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.
Bonagura JD.Equine heart diseases can be categorized with morphologic, etiologic, and physiologic diagnoses and classified anatomically as diseases of the pericardium, myocardium, valves (endocardium), and great vessels. An appreciation of normal and pathologic physiology is a key to understanding diagnosis and therapy of heart disease. Pathophysiologic diagnoses include arrhythmias, congestive heart failure, and pulmonary hypertension. Heart rhythm disturbances can occur in isolation or with structural disease. Heart failure stems from arterial filling owing to insufficient cardiac output. Pulmonary hype...
Shih AC.Monitoring variables of cardiac performance in horses is challenging owing to patient size, temperament, and anatomic peculiarities. Blood pressure is a major determinant of afterload, but it is not a reliable surrogate of cardiac performance and tissue perfusion. Cardiac output, together with arterial and venous oxygen content, provides insight as to the adequacy of delivery of blood and oxygen to the body as a whole and can be used to gauge the fluid responsiveness and cardiovascular status of the patient. Measurement of intracardiac pressures serves to assess cardiac filling pressures, myoc...
Navas de Solis C.The physiology of exercise and training is fascinating, and hundreds of interesting studies have given insight into its mechanisms. Exercise testing is a useful clinical tool that can help veterinarians assess poor performance, fitness, and performance potential and prevent injuries. The clinically applicable aspects of cardiovascular adaptions to training and exercise testing are highlighted in this review. Different exercise tests should be used to evaluate horses performing in different disciplines and levels. Exercise tests that simultaneously assess several body systems can be beneficial ...
Lopez BS, Hurley DJ, Giancola S, Giguère S, Felippe MJB, Hart KA.Neonatal foals are uniquely susceptible to certain infections early in life. Dendritic cells (DC) are vital in the transition between the innate and adaptive immune response to infection, but DC biology in foals is not fully characterized. Monocyte-derived DC represent a suitable in vitro model similar to DC that differentiate from monocytes recruited from circulation. We hypothesized that foal monocyte-derived DC (MoDC) would exhibit age-dependent phenotypic and functional differences compared to adult horse MoDC. MoDC generated from 9 horses (collected once) and from 8 foals (collected at 1,...
Murphy BA.Biological rhythms evolved to provide temporal coordination across all tissues and organs and allow synchronization of physiology with predictable environmental cycles. Most important of these are circadian and circannual rhythms, primarily regulated via photoperiod signals from the retina. Understanding the nature of physiological rhythms in horses is crucially important for equine management. Predominantly, they have been removed from exposure to their natural environmental stimuli; the seasonally changing photoperiod, continuous foraging and feeding activity, social herd interactions, and t...
Redaelli V, Luzi F, Mazzola S, Bariffi GD, Zappaterra M, Nanni Costa L, Padalino B.The aim of this pilot study was to document the effects of endurance training at different intensities on heart rate (HR), blood count, serum cortisol, and maximal temperatures of different body locations, namely eye, crown, pastern pasterns, and muscle (, measured by infrared thermography technique (IRT) in horses trained for endurance. Possible associations among the studied parameters were also investigated. Our hypothesis was that temperature, measured by IRT after endurance training of different intensities would vary depending on the intensity and would be positively correlated with HR...
Linardi RL, Dodson ME, Moss KL, King WJ, Ortved KF.Cartilage injury occurs commonly in equine athletes, often precipitating posttraumatic osteoarthritis (PTOA). Orthobiologics such as autologous conditioned serum (ACS) and autologous protein solution (APS) may be useful in decreasing posttraumatic inflammation, thereby preventing PTOA. The objective of this study was to quantify cytokine concentrations in ACS and APS and evaluate the protective effects of ACS and APS on inflamed chondrocytes cultured . We hypothesized that the combination of platelet-derived growth factors (PDGF) and anti-inflammatory cytokines present in APS would be superior...
Dutra GA, Ishak GM, Pechanova O, Pechan T, Peterson DG, Jacob JCF, Willard ST, Ryan PL, Gastal EL, Feugang JM.Proteomic studies of follicular fluid (FF) exist for several species, including the horse; however, the seasonal influence on FF proteome has not been explored in livestock. The application of high-throughput proteomics of FF in horse has the potential to identify seasonal variations of proteins involved in follicle and oocyte growth. Methods: This study (i) profiles the proteomes of equine FF collected from dominant growing follicles during the spring anovulatory season (SAN), and spring (SOV), summer (SUM), and fall (FOV) ovulatory seasons; and (ii) identifies season-dependent regulatory net...
