The physiology of horses encompasses the study of the biological functions and processes that occur within the equine body. This includes the examination of various systems such as the cardiovascular, respiratory, musculoskeletal, digestive, and nervous systems. Understanding equine physiology is essential for comprehending how horses adapt to different environmental conditions, perform physical activities, and respond to health challenges. Research in this field often focuses on the mechanisms of energy metabolism, thermoregulation, and muscle function during exercise, as well as the physiological responses to stress and disease. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine physiology, providing insights into the biological processes that support the health and performance of horses.
McCue PM, Troedsson MH, Liu IK, Stabenfeldt GH, Hughes JP, Lasley BL.Thirty-seven seasonally anoestrous mares were divided into treatment and control groups and given 10 micrograms of native GnRH (GnRH) per hour using a peristaltic pump, or 10 micrograms GnRH agonist (GnRHa) twice daily, beginning on either 13 January, 13 February or 14 March. Treatment with GnRH was equally effective in inducing ovulation in January (4/5), February (4/5) and March (3/4). GnRHa treatment was more effective in inducing ovulation in February (4/5) and March (4/4) than in January (2/8). Peak luteinizing hormone (LH) concentrations in mares induced to ovulate with GnRH (7.4 +/- 1.5...
Nielsen AH, Gotfredsen P, Nielsen PB, Hyttel P, Poulsen K.1. Species specific problems complicating the measurement of prorenin and renin concentrations were studied in bovine, hog and horse plasma. 2. In contrast to horse renin, bovine and hog renin reacted with rat angiotensinogen, allowing measurement of the plasma renin concentration in cattle and hog with rat angiotensinogen as exogenous substrate. 3. Trypsin treatment of plasma in order to activate prorenin generated an interfering angiotensin I immunoreactive material in all three species, most extensively in horse plasma. 4. This material could be removed in bovine and hog plasma by a cation-...
Baker CB, Adams MH, McDowell KJ.Horse conceptuses were collected on Days 13, 15, 20 and 25 after ovulation. Whole conceptuses (Days 13 and 15) or extra-embryonic membranes (Days 20 and 25) were homogenized and poly-adenylated RNA (poly A RNA) was isolated by binding to oligo (dT)-cellulose. Poly A RNA (1 microgram/well) was separated by size on a denaturing 1% agarose gel and blotted onto nitrocellulose filters (northern blotting). DNA probes were prepared from plasmids containing equine alpha 1, omega 1 and omega 2 interferons and human beta actin. The presence of messenger RNA (mRNA) was detected by specific hybridization ...
Vallejo AN, Miller NW, Clem LW.This work was undertaken to investigate whether or not antigen processing and presentation are important in channel catfish in vitro secondary immune responses elicited with structurally defined proteins, namely, pigeon heart cytochrome C (pCytC), hen egg lysozyme, and horse myoglobin. The use of in vitro antigen-pulsed and fixed B cells or monocytes as antigen presenting cells (APC) resulted in autologous peripheral blood leukocytes (PBL) responding with vigorous proliferation and antibody production in vitro. In addition, several long-term catfish monocyte lines have been found to function a...
Hermanson JW, Hegemann-Monachelli MT, Daaod MJ, LaFramboise WA.The biceps brachii of horses is subdivided into a lateral and medial head. Electrophoresis of samples from the lateral head revealed three slow-migrating native myosin isoforms, including one that does not correspond to slow myosin isoforms described for other mammalian muscles. In contrast, the medial head contained a single slow isoform. Both the lateral and medial heads contained three fast-migrating isoforms corresponding with the FM-2, FM-3 and FM-4 isoforms reported for other mammalian fast-twitch muscle fibers. Electrophoresis of myosin heavy chains (MHCs) revealed only two MHC bands, o...
Battut I, Bézard J, Palmer E.A culture for equine oviduct epithelial cells is described. Primary cultures reached confluence in 5-8 days, forming a monolayer of polygonal cells and remaining morphologically intact for about 20 days. Subcultures were obtained by collecting cells detached spontaneously from the monolayers, and confluence was reached again after 5-7 days. Cells frozen before primary culture were confluent 10-15 days after thawing. Dishes containing confluent cells also were frozen, and some cohesive monolayers formed after thawing. Equine embryos, collected 2 days after ovulation, were cultured alone or with...
