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.
Requena F, Campos MJAPM, Martínez Marín AL, Camacho R, Giráldez-Pérez RM, Agüera EI.In equine reproduction, accurate and timely detection of the moment of ovulation is of great importance. Power Doppler ultrasound technology is a non-invasive method that enables to assess the morpho-echogenic features and blood flow changes during the estral cycle in mares. The objective of the present study was to evaluate the influence of age on ultrasonographic parameters (follicular diameter, follicular blood flow-FBF, corpus luteum (CL) area and corpus luteum blood flow-CLBF) and blood plasma progesterone concentrations in cycling Spanish Purebred mares (15 less than 8 years old and 15 e...
Ginther OJ.The equine embryo or embryonic vesicle on Days 11-15 postovulation travels with profound physiologic purpose throughout the lumen of the two uterine horns and uterine body making 12 to 22 trips between the two uterine horns per day. This phenomenon is termed embryo mobility and is unique in equids among domestic species. Apparently, the embryo first reaches the uterine body on Days 8 or 9. Mobility increases to maximum by Days 11 or 12 and continues until an abrupt cessation of mobility (fixation) on Days 15 (ponies) or 16 (horses and donkeys). The embryo is propelled by uterine contractions i...
Muhonen S, Sadet-Bourgeteau S, Julliand V.Fibrous feeds are essential for horses. When developing feeding regimens promoting health and performance, we need to understand the digestion of plant cell walls and the functioning of the hindgut microbial ecosystem. Our objective was to investigate the effect of grass fibre maturity and legume forage on the hindgut microbiota and its activity. Six caecum and colon fistulated geldings were fed three diets differing in fibre composition: concentrate and late harvested grass haylage (35:65 energy ratio) (C); early and late harvested grass haylage (80:20) (G); lucerne and late harvested grass h...
Szóstek-Mioduchowska AZ, Shiotani H, Yamamoto Y, Sadowska A, Wójtowicz A, Kozai K, Hojo T, Kimura K, Skarzynski DJ, Okuda K.Glucocorticoids (GCs) are known to play an important role in maintaining basal and stress-related homeostasis by interacting with endocrine mediators and prostaglandins (PGs). Although a growing body of evidence shows that GCs exert their regulatory action at a multitude of sites in the reproductive axis through corticosteroid receptors, little is known about the direct role of cortisol, an active form of GCs, in the equine endometrium. Thus, the study aimed to determine the effect of cortisol on PGF synthesis in the endometrial tissue and cells in vitro. In Exp.1, the immunolocalization and ...
Dias DCR, Ribeiro Filho JD, Viana RB, Bittencourt TCC, Dantas FTDR, Teixeira RBC, Di Filippo PA, Manso Filho HC, Alves SR, Santos PVM, Moreira NS.Continuous flow enteral fluid therapy with isotonic and hypotonic enteral electrolyte solutions are as safe and effective as intravenous fluid therapy. The aim of this study was to carry out a comparative assessment between continuous flow enteral and intravenous (IV) fluid therapy in adult experimentally dehydrated horses. Six experimentally dehydrated adult mares were used in a study carried out in a 6 × 3 crossover design, which each animal received three different treatments (isotonic enteral fluid therapy-EsISO, hypotonic enteral fluid therapy-EsHYPO and intravenous fluid therapy with La...
Rodrigues JB, Garrett C, Norris SL, Albuquerque F, Queijo L, Cooke F, Judge A.Working donkeys represent an important source of energy worldwide. Poor working conditions and equipment affect their ability to work. Poorly designed, ill-fitted harness causes inefficient transfer of power and leads to health and welfare issues. Using technology to assess different types of collars provides a better understanding of those that are most efficient for working donkeys. Methods: Seven different collars were tested using pressure pads. Contact area, median, maximum and peak pressures were obtained for the whole collar and critical points. Eight donkeys pulled 20% and 40% of their...
Animals must attend to a diverse array of stimuli in their environments. The emotional valence and salience of a stimulus can affect how this information is processed in the brain. Many species preferentially attend to negatively valent stimuli using the sensory organs on the left side of their body and hence the right hemisphere of their brain. Here, we investigated the lateralisation of visual attention to the rapid appearance of a stimulus (an inflated balloon) designed to induce an avoidance reaction and a negatively valent emotional state in 77 Italian saddle horses. Horses' eyes are late...
