"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Blythe LL, Kitchell RL, Holliday TA, Johnson RD.Normal nerve conduction velocity values in 10 ponies were determined for sensory nerve fibers in the median and ulnar nerves. A percutaneous signal-averaging technique was developed and used. Medial and lateral palmar digital nerves on the abaxial surface of the proximal sesamoid bones were used as the sites for percutaneous stimulation, whereas recording sites included the medial and lateral palmar nerves just distal to the carpus and the median and ulnar nerves in the middle of the radius. Sensory nerve conduction velocities can be evaluated simply and clinically in the limbs of horses, usin...
Toro M, León E, López R, Pallota F, Garcia JA, Ruíz A.Assays dealing with the therapeutic and prophylactic activity of isometamidium on experimental infections by Trypanosoma vivax and T. evansi were carried out. The drug was found to be highly effective against T. vivax infection in sheep and cattle in which periods of protection ranging from 118 to 195 days were achieved. No complete effects against infection by T. evansi were observed. The drug was well tolerated in sheep and cattle while side-effects were noted in treated mares. It was concluded that isometamidium could be used to prevent damage and economical losses caused by T. vivax in Ven...
Leach DH, Oliphant LW.The ultrastructure of cells of the secondary epidermal lamellae from the hoof wall of 8 adult horses was described. Stages of progressive keratinization were not observed in this cell population. The morphologic features of cells of the secondary epidermal lamellae indicated that these lamellae were composed of nonmobile populations of cells and that primary epidermal lamellae moved past the secondary lamellae by breaking of the desmosomes connecting these 2 cell populations. Seemingly, debris present in the intercellular space between primary and secondary lamellae was a by-product of this re...
Parks C, Manohar M, Lundeen G.To examine the effects of tachycardia on coronary circulation, transmural distribution of myocardial blood flow (MBF, 15-micron diameter radionuclide-labeled microspheres) was studied in six healthy adult ponies at rest (heart rate = 60 +/- 7 beats . min-1), during ventricular pacing at 150 and 200 beats . min-1, as well as with ventricular pacing at 250 beats . min-1 before and during maximal coronary vasodilatation (iv adenosine infusion; 4 mumole . kg-1 . min-1). Mean aortic pressure and cardiac output were unchanged from control values with ventricular pacing. Whereas ventricular pacing at...
Hodgson DR, Rose RJ, Allen JR.For determination of 3 muscle fiber types in equine skeletal muscle, a comparison of 2 preincubation buffers, each followed by myosin adenosine triphosphatase staining, was made. Serial sections of the muscle samples (n = 75) were preincubated in an acid buffer (pH 4.6) or a formaldehyde-glycine buffer (pH 7.25) and then were stained for myosin adenosine triphosphatase. Differentiation of muscle fibers into type I, IIA, and IIB was identical with both techniques; however, in the samples prepared at pH 4.6, type I fibers were black; type IIA, light gray; and type IIB, dark gray. In the samples ...
Thomas DP, Fregin GF, Gerber NH, Ailes NB.The effects of 5- and 10-wk treadmill exercise training on cardiorespiratory function were evaluated in the horse. Cardiac output (Q), heart rate (HR), and stroke volume (SV), as well as left ventricular (LVP), aortic (AoP), and mean right atrial (RAP) pressures and the peak first time derivative of LVP (LV dP/dtmax), were measured at rest and at five different levels of exercise up to 90% of initial predicted maximal HR (HRmax). Oxygen uptake (VO2) and respiratory exchange ratio (R) were also obtained under the same conditions. At rest, although HR was no different after training, LV dP/dtmax...
Wu MJ, Feldman BF, Zinkl JG, Jain NC.Red blood cell creatine concentration was examined to determine its association with the equine erythropoietic response. Studies were conducted on 9 healthy horses, 4 healthy ponies, 24 anemia horses, and 2 horses in which anemia was experimentally induced. A modified Jaffe reaction was used to measure RBC creatine concentration. The mean RBC creatine concentration of the 9 healthy horses was 5.72 +/- 0.42 mg/dl, and that of the 4 healthy ponies was 2.59 +/- 0.31 mg/dl. Density-separation of erythrocytes from the healthy horses revealed significantly higher (P less than 0.001) creatine content...
Sanderson GN, O'Callaghan MW.This article describes the gross radiographic anatomy of the equine thorax observed on the lateral radiographic projection. The descriptions presented were derived from a retrospective study of a large number of thoracic radiographs of cases referred to the Massey University clinic in conjunction with research studies in bronchography, angiography and in vitro contrast techniques. The characteristics of the thoracic bony structures, the vasculature, and the airways are examined separately; followed by a discussion of the relative contribution of the various structures to the overall thoracic r...
