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.
Tallmadge RL, Lear TL, Antczak DF.The availability of a contig of bacterial artificial chromosome (BAC) clones spanning the equine major histocompatibility complex (MHC) made possible a detailed analysis of horse MHC class I genes. Prior to this study, only a single horse MHC class I gene had been sequenced at the genomic level. Although many ( approximately 60) MHC class I cDNA sequences had been determined and published, from this information, it was not possible to determine how many class I loci are expressed in horses or to assign individual sequences to allelic series. In this study, 15 MHC class I genes were identified ...
Pusterla N, Holmberg TA, Lorenzo-Figueras M, Wong A, Wilson WD.A 10-year-old Thoroughbred gelding was admitted to the Veterinary Medical Teaching Hospital of the University of California-Davis with a 2-week history of intermittent fever and acute onset of lethargy, anorexia, and ataxia. Although the clinical signs were nonspecific, the results of initial hematologic and biochemical analysis were consistent with a chronic inflammatory process. Thoracic radiographs revealed an increased fine reticulonodular interstitial opacity throughout the dorsal caudal lung fields. Cytologic examination of bronchoalveolar lavage (BAL) fluid showed mixed inflammation wit...
Stokol T, Erb HN, De Wilde L, Tornquist SJ, Brooks M.Fibrin(ogen) degradation products (FDPs) and D-dimer are sensitive indicators of excessive fibrinolysis due to disseminated intravascular coagulation (DIC) in dogs. To the authors' knowledge, latex-agglutination-based plasma FDP and D-dimer assays have not been validated for use in horses. Objective: To determine: 1) sensitivity and specificity of latex agglutination serum and plasma FDP and D-dimer assays for diagnosis of DIC; and 2) their prognostic value in horses with severe colic. Methods: At hospital admission and 24 hours later, blood was collected from 30 healthy horses and 20 horses w...
Doube M, Firth EC, Boyde A.Combined backscattered electron scanning electron microscopy (BSE SEM) and confocal scanning laser microscopy (CSLM) have been used to put tissue mineralization data into the context of soft tissue histology and fluorescent label information. Mineralization density (Dm) and linear accretion rate (LAR) are quantifiable parameters associated with mineralizing fronts within calcified tissues. Quantitative BSE (qBSE) may be used to determine Dm, while CSLM may be used to detect label fluorescence from which LAR is calculated. Eighteen-month old Thoroughbred horses received single calcein injection...
Sinnemaa L, Järvimaa T, Lehmonen N, Mäkelä O, Reilas T, Sankari S, Katila T.The effect of artificial insemination (AI) volume on uterine contractility and inflammation and on elimination of semen in the reproductive tract of mares was examined for 4 h after AI using two methods, scintigraphy and ultrasonography. The same doses were used in both methods: 2 and 100 ml of skim milk-extended frozen semen. In the scintigraphic study, the number of reproductively normal mares was four per group and in the ultrasonographic study five per group. For scintigraphy, the semen was radiolabelled with technetium-99m. The static scintigrams were acquired immediately before and 30, 6...
Hemberg E, Lundeheim N, Einarsson S.Changes in the conformation of the vulva predispose the mare to uterine infection. Vulvoplasty for closure of the upper vulvar lips improves fertility. Not all mares are resutured after parturition, but are resutured after mating. No clinical data have hitherto been published on the reproductive outcome in mares that are resutured or not after parturition. The objectives of the present study were to investigate relationships between vulvar status (not Caslick-operated, group A; previously Caslick-operated and/or not resutured after the last parturition, groups B and C respectively) and endomet...
Diakakis N, Patsikas MN, Dessiris AK.An 8-year-old Dutch warmblood gelding was presented with a mechanical lameness (2/10) because of the presence of a soft tissue injury on the top of the right tuber calcanei. Plain radiographs of the tarsus demonstrated the presence of soft tissue swelling caudal to the right tuber calcanei, without osseous involvement, and ultrasonography revealed excessive scar tissue within and around the superficial digital flexor tendon. Extra-corporeal shock wave therapy was applied on the right hock to decrease the amount of scar tissue. One month after the therapy the lameness was greater (3/10) and a m...
