"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.
Riggott JM, Quarmby WB.A surgically excised tumour from the thoracic wall of a hunter mare was diagnosed as a fibrosarcoma on histological examination. Its recurrence necessitated further surgery 6 weeks later. Because of the invasive nature of the lesion a prolonged course of chemotherapy was administered postoperatively. The tumour did not recur a second time.
Parry BW, Gay CC, McCarthy MA.Eighteen horses were used to investigate the influence of head position on arterial blood pressure, measured indirectly at the coccygeal artery. Head height significantly altered systolic pressure, diastolic pressure, pulse pressure, and mean arterial pressure, such that head-lowering decreased and head-raising increased all variables.
Lucke JN, Hall GN.Blood samples were taken before and immediately after 80 km and 40 km rides held on consecutive days and analysed for haematocrit, blood glucose and lactate, plasma sodium, potassium, calcium, albumin, free fatty acids (FFA), glycerol, bicarbonate, insulin, cortisol, glucagon, urea, creatinine, uric acid, bilirubin and alkaline phosphatase. Unusually hot weather probably contributed to haemoconcentration with a significant (P < 0.001) increase in haematocrit and plasma albumin. A fall in blood glucose, with a rise in FFA and glycerol were consistent with long distance riding and were associ...
Brouwer GJ, Hall LW, Kuchel TR.The effects of combining large doses of xylazine (1.1 mg per kg intravenously) with ketamine, methohexitone and thiopentone were studied in four experimental ponies. Onset of anaesthesia was more delayed after ketamine than after the barbiturates. Assessment of smoothness of induction and recovery indicated that all three combinations were effective and acceptable. Injection of xylazine was followed by atrioventricular (A-V) block which could be prevented by the prior administration of atropine. Blood pressure was well maintained with all three combinations of drugs. Arterial oxygen tension de...
Kamada M, Ando Y, Fukunaga Y, Kumanomido T, Imagawa H, Wada R, Akiyama Y.A primary enzootic of equine Getah virus infection involving 722 of 1,903 racehorses occurred at a training center in Japan between September and November of 1978. Sixty-two viral agents were isolated from the plasma of 209 sick horses which exhibited pyrexia with rectal temperatures ranging from 38.5--40 degrees C, urticarial rash on various portions of the body, and edema of the hind legs. The viruses were antigenically related to the AMM 2021, Haruna, and Sagiyama strains of Getah virus. Infection and disease were produced experimentally in horses when inoculated by the intramuscular or int...
Maget-Dana R, Michalski JC.A simple method for the isolation of hematoside NeuNG1-Lac-Cer from horse erythrocytes is described. An aliquot of the crude ganglioside fraction was labeled by tritiated sodium borohydride after mild periodate oxidation. The compounds obtained were used as radioactive tracers in column chromatography. Gangliosides were applied onto a silicic acid column and eluted stepwise by solvents of steadily increasing polarity. The major ganglioside, NeuNG1-Lac-Cer, was eluted in a high yield by the solvent mixture chloroform/methanol/water (60:35:8, v/v/v).
Littlejohn A.Twenty cases of chronic cough originating in the lung and associated with loss of performance were clinically examined. The physical signs observed were compared with those observed in a control series of 38 clinically normal horses. Reduced work tolerance, coughing for more than 3 months and abnormal pulmonary sounds (râles) were primary signs of chronic obstructive pulmonary disease (COPD). Forced abdominal expiratory efforts and pumping of the anus were regarded as confirmatory signs. Neither nasal discharge nor increased marginal distance was found to be a reliable sign of COPD. The mean ...
Glick DM, Mockel J.The disposition of 45Ca was studied in equine parathyroid gland slices. This preparation was shown to be viable by its ability to carry out protein synthesis, by the responsiveness of its respiration to effectors of oxidative phosphorylation, and by its calcium-inhibitable PTH secretion. 45Ca accumulates in the slices as the extracellular calcium is raised through the range in which physiological serum calcium concentration lies. The tissue slices behave as if they have no calcium pump: (a) depriving the cells of energy by treatment with antimycin A does not admit more calcium to the tissue, (...