Bonelli F, Rota A, Aurich C, Ille N, Camillo F, Panzani D, Sgorbini M.Salivary cortisol provides information about free plasma cortisol concentration, and salivary sampling is a noninvasive well-tolerated procedure. The aim of this study was to validate a commercial enzyme immunoassay for the determination of salivary cortisol in donkeys. Saliva samples were collected in four donkey stallions on 13 nonconsecutive days at 8:30 AM to avoid circadian variation. Animals were already accustomed to be handled. Saliva was collected using a swab inserted at the angle of the lips, placed onto the tongue for 1 minute and returned into a polypropylene tube. Tubes were cen...
Fehlberg LK, Lattimer JM, Drouillard JS, Douthit TL.Effects of Co on fiber digestibility in horses are largely unknown. Our objective was to evaluate effects of Co chloride on in vitro gas production, VFA production, and dry matter (DM) disappearance (IVDMD) using cecal fluid from 4 cannulated Quarter Horses. Five grams DM of alfalfa or smooth bromegrass hay were provided as substrate with Co added at 0.0, 0.5, 5.0, 25.0, or 50.0 mg/kg substrate DM. Ten milliliters cecal fluid and 140 mL McDougall's buffer were incubated in duplicate, and pH, VFA concentrations, and IVDMD were measured after 48 hours. Gas production, used as an indicator of...
Klohonatz KM, Nulton LC, Hess AM, Bouma GJ, Bruemmer JE.Maternal recognition of pregnancy (MRP) in the mare is an unknown process. In a non-pregnant mare on day 14 post-ovulation (PO), prostaglandin F2α (PGF) is secreted by the endometrium causing regression of the corpus luteum. Prior to day 14, MRP must occur in order to attenuate secretion of PGF. The embryo is mobile throughout the uterus due to uterine contractions from day of entry to day 14. It is unknown what signaling is occurring. Literature stated that infusing oil or placing a glass marble into the equine uterus prolongs luteal lifespan and that in non-pregnant mares, serum exosomes co...
Diaz-Jimenez M, Dorado J, Consuegra C, Ortiz I, Pereira B, Carrasco JJ, Gomez-Arrones V, Domingo A, Hidalgo M.The aim of this study was to assess the effect of different factors affecting vitrification success of donkey sperm: extender, sperm concentration, volume and storage vessel type. In Experiment 1, sucrose supplementations at 0.25 and 0.1 M were compared using two base extenders (containing or not egg-yolk); in Experiment 2, three sperm concentrations were assessed: 100, 200 or 300 million sperm/mL; and in Experiment 3, three different sperm volumes (100, 160 and 200 μL) and two different storage vessels (0.25 and 0.5 mL straws) were assessed. Sperm motility variables (CASA), plasma memb...
Caron JP, Gandy JC, Brown JL, Sordillo LM.Omega-3 fatty acid (n-3 PUFA) supplementation may have beneficial effects in certain chronic diseases, potentially including osteoarthritis. Favorable effects are attributed, in part, to downstream pro-resolving oxylipid metabolites. We investigated the role of n-3 PUFA and docosahexaenoic acid (DHA)-derived oxylipids (docosanoids) on equine synoviocyte metabolism. We hypothesized that n-3 PUFA and selected docosanoids would modulate inflammatory mediator gene expression by recombinant equine (re)IL-1β-stimulated synovial fibroblasts. Synoviocyte monolayer cultures were prepared from grossly ...
Mama KR, Hector RC.Many drugs and non-drug modalities are used to manage pain in horses, but evidence regarding efficacy and safety remains limited. This manuscript will first briefly review tried and tested techniques, e.g. the use of non-steroidal anti-inflammatory drugs, in the management of pain. Newer approaches to administering medications such as oral use of detomidine, which was previously only administered by injection, will also be discussed. Finally, introductory information on newer therapies, for example acupuncture and chiropractic manipulation, that the veterinarian may consider for the management...
Donaldson MC, Holter AM, Neuhoff S, Arnosky JA, Simpson BW, Vernon K, Blob RW, DesJardins JD.Although horseback riding is a well-established means of rehabilitation therapy for a variety of human patients, there are few data on the biomechanical relationships between horse and rider during such hippotherapy. We simultaneously tracked the movements of a horse with several different novice riders, under conditions similar to hippotherapy, to evaluate whether horses pass the same motion to different riders while being lead at a walk. Riders were outfitted with a goniometric data collection system that recorded the angles of flexion and extension and lateral bending of the thoracic and lu...