Paul LJ, Ericsson AC, Andrews FM, Keowen ML, Morales Yniguez F, Garza F, Banse HE.The role of the gastric microbiome in development or persistence of equine glandular gastric disease (EGGD) remains to be investigated. Objective: The objective was to characterize the glandular mucosal and gastric fluid microbiomes of horses with and without EGGD. It was hypothesized that differences in the mucosal microbiome are associated with EGGD. Methods: Twenty-four horses were enrolled. Methods: Gastroscopy was performed and EGGD scores recorded (score 0, n = 6; score 1, n = 8; score ≥2, n = 10). Gastric fluid and pinch biopsies of healthy glandular mucosa and EGGD lesions were...
Fernández-Hernández P, Marinaro F, Sánchez-Calabuig MJ, García-Marín LJ, Bragado MJ, González-Fernández L, Macías-García B.Equine fertilization cannot be performed in the laboratory as equine spermatozoa do not cross the oocyte's zona pellucida . Hence, a more profound study of equine oviductal fluid (OF) composition at the pre-ovulatory and post-ovulatory stages could help in understanding what components are required to achieve fertilization in horses. Our work aimed to elucidate the proteomic composition of equine OF at both stages. To do this, OF was obtained postmortem from oviducts of slaughtered mares ipsilateral to a pre-ovulatory follicle ( = 4) or a recent ovulation ( = 4); the samples were kept at -80°...
Brownlow MA, Brotherhood JR.Exertional heat illness (EHI) is a syndrome that occurs when metabolic heat production from muscular contraction exceeds the rate at which it can be dissipated. Core body temperature rises to critical levels, causing hyperthermia and central nervous system dysfunction. Best practice for the prevention of EHI centres around early detection, rapid response and aggressive cooling. Advance planning enables risk mitigation measures. The more that is known about EHI in horses, the better prepared those in the positions of responsibility can be to anticipate events in which the risk of EHI may be ele...
D' Fonseca NMM, Beukers M, Wijnberg ID, Navas de Solis C, de Ruijter-Villani M, van Doorn DA, Stout TAE, Roelfsema E.Changes in cardiovascular parameters, including blood pressure (BP) and cardiac anatomical dimensions, are an inconsistent feature of the equine metabolic syndrome. The order in which these changes arise is unknown. Objective: Determine the order in which EMS-associated changes in cardiovascular parameters arise. Methods: Twenty Shetland pony mares. Methods: High-energy (HE) diet mares were fed 200% of net energy requirements for 1 (n = 3) or 2 (n = 7) consecutive diet-years, with 17 weeks of hay-only between years. Noninvasive BP measurements and echocardiograms were performed during bo...
Quam V, Yardley J, Quam M, Paz C, Belknap J.The analgesic effect of cryotherapy in an induced lameness model was evaluated. Lameness was induced with solar pressure from a custom-made shoe in a 10-horse, cross-over study. The degree of lameness was recorded with a commercial non-invasive inertial sensor. The distal limbs were maintained in an ice and water slurry (cryotherapy) or at ambient temperature (control) for 1 hour. Lameness was assessed serially over the following hour. Lameness at each time point was compared to the baseline induced lameness, within and between groups. Lameness had improved significantly in all horses 5 minute...
Adolfsson KH, Sjöberg I, Höglund OV, Wattle O, Hakkarainen M.A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo a...
Pennington PM, Splan RK, Jacobs RD, Wang Y, Wagner AL, Freeman EW, Pukazhenthi BS.The reproductive cycle and early pregnancy represent dynamic physiological states in mammals, but mechanisms involved in early pregnancy in the domestic horse remain poorly understood. Proteins in uterine secretions have been studied, but the proteome of peripheral serum during various reproductive states has not been investigated. This study characterized and compared the serum proteome in the domestic horse during various reproductive states. Serum was collected from three mares during: (1) estrus (day [d] -1; d 0 = ovulation), (2) diestrus (d 12.5, non-mated), (3) early pregnancy (d 12.5,...
Hales EN, Habib H, Favro G, Katzman S, Sakai RR, Marquardt S, Bordbari MH, Ming-Whitfield B, Peterson J, Dahlgren AR, Rivas V, Ramirez CA, Peng S....Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder associated with a vitamin E deficiency within the first year of life. Vitamin E consists of 8 isoforms metabolized by the CYP4F2 enzyme. No antemortem diagnostic test currently exists for eNAD/EDM. Objective: Based on the association of α-tocopherol deficiency with the development of eNAD/EDM, we hypothesized that the rate of α-tocopherol, but not γ-tocopherol or tocotrienol metabolism, would be increased in eNAD/EDM-affected horses. Methods: Vitamin E metabolism: Proof...