Kono Y, Sentsui H, Ito Y.A virus (Sakai) which had been recovered from an outbreak of disease in horses was found to be a small spherical enveloped RNA virus with a diameter of approximately 70 nm and a buoyant density of 1.22 g per ml. It grew well and produced a cytopathic effect in a variety of cell cultures; it was sensitive to organic solvents, heat and low pH. It agglutinated goose erythrocytes in a 0.35 M sodium chloride solution at an optimum pH of 6.2 and was antigenically identical or closely related to Getah virus, a member of the alphavirus subgroup of the Togaviridae.
Chacon-Arellano JT, Woolley DM.Smooth muscle cells are present in the tunica albuginea testis of the horse, pig and sheep. typical fusiform muscle cells constitute a distinct layer up to 0.3 micrometer thick in the horse; there are fewer muscle cells, mainly of the branched form, in the pig; whereas in the sheep the muscle component is least well developed, with some cells intermediate in form between smooth muscle cells and fibroblasts (myofibroblasts). Attention is drawn to the continuity of this capsular muscle with the smooth muscle associated with the vasculature of the spermatic cord in the horse. This association sug...
Button C, Gross DR, Johnston JT, Yakatan GJ.The pharmacokinetics of IV administered digoxin and the bioavailability of intragastrically administered powdered digoxin tables suspended in water were investigated in 6 clinically normal adult horses by 125I radioimmunoassay. The effect of 3 to 5 sequential IV doses of 5 micrograms of digoxin/kg of body weight at 2-hour intervals on a left ventricular index of contractility (Vmax) was assessed in 5 clinically normal horses. Standard pharmacokinetic equations and mean pharmacokinetic variables were used to derive parenteral and oral (loading and maintenance) doses for digoxin in horses. The c...
Dietz HH, Nielsen K.Four horses with a history of chronic diarrhoea and weight loss were studied. Three of them revealed malabsorption, as indicated by decreased absorption of D(+)-xylose. Three patients had distinct hypoalbuminaemia, and 131I-albumin turnover rates of these three horses were increased, compared to two normal control horses. However, the increases were not very marked, probably because actual signs of enteric disease were few in the patients, all of which were studied during convalescence. It is suggested that the observed hypoalbuminaemia is due to a gastrointestinal protein loss during the chro...
Niilo L, Bainborough AR.Sera from human, cattle, sheep, swine, and horse populations in western Canada were tested for the presence of Clostridium perfringens enterotoxin antibody by the passive hemagglutination (PHA) test, supplemented by an immunodiffusion test and by counterimmunoelectrophoresis. A total of 224 human, 345 cattle, 165 sheep, 620 swine, and 768 horse serum samples were examined. Low-titer reactions in the PHA test were detected in human, cattle, horse, and swine sera, in that order, with no titers demonstrated in sheep. The titers in human sera ranged up to 1:128 and three of these samples were also...
Irwin DH, Howell DW.Several indications for swimming horses are recalled. A satisfactory pool and the technique for its use are described. Some observations on the effect on swimming are offered.
Chapman DI, Moss MS, Tomlinson PW, Harrison MP, Simmons PJ.1. Following single intramuscular doses of [14C]fluprostenol (0.5--2.4 micrograms/kg) to three female horses and to three gelded male horses, radioactivity was present in the plasma within 5 min; peak concn. (0.32--1.30 ng/ml fluprostenol equiv.) occurred 5 to 90 min after injection. Radioactivity was still present in the plasma of the females after three days. About 88% of fluprostenol is bound to plasma proteins. 2. Radioactivity was present in the parotid saliva of the gelded male horses within 10 min. Peak concn. (45--91 pg/ml fluprostenol equiv.) occurred from 5 min to 1 h after injection...