Roser JF, Hughes JP.Hormonal effects of prolonged administration of gonadotrophin-releasing hormone (GnRH) were investigated in 7 fertile stallions in winter and summer. The stallions were divided into 4 groups so that 1 animal received 0.625 micrograms of GnRH and each of 2 animals received 1.25, 2.5 or 5.0 micrograms of GnRH subcutaneously every 30 min for 5 days. Daily blood samples were collected from 5 days before to 5 days after treatment for measurement of plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T) and oestrogen conjugates (EC). Five-minute blood...
Lees MJ, Fretz PB, Bowen CV, Leach DH.Equine limb wounds often heal slowly by epithelialization, and large scars are a frequent end result. In some ways, they resemble the wound associated with human tibial injuries. The literature indicates that previous investigators have failed to transfer free skin flaps successfully in the horse. In this paper, we review our experimental work with the deep circumflex iliac flap in the horse. Dissections of 20 cadavers confirmed the anatomical consistency of the flap. Four flaps survived well when elevated as island flaps, but five orthotopic and nine heterotopic free flap transfers all failed...
Guillaume D, Palmer E.Two experiments tested the hypothesis that exogenous melatonin (12 mg) given 4 h before dusk (evening melatonin), or near dawn (morning melatonin), would mimic a prolongation of the night and suppress stimulation of the ovaries induced by long days. Experiment 1 consisted of a non-stimulated control group, a control group stimulated by 14.5 h of light, a treated group stimulated with 14.5 h of light plus evening melatonin, a control group given 17.5 h of light and a treatment group given 17.5 h of light plus morning melatonin. The mean (+/- s.e.m.) intervals from the start of treatment to the ...
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and values of pH were studied in standard-bred mares and their foals, for 13 weeks of foal life, throughout 2 years. 2. The studies began when a foal was 7 days old and were repeated every 2 weeks until foals reached 13 weeks of age. 3. Blood samples were taken every 4 hr for one day, each second week. 4. In the LA, PA levels and pH values no diurnal rhythm was stated in lactating mares during study periods. 5. In foals the diurnal rhythm in LA and PA occurred in the 3rd month of their life, with the acrophase at night ...
Fowden AL, Mundy L, Ousey JC, McGladdery A, Silver M.Glycogen and glucose 6-phosphatase levels were measured in a variety of tissues from fetal, newborn and adult pregnant mares. Hepatic and renal glucose 6-phosphatase activities increased with increasing gestational age and rose further in the 24 h after birth to values similar to those observed in maternal tissues. The glycogen content of fetal liver and skeletal muscle also increased in late gestation, whereas that of fetal lung and cardiac muscle decreased toward term. No significant change in renal glycogen content with fetal age was observed. The values of hepatic glycogen and glucose 6-ph...
Argo CM, Cox JE, Gray JL.This study tested the role of melatonin in the regulation of seasonal physiological change in the pony stallion. Four 3-year-old, Welsh Mountain pony stallions were housed initially under the prevailing short-day photoperiod in December (8 of light [L]:16 h of darkness [D]) before being transferred to long days (16L:8D) on 13 January for the remaining 22 weeks of the study. On Day 76 (11 weeks later) the stallions began an 11-week period of daily melatonin treatment (20 mg orally, 8 h after lights on). Marked changes in mean plasma testosterone, beta-endorphin and cortisol concentrations occur...
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...
Baxter GM, Moore JN, Tackett RL.The in vitro responses of isolated vascular preparations of digital arteries and veins obtained from healthy anaesthetised horses were determined for dopamine and fenoldopam. The digital vessels were harvested, cut into 4 mm vascular segments, suspended in tissue baths and attached to force-displacement transducers. Dose-response studies between 10(-8) and 10(-4)M concentrations were performed for all drugs. The change in tension of each vascular ring was measured in grams of force. The reactivity between palmar and plantar digital vessels and baseline vascular responses were determined for do...
Pantke P, Hyland J, Galloway DB, MacLean AA, Hoppen HO.Equine plasma luteinizing hormone (LH) possesses both biological (in vitro bioassay, B) and immunological (radioimmunoassay, I) activities and the ratio of B:I varies with stage of the oestrous cycle. To estimate the contribution made by pituitary secretion and peripheral metabolism to changes in the B:I ratio, pituitary venous effluent and circulating plasma from 5 dioestrous and 2 oestrous mares were analyzed using both an in vitro bioassay and a radioimmunoassay. During dioestrus, LH was released in a pulsatile fashion with a frequency of 1.4 pulses/24 h and a pulse duration of 20-40 min (c...