Juśkiewicz J, Fotschki B, Jaworska J, Siemieniuch M.Gastrointestinal microbiota play a key role in the nutrients digestion and hence maintaining animal health and welfare. The diet offered to the animals in captivity may differ considerably from that on natural pastures. In a stabled maintenance system, horses have a limited choice of habitat and feed. Time spend for feeding is relevant for equine welfare because the reduction of the time devoted for foraging may be responsible for inducing gastric inflammation and ulceration. Therefore, in the present study, it was hypothesized that fecal bacterial fermentative processes differ between free-ro...
Viana GF, Midon M, Fonseca MW, Hataka A, Carandina L, Bueno LMC, Puoli Filho JNP, Machado VMV.In humans and pets, magnetic resonance imaging (MRI) provides important adjunctive anatomic information about the thyroid and its adjacent structures. To the best of our knowledge, however, no studies have been reported regarding the use of MRI for thyroid evaluation in horses. The aim of this study was to obtain qualitative and quantitative parameters of healthy thyroid gland in adult horses by MRI. Eleven horses were submitted to thyroid MRI evaluation. The healthy thyroid of these animals was ensured by normal examinations performed before (free thyroxine and ultrasound) and after (cytology...
Brom-de-Luna JG, Salgado RM, Felix MR, Canesin HS, Stefanovski D, Diaw M, Hinrichs K.In vitro production of horse embryos via intracytoplasmic sperm injection (ICSI) is a useful clinical and research technique. Current rates of blastocyst production are typically sub-optimal, and few methods to increase the rate of equine blastocyst development have been reported. Factors that might improve blastocyst production in a horse embryo culture system were explored. Myo-inositol is found in the horse oviduct and improves blastocyst development in other species, thus Experiment 1 was conducted to assess the effect of 10 mM myo-inositol added to Day 0-5 embryo culture medium, using hor...
Gray SM, Gutierrez-Nibeyro SD, Couëtil LL, Horn GP, Kesler RM, McCoy AM, Stewart MC, Schaeffer DJ.To evaluate the airway mechanics of modified toggle LP constructs in an airflow chamber model and compare these to the airway mechanics of standard LP constructs. Methods: Ex-vivo experimental study. Methods: Fifty-one equine cadaveric larynges. Methods: Bilateral LP constructs were performed using a modified toggle (n = 23) or a standard (n = 21) LP technique. Constructs were tested in an airflow model before and after cyclic loading which was designed to mimic postoperative swallowing. The cross-sectional area (CSA), peak translaryngeal airflow (L/s), and impedance (cmH 0/L/s) were deter...
Gandarillas M, Keim JP, Gapp EM.Horses are hindgut fermenters, and it is therefore important to determine the postgastric nutritive value of their feedstuffs and diets. Moreover, it has been demonstrated in other animal species that the fermentation of diets results in different values than those expected from pure ingredients. Therefore, the general objective of this work is to evaluate the gas production (GP) and volatile fatty acid (VFA) concentration, as well as the associative effects, of mixtures of different forages and concentrated foods, which are representative of the traditional diets of high-performance horses. M...
Olvera-Maneu S, Carbajal A, Gardela J, Lopez-Bejar M.The monitoring of stress physiology includes studying a wide range of endocrinological mechanisms, which can be assessed using multiple tissue samples. This study aimed to evaluate the seasonal variations of hair C, T and DHEA-S in horses for a whole year, as well as to assess the variations between seasons of C/DHEA-S and T/C ratios as a retrospective measure of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axis activity. Ten pure-breed Menorca stallions were included in the study. The hair samples were collected approximately every two months following the shave-resha...
Medica AJ, Aitken RJ, Nicolson GL, Sheridan AR, Swegen A, De Iuliis GN, Gibb Z.Stallion sperm membranes comprise a high proportion of polyunsaturated fatty acids, making stallion spermatozoa especially vulnerable to peroxidative damage from reactive oxygen species generated as a by-product of cell metabolism. Membrane lipid replacement therapy with glycerophospholipid (GPL) mixtures has been shown to reduce oxidative damage in vitro and in vivo. The aims of this study were to test the effects of a commercial preparation of GPL, NTFactor® Lipids, on stallion spermatozoa under oxidative stress. When oxidative damage was induced by the addition of arachidonic acid to stall...