Lazary S, Bullen S, Müller J, Kovacs G, Bodo I, Hockenjos P, De Weck AL.Mono- and oligospecific lymphocytotoxic alloantibodies from primiparous mares were tested on cells from horse families of various breeds in the two-step microcytotoxicity assay. The results showed that the detected antigens were inherited co-dominantly and autosomally as simple Mendelian traits. The membrane antigens showed different linkage with one or more other antigens and seem to be coded by a limited number of loci (at least three) from one chromosome. In the families tested one recombinant for the serologically defined antigens was recognized. The mixed leukocyte reactions of cells from...
Sentsui H, Kono Y.During the autumn of 1978 a disease characterised by fever and occasionally by exanthema and/or oedema of the limbs was seen in approximately 13 per cent of horses in a training stable in the Kanto district of Japan. A virus was isolated by the intracerebral inoculation of one-day-old mice from blood and nasal swabs taken from naturally and experimentally infected horses. The virus was subsequently passaged in two monkey kidney cell lines in which it produced complete cytopathic changes. Infected horses developed neutralising, complement fixing and haemagglutinin inhibiting antibodies to the v...
Levene A.In man the epidermis is the final destination for most of the melanocytes which are of neural crest origin, and they migrate to a variety of sites. Dermal melanocytic distribution, conspicuous in some lower animals, has a very restricted normal distribution in man, and of the variety of anomalies which exist the blue naevus is the most frequently encountered. It is comparable to the common melanocytoma of dog and hamster. More widespread dermal melanocytoses are rare, and a unique case in which death from melanoma supervened, recently recorded by the author, is an example of a syndrome the onl...
Al-Khalidi NW, Weisbrode SE, Dubey JP.Nine ponies were fed 100,000 infective Toxoplasma gondii oocysts and were given corticosteroid injections before and after feeding the T gondii oocysts. Titers to the Sabin-Feldman dye tests (1:2 to 1:16,384) developed within postinoculation days (PID) 7 to 21 and antibodies persisted to PID 133. Toxoplasma organisms were isolated from the tissues of 4 ponies (heart of 4, brain of 2, spinal cord of 3, diaphragm of 1, skeletal muscle of 1, liver of 1, kidneys of 1) killed between PID 36 and 63, but not from 5 ponies killed between PID 117 and 150. Seemingly, ponies are one of the more resistant...
Valdez H, Clark RG, Hanselka DV.Flexible medical grade carbon fiber was surgically implanted in tenectomized or lacerated superficial and deep digital flexor tendons of 13 horses (7 clinical cases and 6 experimental), ranging in age from 15 months to 10 years and weighing 300 to 500 kg. The 6 experimental horses were euthanatized at 30-, 45-, 60-, and 90-day intervals for gross and histologic evaluation of the results. Three of the experimental horses served as their own controls. Of the 7 clinically affected horses, 3 were euthanatized because they developed laminitis or the wound failed to heal. The remaining 4 horses in t...
Hunt JP, Haywood PE, Moss MS.A gas chromatographic screening procedure for the non-steroidal anti-inflammatory group of drugs is described. The method invovles on-column methylation of the carboxylic acid group using trimethylanilinium hydroxide as the methylating reagent. Fifteen such drugs were studied. Eight of these were detected in urine collected from horses that had received these compounds orally and for these drugs, rates of urinary excretion are recorded. Seven other members of this group of drugs were shown to be detectable by this procedure but in these cases the drug was added to urine and not administered to...
Singh AK, Mishra U, Ashraf M, Abdennebi EH, Granley K, Dombrovskis D, Hewetson D, Stowe CM.Chemical ionization- and electron impact ionization-selective ion monitoring provided a simple and sensitive method for measuring detomidine (Domosedan), a potent sedative-analgesic drug for horses and cattle. Chemical ionization was at least 10 times more sensitive than electron impact ionization. By using propranolol as an internal standard, we found that the recovery of detomidine from the extraction procedure used in this study was greater than 75% for plasma, whole blood, or urine samples. Approximately 68% of detomidine was bound to plasma protein and 53% was bound to red blood cells.