Boyle AG, Magdesian KG, Ruby RE.To assess data regarding clinical features, clinicopathologic and blood gas variables, and outcome from horse and mule foals with confirmed neonatal isoerythrolysis (NI). Methods: Retrospective case series. Methods: 17 horse and 1 mule foals. Methods: Medical records of foals (< 14 days old) with NI were reviewed. Information collected included signalment; clinical examination findings; results of hematologic, serum and plasma biochemical, and venous blood gas analyses and urinalysis; treatments; and outcome. Results: Data from 17 horse foals and 1 mule foal with NI (mean age, 71 hours) were e...
Muir P, McCarthy J, Radtke CL, Markel MD, Santschi EM, Scollay MC, Kalscheur VL.The mechanisms that regulate functional adaptation of the articular ends of long bones are poorly understood. However, endochondral ossification of articular cartilage and modeling/remodeling of the subchondral plate and epiphyseal trabeculae are important components of the adaptive response. We performed a histologic study of the distal end of the third metacarpal/metatarsal bone of Thoroughbreds after bones were bulk-stained in basic fuchsin and calcified sections were prepared. The Thoroughbred racehorse is a model of an extreme athlete which experiences particularly high cyclic strains in ...
Oikawa M, Kusunose R.The purpose of this report is to describe the results of epidemiological surveys of racing-related fractures in Thoroughbred horses in Japan. In the period 1987-2000, a total of 10,203 fractures were diagnosed in 556,705 runners, resulting in an overall incidence of 1.83%. The annual incidence of fractures in flat racing during the 14-year period fluctuated between 1.44% and 2.19%. The majority of fractures affected the forelimbs. We found significant effects of track condition on injury incidence. The incidence of fractures decreased as track conditions on turf became softer and increased as ...
Kaikkonen M, Hyyppä S.Like potassium (K+), caesium (Cs+) tends to concentrate intracellularly. The aim here was to determine how moderate exercise affects the uptake of Cs+ from blood plasma. Methods: After an intravenous Cs+ dose of 5 micromol kg(-1), plasma Cs+ concentration was followed for 100 min in goats and for 60 min in horses. The latter were divided into two groups, one resting and the other trotting on a treadmill (inclination 3 degrees, speed 5 m s(-1)). Results: The plasma Cs+ concentration follows a multiphase exponential decay curve, which initially could be approximated with a two-phase curve. The i...
Munsterman AS, Bertone AL, Zachos TA, Weisbrode SE.To determine the effects of pretreatment with alpha-linolenic acid, an omega-3 polyunsaturated fatty acid, on equine synovial explants challenged with lipopolysaccharide (LPS). Methods: 8 mature mixed-breed horses (4 mares and 4 geldings). Methods: Synovial explants were assigned to receive 1 of 7 concentrations of alpha-linolenic acid, ranging from 0 to 300 microg/mL. At each concentration, half of the explants were controls and half were challenged with 0.003 microg of LPS as a model of synovial inflammation. Cell inflammatory response was evaluated by measurement of prostaglandin E2 product...
Eiler H, Frank N, Andrews FM, Oliver JW, Fecteau KA.To characterize the physiologic response to i.v. bolus injection of glucose and insulin for development of a combined glucose-insulin test (CGIT) in horses. Methods: 6 healthy mares and 1 mare each with pituitary adenoma and urolithiasis. Methods: Horses were given a CGIT (glucose, 150 mg/kg; insulin, 0.1 U/kg); results were compared with a singular i.v. glucose tolerance test (GTT; 150 mg/kg) and a singular i.v. insulin sensitivity test (IST; 0.1 U/kg). Healthy horses were also given a CGIT after receiving xylazine and undergoing stress. Results: Physiologically, the CGIT resulted in a 2-phas...
da Costa RP, Branco V, Pessa P, Silva JR, Ferreira-Dias G.Steroid hormones act via specific receptors, and these play an important physiological role in the ovary. The objective of this study was to evaluate the cellular distribution of progesterone receptors and their staining intensity in different equine luteal structures during the breeding season, as well as their relationship to luteal cell composition, cell proliferation pattern and plasma progesterone (P4) concentration. There was an increase in proliferating cell nuclear antigen (PCNA) expression in large luteal cells from the corpus hemorrhagicum (CH) to mid-luteal phase, followed by a decr...