Godwin T, Webb G, Lancaster P.Previous research indicates equine fecal inoculates produce comparable results to cecal fluid when used for in vitro procedures to analyze dry matter digestibility (DMD). Equine hindgut microbial communities represented in fecal samples have been shown to be affected by diet. The study's objective was to determine the effect of the donor diet on in vitro DMD when fecal donors were fed high starch, or high fiber diets. Six Quarter Horses were used in a crossover design to compare the effects of a grain versus forage diet on in vitro digestion of forages ranging from: CP 7.7 to 16.4 %DM, NDF 53 ...
Saljic A, Friederike Fenner M, Winters J, Flethøj M, Eggert Eggertsen C, Carstensen H, Dalgas Nissen S, Melis Hesselkilde E, van Hunnik A....Fibroblasts maintain the extracellular matrix homeostasis and may couple to cardiomyocytes through gap junctions and thereby increase the susceptibility to slow conduction and cardiac arrhythmias, such as atrial fibrillation (AF). In this study, we used an equine model of persistent AF to characterize structural changes and the role of fibroblasts in the development of an arrhythmogenic substrate for AF. Methods: Eleven horses were subjected to atrial tachypacing until self-sustained AF developed and were kept in AF for six weeks. Horses in sinus rhythm (SR) served as control. In terminal open...
Kruse CJ, Stern D, Mouithys-Mickalad A, Niesten A, Art T, Lemieux H, Votion DM.Equine atypical myopathy is a seasonal intoxication of grazing equids. In Europe, this poisoning is associated with the ingestion of toxins contained in the seeds and seedlings of the sycamore maple (Acer pseudoplatanus). The toxins involved in atypical myopathy are known to inhibit ß-oxidation of fatty acids and induce a general decrease in mitochondrial respiration, as determined by high-resolution respirometry applied to muscle samples taken from cases of atypical myopathy. The severe impairment of mitochondrial bioenergetics induced by the toxins may explain the high rate of mortality obs...
Rajabi-Toustani R, Watanabe H, Tsogtgerel M, Gao Y, Canbo L, Haneda S, Cheong SH, Nambo Y.The main difficulty of large equine embryo cryopreservation is the replacement of blastocoel fluid with cryoprotectant solution. The objective of this study was to improve the cryopreservation of large equine embryos with PMAP and/or LAP. Embryos were collected via the non-surgical transcervical procedure and divided into three groups based on their size (A ≤ 300 µm, 300 µm<B 300 µm). However, more research is required to find the best method for embryos ≥700 µm.
Keller LE, Tait Wojno ED, Begum L, Fortier LA.To gain insight into Treg interactions with synovial tissues in early OA, an equine tri-culture model of OA was used to test the hypothesis that Tregs, in the absence of T Helper 17 cells, are sufficient to resolve inflammation elicited by IL-1β. Unassigned: To model normal and OA joints, synoviocytes were co-cultured with chondrocytes in a transwell system and ± stimulated with IL-1β. Tregs were activated and enriched, then added to co-cultures, creating tri-cultures. At culture end, synoviocytes and chondrocytes were analyzed for gene expression, Treg Foxp3 expression was reexamined b...
Ragno VM, Klein CD, Sereda NS, Uehlinger FD, Zello GA, Robinson KA, Montgomery JB.In human metabolic syndrome and type II diabetes, methylglyoxal (MG), D-lactate, and several cytokines have been recognized as biomarkers of important metabolic and inflammatory processes. Equine metabolic syndrome (EMS) shares many similarities with these human counterparts. The objectives of this cross-sectional study were to compare body condition score (BCS), cresty neck score (CNS), resting insulin, MG, D-lactate, L-lactate, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) between horses with and without insulin dysregulation, as clas...
Farinelli F, de Rezende ASC, Fonseca MG, Lana ÂMQ, Leme FOP, Klein BON, Silva RHP, de Abreu AP, Damazio MJ, Melo MM.The Horse Agribusiness Complex is an important activity in the Brazilian agricultural sector. Mangalarga Marchador (MM) is the most numerous breed of horses in Brazil and its temperament and gait characteristics (4-beat stepping gait) allow for the constant growth of the breed and the performance of vs. equestrian activities. The training management currently adopted with MM horses is based on empiricism, and scientific support is necessary to improve the well-being of horses in competitions and maintain the physical integrity of these athletes. Therefore, this study aimed to verify the effect...