Cain PW, Jones JH, Smith BL.A remote data sampling cart has been designed and built for studying environmental factors that produce stress in horses during transportation. This dedicated sampling cart uses an XT-compatible mother board powered by a 12 V battery, with customized BIOS and ROM program. Sampling is performed using two digital and eight A/D (bipolar, differential) channels in burst mode at a frequency of 1 kHz. Digitized data are stored on magnetic tape for retrieval after the experiment. Configuration of sampling parameters is accomplished via a serial communications link to a host computer, and is stored in...
Ledwozyw A, Kadziołka A, Jabłonka S, Tusińska E, Herbut M.The aim of this study was to investigate the platelet factor 3 activity in platelet-rich plasma of horse, cattle, sheep and pig, by the use of chromogenic tripeptide substrate H-D-Phenylalanyl-Pipecolyl-Arginyl-p-nitroanilide. Among species examined the highest activity of this factor was stated in pig, the lowest one in sheep. Chromogenic substrate test was 10 times more sensitive that Stypven clotting time test. Thus, the use of chromogenic tripeptide substrate is fully valuable in platelet factor 3 activity estimation in domestic animals.
Flisińska-Bojanowska A, Komosa M, Gill J.1. The diurnal changes in the glucose level and in activity of FDPA, A1AT and AspAT in four pregnant standard-bred mares were studied. 2. As a control four barren mares, were kept and examined in the same conditions. 3. Blood samples were taken every 4 hr for one day, each month, throughout pregnancy, or one year. 4. A diurnal rhythm in activity of A1AT and AspAT in barren mares was found. The pregnancy masked diurnal rhythm in activities of both transaminases. 5. No diurnal rhythm in glucose level and FDPA activity in both groups of mares was observed. 6. Seasonal cyclicity was found in all i...
Fayrer-Hosken RA, Caudle AB, Shur BD.beta 1, 4-Galactosyltransferase (GalTase) is localized to the plasma membrane of mouse sperm, in which it mediates the binding of sperm to glycoconjugate residues in the egg zona pellucida. In this study, the presence of subcellular distribution of sperm GalTase were determined in two other mammalian species that yield sufficient sperm for subcellular fractionation. Equine and bovine semen were collected, and the plasma membranes (PM), outer acrosomal membranes (OAM), and inner acrosomal membranes (IAM) were sequentially removed. The purities of the isolated membrane preparations were determin...
Cocco MJ, Lecomte JT.A proton nuclear magnetic resonance spectroscopic study of horse apomyoglobin was undertaken in order to define the regions of myoglobin that are and that are not structurally affected by the binding of the prosthetic group. It was found that, in spite of the poor spectral resolution, a number of spin systems could be identified by using standard correlated methods. Four clusters consisting mostly of hydrophobic residues were detected by nuclear Overhauser spectroscopy, two of which involved the tryptophan side chains. Extensive similarities to nuclear Overhauser spectroscopy data collected on...
Merkens HW.Forces occurring between the hoof and the ground during the stance phase (i.e. the ground reaction forces GRF) can be analysed using a force plate. The average of a number of five to stance time and body weight normalised GRF recordings (data) will provide 'representative' GRF patterns. These can be used for objective and quantitative evaluation of various forms of therapy in equine orthopaedics as well as for locomotion research during various forms of equestrian sports.
Kadir FH, Moore GR.Horse spleen ferritin, a spherical protein shell of 24 subunits, contains no haem when extracted. This contrasts with ferritins isolated from bacterial sources which have the capacity to bind up to 24 haem groups [(1990) FEBS Lett. 271, 141-143] via two methionine residues [(1990) Nature 341, 771]. Here it is shown that horse spleen ferritin can bind between 15 and 17 haems per 24 subunits with an apparent association constant of 2.2-3.2 x 10(4) M-1. The strength of haem binding appears to be unaffected either by the presence of the core or by the oxidation state of the haem. The demonstration...
