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.
Gillis JP, Zardiackas LD, Gilbert JA, St John KR.Paired equine third metacarpal bones were drilled and tapped for 4.5 mm and 5.5 mm cortical screws. Tapping was done by hand or with an air-driven reversible orthopedic drill. Screws were inserted and subjected to extraction forces to failure of the osseous threads or the screws. There was no difference in holding power of either screw size between hand-tapped and power-tapped holes.
Lester GD, Bolton JR, Cullen LK, Thurgate SM.Myoelectric activity was monitored from the terminal ileum, cecum, and colonic pelvic flexure by use of AgpAgCl bipolar electrodes in 4 adult horses before, during, and after general anesthesia. Horses were anesthetized by way of 3 commonly used regimens, including xylazine (1.1 mg/kg of body weight) and ketamine hydrochloride (2.2 mg/kg); thiopental sodium (7.7 mg/kg), followed by halothane vaporized in oxygen; and thiopental sodium (2.5 g) in guaifenesin (100 mg/ml) solution given to effect, followed by halothane in oxygen. All 3 anesthetic regimens decreased intestinal spike-burst activity ...
Lester GD, Bolton JR, Thurgate SM.Extracellular myoelectric activity from the terminal ileum, cecum, and colonic pelvic flexure was assessed in 4 adult horses. The collection and analysis of myoelectric data involved the development and use of a computer-based system. After collection, the myoelectric signal was digitally filtered to enhance the activity of interest. The smoothed signal was then processed by use of computer programs designed to identify and count spike-burst activity and estimate burst duration. The intense phases of myoelectric complexes also were identified. The propagation of myoelectric spike-burst activit...
Yamamoto Y, Iwafune K, Chûjô R, Inoue Y, Imai K, Suzuki T.1H-NMR spectra of deoxy myoglobins (Mbs) from shark (Galeorhinus japonicus), horse, and sperm whale have been studied to gain insights into their active site structure. It has been demonstrated for the first time that nuclear Overhauser effect (NOE) can be observed between heme peripheral side-chain proton resonances of these paramagnetic complexes. Val-E11 methyl and His-F8 C delta H proton resonances of these Mbs were also assigned from the characteristic shift and line width. The hyperfine shift of the former resonance was used to calculate the magnetic anisotropy of the protein. The shift ...
Geyer C, Hafner A, Pfleghaar S, Hermanns W.Six canine, one feline and one equine granular cell tumours (GCTs) were investigated electron microscopically and immunohistochemically. The tumours were tested for reactivity with monoclonal antibodies against vimentin and desmin and with polyclonal antibodies against cytokeratin, S-100 protein, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE). All GCTs were characterized by their PAS positive cytoplasmic granules in light microscopy, which in electron microscopy appeared as lysosome-like granules. In each case two canine GCTs were stained by the antibody against cytok...
Slocombe RF, Covelli G, Bayly WM.Normal Standardbred horses were given an incremental exercise test on a horizontal treadmill to evaluate the influence of exercise on gas exchange, resistance, dynamic compliance and inertance of the respiratory system. The exercise test consisted of 2 min exercise steps at each of the following speeds: 2.4 m/sec (walk), 4.5 m/sec (slow trot), 7.0 m/sec (fast trot) and 10 m/sec (gallop). At rest and after 1 min of exercise at each step, airflow, tidal volume, respiratory frequency, pharyngeal, mid-oesophageal and transdiaphragmatic pressures and arterial blood gas tensions were measured. The s...
Koepf EK, Burtnick LD.Horse plasma gelsolin labelled with benzophenone-4-isothiocyanate can be photochemically cross-linked to rabbit cardiac tropomyosin. The cross-linking proceeds with greater efficiency in calcium-containing buffers. Further evidence for interaction between these proteins is provided by retention of fluorescently labelled gelsolin on tropomyosin-agarose affinity columns and by the ability of tropomyosin to cause an increase in the fluorescence intensity of gelsolin labelled with fluorescein-5-isothiocyanate. Both of these effects require the presence of calcium ions.