Mouithys-Mickalad A, Storms N, Franck T, Ceusters J, de la Rebière de Pouyade G, Deby-Dupont G, Serteyn D.Experimental laminitis, characterized by a failure of the dermal-epidermal interface of the foot, can be induced in horses by the oral administration of a black walnut extract (BWE). In the early phase of this severe and painful disease, an activation of neutrophil occurs, with the release of myeloperoxidase (MPO), a pro-oxidant enzyme of neutrophils, in plasma, skin, and laminar tissue. Juglone, a naphthoquinone derivative endowed with redox properties, is found in walnuts and has been incriminated in this neutrophil activation. We report for the first time the inhibitory activity of juglone ...
Franklin SH, Van Erck-Westergren E, Bayly WM.Horses are elite athletes when compared with other mammalian species. In the latter, performance is limited by cardiovascular or musculoskeletal performance whereas in athletic horses it is the respiratory system that appears to be rate limiting and virtually all horses exercising at high intensities become hypoxaemic and hypercapnoeic. This is due to both diffusion limitation and a level of ventilation inadequate for the metabolic level that enables horses to exercise at these intensities. In conjunction with these blood gas changes, total pulmonary resistance increases and the work of breath...
Robert C, Valette JP, Denoix JM.Electromyographic activity (EMG) was used to determine how hindlimb muscle activation patterns vary with speed and incline in the horse. EMG was recorded using surface electrodes over the gluteus medius and tensor fasciae latae muscles during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and inclination (0, 3 and 6%). Raw EMG signals were processed to determine stride duration, activity onset and end, and integrated EMG (IEMG). Stride and stance phase duration decreased linearly with increasing speed. Stride duration was not influenced by the slope. Onset and ...
Davis TA, Nguyen HV, Garcia-Bravo R, Fiorotto ML, Jackson EM, Reeds PJ.To determine whether the amino acid composition of milk changes during lactation, we compared the amino acid pattern (concentration of each individual amino acid relative to the total amino acid concentration) of colostrum with that of mature milk in six mammalian species. In the human, horse, pig and cow, the pattern of amino acids changed between colostrum and mature milk: glutamate, proline, methionine, isoleucine and lysine increased; cystine, glycine, serine, threonine and alanine decreased. In these four species, the total amino acid concentration also decreased 75% between colostrum and...
Secombe CJ, Tan RHH, Perara DI, Byrne DP, Watts SP, Wearn JG.Longitudinal evaluation of plasma endogenous ACTH concentration in clinically normal horses has not been investigated in the Southern Hemisphere. Objective: To longitudinally determine monthly upper reference limits for plasma ACTH in 2 disparate Australian geographic locations and to examine whether location affected the circannual rhythm of endogenous ACTH in the 2 groups of horses over a 12-month period. Methods: Clinically normal horses <20 years of age from 4 properties (institutional herd and client owned animals) in Perth (n = 40) and Townsville (n = 41) were included in the study. M...
Neild DM, Brouwers JF, Colenbrander B, Agüero A, Gadella BM.In this study we used a new method to detect reactive oxygen species (ROS) induced damage at the level of the sperm plasma membrane in fresh and frozen-thawed stallion sperm. Lipid peroxidation (LPO) in sperm cells was assessed by a fluorescent assay involving the labeling of stallion sperm with the LPO reporter probe C11-BODIPY(581/591). The peroxidation dependent spectral emission shift of this membrane probe could be localized using inverted spectral confocal microscopy and quantified on living and deteriorated sperm cells using flow cytometry. Mass spectrometric analysis of the main endoge...
Ferlazzo A, Cravana C, Fazio E, Medica P.The review discusses the hormonal changes during exercise stress. The exercise generally produces a rise of adrenaline (A), noradrenaline (NA), adrenocorticotropic hormone (ACTH), cortisol, glucagon, growth hormone, arginine vasopressine, etc., and a drop of insulin. The hormonal events during reestablishment of homeostasis due to exercise stress can be divided into a catabolic phase, with decreased tolerance of effort, and reversible biochemical, hormonal and immunological changes, and an anabolic phase, with a higher adaptive capacity, and enhanced performance. The two main hormonal axes act...
Helmstaedter V, Feurle GE, Forssmann WG.Equine pancreas was investigated with immunohistochemical methods to study the distribution of endocrine cells immunoreactive to anti-insulin, anti-glucagon, and anti-somatostatin. A-cells demonstrable by anti-glucagon are located in the center of Langerhans islets and frequently in the duct epithelium. Few A-cells are seen associated to acini. Anti-insulin reactive B-cells form a large zone around the center of the Langerhans islets in which some B-cells lie between exocrine cells and others, although few, are located in the duct epithelium. D-cells stained with anti-somatostatin serum form a...