Shawley RV, Mandsager RE.Positive-pressure ventilation is used to provide improved ventilatory support during anesthesia in the horse. Because of the horse's size and the physiologic changes it undergoes during anesthesia, however, the use of positive-pressure ventilation does not always provide the improvement seen in smaller species. Careful attention to respiratory rate, inspiratory pressure, and I:E ratio minimizes the negative aspect of IPPV on the cardiovascular system. The goal of future ventilatory techniques will be to improve oxygenation without cardiovascular compromise and to do so at a reasonable cost to ...
Lindner A, Will Y, Chrispeels J.Reference values for Cortisol, T4 and T-Uptake, determined with the Fluorescence-Polarization-Immunoassays (FPIAs) in blood-plasma of different horse groups were established. The highest Cortisol values were measured in blood samples from thoroughbred racehorses and riding horses taken between 7 and 8 a.m. (181 +/- 37 and 268 +/- 43 nmol/l), the lowest gained between 5 and 6 p.m. (69 +/- 45 and 85 +/- 32 nmol/l respectively). Peak values for T4 in riding horses were found in blood samples collected between 1 and 2 p.m. (28.2 +/- 5.7 nmol/l) followed by the samples taken at 5-6 p.m. and 7-8 a.m...
Art T, Anderson L, Woakes AJ, Roberts C, Butler PJ, Snow DH, Lekeux P.The changes induced by exercise on the mechanics of breathing, as well as the simultaneous changes occurring in arterial blood gas tensions and in respiratory gas exchange were investigated in 6 healthy thoroughbred horses, performing a treadmill exercise of increasing intensity. Respiratory airflow and tidal volume (VT) were measured with ultrasonic flowmeters. Pleural pressure changes were measured by an oesophageal balloon catheter. Gas concentration of the expired air was analysed with a mass spectrometer; the oxygen consumption (VO2) and the carbon dioxide output (VCO2) were computed brea...
Coyne CP, Carlson GP, Spensley MS, Smith J.In this preliminary investigation, various hematologic variables potentially influential in determining the degree of blood viscosity were evaluated in 10 Thoroughbred horses subjected to competitive acute running exercise. Following completion of sprints over a distance of 1.25 miles, mean percent (+/- SD) increases in PCV (38.3 +/- 12.9%), RBC (47.8 +/- 15.3%), and rouleaux index (232.7 +/- 176.8%) were recognized. Simultaneous increases in total plasma protein (28.3 +/- 5.31%), serum albumin (26.7 +/- 6.80%), alpha 1-globulin (60.0 +/- 49.0%), alpha 2-globulin (25.5 +/- 27.9%), beta 1-globu...
McCarthy PH.A detailed description is given of the structures forming the borders of Viborg's triangle and those structures contained within and adjacent to the triangle. Changes in the size, shape and prominence of these structures with changes of head and neck posture of the horse are also described.
Lloyd DR, Evans DL, Hodgson DR, Suann CJ, Rose RJ.We examined the effects of sodium bicarbonate in 6 Thoroughbred horses during submaximal and maximal treadmill exercise. Cardiorespiratory function was assessed together with the effect on exercise capacity by determining the run time to fatigue at maximal intensities. To discriminate between sodium bicarbonate's alkalinising effects and the fluid shifts that could result from the high osmotic load, we administered an equimolar solution of sodium chloride as a control. The horses were given sodium bicarbonate (1 g/kg bwt) or an equivalent number of moles of sodium chloride by nasogastric tube....
van den Heuvel LP, van den Born J, Veerkamp JH, Janssen GH, van de Velden TJ, Monnens LA, Schröder CH, Berden JH.1. Proteoglycans extracted from human and equine glomerular basement membranes (GBM) were purified by ion-exchange chromatography and gel filtration. 2. The glycoconjugates had an apparent molecular mass of 200-400 kDa and consisted of 75% protein and 25% glycosaminoglycan. Glycosidase and HNO2 treatment and the amino sugar and sulfate composition of both proteoglycan preparations identified heparan sulfate (HS) as the predominant saccharide chain. 3. Hydrolysis with trifluoromethanesulfonic acid yielded comparable core proteins with molecular masses of ca 160 and 120 kDa. 4. The HS chains had...