Schwarzwald CC.This article provides an overview on the principles of transthoracic echocardiography in horses. Indications for echocardiography, equipment, and technical considerations are discussed and a systematic approach for a complete echocardiographic examination in horses is described. Methods for assessment of chamber dimensions, allometric scaling of measurements, assessment of systolic and diastolic ventricular function, assessment of atrial function, hemodynamic assessment, and evaluation of valvular regurgitation are explained, focusing on traditional 2-dimensional (2D), motion-mode, and Doppler...
Makrynitsa GI, Ntonti D, Marousis KD, Birkou M, Matsoukas MT, Asami S, Bentrop D, Papageorgiou N, Canard B, Coutard B, Spyroulias GA.Venezuelan equine encephalitis virus (VEEV) is a new world alphavirus which can be involved in several central nervous system disorders such as encephalitis and meningitis. The VEEV genome codes for 4 non-structural proteins (nsP), of which nsP3 contains a Macro domain. Macro domains (MD) can be found as stand-alone proteins or embedded within larger proteins in viruses, bacteria and eukaryotes. Their most common feature is the binding of ADP-ribose (ADPr), while several macro domains act as ribosylation writers, erasers or readers. Alphavirus MD erase ribosylation but their precise contributi...
Christmann U, Hite RD, Witonsky SG, Buechner-Maxwell VA, Wood PL.OBJECTIVE To evaluate the lipidomic profile of surfactant obtained from horses with asthma at various clinical stages and to compare results with findings for healthy horses exposed to the same conditions. SAMPLE Surfactant samples obtained from 6 horses with severe asthma and 7 healthy horses. PROCEDURES Clinical evaluation of horses and surfactant analysis were performed. Samples obtained from horses with severe asthma and healthy horses before (baseline), during, and after exposure to hay were analyzed. Crude surfactant pellets were dried prior to dissolution in a solution of isopropanol:me...
Auckburally A, Grubb TL, Wiklund M, Nyman G.OBJECTIVE To determine the impact of mechanical ventilation (MV) and perfusion conditions on the efficacy of pulse-delivered inhaled nitric oxide (PiNO) in anesthetized horses. ANIMALS 27 healthy adult horses. PROCEDURES Anesthetized horses were allocated into 4 groups: spontaneous breathing (SB) with low ( 70 mm Hg. Data were collected after a 60-minute equilibration period and at 15 and 30 minutes during PiNO administration. Variables included Pao, arterial oxygen saturation and content, oxygen delivery, and physiologic dead space-to-tidal volume ratio. Data were analyzed with Shapiro-Wilk, ...
Valdez R, Cavinder CA, Varner DD, Welsh TH, Vogelsang MM, Ing NH.Glucocorticoids impair testosterone synthesis by an unknown mechanism. Stallions treated with the synthetic glucocorticoid dexamethasone had testes collected at 6 or 12 hours postinjection. The testicular expression of selected genes encoding nuclear receptors and steroidogenic enzymes was measured. At 6 hours, dexamethasone treatment decreased levels of NR0B2, NR4A1, NR5A1, and NR5A2 messenger RNAs (mRNAs) and NR5A2 mRNA levels remained depressed at 12 hours. In contrast, dexamethasone increased levels of NFKBIA mRNA at both time points. At 6 hours, dexamethasone did not alter levels ...
Daniel AJ, Leise BS, Selberg KT, Barrett MF.Injuries to the structures within the digital flexor tendon sheath (DFTS) can lead to lameness with a variable degree of effusion in horses. In some cases, effusion is absent or minimal, and this may be related to the chronicity and type of injury, or veterinary interventions. The purpose of this study was to determine if saline injection into the DFTS would improve ultrasonographic and magnetic resonance imaging of the distal limb without introducing artifact. Nine normal equine cadaver forelimbs were collected. Non-weight-bearing ultrasonographic and magnetic resonance imaging (MRI) examinat...
Elashry MI, Gegnaw ST, Klymiuk MC, Wenisch S, Arnhold S.Cell-based therapies have become a promising approach to promote tissue regeneration and the treatment of musculoskeletal disorders. Bone regeneration maintains bone homeostasis, mechanical stability and physical performance. Mechanical stimulation showed to induce stem cell differentiation into the osteogenic fate. However, the effect of various osteogenic protocols on the osteogenic commitment of equine adipose-derived stem cells is not fully elucidated. Here we examined the influence of fluid-based shear stress (FSS) via mechanical rocking to assess whether mechanical stimulation promotes o...