Al-Dissi A.A wide variety of toxins cause diseases in the horse and are investigated routinely by veterinarians and veterinary pathologists to identify the cause of illness and death. A complete investigation involves performing a thorough necropsy and requires macroscopic and microscopic examination of lesions and a variety of laboratory testing to obtain an accurate diagnosis. The identification of gross lesions by equine practitioners is often the first step in formulating a diagnostic plan. This article provides a description of selected common toxins producing detectable gross lesions in horses in N...
Harrington DD.Acute accidental vitamin D2 (ergocalciferol) toxicosis was diagnosed in a 6-month-old foal with extensive lesions of soft tissue mineralization. In an experimental study, three 18-month-old horses were given ergocalciferol per os at a rate of 9,300, 22,200, or 47,200 IU/kg of body weight/day for 21 days. Clinical signs or lesions were not seen in horses given the low and intermediate doses, whereas the horse receiving the highest dose developed clinical signs and lesions similar to those noted in the foal. Signs included depression, loss of appetite, weakness, limb stiffness with impaired mobi...
Stiglhuber A, Breit S, König HE.The equine fetlock joint cavity shows ten pouches. The dorsal recess, which is oriented to the proximal side, is separated from those three pouches, which show to the distal direction, by several capsular folds. These folds are documented by means of sagittal sections through the fetlock joint. A medial/lateral recess is covered by the deep part of the collateral ligament of the fetlock joint. The collateral ligaments as well as the sesamoidean collateral ligaments are closely connected with the joint capsule, from which two capsular folds are separated. Between the part of the sesamoidean col...
Monzon CM, Jara GA, Hoyos CB.The usefulness of the direct agglutination test (DA) to diagnose Mal de Caderas disease was evaluated. Forty four sera samples from two lots of horses with natural T. evansi infection (Lot 1 and Lot 2) were used. Thirteen (81.2%) of sixteen horses in which parasites were isolated gave positive agglutination titres (> or = 1:512) in the DA test. Treatment of these positive sera with 2-mercaptoethanol drops three to eight dilutions the agglutination titres in twelve samples (92%), showing the IgM nature of these antibodies. The DA test was also positive in seventeen of twenty eight horses in ...
Lehner AF, Almeida P, Jacobs J, Harkins JD, Karpiesiuk W, Woods WE, Dirikolu L, Bosken JM, Carter WG, Boyles J, Holtz C, Heller T, Nattrass C....Remifentanil (4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic acid methyl ester) is a mu-opioid receptor agonist with considerable abuse potential in racing horses. The identification of its major equine urinary metabolite, 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, an ester hydrolysis product of remifentanil is reported. Administration of remifentanil HCl (5 mg, intravenous) produced clear-cut locomotor responses, establishing the clinical efficacy of this dose. ELISA analysis of postadministration urine samples readily detected fentany...
Page AE, Stills HF, Horohov DW.In the horse, Lawsonia intracellularis infection results in equine proliferative enteropathy (EPE). While upwards of 100% of weanlings on an endemic farm may seroconvert, only a small percentage (approximately 5%) will develop clinical disease. Cell-mediated immune mechanisms likely play a role in resistance to L. intracellularis and the absence of a L. intracellularis-specific IFN-γ response has been associated with the development of EPE. The goal of this study was to determine whether protection from clinical EPE is associated with the induction of a systemic IgG sub-isotypic response cons...