Canada NC, Beard WL, Guyan ME, White BJ.Currently, there is no objective information quantifying pressures exerted by distal limb bandages. Objective: To quantify the pressure exerted by each compression layer, a polo wrap (DLP), a compression bandage (DLC), and to measure the effect of time on sub-bandage pressure. Methods: Longitudinal observational experiment. Methods: A DLC construct included a cotton roll compressed with brown gauze and elastic layers and the DLP construct included a pillow pad compressed by a cloth wrap. Dorsal and lateral sensors were placed on the mid-metacarpus. In healthy horses, sub-bandage pressures were...
Geor RJ, Larsen L, Waterfall HL, Stewart-Hunt L, McCutcheon LJ.No studies in horses have examined the effect of route of carbohydrate (glucose) administration on the rate of muscle glycogen storage following glycogen-depleting exercise. Objective: Glucose delivery from the gastrointestinal tract limits the rate of muscle glycogen storage following glycogen-depleting exercise. Methods: In a crossover design, 7 fit horses completed treadmill exercise (EX) on 3 occasions to deplete muscle glycogen by approximately 50%. After EX horses received: 1) i.v. glucose infusion (IV; 0.5 g/kg bwt/h for 6 h), 2) oral glucose boluses (OR; 1 g/kg bwt at 0, 2 and 4 h post...
Ferreira-Dias G, Costa AS, Mateus L, Korzekwa A, Redmer DA, Skarzynski DJ.Soon after ovulation, the corpus luteum (CL) starts secreting progesterone (P(4)), a hormone necessary for implantation. The aim of the study was to evaluate whether P(4) exerts an autocrine/paracrine action on luteal angiogenic activity and P(4), prostaglandin E(2) (PGE(2)) and NO production in the mare. Corpora hemorrhagica (CH) and mid-luteal phase CL (MCL) were cultured with (i) no hormone (Control); (ii) P(4); (iii) a P(4) precursor - pregnenolone; or (iv) a P(4) antagonist - onapristone [10(-4) M;10(-5) M; all steroids]. NO production decreased in MCL, with respect to CH, when treated wi...
Main SC, Brown LP, Melvin KR, Campagna SR, Voy BH, Castro HF, Strickland LG, Hines MT, Jacobs RD, Gordon ME, Ivey JLZ.The large population of emaciated horses continues to be an issue troubling the equine industry. However, little is known regarding the collection of equine metabolites (metabolome) during a malnourished state and the changes that occur throughout nutritional rehabilitation. In this study, ten emaciated horses underwent a refeeding process, during which blood samples were collected for a blood chemistry panel and metabolomics analysis via ultrahigh performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Significant differences among blood chemistry analytes and metabo...
Handler J, Hoffmann D, Weber F, Schams D, Aurich C.The aim of the present study was, to investigate the effects of oxytocin administration on Day 7 post-ovulation on progesterone secretion, pregnancy rate and embryonic growth in mares. Endogenous stimulation of oxytocin release was compared to the administration of native oxytocin or the long-acting oxytocin analogue carbetocin. At Day 7 after ovulation, mares had to undergo four treatments in a crossover design: (a) control, (b) oxytocin (10 IU i.v.), (c) carbetocin (280 microg i.m.) and (d) cervical dilation. On Day 13, all mares (8 of 8 mares) were pregnant on groups control, oxytocin and c...
Herholz C, Straub R, Gerber V, Wampfler B, Lüthi S, Imhof A, Moens Y, Busato A.The pulmonary health of 66 horses was assessed by a clinical examination and simple supplementary diagnostic methods. Single breath diagrams for CO(2) (SBD-CO(2)) and derived lung function indices were used to determine pulmonary function. The clinical signs in different groups were related to the results of the lung function indices derived from the SBD-CO(2). In horses with moderate to severe chronic obstructive pulmonary disease (COPD), a significant relationship was found between the respiratory frequency and the ratio of Bohr's dead space to the tidal volume (VD(Bohr)/VT), and between the...
Tonekaboni FR, Narenjisani R, Staji H, Ahmadi-Hamedani M.This investigation aimed to compare the cell-free fetal DNA (cffDNA) plasma present in three trimesters of pregnancy in Torkaman pregnant mare. Peripheral blood samples of 32 pregnant mares in three trimesters of pregnancy were collected in tubes containing ethylenediaminetetraacetic acid at three time points. Circulating cffDNA was extracted from 3 mL of maternal plasma. Using outer and inner primers, a conventional polymerase chain reaction was performed for the sex-determining region Y (SRY) gene present in the Y chromosome. Of the total 32 Torkaman pregnant mares, 24 were carrying male fe...