Alexeenko V, Fraser JA, Dolgoborodov A, Bowen M, Huang CL, Marr CM, Jeevaratnam K.The analysis of equine electrocardiographic (ECG) recordings is complicated by the absence of agreed abnormality classification criteria. We explore the applicability of several complexity analysis methods for characterization of non-linear aspects of electrocardiographic recordings. We here show that complexity estimates provided by Lempel-Ziv '76, Titchener's T-complexity and Lempel-Ziv '78 analysis of ECG recordings of healthy Thoroughbred horses are highly dependent on the duration of analysed ECG fragments and the heart rate. The results provide a methodological basis and a feasible refer...
Shang S, Yu Y, Zhao Y, Dang W, Zhang J, Qin X, Irwin DM, Wang Q, Liu F, Wang Z, Zhang S, Wang Z.Through domestication and human selection, horses have acquired various coat colors, including seven phenotypes: black, brown, dark bay, bay, chestnut, white, and gray. Here we determined the genotypes for melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) in 709 horses from 15 breeds. We found that the EEEE genotype frequency at MC1R decreased from dark to light colors (black = 64.5%, brown = 67.5%, dark bay = 47.0%, bay = 16.5%, and chestnut = 0.0%), whereas the AAAA genotype frequency at ASIP increased as coat color lightened (black = 0.0%, brown = 22.9%, dark bay = 69.2%, a...
Arfuso F, Assenza A, Fazio F, Rizzo M, Giannetto C, Piccione G.Physical exercise induces several adaptations involving modulation of the energetic pathways to meet the energy demand during physical exercise. The branched-chain amino acids, leucine in particular, are considered as the most relevant amino acids, especially for exercise physiology. In this study, the change of leucine, valine, and tryptophan concentration was investigated in athletic horses before and after different exercise type. A total of 40 sport horses were equally divided into 4 groups according to the exercise type: group A (jumping), group B (reining), group C (32 km ride), and grou...
Asadollahpour Nanaei H, Ayatollahi Mehrgardi A, Esmailizadeh A.Equine athletes have a genetic heritage that has been evolved for millions of years, which provides an opportunity to study the genetics of locomotion pattern and performance in mammals. The Hanoverian, a breed originating in Germany, is arguably among the most athletic of horse breeds, as well as possessing a balanced character and beautiful appearance. Here, we compared the whole genomes of Hanoverian with three other horse breeds (Akhal-Teke, Franches-Montagnes, and Standardbred), using the fixation index (Fst) and cross-population composite likelihood ratio (XP-CLR) methods for testing the...
Plunkett AH, Schoonover MJ, Young JM, Taylor JD, Holbrook TC.To determine the influence of location and movement on subtourniquet pressure (STP) generated by application of a wide-rubber tourniquet (WRT) on equine limbs. Methods: Randomized experimental cross-over design. Methods: Six standing, sedated horses. Methods: Horses were sedated with detomidine hydrochloride (0.2 μg/kg IV), and 4 investigators applied WRTs to the antebrachium (AB), gaskin (GK), and midmetacarpus (MC) of each horse in a predetermined, randomized order. Subtourniquet pressure was consequently measured at 10-minute intervals (T0, T10, T20, T30) for 30 minutes. Indirect systo...
Sheldon SA, Aleman M, Costa LRR, Santoyo AC, Weich KM, Howey Q, Madigan JE.Trigeminal-mediated headshaking results from a low threshold for firing of the trigeminal nerve. A seasonal component has been implicated in onset of clinical signs, which occur during the spring and summer months. Geldings are overrepresented in the affected population and hormonal differences as compared to a healthy control population of geldings might contribute to headshaking. Objective: To assess concentrations of luteinizing hormone (LH) over an 8-hour period in gelded healthy controls and horses affected with headshaking. Our hypothesis was that geldings with seasonal headshaking would...
Bond SL, Greco-Otto P, Sides R, Kwong GPS, Léguillette R, Bayly WM.A prospective, randomized, controlled study was designed to determine relative aerobic and anaerobic (lactic and alactic) contributions at supramaximal exercise intensities using two different methods. Thoroughbred racehorses ( = 5) performed a maximal rate of oxygen consumption (V̇o) test and three supramaximal treadmill runs (105, 115, and 125% V̇o). Blood lactate concentration (BL) was measured at rest, every 15 s during runs, and 2, 5, 10, 20, 30, 40, 50, and 60 min postexercise. In , oxygen demand was calculated for each supramaximal intensity based on the V̇o test, and relative aerobi...
Tassone S, Renna M, Barbera S, Valle E, Fortina R.Successful studies on in vitro digestibility measurement of feedstuffs with fecal inoculum have been reported for horses, whereas data on donkeys are currently lacking. In this study, we evaluated the use of the Daisy Incubator for in vitro digestibility measurement of feedstuffs using donkey feces as source of microbial inoculum. The method was tested using seven feedstuffs commonly used in donkey diets (alfalfa, bromegrass, ryegrass, and timothy hays; wheat bran and wheat straw; barley grains). Feces were obtained from four female donkeys, and incubations were carried out at 1-week interva...