Reitsma JF.A report on infection with Dictyocaulus arnfieldi in a number of ponies and one horse in which complete clinical recovery was obtained following treatment with albendazole (Valbazen), administered by oral route at a dosage of 25 mg/kg of body weight twice daily for five days.
Siess W, Lapetina EG.Phospholipase C has been studied in homogenates, total particulate and soluble fractions of horse and human platelets. This enzyme, assayed with exogenous L-3-phosphatidyl[14C]inositol, is predominantly localized in the soluble fraction and its distribution parallels that of lactate dehydrogenase. A small percentage of activity present in the particulate fraction seems to be due to contamination with soluble enzyme. Enzyme from horse and human platelets appears identical, having a Km of 0.10-0.15 mM, acid pH optimum (pH 5.5) and showing Ca2+-dependency and weak inhibition by deoxycholate. Anal...
Suter M, Fey H.An enzyme-linked immuno sorbent assay (ELISA) for measuring horse IgE specific to ovalbumin, bencylpenicilloic acid and odinitrocarboxyphenol is described. We used a sandwich type of ELISA by which horse serum was incubated in antigen-coated tubes containing one additional polystyrene ball, followed by rabbit anti horse IgE serum. The tubes were then incubated with biotinylated goat anti rabbit globulin followed by avidin coupled to phosphatase. Endpoint titrations were compared. The ELISA is highly reproducible due to the pretreatment of the polystyrene with glutaraldehyde. The increased anti...
George JL, Reif JS, Shideler RK, Small CJ, Ellis RP, Snyder SP, McChesney AE.During an outbreak of strangles in a population of research horses, 4 mares were identified as carriers of Streptococcus equi. Three of the mares had typical signs of strangles (severe regional lymphadenitis with or without rupture of abscessed lymph nodes). The 4th mare experienced episodes of serous to mucopurulent nasal discharge, but never had more than a mild degree of lymph node enlargement. Streptococcus equi was isolated from the abscessed lymph nodes and from nasopharyngeal swab specimens from the first 3 mares from 6 to 19 weeks after rupture of involved nodes. Streptococcus equi was...
Suter M, Fey H.Horse IgE was isolated from a serum pool collected from foals naturally infected with endoparasites. The serum was precipitated with ammonium sulfate, delipidated with dextran sulfate and further purified by gel filtration, anionic exchange, immunosorption or preparative polyacrylamide gelelectrophoresis. By these methods IgE could be isolated at a purity of 81%. The sera from rabbits immunized with the purified horse serum fractions were tested using reversed passive cutaneous anaphylaxis and an enzyme linked immunosorbent assay (ELISA). By the ELISA method cross reaction of rabbit anti horse...
McPherson EA, Thomson JR.The aetiology, pathophysiological changes, pathology and clinical signs of the disease as presently understood are discussed. The condition appears to be a hypersensitivity of the respiratory system in some horses to poor quality hay and straw. Micropolyspora faeni is the chief agent identified in the northern part of the United Kingdom. In other locations, the chief agent is probably different. The principal changes are spasm of the airways and bronchiolitis of the small airways. Onset may be acute or insidious. The chief clinical signs are well known but the disease process is reversible if ...
Coffman JR, Colles CM.Sensitivity to insulin was assessed in ponies episodically affected with chronic laminitis by measurement of blood glucose and arterial blood pressure during insulin tolerance tests. In terms of blood glucose values, laminitic ponies were significantly less sensitive to insulin than controls. Conversely, a post-insulin decline in diastolic, systolic and mean blood pressure values was significantly greater in laminitic ponies than in controls.
Bossut DF, Leshin LS, Stromberg MW, Malven PV.Electro-acupuncture (EA) treatment of horses to induce cutaneous analgesia also increased plasma concentrations of beta-endorphin (beta-EP) and cortisol. The magnitude of these increases did not relate consistently to the degree of EA-induced analgesia. Respiration and heart rates were also markedly increased during EA treatment. Intact female horses had higher packed cell volume and plasma beta-EP as well as lower plasma total protein than castrated male horses. Plasma cortisol, heart rate, and respiration rate did not differ significantly between sexes. None of the parameters measured before...
Roberts MC, Seawright AA.Colic was induced in horses and ponies following topical or intravenous (iv) administration of amitraz, a formamidine acaricide. The condition was characterised by rapid cessation of intestinal sounds, stasis, extensive impaction and tympany throughout the large colon. Three animals that were necropsied had a faecalith obstructing the proximal small colon aboral to marked colonic impaction. A reproducible and reversible impaction colic syndrome could be induced by an iv injection of 1 mg amitraz/kg body weight in solvent. There were immediate central nervous system and intestinal signs. Large ...