Danton CA, Peacock PJ, May SA, Kelly DF.A 16-year-old showjumping gelding was examined because of a non-painful, slowly progressive caudal thigh swelling, which was associated with 2/10th lameness at the trot. Radiography, real time beta-mode ultrasonography and gamma-scintigraphy of the caudal thigh for the presence of chip fractures, sequestrum formation and, or, abscessation were inconclusive. Radiographic examination of the chest revealed multifocal, nodular cannon ball-like opacities throughout the entire lung fields from which a diagnosis of a primary soft tissue tumour with metastasis to the thorax was made. An anaplastic sar...
Olsen SN.Five horses with squamous cell carcinoma of the stomach are described. The clinical findings included anorexia, weight loss, abdominal distension, abnormal chewing and swallowing behaviour and abdominal masses palpable per rectum in four cases. Haematological studies revealed a normocytic anaemia in three horses, and neutrophilia and hypoalbuminaemia in two. Analysis of peritoneal fluid revealed abnormal effusions in all five horses and neoplastic cells were identified in three of them. The tumours originated in the cardia and metastases were present in all the horses. Three of them had many s...
Sarasola P, McKellar QA.The effect of an oral dose of probenecid on the disposition kinetics of ampicillin was determined in four horses. An intravenous bolus dose (10 mg/kg) of ampicillin sodium was administered to the horses on two occasions. On the first occasion the antibiotic was administered on its own, and on the second occasion it was administered one hour after an oral dose of 75 mg/kg probenecid. The plasma concentration of probenecid reached a mean (+/- se) maximum concentration (Cmax) of 188-6 +/- 19.3 micrograms/ml after 120.0 +/- 21.2 minutes and concentrations greater than 15 micrograms/ml were present...
McGorum BC, Dixon PM.Horses with asymptomatic or symptomatic chronic obstructive pulmonary disease (COPD) and control horses were challenged with oil seed rape either by exposure to a field of flowering Brassica campestris for six days, or by an inhalation challenge with freshly collected pollen from Brassica napus, or by inhalation challenge with a commercial extract of B napus pollen. Clinical and bronchoscopic examinations showed that the challenges did not induce detectable pulmonary disease in the control or asymptomatic COPD affected horses and did not significantly affect their pulmonary mechanics, arterial...
Haezebrouck P, Noppe W, Van Dael H, Hanssens I.From fluorescence measurements on mixtures of bis-ANS and equine lysozyme and from Ca(2+)-dependent hydrophobic interaction chromatography of equine lysozyme, it is demonstrated that Ca2+ binding induces a conformational change upon which hydrophobic regions in the protein become less accessible. Bis-ANS fluorescence titrations in the absence of Ca2+ and in 2 mM Ca2+ are also performed with equine alpha-lactalbumin variants B and C. These variants differ by an amino-acid exchange Asp----Ile at residue 95. The fluorescence titration curves indicate that the accessibility of the probe to the Ca2...
Baumann U, Bode W, Huber R, Travis J, Potempa J.The crystal structure of active-site cleaved equine leucocyte elastase inhibitor, a member of the serpin superfamily, has been solved and refined to a crystallographic R-factor of 17.6% at 1.95 A resolution. Despite being an intracellular inhibitor with rather low sequence homology of 30% to human alpha 1-antichymotrypsin and alpha 1-proteinase inhibitor, the three-dimensional structures are very similar, with deviations only at the sites of insertions and few mobile secondary structure elements. The better resolution in comparison with the structures of other cleaved serpins allows a more pre...
Matthews NS, Miller SM, Hartsfield SM, Slater MR.Recovery from isoflurane anesthesia was shorter, with no difference in quality, compared with halothane anesthesia in 2 groups of horses. In 1 group, 12 horses scheduled for elective arthroscopy were randomly assigned to receive halothane or isoflurane for maintenance of anesthesia during surgery. In the other group, 6 horses received anesthesia only, on 2 occasions, with halothane on 1 occasion, and isoflurane on the other. Difference in the quality of recovery was not seen between isoflurane and halothane anesthesia in either group. In the group that had surgery, recovery to sternal position...