Mari G, Bucci D, Love CC, Mislei B, Rizzato G, Giaretta E, Merlo B, Spinaci M.The aim of this study was to compare the effect of presorting centrifugation (cushioned [CC] or single-layer colloid [SLC]), with simple dilution (SD), on the quality of sex-sorted stallion semen before and after sorting and after freezing and thawing. Four ejaculates from each of two fertile stallions were collected 1 week apart and evaluated for percent total sperm motility (TM), percent viable acrosome-intact sperm (VAI), and DNA quality (percentage of DNA fragmentation index). Freezing caused, independently from CC and SLC treatments, a significant decrease of TM (P < 0.05) and VAI (...
Henry M, Amaral D, Tavares FF, Santos NR.The aim of the present study was to analyse the effect of hydrocoele of the vaginal cavity of stallions on semen characteristics, libido and fertility, and to contribute to the understanding of the aetiopathology of this condition in stallions. Hydrocoele did not substantially affect either the libido or semen characteristics of affected stallions compared with a control group, and had no effect on fertility. However, the protein content of hydrocoelic fluid was significantly higher than that of peritoneal fluid and was lower than the protein content of blood serum. Electrophoretic profiles of...
Gondim FJ, Modolo LV, Campos GE, Salgado I.Mammalian skeletal muscle expresses splice variants of neuronal nitric oxide synthase (nNOS). Skeletal muscles have a metabolically heterogeneous population of myofibers, and fiber composition in equine skeletal muscle is correlated with athletic ability in endurance events. In this study, we investigated whether nNOS expression in equine skeletal muscle is related to fiber type and endurance training. Biopsy samples obtained from the gluteus medius of sedentary- (SH) and endurance-trained (TH) horses were examined for the electrophoretic mobility of myosin heavy chain (MHC) and NOS activity. ...
Stewart AJ, Wright JC, Behrend EN, Martin LG, Kemppainen RJ, Busch KA.To determine the lowest ACTH dose that would induce a significant increase in serum cortisol concentration and identify the time to peak cortisol concentration in healthy neonatal foals. Methods: Prospective randomized crossover study. Methods: 11 healthy neonatal foals. Methods: Saline (0.9% NaCl) solution or 1 of 4 doses (0.02, 0.1, 0.25, and 0.5 μg/kg [0.009, 0.045, 0.114, and 0.227 μg/lb]) of cosyntropin (synthetic ACTH) was administered IV. Serum cortisol concentrations were measured before and 10, 20, 30, 60, 90, 120, 180, and 240 minutes after administration of cosyntropin or saline s...
Zantingh AJ, Ducharme NG, Mitchell LM, Cheetham J.To determine the effects of hypoglossal nerve block and electrical stimulation of the thyrohyoideus muscles on position of the larynx and hyoid apparatus in resting horses. Methods: 16 healthy horses that underwent hypoglossal nerve block and 5 healthy horses that underwent electrical stimulation of the thyrohyoideus muscles. Methods: Horses underwent bilateral hypoglossal nerve block or electrical stimulation of the thyrohyoideus muscles. Positions of the basihyoid bone, ossified part of the thyroid cartilage, and articulations of the thyrohyoid bones and thyroid cartilage were determined in ...
Cordes V, Lüpke M, Gardemin M, Seifert H, Staszyk C.In equine dentistry periodontal diseases, especially periapical inflammation, are frequently occurring problems. Anachoresis is believed to be the most common cause for the development of such disorders. Nevertheless, there is still no substantiated explanation why settlement of pathogen microorganisms occurs in equine periodontal tissues. It is expected that excessive strains and stresses occurring in the periodontal ligament (PDL) during the horse's chewing cycle might be a predisposing factor. In this study this assumption was examined by finite element (FE) analyses on virtual 3-D models o...
Littlejohn A, Bowles F.Radiometer Blood Micro-system 2 was used in studies designed to, (a) compare the mean blood gas and acid-base values of 38 normal horses and 20 horses with chronic obstructive pulmonary disease (COPD), (b) determine the means and standard deviations of blood gas and acid-base values of Thoroughbred horses in training, and (c) investigate the relationships between clinical data, blood gas values, intracardiac and pulmonary arterial pressures in subjects with COPD. There were significant differences between the mean values for partial pressure of arterial oxygen (PaO2), arterial carbon dioxide (...
