis RB, Lyons ET.Parascaris equorum generally infects horses less than 18 months old and its pathological effects can be severe. Infection occurs when larvated eggs, present in pastures, paddocks, stalls, and on feeding and watering equipment are ingested. The purpose of this study was to examine the effects of windrow composting on the viability of P. equorum eggs at a cooperating central Kentucky horse farm. Three grams of feces containing 2216 P. equorum eggs per gram were sealed in filter bag sentinel chambers. Chambers were exposed to 1 of 3 treatments: constant exposure or intermittent exposure to the in...
Reed RA, Knych HK, Barletta M, Sakai DM, Ruch MM, Smyth CA, Ryan CA.To compare the pharmacokinetics and pharmacodynamics of hydromorphone in horses after intravenous (IV) and intramuscular (IM) administration. Methods: Randomized, masked, crossover design. Methods: A total of six adult horses weighing [mean ± standard deviation (SD))] 447 ± 61 kg. Methods: Horses were administered three treatments with a 7 day washout. Treatments were hydromorphone 0.04 mg kg IV with saline administered IM (H-IV), hydromorphone 0.04 mg kg IM with saline IV (H-IM), or saline IV and IM (P). Blood was collected for hydromorphone plasma concentration at multiple time points for ...
Martinez de Andino EV, Brom-de-Luna JG, Canesin HS, Rader K, Resende HL, Ripley AM, Love CC, Hinrichs K.To assess meiotic and developmental competence after transfer of immature cumulus-oocyte complexes (COCs) to the preovulatory follicles of mares (intrafollicular oocyte transfer (IFOT)). Methods: In Experiment 1, mares received an ovulatory stimulus at IFOT. Thirty hours later, COCs were recovered from the follicle, and mature oocytes underwent ICSI and embryo culture. In Experiments 2 and 3, autologous vs. allogeneic COCs were used. The mares were inseminated and embryos were recovered. In Experiment 3, the ovulatory stimulus was administered 9 h (autologous) and 15 h (allogeneic) before IF...
Mayhew IG.Parameters for the accuracy of clinical diagnosis of neurologic diseases in the horse were determined from 210 horses in which a definitive pathologic diagnosis was confirmed. The overall efficiency of diagnosis for all diseases was 0.95 although the validity varied from 0.79 to 1.00, the sensitivity varied from 0.73 to 0.95, and the specificity varied from 0.88 to 1.00 for individual disease categories. Equine protozoal myeloencephalitis was overdiagnosed, whereas Eastern equine encephalomyelitis, equine degenerative myeloencephalopathy, and traumatic neurologic disease were underdiagnosed. T...
Dyer RM, Leid RW.Isolated equine alveolar macrophages obtained by bronchopulmonary lavage of four live ponies demonstrated surface receptors for equine IgG, equine IgM, and complement-coated sheep red blood cells, but not equine IgM or complement-coated erythrocytes alone. In addition, demonstration of IgG receptors was found to depend on the level of erythrocyte sensitization and could not be demonstrated by red blood cell rosetting techniques at low levels of sensitization. Demonstration of receptors for equine complement by red cell rosetting techniques required the presence of both IgM antibody and serum d...
Wilson DV, McFeely AM.Positive end-expiratory pressure (PEEP) was applied in 74 anesthetized, ventilated horses during colic surgery, to attempt to increase arterial oxygen tensions. In 28 horses with an initial PaO2 less than 70 mm of Hg, PEEP increased PaO2 values to a mean of 173 +/- 24 mm of Hg. Arterial oxygen content increased from 14.1 +/- 0.05 ml/dl to 17.2 +/- 0.05 ml/dl. In the remaining 46 horses, PEEP increased PaO2 from a mean value of 101 +/- 6 mm of Hg to 194 +/- 15 mm of Hg, and arterial oxygen content increased from 14.9 +/- 0.09 ml/dl to 16.9 +/- 0.07 ml/dl. Cardiovascular depression and decrease ...
Cook AG, Maxwell VB, Donaldson LL, Parker NA, Ward DL, Morrow JK.To determine whether antibodies against Sarcocystis neurona could be detected in CSF from clinically normal neonatal (2 to 7 days old) and young (2 to 3 months old) foals. Methods: Prospective study. Methods: 15 clinically normal neonatal Thoroughbred foals. Methods: Serum and CSF samples were obtained from foals at 2 to 7 days of age and tested for antibodies against S. neurona by means of western blotting. Serum samples from the mares were also tested for antibodies against S. neurona. Additional CSF and blood samples were obtained from 5 foals between 13 and 41 days after birth and between ...