Traub-Dargatz JL, Schultheiss PC, Kiper ML, Stashak TS, Wrigley R, Schlipf J, Applehans FM.Fibrosis of the small intestine led to recurrent colic and weight loss in 2 ponies and 5 horses. There was a reduction in the length of the small intestine to one-half normal in horses 4 to 7. Histologic examination revealed substantial small intestinal submucosal fibrosis and arteriole sclerosis. The cause was not determined, but an environmental factor was suspected because 3 horses were from the same farm and the other animals were from within a 10-mile radius of the farm. The submucosal fibrosis appeared to be secondary to sclerosis of arterioles in the submucosa and mesentery, with low bl...
Poulos PW.Adequate radiographic evaluation of the horse relevant to purchase examination requires the successful integration of technique, interpretation, and reporting. A thorough knowledge of lameness and disease can be masked by incorrect interpretation resulting from poor-quality films or an incomplete examination. Thus, care must be taken to produce an adequate number of high-quality films on which to base a report, which allows you to describe changes that are present. This information, coupled with your physical examination, other laboratory data, and the knowledge of the expressed use of the hor...
Pilsworth RC.Pelvic fracture is a relatively common spontaneous fracture in thoroughbred racehorses. Its diagnosis can be difficult, and radiography in the acute phase carries the risks associated with anaesthesia and recumbency. This paper describes the use of a hand-held probe for point counting after the injection of technetium-99m in the investigation of four cases of pelvic fracture. The level of increased uptake of radioactivity was lower (40 to 61 per cent increase) than for distal limb bone fractures.
Freeman DE, Ferrante PL, Palmer JE.A Latin square design was used to compare the effects of laxatives and a corresponding volume of water on gastrointestinal tract function in 4 healthy horses. Horses were intragastrically infused with each of the following: dioctyl sodium sulfosuccinate (DSS; 50 mg/kg of body weight); magnesium sulfate (0.5 g/kg--low dosage); magnesium sulfate (1.0 g/kg--high dosage); and an equal volume of water (6 L) given as a control infusion. From 5 to 33 hours after the high dosage of magnesium sulfate, feces were slightly softer than usual in all horses. In 1 horse, DSS caused mild colic, hyperpnea, and...
Olson LE.We evaluated the pressure-flow relationships in collaterally ventilating segments of excised pony lungs by infusing N2, He, Ne, or SF6 at known flows (V) through a catheter wedged in a peripheral airway. Measurements were made at segment- (Ps) to-airway opening (Pao) pressure differentials of 3-15 cmH2O when the lungs were held at transpulmonary pressures of 5, 10, and 15 cmH2O. The data were analyzed both by calculating collateral resistance (Ps-Pao/V) and by constructing Moody-type plots of normalized pressure drop [(Ps-Pao)/(1/2 rho U2, where rho is density and U is velocity)] against Reyno...
McKeever KH, Hinchcliff KW, Schmall LM, Reed SM, Lamb DR, Muir WW.Six untrained mares were subjected to incremental treadmill exercise to examine exercise-induced changes in plasma renin activity (PRA) and plasma aldosterone (ALDO) and plasma arginine vasopressin (AVP) concentrations. Plasma renin activity, ALDO and AVP concentrations, and heart rate (HR) were measured at each step of an incremental maximal exercise test. Mares ran up a 6 degree slope on a treadmill set at an initial speed of 4 m/s. Speed was increased 1 m/s each minute until HR reached a plateau. Plasma obtained was stored at -80 C and later was thawed, extracted, and assayed for PRA and AL...
Fincham DA, Ellory JC, Young JD.In thoroughbred horses, red blood cell amino acid transport activity is Na(+)-independent and controlled by three codominant genetic alleles (h, l, s), coding for high-affinity system asc1 (L-alanine apparent Km for influx at 37 degrees C congruent to 0.35 mM), low-affinity system asc2 (L-alanine Km congruent to 14 mM), and transport deficiency, respectively. The present study investigated amino acid transport mechanisms in red cells from four wild species: Przewalski's horse (Equus przewalskii), Hartmann's zebra (Zebra hartmannae), Grevy's zebra (Zebra grevyi), and onager (Equus hemonius). Re...