Valberg SJ.Optimal function of skeletal muscle is essential for successful athletic performance. Even minor derangements in locomotor muscle function will impact power output, coordination, stamina, and desire to work during exercise. In this review, the presenting clinical signs, differential diagnoses, approach to diagnostic testing and treatment of muscle atrophy and weakness, focal muscle strain, and exertional myopathies are discussed. Exertional myopathies include polysaccharide storage myopathies, recurrent exertional rhabdomyolysis, malignant hyperthermia, and myofibrillar myopathy.
Aupperle H, Ozgen SSchoon HA, Schoon D, Hoppen HO, Sieme H, Tannapfel A.The aims of this study were to investigate the steroid hormone receptor expression and the proliferation intensity during the equine endometrial cycle by immunohistological methods, established for routine examination of formalin-fixed, paraplast-embedded specimens. Endometrial biopsy specimens were obtained during one cycle from 7 mares. In comparison with the blood steroid hormone levels the quantity and distribution of oestrogen (ER) and progesterone receptors (PR) and the proliferation marker Ki-67 antigen expression were investigated. Rising 17beta-oestradiol concentrations in preoestrus ...
Zhang Y, Cao QS, Rubenstein DI, Zang S, Songer M, Leimgruber P, Chu H, Cao J, Li K, Hu D.Acquiring water is essential for all animals, but doing so is most challenging for desert-living animals. Recently Przewalski's horse has been reintroduced to the desert area in China where the last wild surviving member of the species was seen before it vanished from China in the 1960s. Its reintroduction placed it within the range of a close evolutionary relative, the con-generic Khulan. Determining whether or not these two species experience competition and whether or not such competition was responsible for the extinction of Przewalski's horses in the wild over 50 years ago, requires ident...
Nagata S, Tsunoda N, Nagamine N, Tanaka Y, Taniyama H, Nambo Y, Watanabe G, Taya K.The cellular localization of inhibin alpha, betaA, and betaB subunits, 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and cytochrome P450 aromatase (aromatase) in stallion testes was investigated. In addition, detailed seasonal changes in circulating immunoreactive (ir)-inhibin were investigated in correlation with testosterone, estradiol, LH, and FSH. Inhibin alpha subunit-positive staining was observed in Sertoli cells, and more clearly positive staining was noted in Leydig cells. Inhibin betaA and betaB subunits were also stained in both types of cells. Immunoreactivity of 3beta-HSD and ar...
Krishnan A, Wilson A, Sturgeon J, Siedlecki CA, Vogler EA.A systematic study of water-air (liquid-vapor, LV) interfacial tension gamma(lv) of blood plasma and serum derived from four different mammalian species (human, bovine, ovine and equine) reveals nearly identical concentration-dependence (dgamma(lv)/dlnC(B); where C(B) is plasma/serum dilution expressed in v/v concentration units). Comparison of results to a previously-published survey of purified human-blood proteins further reveals that dgamma(lv)/dlnC(B) of plasma and serum is surprisingly similar to that of purified protein constituents. It is thus concluded that any combination of blood-pr...
Fureix C, Benhajali H, Henry S, Bruchet A, Prunier A, Ezzaouia M, Coste C, Hausberger M, Palme R, Jego P.Stereotypic behaviours, i.e. repetitive behaviours induced by frustration, repeated attempts to cope and/or brain dysfunction, are intriguing as they occur in a variety of domestic and captive species without any clear adaptive function. Among the different hypotheses, the coping hypothesis predicts that stereotypic behaviours provide a way for animals in unfavourable environmental conditions to adjust. As such, they are expected to have a lower physiological stress level (glucocorticoids) than non-stereotypic animals. Attempts to link stereotypic behaviours with glucocorticoids however have y...
Holmström M, Fredricson I, Drevemo S.The trotting gait of 4 approved Swedish Warmblood stallions with a mean gait score > or = 8.67 (maximum score = 10) at official performance tests was recorded by high speed film (approximately 250 frames/sec). Angular patterns and hoof trajectories of the left fore and hind limbs were analysed, and presented as mean and standard deviation curves. The horses had a mean stride duration of 794.0 msec (sd 13.7) and the mean diagonal advanced placement was +29.8 msec (sd 7.6). The variation in angular patterns between the horses was greatest during the swing phase. The trajectory of the hind hoof r...