Dall'Aglio C, Bazzucchi C, Mercati F, Ceccarelli P.Leptin is a hormone widely diffused in the mammalian body in which it plays functions that go far beyond control of appetite and energy metabolism. The finding that it is present in the major salivary glands of various animal species is of interest for the functional implications that it may imply. Since there are no data on the presence of leptin and its receptor in the minor salivary glands, the aim of this study was to demonstrate their presence and distribution in such glands of donkeys. This latter was chosen as species of reference because the monogastric herbivore shows intense salivati...
Ghassab S, Dulin J, Bertone AL.To compare clotting efficiency of platelet-rich plasma (PRP) and concentrated platelet-poor plasma (cPPP) to citrated whole blood after activation by autologous thrombin, bovine thrombin, or calcium chloride (CaCl2 ). Methods: Experimental study. Methods: Healthy adult horses (n = 6). Methods: PRP and cPPP were prepared by commercial devices. Using thromboelastography, clotting variables were compared after activation of citrated autologous blood, PRP, and cPPP by autologous thrombin, bovine thrombin, or CaCl2 , respectively. Results: PRP had the greatest clot strength and quickest clot rate, ...
Buss DD, Bisgard GE.Hemodynamics and myocardial contractility were evaluated in 6 unanesthetized ponies during hypocapnic and isocapnic hypoxia and during hypocapnic hypoxia after beta adrenergic blockade with propranolol. Hypocapnic hypoxia, with a mean arterial oxygen pressure (PaO2) of 41.9 mm of Hg, produced a decrease in stroke index and an increase in heart rate, with no change of cardiac index. A moderate increase in left ventricular contractility occurred during hypocapnic hypoxia. Beta adrenergic blockade abolished changes in nearly all indices of left ventricular contractility during hypocapnic hypoxia,...
Álvarez C, Luño V, González N, Gil L.Sperm quality in donkeys (Equus asinus) after freezing thawing is still considered lower than that from other animals, including horses. The aim of this study was to test a new freezing extender supplemented with jenny colostrum on donkey sperm. After thawing, we evaluated sperm motility by means of computer-assisted analysis, viability by SYBR-14 and propidium iodide (PI), membrane functional integrity by HOS-test and acrosome integrity by isothiocyanate conjugated with peanut agglutinin (FITC-PNA) and PI. Ejaculates were collected from five fertile Donkeys. Sperm samples were pooled, diluted...
Lefranc A-, Allen WR.The morphology and surface density of endometrial glands responsible for the nutrition of the placenta requires further study employing computer assisted morphometric analysis. Objective: To analyse changes in the morphology and surface density of endometrial glands situated adjacent to, and remote from, the conceptus during the first 30 days of gestation. Methods: Endometrial biopsies were recovered, under videoendoscopic control, from both nonpregnant and pregnant mares 12 days after ovulation, as well as from pregnant mares on Days 16, 20, 25 and 30 of gestation. One biopsy was taken at the...
Mérant C, Messouak A, Cadoré JL, Monier JC.In mammals, the binding of peanut agglutinin (PNA) on the plasma membrane defines subpopulations among lymphocytes from peripheral blood and lymphoid organs. PNA binds Galbeta 1,3GalNAc residues provided that they are not sialylated. Here, we studied the expression of PNA-binding glycans on healthy horse peripheral blood, thymus, lymph node and spleen lymphocytes. We first demonstrated the binding specificity of PNA for galactose residues by competition experiments and the inhibitory role of sialic acids in PNA binding by sialidase digestion. Unlike human and murine lymphocytes, all equine lym...
Galuppo LD, Stover SM, Jensen DG, Willits NH.To compare drilling, tapping, and screw-insertion torque, force, and time for the 4.5-mm AO and 6.5-mm Acutrak Plus (AP) bone screws, and to compare the mechanical shear strength and stiffness of a simulated complete lateral condylar fracture of the equine third metacarpal bone (MC3) stabilized with either an AO or AP screw. Methods: In vitro biomechanical assessment of screw-insertion variables, and shear failure tests of a bone-screw-stabilized simulated lateral condylar fracture. Methods: Eight pairs of cadaveric equine MC3s Methods: Metacarpi were placed in a fixture and centered on a biax...