Thijssen HH, van den Bogaard AE, Wetzel JM, Maes JH, Muller AP.The pharmacokinetics of racemic warfarin were studied in 6 adult horses. After IV administration, the plasma concentration of warfarin showed a biphasic decline in time. Analysis of the data, according to 2-compartment kinetics, revealed the following constants: biological half-life was 13.3 hours, apparent volume of distribution was 0.46 L X kg-1, body clearance was 25.3 ml X hour-1 X kg-1. Warfarin was bound (91.5%) to plasma proteins. Unchanged warfarin was not detected in the urine. Absorption from the gastrointestinal tract was almost complete. Concentrations of warfarin in tissue were ex...
Johnson JA, Prescott JF, Markham RJ.The intragastric inoculation of a suspension of Corynebacterium equi on five consecutive days induced severe ulcerative colitis, typhlitis, and lymphadenitis of colonic and cecal nodes in two ponies necropsied three weeks after infection. No gross lesions were observed in two ponies necropsied ten days after infection. A single inoculum of equivalent size failed to induce gross lesions in four ponies killed at ten or 20 days after infection. Microscopic lesions consistent with early C. equi infection of Peyer's patches were seen in two of the ponies killed ten days after infection. Only one sm...
Brumbaugh GW.The goal of antimicrobial drug use is quite specific. Consideration of many microbe-related, host-related, and drug-related factors is necessary for appropriate selection and use of antimicrobial drugs in equine patients. The concepts and data presented in this article demonstrate that fact. At the risk of oversimplification, "The bug denotes the drug, and the horse directs the course."
Finger MA, Biava JS, Dornbusch PT, Perotta JH, Ullmann LS, Serpa PBDS, Kmetiuk LB, Dos Santos AP, Biondo AW, Leutenegger C, Filho IRB.Molecular approaches to diagnose respiratory viruses have provided an opportunity for early and subclinical pathogen detection, particularly in samples from the upper respiratory tract. This study aimed to investigate the presence of herpesviruses, particularly equid herpesvirus (EHV)-2 and EHV-5, in samples from the lower respiratory tract of healthy racehorses from Southern Brazil. Unassigned: Samples from the lower respiratory tract (i.e., bronchoalveolar lavage fluid [BALF]) were assessed by video endoscopy, cytological evaluation of BALF, and tracheal aspirates (TA), along with quantitati...
Pu F, McKinney AR, Stenhouse AM, Suann CJ, McLeod MD.A study of the equine phase II metabolism of the anabolic agent boldenone is reported. Boldenone sulfate, boldenone glucuronide and their C17-epimers were synthesised as reference standards in our lab and a method was developed for their detection in a horse urine matrix. Solid phase extraction was used to purify the analytes, which were then detected by ion trap LC/MS. Negative and positive ionisation mode MS(2) were used for the detection of sulfate and glucuronide conjugates, respectively. Boldenone sulfate and 17-epiboldenone glucuronide were detected as the major and minor phase II metabo...
Kalmykov NP.This report analyzes a find of fossils of Pliocene three-toed horse (Hipparion tchicoicum) in western Transbaikalia. The age of the mammalian fauna from red-brown clay in the Udunga locality indicates that Chikoi hipparion lived in the south of Eastern Siberia as early as the second half of the Early Pliocene; its remains in this area were known only from the red beds of the Upper Pliocene. This find made it possible to fill the existing hiatus (Early Pliocene) in its stratigraphic distribution: Late Miocene-Late Pliocene. The range of this three-toed horse species did not go beyond the border...
Sloet van Oldruitenborgh-Oosterbaan MM, Kalsbeek HC.A 14-year-old Friesian breeding mare had strangury, depression, inappetence, neutrophilia and uraemia. Its urine had a low specific gravity and contained protein, blood cells and bacteria. Rectal examination showed that both kidneys and ureters were enlarged. Post mortem examination confirmed the diagnosis of pyelonephritis and revealed that small tumours in the vulva were probably the cause of the uropathy.
Baird AN, Freeman DE.Rectal tears have important medicolegal implications, and severe tears have a poor prognosis. Prompt diagnosis, immediate application of first aid measures, early referral, use of appropriate definitive treatments, and aggressive aftercare will improve the prognosis. The grade of rectal injury will determine the definitive treatment, but there are few guidelines to determine which treatment is best in each case. Bypass procedures, such as colostomy and indwelling rectal liner, have their own advantages and disadvantages, but can facilitate healing and prevent life-threatening complications if ...