Staempfli S, Janett F, Burger D, Kuendig H, Haessig M, Thun R.In this study the effect of exercise (treadmill, riding) on scrotal surface temperature (SST) in the stallion with and without suspensory was evaluated. Our results show that SST was significantly influenced by exercise and suspensory the latter causing in general a rise in SST. Furthermore, from SST measurements in stallions exercised on treadmill and by riding, it is concluded that air circulation near the scrotum must be considered an important thermoregulatory factor.
Vandenplas ML, Moore JN, Barton MH, Roussel AJ, Cohen ND.To determine concentrations of 2 acute-phase proteins (serum amyloid A [SAA] and lipopolysaccharide-binding protein [LBP]) in serum samples obtained from horses with colic and identify relationships among these acute-phase proteins and clinical data. Methods: 765 horses with naturally developing gastrointestinal tract diseases characterized by colic (ie, clinical signs indicative of abdominal pain) and 79 healthy control horses; all horses were examined at 2 university teaching hospitals. Methods: Serum concentrations of SAA and LBP were determined by immunoturbidometric and dot-blot assays, r...
Peroni JF, Moore JN, Noschka E, Grafton ME, Aceves-Avila M, Lewis SJ, Robertson TP.Equine laminitis is a crippling condition associated with a variety of systemic diseases. Although it is apparent that the prodromal stages of laminitis involve microvascular dysfunction, little is known regarding the physiology of this vasculature. The aim of the present study was to determine the relative responses of equine laminar arteries and veins to the vasoconstrictor agonists phenylephrine (1 nM-10 microM), 5-HT (1 nM-10 microM), PGF2alpha (1 nM-100 microM), and endothelin-1 (1 pM-1 microM). We have determined that laminar veins were more sensitive, with respect to the concentration o...
Rees WA, Harkins JD, Lu M, Holland RE, Lehner AF, Tobin T, Chambers TM.To determine pharmacokinetics of single and multiple doses of rimantadine hydrochloride in horses and to evaluate prophylactic efficacy of rimantadine in influenza virus-infected horses. Methods: 5 clinically normal horses and 8 horses seronegative to influenza A. Methods: Horses were given rimantadine (7 mg/kg of body weight, i.v., once; 15 mg/kg, p.o., once; 30 mg/kg, p.o., once; and 30 mg/kg, p.o., q 12 h for 4 days) to determine disposition kinetics. Efficacy in induced infections was determined in horses seronegative to influenza virus A2. Rimantadine was administered (30 mg/kg, p.o., q 1...
Fuehrer HP, Alho AM, Kayikci FN, Shahi Barogh B, Rosa H, Tomás J, Rocha H, Harl J, Madeira de Carvalho L.Vector-borne diseases of zoonotic and/or veterinary relevance have been increasingly reported in horses globally, although data regarding working and military horses is lacking. Portuguese military horses may constitute a risk group for these pathogens, as they frequently work outdoors in various regions of the country. This study included 101 apparently healthy horses belonging to the Portuguese National Republican Guard. Blood samples were analyzed to determine the presence and prevalence of piroplasms, Anaplasmataceae, Rickettsia spp., and filarioid helminths. Overall 32.7% of the horses ga...