Armstrong RA, Lawrence RA, Jones RL, Wilson NH, Collier A.1. This study describes attempts to compare prostacyclin (IP-) receptors in human, pig, horse, rabbit and rat platelets and in circular muscle of human, rabbit and dog mesenteric and pig gastroepiploic arteries. Three stable prostacyclin analogues, iloprost, cicaprost and 6a-carba-prostacyclin (6a-carba-PGI2) and a prostaglandin endoperoxide analogue EP 157 (previously shown to mimic prostacyclin on human platelets) were used. 2. Our main conclusion is that prostacyclin receptors on human, pig and horse platelets are similar in nature, but distinct from those on rabbit and rat platelets. Funct...
Couto MA, Harwig SS, Cullor JS, Hughes JP, Lehrer RI.Endogenous, cysteine-rich antimicrobial peptides known as defensins are prominent components of human, rabbit, and rat neutrophils, yet little is known about their occurrence in other mammalian species. Although we did not detect mature (i.e., processed) defensins in equine neutrophil granules, we found that these granules contained small amounts of other cysteine-rich peptides with antimicrobial activity. One of these, eNAP-1, was purified by a combination of gel permeation and reversed-phase high-performance liquid chromatography from acid extracts prepared from the cytoplasmic granules of e...
Nitschke M, Korte T, Tielesch C, Ter-Avetisyan G, Tünnemann G, Cardoso MC, Veit M, Herrmann A.Equine arteritis virus (EAV) is an enveloped, positive-stranded RNA virus belonging to the family Arteriviridae. Infection by EAV requires the release of the viral genome by fusion with the respective target membrane of the host cell. We have investigated the entry pathway of EAV into Baby Hamster Kidney cells (BHK). Infection of cells assessed by the plaque reduction assay was strongly inhibited by substances which interfere with clathrin-dependent endocytosis and by lysosomotropic compounds. Furthermore, infection of BHK cells was suppressed when clathrin-dependent endocytosis was inhibited ...
Peña FJ, García BM, Samper JC, Aparicio IM, Tapia JA, Ferrusola CO.We review recent developments in the technology of freezing stallion sperm, paying special attention to the molecular lesions that spermatozoa suffer during freezing and thawing, such as osmotic stress, oxidative damage, and apoptotic changes. We also discuss the applicability of colloidal centrifugation in stallion sperm cryobiology. Increased knowledge about the molecular injuries that occur during cryopreservation may lead to improved protective techniques and thus to further improvements in fertility in the current decade.
Arfuso F, Giudice E, Panzera M, Rizzo M, Fazio F, Piccione G, Giannetto C.The monitoring of endocrine and immunologic markers during exercise is of paramount importance to assess and/or maintain the physical well-being of athletes as well as to optimize the athletic performance. This study aimed to investigate the linkage between acute stress response and immune status in Thoroughbred horses competing in an official 1300-m race. From 10 horses blood was collected 1 week before the day of the race (1W-BEFORE), before (REST) and immediately after the race to assess the cortisol, Interleukin-1 receptor antagonist (IL-1Ra), total proteins, white blood cells (WBC), red b...
Reynolds A, Keen JA, Fordham T, Morgan RA.Obesity is a common feature of equine metabolic syndrome (EMS). In other species, obese adipose tissue shows pathological features such as adipocyte hypertrophy, fibrosis, inflammation and impaired insulin signalling all of which contribute to whole body insulin dysregulation. Such adipose tissue dysfunction has not been investigated in horses. Objective: To determine if obese horses with EMS have adipose tissue dysfunction characterised by adipocyte hypertrophy, fibrosis, inflammation and altered insulin signalling. Methods: Cross-sectional post-mortem study. Methods: Samples of peri-renal (v...
Cannon SC, Hayward LJ, Beech J, Brown RH.1. Equine hyperkalemic periodic paralysis (E-HPP) is a dominantly inherited disorder of muscle that causes recurrent episodes of stiffness (myotonia) and weakness in association with elevated serum K+. Affected horses carry a mutant allele of the skeletal muscle isoform of the Na channel alpha-subunit. To understand how this mutation may cause the disease phenotype, the functional defect in Na channel behavior was defined physiologically by recording unitary currents from cell-attached patches on normal and affected equine myotubes. 2. The presence of the mutation was confirmed in our cell lin...
Brown NA, Kawcak CE, McIlwraith CW, Pandy MG.Articular injuries in athletic horses are associated with large forces from ground impact and from muscular contraction. To accurately and noninvasively predict muscle and joint contact forces, a detailed model of musculoskeletal geometry and muscle architecture is required. Moreover, muscle architectural data can increase our understanding of the relationship between muscle structure and function in the equine distal forelimb. Muscle architectural data were collected from seven limbs obtained from five thoroughbred and thoroughbred-cross horses. Muscle belly rest length, tendon rest length, m...