Brinsko SP, Squires EL, Pickett BW, Nett TM.The objective of this study was to determine if prolonged pulsatile administration of homologous gonadotropin-releasing hormone (GnRH) at therapeutic or 5x therapeutic doses would cause down-regulation of the stallion's hypothalamic-pituitary-testicular axis. Fifteen stallions were randomly assigned to three treatment groups (n=5/group) and received a 0.5 ml subcutaneous dose of saline (group 1), 50 microg GnRH (group 2), or 250 microg GnRH (group 3) every 2 hours for 75 days. Weekly evaluations of follicle stimulating hormone, luteinizing hormone, and testosterone and monthly evaluations of d...
Arden WA, Stick JA, Parks AH, Chou CC, Slocombe RF.Physiologic effects of 1 hour of ischemia and 1 hour of reperfusion on equine jejunum and protective effects of systemic administration of dimethyl sulfoxide (DMSO, 1 g/kg of body weight) were investigated in 18 ponies, using neurally intact segments of jejunum perfused at constant flow with heparinized blood. Ponies were allotted to 4 groups: group 1, saline solution administered (control, n = 3); group 2, DMSO administered (DMSO, n = 3); group 3, ischemia induced and saline solution administered (ischemia, n = 6); and group 4, ischemia induced and DMSO administered (ischemia-DMSO, n = 6). In...
O'Donnell MM, Harris HM, O'Toole PW, Ross RP.We report the draft genome sequence of Lactobacillus equi strain DPC6820, isolated from equine feces. L. equi is a predominant Lactobacillus species in the horse hindgut microbiota. An examination of the genome identified genes and enzymes highlighting L. equi adaptations to the herbivorous gastrointestinal tract of the horse, including fructan hydrolases. This genome sequence may help us further understand the microbial ecology of the equine hindgut and the influence lactobacilli have on it.
Buntenkötter K, Osmers M, Schenk I, Schänzer W, Machnik M, Düe M, Kietzmann M.Although acetylsalicylic acid (ASA) is not frequently used as a therapeutic agent in horses, its metabolite SA is of special interest in equestrianism since it is a natural component of many plants used as horse feed. This led to the establishment of thresholds by horse sport organizations for SA in urine and plasma. The aim of this study was to investigate plasma and urine concentrations of salicylic acid (SA) after oral administration of three different single dosages (12.5 mg/kg, 25 mg/kg and 50 mg/kg) of acetylsalicylic acid (ASA) to eight horses in a cross-over designed study. Results:...
Rigby BR, Papadakis Z, Bane AA, Park JK, Grandjean PW.The purpose of this study was to determine the reliability of cardiorespiratory and pelvic kinematic responses to simulated horseback riding (SHBR) and to characterize responses to SHBR relative to walking in apparently healthy children. Methods: Fifteen healthy children (M(age) = 9.5 ± 2.6 years) completed SHBR on a commercially available simulator at low intensity (0.27 Hz) and high intensity (0.65 Hz) during 3 sessions on different occasions. Heart rate (HR), blood pressure, and respiratory gases were measured at rest and during steady-state exercise at both intensities. Pelvic displacemen...
LeBlanc MM, McLaurin BI, Boswell R.Postpartum, presuckle, colostrum samples were collected from 100 mares. Colostral specific gravities significantly correlated (r = 0.9) with colostral immunoglobulin (Ig)G concentrations. Foal serum IgG concentrations highly correlated (r = 0.82) with specific gravities of the colostrum each foal ingested. Eight of 48 foals (17%) had serum IgG concentrations less than 400 mg/dl. The dams of these 8 foals had colostral sp gr less than 1.06 and colostral IgG concentrations less than 3,000 mg/dl. Foals had serum IgG concentrations greater than 520 mg/dl 24 hours after parturition, when the colost...
Logan AA, Snyder AJ, Nielsen BD.The effects of gait and diameter have been studied independently, but rarely together in equine circular exercise studies. This study aimed to determine the impact of diameter (10-m or 15-m) at various gaits (walk, trot, and canter) on stride frequency or forelimb stance duration. Nine mature horses were outfitted with Tekscan™ Hoof Sensors on their forelimbs during circular and straight-line exercise at various gaits on a clay and sand arena surface. Statistical analysis was performed in SAS 9.4 with fixed effects of exercise type, recording, leg, and breed (PROC GLIMMIX, p < 0.05 significa...