Evans DR.In reporting the results of the medical examination for purchase, the veterinarian should not make an evaluation as to the animal's suitability for the purpose intended but should rather reveal all of the abnormal and undesirable findings and give his or her opinion as to the effect these findings will have on the performance of the horse for the purpose intended. A written report should be provided, and any factors that have had an influence on the opinion rendered should be a part of the report. A record of all procedures performed, the results of these procedures, the names and addresses of...
Shoemaker RS, Bertone AL, Martin GS, McIlwraith CW, Roberts ED, Pechman R, Kearney MT.The effects of intra-articular administration of methylprednisolone acetate (MPA) on the healing of full-thickness osteochondral defects and on normal cartilage were evaluated in 8 horses. In group-1 horses (n = 4), a 1-cm-diameter, full-thickness defect was created bilaterally in the articular cartilage on the dorsal distal surface of the radial carpal bone. Cartilage defects were not created in group-2 horses (n = 4). One middle carpal joint was randomly selected in each horse (groups 1 and 2), and treated with an intra-articular injection of 100 mg of MPA, once a week for 4 treatments. Inje...
Lavach D.Performance and pleasure horses depend upon their ability to see and assess the environment. Thus, the veterinarian must be able to examine the eyes and recognize abnormalities so that the owner or purchaser can be informed about the visual status and prognosis for the horse's vision. If the veterinarian encounters suspicious or abnormal findings during the examination, a more detailed examination and/or referral to a veterinary ophthalmologist can be recommended to the owner or purchaser.
Hohenhaus MU, Bostedt H.108 mares with a total of 135 oestrous cycles were examined. 30% of the mares showed development of double follicles, found by palpation and ultrasonography. Eight cases of double ovulation, four of them synchronous and four asynchronous, were examined closely. These cases of double ovulation showed different growth and different development of the follicular wall. This occurred at the same time in cases of synchronous double ovulation whereas it differed in case of asynchronous double ovulation. The later ovulating follicle was still growing while the first one had already burst. With both fo...
McFarlane JR, Cabrera CM, Coulson SA, Papkoff H.The rhinoceros is an endangered species related to the horse family. Little is known of its reproductive endocrinology. The objectives of this study were to partially purify rhinoceros pituitary hormones, determine which assays could be used for their assessment, and to ascertain whether rhinoceros LH possesses the intrinsic FSH activity of equine LH. A single pituitary each from a White (1.3 g) and a Black (1.2 g) Rhinoceros was homogenized and extracted (pH 9.5), then subjected to pH and salt fractionation, and ion-exchange chromatography (DEAE and Sephadex SP-C50) to yield partially purifie...
Sudheer Kumar C, Swamy MJ.The major protein of horse seminal plasma, HSP-1/2, exhibits membranolytic and chaperone-like activities and plays a crucial role in regulating sperm capacitation. L-Carnitine is a small polar molecule present in high concentrations in mammalian seminal plasma. The present results demonstrate that L-carnitine binds to HSP-1/2 and increases its thermal stability, enhances cooperativity of its chemical unfolding and decreases both chaperone-like and membranolytic activities of this protein. The HSP-1/2-L-carnitine complex exhibits anti-oxidative behaviour by inhibiting the production of hydroxyl...
Ramsay JD, Evanoff R, Mealey RH.Hepacivirus A (also known as nonprimate hepacivirus and equine hepacivirus) is a hepatotropic virus that can cause both transient and persistent infections in horses. The evolution of intrahost viral populations (quasispecies) has not been studied in detail for hepacivirus A, and its roles in immune evasion and persistence are unknown. To address these knowledge gaps, we first evaluated the envelope gene (E1 and E2) diversity of two different hepacivirus A strains (WSU and CU) in longitudinal blood samples from experimentally infected adult horses, juvenile horses (foals), and foals with sever...