Gulevsky AK, Grischenko VI, Tereschenko OS, Shchenyavcky IJ.The experimental data presented in the work testify to the cytostatic activity of 1-10 kD polypeptide fractions from brains of the hibernating ground squirrel and the Yakut horse towards Ehrlich ascitic carcinoma (EAC) cells. The experiments on the investigation of the inhibiting influence of 1-10 kD fractions from tissues of the hibernating and cold-adapted animals on protein-synthesizing system of EAC cells allow us to conclude that the cytostatic effect of the fractions is effected at the genetic level in the tumor cells.
Stewart-Scott IA, Pearce PD, Burkin DJ.Sex chromosome abnormalities have been detected in a further five mares with clinical histories of small ovaries and absent or irregular oestrous cycles. Three mares had 63,XO karyotypes (X monosomy) and two were sex chromosome mosaics with karyotypes of 63,XO/64,XY and 63,XO/64,XX/64,XY respectively. A sex chromosome abnormality (X monosomy) has also been found in a filly where it was suspected because of her short stature.
Ellis PM.An accurate modified auscultatory technique for the indirect measurement of arterial pressure in the horse is described. Limitations of the method were sensitivity to external motion in nervous, conscious horses, and the failure to detect Korotkoff sounds in shocked, anaesthetized surgical cases. The apparatus required for the method is expensive and is probably impractical for routine monitoring during anaesthesia.
May SA, Hooke RE, Lees P.The presence, in equine synovial fluid, of inhibitors of interleukin-1 (IL-1) activity has been investigated by means of an assay involving IL-1-mediated production of PGE2 by synovial cells. Inhibitors of IL-1 alpha and IL-1 beta were identified in normal synovial fluid and synovial fluid from two horses with early joint disease. Inhibitors of IL-1 alpha were also present in synovial fluid from two horses with long-standing joint disease. However, IL-1 beta inhibitory activity was not present in fluid from the horses with more chronic joint disease. The effect appeared to be specific for IL-1...
Cook G, Papich MG, Roberts MC, Bowman KF.To determine the i.v. pharmacokinetics of cisapride and measure systemic absorption after rectal administration. Methods: 5 healthy adult mares (380 to 610 kg). Methods: Cisapride was administered, i.v., at a dosage of 0.1 mg/kg of body weight. In the same horses, after a 1-week washout period, cisapride was administered rectally at a dosage of 1 mg/kg by mixing crushed tablets with propylene glycol and administering the mixture into the rectum. After each drug administration, a series of blood samples were collected. Plasma was obtained and analyzed by high-performance liquid chromatography t...
Pihl TH, Jacobsen S, Olsen DT, Højrup P, Grosche A, Freeman DE, Andersen PH, Houen G.OBJECTIVE To purify and characterize equine vitamin D-binding protein (VDBP) from equine serum and to evaluate plasma concentrations of VDBP in healthy horses and horses with gastrointestinal injury or disease. ANIMALS 13 healthy laboratory animals (8 mice and 5 rabbits), 61 healthy horses, 12 horses with experimentally induced intestinal ischemia and reperfusion (IR), and 59 horses with acute gastrointestinal diseases. PROCEDURES VDBP was purified from serum of 2 healthy horses, and recombinant equine VDBP was obtained through a commercial service. Equine VDBP was characterized by mass spectr...
Suarez-Fuentes DG, Caston SS, Tatarniuk DM, Kersh KD, Ferrero NR.Contaminated or septic navicular bursitis has been reported to have a guarded prognosis after surgical treatment with navicular bursotomy only. In our experience, the use of navicular bursotomy for the treatment of this disease in combination with systemic and local delivery of antimicrobials can provide a good prognosis, even in horses with chronic disease. Objective: To report the outcome of horses undergoing navicular bursotomy for the treatment of contaminated or septic navicular bursitis. Methods: Descriptive case series. Methods: Navicular bursotomy was performed in combination with syst...
Liggett AD, Weiss R, Blue JL.Myospherulosis was diagnosed in a mature pony. Several parent bodies containing many spherules were observed microscopically in biopsy material from an area of cellulitis. The spherules are altered red blood cells that form as the result of prolonged contact with necrotic fat or petrolatum-based ointments. These structures must be differentiated from fungal elements. The recommended treatment is surgical excision.
Vermedal H, Strand E.To report dynamic laryngeal collapse (DLC) associated with poll flexion as a potential complication of the laryngeal tie-forward procedure (LTFP) in harness racehorses. Methods: Short case series. Methods: Three harness racehorses. Methods: Preoperative and postoperative medical records of all harness racehorses that underwent the LTFP were reviewed, as were high-speed treadmill videoendoscopy recordings of 35 horses that returned for upper airway evaluation postoperatively. Results: One standardbred and two Norwegian coldblooded trotters in which dorsal displacement of the soft palate had bee...