"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.
Forster HV, Pan LG, Bisgard GE, Kaminski RP, Dorsey SM, Busch MA.We studied the effect of changes in inspired [O2] on partial pressure of CO2 in arterial blood (PaCO2) during treadmill exercise (3 mph, 3% grade) in normal, acute (+2-4 wk), and chronic (+1-2 yr) carotid body-denervated (CBD) ponies. In all studies, PaCO2 decreased (P less than 0.01) from rest during exercise, reaching a nadir usually between 15 and 30 s of exercise. During normoxia [partial pressure of O2 in arterial blood (PaO2) approximately 95 Torr], the PaCO2 nadir was 2.3 +/- 0.6 Torr below resting level in normal ponies, but the nadir was greater (P less than -0.01) in acute (delta = 6...
Davies JV, Gerring EL.The effect of acepromazine, Buscopan (Crown Chemicals), pethidine and methadone was evaluated in ponies prepared with Thiry-Vella (T-V) loops. Motility was assessed by electrophysiological means (bipolar electrodes and strain gauge transducers) and by the passage through the T-V loop of a fluid test meal. Results were obtained from 26 experiments in three ponies and compared with six control experiments, in which saline had been administered to the same ponies. Each pony acted as its own control in each experiment and pre and post treatment values for slow wave frequency, spiking activity, del...
Davies JV, Gerring EL.Motility patterns in the equine small intestine were investigated in eight ponies. Muscular activity was assessed by means of extramural strain gauge transducers, bi-polar electrodes and in three of the animals, fitted with Thiry-Vella loops, the transit of fluid. Circular muscle contractions were preceded by spiking superimposed on the slow wave and fluid transit in the loops correlated with both these events.
Arosio P, Gatti G, Bolognesi M.Various precipitating agents were examined in order to crystallize horse heart and spleen ferritins. Cadmium sulfate induced the crystallization of the spleen ferritin, while 2-methyl-2,4-pentanediol and poly(ethylene glycol) only induced that of the heart ferritin. Isoelectric focusing analysis showed that the crystals grown from cadmium sulfate contained only the more acidic isoferritins, and those grown from methyl pentanediol only the less acidic isoferritins. Heart ferritin crystallizes in a cubic space group, as previously reported for spleen ferritin crystals grown from cadmium sulfate....
Baker JR, Wyn-Jones G, Eley JL.A brief review of the literature on equine goitre is presented, together with a case of congenital goitre in a foal. This animal showed localised swelling of the neck, hyperextension of the lower limbs and initial difficulty in sucking. The goitre was removed surgically and the hyperextension successfully treated with surgical shoes and bandaging. The cause was probably iodine deficiency coupled with a goitrogen in the diet.
Turner TA, Fessler JF, Lamp M, Pearce JA, Geddes LA.The distal forelimbs of 10 clinically normal horses with hair clipped on 1 limb were thermographically scanned before and after exercise. The thermal patterns, temperature distribution, and temperature changes after exercise were determined and compared with those of 8 horses with podotrochlosis. Clipping the hair did not cause changes in the thermal patterns, but the clipped limbs were warmer than the unclipped limbs. The temperature of the limbs of horses with podotrochlosis did not increase as much after exercise as did the limbs of normal horses. The failure of skin temperature increase co...
Marsh MV, Caldwell J, Sloan TP, Smith RL, Horner M, Moss MS.14C-Fenclofenac (2-(2'-4'-dichlorophenoxy)-phenylacetic acid) was administered orally to horses, and urinary metabolites investigated by chromatography. Fenclofenac was rapidly absorbed and eliminated, with a plasma half-life (t1/2) of 2.3 h, with 83.2 and 85.8% of the dose being recovered in the urine in 0-24 h. The major urinary metabolite was the ester glucuronide (58.8, 70.0% dose), and evidence is presented that this metabolite undergoes a structural rearrangement to give beta-glucuronidase-resistant isomers. The other 14C-labelled components in horse urine were unchanged fenclofenac (13....
Thompson DL, Reville SI, Walker MP, Derrick DJ, Papkoff H.To study the possible role of ovarian androgens in regulation of follicle stimulating hormone (FSH) secretion in the cycling mare, five mature, intact mares were treated with testosterone (20 micrograms/kg of body weight) daily during estrus; five control mares received safflower oil on the same schedule. Mares were teased for estrus and samples of jugular blood were drawn daily through one full estrous cycle. Concentrations of FSH in plasma were measured by a newly developed radioimmunoassay based on anti-ovine FSH serum and radioiodinated equine FSH. Testosterone treatment during estrus had ...