McGreevy PD, McLean AN, Keay KA, Thomson PC.Trained responses are said to be under stimulus control when they appear reliably and exclusively on cue. The SMART system is a conceptual, three-dimensional graphic that uses four quadrants to chart a horse's responsiveness to various cues from two reins and the trainer's legs and seat. The current plots have been designed for ridden horses. The models assume that the trainer's cues are bilaterally equivalent, unless the intention is to signal a turn or a lateral movement. The extent to which 'go' signals manifest as straight, forward locomotion reflect the bilateral balance of the horse's re...
Léon A, Versmisse Y, Despois L, Castagnet S, Gracieux P, Blanchard B.Isolation and identification of Taylorella equigenitalis, the causative agent of contagious equine metritis, by bacteriology is laborious and does not permit differentiation from the other member of the genus, Taylorella asinigenitalis. Moreover, other organisms such as Klebsiella pneumoniae and Pseudomonas aeruginosa can also cause endometritis in mares and warrant diagnostic detection. Our objectives were to develop a rapid preparation method for field swab samples and to validate this protocol using new multiplex real-time polymerase chain reaction (rtPCR) detection tools for identification...
Fintl C, Milne EM, McGorum BC.To determine whether urinalysis can aid the diagnosis of equine grass sickness, samples of urine from 15 horses with acute grass sickness, eight horses with subacute grass sickness, 17 co-grazing horses and 17 stabled control horses were analysed. The samples from all of the horses with grass sickness had a significantly higher specific gravity, higher protein and creatinine concentrations and a significantly lower pH; the samples from the horses with acute grass sickness also had significantly higher glucose concentrations. These differences may support a diagnosis of grass sickness but they ...
Cramp PA, Prange T, Nickels FA.The purpose of this article is to review the literature and personal experiences of equine surgeons so as to describe procedures that can be performed in the standing sedated horse to alleviate conditions that result in upper respiratory tract obstruction. Upper respiratory tract surgery requires attention to detail, meticulous planning, and careful dissection and execution with little room for error. This article describes a selection of standing upper airway procedures, the indications for and possible complications of these surgeries, and advantages and disadvantages of a particular method....
Rainger JE, Evans DL, Hodgson DR, Rose RJ.The distribution of lactate between red blood cells (RBC) and plasma was examined at rest, during exercise and 30 min after exercise in six Standardbred horses. Lactate and water concentrations were measured in blood and plasma samples collected prior to exercise, during the last 15 s of each step of an incremental exercise test and at 5 min intervals during the first 30 min after exercise. The mean ratio of RBC lactate concentration (RBCLa) to plasma lactate concentration (PLa) prior to exercise was 1.02 +/- 0.34. Haemoconcentration during exercise was associated with more rapid accumulation ...
Szalai G, Bailey E, Gerber H, Lazary S.The genetic diversity at the ELA DQ beta locus was investigated using polymerase chain reaction and DNA sequencing. Based upon serological methods 16 class II homozygous animals were selected and their genomic DNA was used. A DQ beta gene from an equine cDNA library was also sequenced. Our methodology and the similarity between the genomic and the cDNA sequences suggest that the studied locus is expressed on equine lymphocytes. In the predicted amino acid sequence the most extensive variation is located at residues 56-60. The pattern of these five amino acids is strongly correlated to the sero...
Fulton IC, Derksen FJ, Stick JA, Robinson NE, Duncan ID.A nerve muscle pedicle (NMP) graft was placed in the cricoarytenoideus dorsalis (CAD) muscle of 6 horses with induced left laryngeal hemiplegia. The NMP graft was created by use of the first cervical nerve and omohyoideus muscle. In 1 horse (control), the first cervical nerve was transected after placement of the NMP graft. One year after the surgical procedure, horses were examined endoscopically and then anesthetized. While the larynx was observed endoscopically, the first cervical nerve was stimulated. Horses were subsequently euthanatized, and the larynx was harvested. Prior to anesthesia,...