Sandersen C, Mouithys-Mickalad A, de la Rebière G, Deby G, Serteyn D, Franck T.To investigate the effect of acepromazine (ACP) on reactive oxygen species (ROS) production by stimulated equine neutrophils. Methods: Ex vivo biochemical experiments. Methods: Isolated neutrophils from healthy untreated horses. Methods: Neutrophils were incubated with ACP at concentrations of 10(-4), 10(-5) or 10(-6) M and then stimulated with phorbol-myristate-acetate (PMA) before measurement of lucigenin-enhanced chemiluminescence (CL). In a second experiment neutrophils were incubated in the presence of α-keto-γ methylthiobutyric acid (KMB) and treated with ACP at concentrations of 10(-4...
Leigh H, Gozalo-Marcilla M, Esteve V, Gutiérrez Bautista ÁJ, Martin Gimenez T, Viscasillas J.Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). Objective: To describe a technique for USG PB in horse cadavers. Methods: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised t...
Scott TW, Olson JG, All BP, Gibbs EP.Sensitivity and specificity of an antigen-capture ELISA vs virus isolation in cell culture were evaluated for the detection of eastern equine encephalomyelitis (EEE) virus in the brain tissue of naturally infected equids. Brain specimens from 16 equids with neurologic disease were examined by ELISA and by inoculation onto baby hamster kidney cell cultures. Of 10 brain samples from which virus was isolated in the cell culture bioassay, all were correctly identified as containing EEE virus antigen by ELISA. None of the remaining 6 specimens, without detectable infectious EEE virus, contained det...
Kienzle E, Bockhorni T.The nutritional status of 36 patients with equine pituitary pars intermedia dysfunction (PPID) under pergolide treatment was investigated. Methods: The body condi tion score (BCS) and feeding were determined at the beginning of the study and after 60 and 120 days. Sampled blood for control of pergolid therapy were used for insulin and glucose measurement. A standardized questionnaire regarding the symptoms of the disease, including hypertrichosis and weight change, was completed by the owners. Results: The mean BCS (scale of 1 = cachexia to 9 = grossly obese) was 3.1 ± 0.8 (large horses 2.7 ...
Anderson GA, Mount ME, Vrins AA, Ziemer EL.Acorn poisoning was diagnosed in an 11-year-old Quarter Horse with signs of severe colic, tachycardia, hyperpnea, abdominal borborygmus, rectal tenesmus, and hemorrhagic diarrhea. The diagnosis was based on history and predisposing factors, clinical signs, laboratory data, acorn husks in the feces, the urinary gallic acid equivalent concentration, and necropsy findings. The most striking pathologic changes were gastrointestinal and mesenteric edema, ulcerative enterocolitis, and nephrosis.
Tomasic M, Mann LS, Soma LR.To determine the effects of endotracheal intubation on respiratory mechanics during xylazine sedation and xylazine-diazepam-ketamine anesthesia in adult horses. Methods: 5 healthy adult horses. Methods: Measurements were derived from recordings of respiratory gas flow, and transpulmonary and transtracheal pressures. Total pulmonary resistance (RT) was partitioned into upper airway resistance (extrathoracic portion of trachea, larynx, pharynx, nasal cavity, nares; RUA) and lower airway resistance (intrathoracic portion of trachea, bronchi, bronchioles). Baseline measurements were obtained in un...
Knych HK, Stucker K, Gretler SR, Kass PH, McKemie DS.In humans, codeine is a commonly prescribed analgesic that produces its therapeutic effect largely through metabolism to morphine. In some species, analgesic effects of morphine have also been attributed to the morphine-6-glucuronide (M6G) metabolite. Although an effective analgesic, administration of morphine to horses produces dose-dependent neuroexcitation at therapeutic doses. Oral administration of codeine at a dose of 0.6 mg/kg has been shown to generate morphine and M6G concentrations comparable to that observed following administration of clinically effective doses of morphine, witho...
Hayden SS, Blanchard TL, Brinsko SP, Varner DD, Hinrichs K, Love CC.Placement of sperm deep in the equine uterine horn allows fewer sperm to be inseminated while maintaining acceptable fertility, and has been promoted for use in circumstances when fertility would be expected to be low if standard insemination were used (e.g., semen from a subfertile stallion, or frozen-thawed semen). Two main techniques, transrectally guided (TRG) and hysteroscopic (HYS) insemination, have been developed for this purpose; however, there is some controversy regarding their comparative efficacy. This study was conducted to compare pregnancy rates when mares were inseminated by T...