Zweygarth E, Ahmed JS, Rehbein G, Voigt WP.The capacity of equine peripheral blood lymphocytes (PBL) to proliferate in the presence of Babesia equi-transformed lymphoblastoid stimulator cells was tested in an autologous as well as in an allogenic one way mixed lymphocyte reaction (MLR). It was found that both autologous and allogeneic responder lymphocytes incorporated high amounts of 3H-thymidine. The incorporation of 3H-thymidine was lower in MLR using as stimulator cells lymphocytes from which the cell line had previously been established, than when using parasitized culture cells as stimulator. Proliferation of PBL was achieved onl...
Rose RJ, Hodgson DR, Sampson D, Chan W.Plasma biochemical values were measured in 14 horses, before a 160 km endurance ride, immediately after 85 km, immediately after 160 km, after 30 min recovery period and the day after the ride. For statistical analysis, a group of 7 horses that completed the ride at a mean speed of 234 metres per min (m/min) (Fast Group) was compared with 7 horses that completed the ride at a mean speed of 144 m/min (Slow Group). Estimations were made of sodium, potassium, chloride, bicarbonate, glucose, creatinine, urea, bilirubin, iron, total protein, albumin, calcium, phosphate, cholesterol, alkaline phosph...
Nara PL, Krakowka S, Powers TE, Garg RC.Fourteen young outbred horses, divided into 2 groups on the basis of 18- or 24-hour skin-test reactions to Streptococcus equi, were inoculated nasopharyngeally with virulent S equi. Animals (n = 6, group I) with evidence of previous exposure to S equi (positive dermal response and existing serum antibodies), with one exception, developed minimal or no signs of disease after inoculation. In contrast, S equi skin-test negative and seronegative horses (n = 8, group II) developed predictable and severe clinical signs of infection after their inoculation, including shedding of the organism from nas...
Walji AH, Fasana FV.Gross and microscopic study of Cercopithecus aethiops pygerythrus and Papio cyanocephalus anubis shows that these cercopithecines have a quadriceps tendon the distal portion of which consists mostly of dense collagenous bundles with scattered fine elastic fibres most of which lie in the loose connective tissue planes within and around the tendon and around blood vessels. A distinct fibrovesicular structure, the suprapatella, lies within the tendon of the vastus intermedius above the pony patella. Histologically, this structure is characterised by interwoven bundles of collagenous fibres, among...
Cho SN, Collins MT, Reif JS, McChesney AE.Attempts to infect horses with Legionella pneumophila were undertaken to determine pathogenicity and to evaluate the possibility that horses serve as a reservoir for the organism. A previous study showed that the prevalence of antibodies to L pneumophila in the equine population exceeded 30% of over 600 sera examined. Horses were infected experimentally with the Philadelphia 1 or Bloomington 2 strain of L pneumophila IV or by aerosolization. Signs of clinical illness were restricted to a transient febrile response. A transient decrease in circulating lymphocytes occurred 2 days after inoculati...
Trueman KF, Lumsden JH, McSherry BJ.Serum alkaline phosphatase activity was found to be increased in 32.6% of equine samples analyzed at the Ontario Veterinary College over an 18 month period. An attempt was made using sensitivity to L-phenylalanine and heat to identify the origin of increased serum alkaline phosphatase isoenzymes present in 44 clinical cases. No difference in sensitivity to either procedure was observed for serum alkaline phosphatase from groups of foals and horses representing different clinical problems. Alkaline phosphatase of osseous tissue origin appeared to be the major source of activity for each group o...
Olson JG, Ksiazek TG, Gubler DJ, Lubis SI, Simanjuntak G, Lee VH, Nalim S, Juslis K, See R.Sera were collected from humans, cattle, horses, goats, ducks, chickens, wild birds, bats and rats in Lombok, Indonesia, and were tested by haemagglutination inhibition (HI) for antibodies to JE, ZIKA, CHIK and RR. Selected sera were tested by microneutralization tests for antibodies to the following viruses: JE, ZIKA, MVE, TMU, LGT, KUN, SEP, DEN-2, CHIK, RR, GET, SIN, BUN, BAT and BAK. Human sera had JE HI antibody in 135 (30%) of 446 tested. Neutralization tests indicated that DEN-2, ZIKA, TMU, KUN and SEP may have caused flavivirus infections. Antibodies to other arboviruses tested for wer...