Apprich V, Spergser J, Rosengarten R, Stanek C.The effects of two dermatophytes (Microsporum gypseum and Trichophyton mentagrophytes) and four moulds (Scopulariopsis brevicaulis, Alternaria alternata, Geotrichum candidum and Penicillium spp.) on living keratinocyte cultures were examined in vitro using primary human keratinocytes. Rates of apoptosis of infected cells were determined using a colorimetric TUNEL system which detects the characteristic nuclear DNA fragmentation of apoptotic cells. The cytotoxicity of the individual fungi was tested by quantitatively measuring cytosolic enzyme lactate dehydrogenase, released upon cell lysis, in...
Sim RR, Padilla LR, Joyner PH, Anikis P, Aitken-Palmer C.Anaplasma phagocytophilum (formerly Ehrlichia equi ) is a tickborne pathogen of domestic horses and the causative agent of equine granulocytic anaplasmosis. After the occurrence of clinical anaplasmosis in a Przewalski's horse ( Equus ferus przewalskii) housed at the Smithsonian Conservation Biology Institute in 2008, opportunistic serosurveillance of the herd was initiated. From 2008 to 2014, 57 serum samples were collected from 27 individuals (10 males; 17 females). Using indirect immunofluorescent antibody assays for anti- Anaplasma phagocytophilum antibodies, it was determined that prevale...
Timoney JF.An R antigen of the group C streptococcus S. equi that cross reacts with a similar antigen of S. zooepidemicus has been identified and characterized. It is acid, heat and trypsin resistant, but pepsin sensitive and has an isoelectric point of 4.8. The amino acids in highest concentration are glutamic, aspartic, alanine, leucine, and valine. Bacterial components released in a French Press contain large amounts of R antigen, which is present also in culture supernatants and acid extracts. It has a molecular weight of about 82,000. Trypsin extraction of cells yields molecules of predominantly 56,...
Miller PJ, Holmes JR.Systolic time intervals (STIs), isovolumic contraction time (ICT) and left ventricular ejection time (LVET) were recorded from seven horses with supraventricular arrhythmia. The STIs were measured over a number of beats (33 to 100) directly from the left ventricular (LV) and aortic (Ao) pressure contours which were recorded simultaneously using two catheter-mounted transducers. ICT was significantly (P less than 0.01) and directly related to beat-by-beat heart rate (HR = 60/pulse interval) and LVET was significantly (P less than 0.01) and inversely related to heart rate in each of five horses....
Welles EG, Prasse KW, Duncan A, Morris MJ.An antigenic assay was developed for determination of protein C in horses. Protein C, a natural, vitamin K-dependent anticoagulant component in blood, was isolated from equine plasma, a specific antibody was produced in goats, and a rocket electroimmunophoresis assay was established. Tests were performed to verify the identity of the isolated protein C and to determine the purity of the antibody. Protein C antigen was measured in plasma from 34 clinically normal horses, and values were compared with amidolytic function values. The mean (+/- SD) values for the 2 test methods were similar (antig...
Al-Wabel NA.Semicarbazide-sensitive amine oxidase (SSAO) activity was measured spectrophotometrically using benzylamine as a substrate, in the serum of healthy males and females of horses, camels, cattle, sheep and goats. The animals were born and raised in the same area, and the blood collection was made on the same day to avoid variations. Also the concentrations of protein and copper were measured in the same samples. There were no significant gender-related differences in SSAO activity between the tested animals regardless of species. Activities of SSAO in either male or female of horse were significa...
Gasthuys F, De Moor A, Parmentier D.The influence of digoxin (0.01 mg/kg) given as an intravenous bolus followed by dopamine at different infusion rates (1.25, 2.5 and 5.0 micrograms/kg/min) on the cardiovascular depression during a standard halothane anaesthesia was studied in dorsally recumbent ventilated ponies. Preanaesthetic digitalization induced no clear positive cardiovascular effects over 30 minutes, except for non-significant increases in mean pulmonary artery pressure and total pulmonary resistance. These changes were probably time-related. No specific side-effects related to the fast intravenous digitalization were n...