Hall CA, Cassaday HJ, Vincent CJ, Derrington AM.Six horses (Equus caballus) were trained to discriminate color from grays in a counterbalanced sequence in which lightness cues were irrelevant. Subsequently, the pretrained colors were presented in a different sequence. Two sets of novel colors paired with novel grays were also tested. Performance was just as good in these transfer tests. Once the horse had learned to select the chromatic from the achromatic stimulus, regardless of the specific color, they were immediately able to apply this rule to novel stimuli. In terms of the underlying visual mechanisms, the present study showed for the ...
Schenzel S, Rohde C, Fugazzola MC.A three-week-old warmblood colt was referred for a two-week history of lameness on the left thoracic limb, and a two-month-old Quarter Horse-mix filly was referred for malaligned pelvic limbs since birth. The foals were diagnosed with agenesis and dysgenesis of the navicular bone, respectively. In this report, we present clinical signs, diagnostics, and postmortem workup of the two cases.
Wendt-Hornickle EL, Snyder LB, Tang R, Johnson RA.To investigate changes in colloid osmotic pressure (COP), total protein (TP) and osmolality (OSM) during anesthesia in horses given intravenous lactated Ringer's solution (LRS) or LRS and hetastarch (HES). Methods: Prospective, clinical trial. Methods: Fourteen horses presented for surgery. Mean age 8.3 ± 1.9 years; mean weight 452 ± 25 kg. Methods: Horses were premedicated with xylazine intravenously (IV); anesthesia was induced with ketamine and diazepam IV, and maintained with sevoflurane. Butorphanol was administered IV with pre-medications or immediately after induction. Xylazine was ad...
Medica AJ, Gibb Z, Sheridan A, Harrison N, Aitken RJ.MTT is a commonly used cell vitality probe, due to its ability to form insoluble formazan deposits at cellular locations of intense oxidoreductase activity. Although this response is considered a reflection of mitochondrial redox activity, extra-mitochondrial sites of MTT reduction have been recognized within the spermatozoa of several mammalian species. Therefore, the aim of this study was to determine the major sites and causative mechanisms of MTT reduction in stallion spermatozoa. Our results show that stallion spermatozoa displayed substantial mitochondrial formazan deposition, as well as...
Bouhamidi R, Gaillard JL, Silberzahn P, Martin B.The binding of estrone-3-sulfate (E1-3-S) and estradiol-3-sulfate (E2-3-S) to adult stallion plasma was determined and compared with the binding to equine serum albumin (ESA). On the ESA molecule, two binding sites for E1-3-S with an association constant of 1.3 x 10(5) M-1 and several sites of weaker affinity were found; the data for E2-3-S showed the existence of four binding sites of moderate affinity (1 x 10(5) M-1) and several sites of weaker affinity. The removal of albumin from the stallion plasma resulted in the absence of binding of E1-3-S or E2-3-S, whereas the removal of glycoprotein...
Piccione G, Giudice E, Giannetto C, Mortola JP.Heart rate (FH) accelerates in inspiration and decelerates in expiration, a phenomenon known as Respiratory Sinus Arrhythmia (RSA). Although the presence of RSA has been documented in many species, how its magnitude compares among species is unknown. We asked whether the magnitude of RSA in a large mammal, the horse, differed from that of previously measured humans. From electrocardiogram and pneumography, the peaks and troughs of FH were identified breath-by-breath in four horses (Italian Saddlebred geldings) during resting wakefulness. RSA was computed as the peak-trough FH difference, in pe...