Fredricson I, Drevemo S, Dalin G, Hjertén G, Björne K, Rynde R, Franzen G.A treadmill for equine locomotion analysis is described and its potential considered for locomotive research and clinical investigation. The treadmill comprised an endless belt driven by a hydraulic motor at various speeds up to 14 m/sec and the direction of belt movement was reversible. The carrying side of the belt ran over a steel-concrete table which acted as a flat support. The belt itself consisted of a steel base on to which was glued a rubber belt and the surface was covered with a layer of coir matting which permitted some forward sliding of the landing hooves simulating the condition...
Snow DH, Ricketts SW, Mason DK.The haematological response to racing and to fast and slow training exercise was investigated in studies involving two populations of horses which differed widely in geographical location, climatic factors and management (Newmarket and Hong Kong). The well documented elevations in erythrocyte parameters were demonstrated and changing responses in leucocyte parameters, resulting in variations in the neutrophil to lymphocyte (N/L) ratio were described. It was shown that the immediate response to the anticipation or stress of exercise was a decrease in N/L ratio in association with an increase in...
Simmons HA, Ford EJ.The rate of flow of fluid from the caecum and from the large colon was measured in four Shetland-type ponies fed a hay diet. In two ponies with cannulas in the caecum and at the origin of the right ventral colon, a continuous intracaecal infusion of a solution of chromium EDTA was used and samples were obtained from the cannula at the origin of the right ventral colon. Based on four determinations, the liquid flow from the caecum was 54.2 +/- 1.89 litres d-1. In the other two ponies with cannulas in the origin of the right ventral colon and near the end of the right dorsal colon, a continuous ...
Gerard MP, Hodgson DR, Lambeth RR, Ray SP, Rose RJ.The recent availability of recombinant equine somatotropin (eST) has led to concern about its use as an ergogenic aid in racehorses. This study was undertaken to investigate the changes in exercise capacity in maturing horses in a training programme, and to assess whether eST is an ergogenic aid to this group. We tested the hypothesis that the combination of training and eST, compared to training alone, would further improve exercise capacity in maturing Standardbreds, by virtue of ST's anabolic effects and potential to enhance cardiac function, circulating fluid volume and red cell mass. Twel...
Skolek-Winnisch R, Lipp W, Stöckl W, Bamberg E.The localization of beta-N-acetylhexosaminidase activity in 6 different segments of the epididymis was investigated in 8 stallions using biochemical and histochemical methods. The highest enzyme activity was found in segment D while the other segments displayed a much weaker reaction There was no or only low enzyme activity present in the epididymal fluid of the proximal 3 segments, whereas it was high in the distal 3 segments. The biological function of beta-N-acetylhexosaminidase in the epididymis is discussed briefly.
Borgsteede FH.A comparison was made of the efficacy of Ivermectin administered as an injection and as a paste. Fourteen horses which were naturally infected with small strongyles were divided into three groups. Animals of group 1 received an injection of 5 ml Ivermectin, equivalent to 500 kg bodyweight, horses of group 2 received one injector with Ivermectin as a paste (for 500 kg body weight), a third group remained untreated as a control. Faecal examinations and larval cultures on the day of treatment and 14, 28 and 42 days later showed that both injection and paste had a 100 percent efficacy against matu...
Knych HK, Finno CJ, Baden R, Arthur RM, McKemie DS.The in vivo metabolism and pharmacokinetics of flunixin meglumine and phenylbutazone have been extensively characterized; however, there are no published reports describing the in vitro metabolism, specifically the enzymes responsible for the biotransformation of these compounds in horses. Due to their widespread use and, therefore, increased potential for drug-drug interactions and widespread differences in drug disposition, this study aims to build on the limited current knowledge regarding P450-mediated metabolism in horses. Drugs were incubated with equine liver microsomes and a panel of r...
Moens Y, De Moor A.The carbon dioxide content of respiratory gases may be monitored by the use of an infra-red carbon dioxide analyser. The technique allows continuous and non-invasive recording of important information concerning the ventilatory, circulatory and metabolic states of the anaesthetised horse. Some of the monitoring capabilities of a carbon dioxide analyser (capnograph) are reviewed with illustrations from cases anaesthetised in the authors' clinic. Technical faults in the anaesthetic apparatus and the connections with the "patient" could be readily detected and emergency situations immediately rec...
Lischer ChJ, Bischofberger AS, Fürst A, Lang J, Ueltschi G.Lameness in horses due to pain originating from the proximal metacarpal/metatarsal region remains a diagnostic challenge. In cases of obvious lameness the pain can be localised to this region by diagnostic anaesthesia. Because a variety of disorders can cause lameness in this region different imaging modalities including radiography, ultrasonography and scintigraphy should be used to arrive at an accurate diagnosis. Even though a precise anatomic-pathologic diagnosis can still be an enigma, because not only bone and joints, but also soft tissue structures including the proximal suspensory liga...