Endo Y, Hobo S, Korosue K, Ootsuka K, Kitauchi A, Kikkawa R, Hidaka Y, Hagio M, Tsuzuki N.The present study evaluated the effects of single-dose filgrastim on hematology in 16 healthy horses after long-distance transportation. Horses were assigned to receive filgrastim (0.23 µg/kg, SC, once; G-CSF group; n=8) or saline (0.9% NaCl) solution (0.3 ml, SC, once; control group; n=8) ≤ 1 hr before transportation. Horses were transported 2,530 km using commercial vans over the course of approximately 44 hr. Clinical examinations and hematologic analyses were performed on all horses before and after transportation. Because the post-transportation white blood cell counts and bacillary ne...
Olsman AF, Sloet van Oldruitenborgh-Oosterbaan MM.The clinical signs of liver disease are highly variable and non-specific. Irrespective of the cause or the duration of liver disease, more specific clinical signs, e.g. hepatic encephalopathy, become apparent in the advanced stages of the disease. Due to the non-specific clinical signs, the possible diagnosis of liver disease is frequently not taken into consideration. However, measurement of the plasma or serum concentrations of total bile acids and gamma glutamyl transferase (gamma GT) may provide valuable diagnostic information. The specific diagnosis can be confirmed by ultrasound examinat...
Miro J.Ultrasonography has become indispensable in the control of equine reproduction. Mare ovary layers are inverted with respect to other species, with the follicles and corpus luteum found inside the ovary; only large follicles protrude from the organ's surface. This renders the making of diagnoses via rectal palpation of the ovaries very difficult. Ultrasound imaging, however, provides another avenue of examination. Since its first use in 1980, the diagnostic potential of ultrasonography has greatly improved. Colour Doppler ultrasonography can even asses blood flow, allowing for much better monit...
Witte S, Thorpe PE, Hunt RJ, Spirito MA, Rodgerson DH.A lag-screw technique for transphyseal bridging of the medial aspect of the distal tibial physis in foals with tarsal valgus deformities and results of the technique in 11 foals (6 with bilateral tarsal valgus deformities and 5 with unilateral tarsal valgus deformities) are described. Briefly, horses were anesthetized, and a single stab incision was made through the skin to the underlying bone over the most distal aspect of the medial malleolus. A 20-gauge needle was placed in the incision to guide screw placement, and a lag screw was inserted parallel to the medial cortex of the tibia under r...
Ginther OJ.Ultrasonography was used to determine whether there is embryo reduction in mares with unilaterally fixed twins when a major portion of the vascularized area of the wall of one of the embryonic vesicles is in apposition with the wall of the adjacent vesicle, rather than with the endometrium (deprivation hypothesis). In addition, the effect of ovulatory pattern (synchronous and asynchronous) on the incidence of embryo reduction was studied. Twin vesicles were ultrasonically detected on days 11 to 15 (ovulation = day 0) and were examined daily until there was embryo reduction or until day 40. In ...
D'Arcy-Moskwa E, Weston L, Noble GN, Raidal SL.Mucosal integrity may be objectively assessed by determination of the absorption of exogenous substances such as sucrose. Gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-mass spectrometry (LC/MS) have been reported for the accurate quantification of low concentrations of sucrose in serum. LC/MS offered the advantage of high sensitivity and mass selectivity without the need for extensive sample derivatization required for GC/MS methods. However, the high polarity and non-volatile nature of the sucrose molecule renders LC/MS techniques challenging. Previously published rep...
Vandeplassche MM.From a total of 601 severe dystocias in mares, 408 (68%) of the fetuses were in anterior, 95 (16%) in posterior and 98 (16%) in transverse presentation, compared with 99%, 1% and 0.1% respectively for spontaneous parturitions. From the cases with anterior presentation, 151 (37%) showed reflected heads and necks. From the cases with posterior presentation, 47 (50%) presented hip flexions, 25% had hock flexions, and 25% had stretched hind legs, 45 (47%) of the fetuses were in lateral or ventral position, and 28 (30%) of the fetuses were malformed (mainly torticollis and head scoliosis). All 98 c...
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...