McAfoos JL, Ellerbrock RE, Canisso IF.A 14-year-old, 530-kg, multiparous, pregnant Quarter Horse mare was referred for evaluation of premature mammary gland development and lactation. The mare was in the seventh month of gestation. The mare had a history of subfertility and was receiving weekly injections of long-acting progesterone, prescribed by the referring veterinarian. The last dose had been administered four days before presentation. Upon presentation, the mare had vital signs within normal limits, a moderately developed, nonpainful udder with galactorrhea, and no vulvar discharge. Transrectal palpation revealed a well-tone...
Nasir L, McFarlane ST, Torrontegui BO, Reid SW.Papillomaviral DNA has been identified in peripheral blood cells of both cattle and humans with and without associated disease and it has been suggested that such cells may act as sites of viral latency. In order to investigate the possibility of latent papillomaviral infection in the aetiopathogenesis of the equine sarcoid, peripheral blood derived DNA samples from 20 healthy and 34 sarcoid-affected donkeys were subject to polymerase chain reaction (PCR) using papillomaviral specific primers. Analysis of blood derived DNA samples failed to demonstrate the presence of papillomaviral DNA in any...
van Niekerk FE, van Niekerk CH.Sixty-four Thoroughbred and Anglo-Arab mares aged 6-12 years were randomly allocated to 4 dietary groups and fed diets that differed in the total protein content and quality (essential amino-acids). Forty mares were non-lactating and 24 lactating. Eight mares were withdrawn from the investigation owing to injuries or gynaecological pathology. An overall conception rate of 94.6% and a foaling rate of 80% was achieved. Five of 14 (35.7%) mares (Group 1) fed a low-quality protein diet suffered from early embryonic loss before 90 days of pregnancy compared to 3 of 41 (7.3%) mares in the remaining ...
Lieto LD, Cothran EG.Epitheliogenesis imperfecta (EI) is a hereditary junctional mechanobullous disease that occurs in newborn American Saddlebred foals. The pathological signs of epitheliogenesis imperfecta closely match a similar disease in humans known as Herlitz junctional epidermolysis bullosa, which is caused by a mutation in one of the genes (LAMA3, LAMB3 and LAMC2) coding for the subunits of the laminin 5 protein (laminin alpha3, laminin beta3 and laminin gamma2). The LAMA3 gene has been assigned to equine chromosome 8 and LAMB3 and LAMC2 have been mapped to equine chromosome 5. Linkage disequilibrium betw...
Machtinger ET, Geden CJ.House flies (Musca domestica L.) and stable flies (Stomoxys calcitrans (L.)) (Diptera: Muscidae) are common pests in equine and cattle facilities. Pupal parasitoids, primarily in the genera Spalangia and Muscidifurax (Hymenoptera: Pteromalidae), can be purchased for biological control of these flies. However, little is known about the host-habitat preferences associated with host-seeking by these parasitoids. The preferences of two Spalangia and two Muscidifurax species to odors associated with house fly hosts in equine and bovine manure were investigated in the laboratory using a Y-tube olfac...
Derham AM, O'Leary JM, Connolly SE, Schumacher J, Kelly G.Racehorses may perform poorly because of impinging dorsal spinous processes (DSPs) of the thoracolumbar vertebrae. No study has looked objectively at the long-term outcome of racehorses undergoing desmotomy of the interspinous ligament as a treatment for horses with poor performance caused by impinging DSPs. The aim of this study was to examine objectively, by using pre-operative and post-operative racing records, the effectiveness of desmotomy of the interspinous ligament (DISL) in improving the performance of racehorses with impinging DSPs. Medical records of all horses undergoing desmotomy ...
Clothier J, Small A, Hinch G, Barwick J, Brown WY.Chronic musculoskeletal pathologies are common in horses, however, identifying related effects can be challenging. This study tested the hypothesis that movement sensors and analgesics could be used in combination to confirm the presence of restrictive pathologies by assessing lying time. Four horses presenting a range of angular limb deformities (ALDs) and four nonaffected controls were used. The study comprised two trials at separate paddock locations. Trial A consisted of a 3-day baseline phase and 2 × 3-day treatment phases, during which two analgesics were administered to two ALD horses...