McKeever KH, Hinchcliff KW, Cooley JL, Lamb DR.The purpose of this study was to test the hypothesis that furosemide administration before exercise would cause greater increases in plasma arginine vasopressin (AVP) concentration in exercising horses than exercise alone. Six adult, clinically normal, unfit mares underwent three randomly ordered 60 minute standard exercise tests on an equine treadmill to examine the effect of furosemide administration on plasma AVP concentration. In one trial, furosemide (1 mg kg-1) was infused four hours before exercise (FUR-4) and a placebo (10 ml saline) was infused two minutes before exercise; in another ...
Art T, Lekeux P.This study was conducted in order to assess whether exercise- and training-induced cardio-respiratory adjustments are modified during the 10-day period which follows a booster vaccination with an oily adjuvanted inactivated vaccine against influenza and equine herpesvirus-1 (Equiffa). Nine healthy vaccinated thoroughbred horses were used. Six were revaccinated and three were kept as control. All the horses completed a standardised exercise test (SET) that was repeated 4 times, i.e. 10 (SET1) and 2 (SET2) days before revaccination, and 2 (SET3) and 10 (SET4) days after revaccination. During the...
Lord CC, Woolhouse ME, Mellor PS.Factors affecting epidemics of African horse sickness in Spain were studied using a mathematical model. The model examined the likelihood of an epidemic after the introduction of the virus, and the effectiveness of vaccination strategies. Two host species (horses and donkeys) and one vector species (the biting midge Culicoides imicola) were included. A stratified random sampling method (Latin hypercube sampling) was used for sensitivity analysis of the likelihood of an epidemic. Systematic variation of vaccination parameters was used to consider alternative control strategies. In general, when...
Hon WK, Ng TB.Equine pancreatic acetone powder was extracted with an acetone-water-HCl mixture. An acid acetone powder resulted by adding a copious volume of acetone to the extract. The powder was subjected to salt fractionation, gel filtration and chromatography on CM-cellulose. Steroidogenic activity, ACTH-like immunoreactivity and opiate receptor binding activity were distributed among the CM-cellulose chromatographic fractions derived from material unretarded as well as from material retarded on Sephadex G-25. The data indicates a separation of steroidogenic and opiate receptor binding activities, and t...
Etcheverrigaray ME, Oliva GA, Zabala Suárez JE.Twenty seven per cent of 238 serum samples obtained from horses with clinical diagnosis were positive for the immunodifusion test, while 17% of the 452 sera obtained from asintomatic horses were positive. Twenty one per cent of the 870 sera studied were positive.
Velásquez J, da Silva LLC, Miglino MA.There are many challenges in teaching veterinary anatomy, such as available classroom time, costs, and difficulties accessing animal cadavers, mainly due to animal welfare concerns. Furthermore, veterinary surgeons and radiologists complain that recent graduates lack anatomical knowledge. On the other hand, the current limitations of face-to-face teaching due to the COVID-19 pandemic suggest that the development of online distance education tools is necessary, mainly in specialties that lack this type of material. Teaching platforms promoting the integration of anatomy with other applied disci...
Mair TS, Stokes CR, Bourne FJ.Lavage techniques were used to obtain secretions from the nasal cavity, trachea and bronchi of conscious horses. The techniques, which utilised fibreoptic endoscopy for recovery of tracheal and bronchial secretions, were well tolerated by the horses. The recovery rates of the lavaged fluids were acceptable, but were lowest for bronchial secretions, and there was minimal contamination by blood. The fluids were analysed for IgG and IgM by single radial immunodiffusion, and for IgA and albumin by rocket immunoelectrophoresis. Relative to albumin there was significantly more IgA and IgM, and signi...
Delbeke FT, Baert K, De Backer P.Urinary and plasma concentrations of the nonsteroidal anti-inflammatory drug tiaprofenic acid were determined following oral and intramuscular administration of a dose of 1 g to five fasted horses. Quantitation was performed by high-performance liquid chromatography (HPLC). The limit of quantitation (LOQ) was 0.1 microg/ml and 0.5 microg/ml in 2 ml plasma and 1 ml urine, respectively. Assay precision and extraction recovery were between acceptable values. Tiaprofenic acid pharmacokinetics were described by non-compartment analysis of the data. Absorption was faster after oral administration as...
van Foreest AW, Wiemer P.Periapical disorders in horses can be treated by resection of the apex. The indications, contraindications, diagnosis, treatment and complications of the intervention are discussed. Four case reports of horses in which apicoectomy with retrograde endodontic treatment was performed are reviewed.