Robert C, Valette JP, Denoix JM.The purpose of this study was to evaluate the effects of speed and slope on the activity of trunk muscles. The electromyographic (EMG) activity of the splenius (Sp), longissimus dorsi (LD) and rectus abdominis (RA) muscles was recorded with surface electrodes during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and slope (0 to 6%). Raw EMG signals were processed to determine activity duration, onset and end and integrated EMG (IEMG). For the 3 muscles investigated, onset and end of activity were obtained earlier in the stride cycle when speed increased. A long...
Jiang L, Campagne C, Sundström E, Sousa P, Imran S, Seltenhammer M, Pielberg G, Olsson MJ, Egidy G, Andersson L, Golovko A.Constitutive activation of the ERK pathway, occurring in the vast majority of melanocytic neoplasms, has a pivotal role in melanoma development. Different mechanisms underlie this activation in different tumour settings. The Grey phenotype in horses, caused by a 4.6 kb duplication in intron 6 of Syntaxin 17 (STX17), is associated with a very high incidence of cutaneous melanoma, but the molecular mechanism behind the melanomagenesis remains unknown. Here, we investigated the involvement of the ERK pathway in melanoma development in Grey horses. Methods: Grey horse melanoma tumours, cell lines ...
Volpe S, Galeati G, Bernardini C, Tamanini C, Mari G, Zambelli D, Seren E, Spinaci M.Heat shock proteins (Hsp)-60, -70 and -90 are important testis chaperones that fulfil several functions during sperm cell maturation. In post-meiotic cells, their expression may change or may be undetectable and in some species it may be evident in mature spermatozoa. The aims of this study were to verify whether Hsp60, -70 and -90 are present in the sperm, and to compare their localization in boar, stallion, cat and dog spermatozoa by immunofluorescence. Hsp-60 immunoreactivity was detected in sperm midpiece in all the species examined. In stallion sperm, Hsp70 signal was localized in the sub...
Docking SI, Daffy J, van Schie HT, Cook JL.Investigations into the response of the superficial digital flexor tendon (SDFT) of the Thoroughbred horse to mechanical stimuli have been limited to in vitro cell culture studies focused primarily on gene expression of critical matrix proteins. It is uncertain how well in vitro outcomes translate to the tendon of the horse during exercise. The current study examined changes in tendon structure in response to maximal exercise using ultrasound tissue characterisation (UTC) to scan the SDFT prior to and after competitive racing. UTC uses contiguous transverse ultrasound images to assess the dyna...
Ralston JS, Main AR, Kilpatrick BF, Chasson AL.Two large-scale methods based primarily on the use of procainamide-Sepharose gels were developed for the purification of horse and human serum non-specific cholinesterases. With method I, the procainamide-Sepharose 4B gel was used in the first step to handle large volumes of serum. With method II, the procainamide-Sepharose 4B gel was used in the final step to obtain pure enzyme. Although both methods gave electrophoretically pure cholinesterase preparations in good yields, they were significantly more efficient at purifying the horse enzyme than the human enzyme. To study this problem, the re...
Larsson M, Pettersson T, Carlström A.The binding of [125I]T4 to serum proteins was studied in human, monkey, cattle, sheep, goat, water buffalo, horse, swine, dog, cat, rabbit, rat, chicken, frog, and salmon. Attempts were made to isolate thyroxine-binding globulin (TBG) and thyroxine-binding prealbumin (TBPA) from serum of all species, utilizing purification methods based on the specific properties of these proteins. TBPA was found to exist in all species examined. The protein was found anodal to albumin only in human, monkey, horse, and chicken. In cattle, swine, dog, cat, rabbit, frog, and salmon, TBPA was found cathodal to al...
Colborn DR, Thompson DL, Roth TL, Capehart JS, White KL.Sexual stimulation induces rapid secretion of cortisol and prolactin (PRL) in stallions. Experiment 1 was designated to determine whether stallions associated location and(or) procedure with previous sexual stimulation in that location. After a control period on d 1, four stallions were exposed to an estrous mare for 5 min on d 2. On d 3, 4, 5, and 6, the same procedure was followed with no mare present. Concentrations of PRL and cortisol increased (P less than .05) after mare exposure on d 2 but did not vary (P greater than .05) on d 1, 3, 4, 5, or 6. In Exp. 2, six stallions were used to det...