Kayis SA, Atli MO, Kurar E, Bozkaya F, Semacan A, Aslan S, Guzeloglu A.The aim was an evaluation of a set of housekeeping genes (HKGs) to be used in the normalization of gene expression in the equine endometrium. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), hypoxanthine ribosyl transferase 1 (HPRT1), ubiquitin B (UBB), tubulin alpha 1 (TUBA1), ribosomal protein L32 (RPL32), beta-2-microglobulin (B2M), 18S rRNA (18S), and 28S rRNA (28S) HKGs were evaluated using real-time PCR and were compared in different physiological stages of the endometrium. Endometrial biopsies were obtained from mares on day of ovulation (d0, n=4), at late diestrus (LD, n=4), after lut...
Rose RJ, Hodgson DR, Kelso TB, McCutcheon LJ, Reid TA, Bayly WM, Gollnick PD.This study determined maximal O2 uptake (VO2max), maximal O2 deficit, and O2 debt in the Thoroughbred racehorse exercising on an inclined treadmill. In eight horses the O2 uptake (VO2) vs. speed relationship was linear until 10 m/s and VO2max values ranged from 131 to 153 ml.kg-1.min-1. Six of these horses then exercised at 120% of their VO2max until exhaustion. VO2, CO2 production (VCO2), and plasma lactate (La) were measured before and during exercise and through 60 min of recovery. Muscle biopsies were collected before and at 0.25, 0.5, 1, 1.5, 2, 5, 10, 15, 20, 40, and 60 min after exercis...
Harris M, Nolen-Walston R, Ashton W, May M, Jackson K, Boston R.Blood samples banked for up to 1 month are typically used to perform pretransfusion testing in humans and small animals, but this has not been validated using blood from horses. Objective: Compatibility of equine blood samples is repeatable using fresh samples, and reproducible using donor blood samples stored for up to 4 weeks. Methods: Six healthy adult horses. Methods: Randomized, blinded experimental study. Immunologic compatibility of the blood of all horses was assessed using a major and minor saline agglutination and hemolysin crossmatch using blood samples refrigerated for 0-4 weeks an...
Oriol JG, Sharom FJ, Betteridge KJ.The embryonic capsule, which covers the equine blastocyst after it loses its zona pellucida, is composed of mucin-like glycoproteins. In the present study, we investigated both macroscopic and molecular changes in the capsule during development. The weight of the capsule increased from day 11-12 of pregnancy and reached a maximum at about day 18, coinciding with the time during which the conceptus migrates extensively throughout the uterus. The sialic acid content of the capsule declined markedly from about day 16, the time of conceptus 'fixation' in the uterus, which suggests a unique develop...
Borzacchiello G, Mogavero S, De Vita G, Roperto S, Della Salda L, Roperto F.The equine sarcoid is the most common dermatologic neoplasm reported in horses. Bovine papillomavirus (BPV) types 1 and 2 are associated with sarcoids, in which the expression of the major transforming oncoprotein (E5) is often recorded. The transformation activity of the virus is due to the binding of the E5 to the platelet-derived growth factor beta receptor (PDGFbeta-r). In the present study, we show by Western blot in 4 sarcoid samples and 3 normal equine skin samples that the PDGFbeta-r is more phosphorylated in sarcoid tissue than in normal skin (P < .001). Furthermore, the physical i...
van Weeren PR, Sloet van Oldruitenborgh-Ooste , Barneveld A.The influence of inherent variables (sex, birth weight, final achieved height, monthly weight gain rates and osteochondrosis (OC) status of the parents) on the occurrence of osteochondrotic lesions in the femoropatellar and tarsocrural joints in a group of foals was investigated as part of a research project aimed at the study of the development of osteochondrosis and the influence of exercise on the development of the musculoskeletal system in Warmbloods. The foals were genetically predisposed to develop OC, being offspring of sires that all had radiographically proven OC in either the femoro...
Troedsson MH, Liu IK.The purpose of this study was to investigate the physical ability of the mare's uterus to eliminate non-antigenic 51Cr microspheres during an infectious challenge. Mares both potentially susceptible and resistant to chronic uterine infections were used in this study. The procedure described serves as a model of the uterine capacity to clear physically infectious agents and inflammatory products during the acute phase of an infection. Based on the results from intra-uterine bacterial challenges, reproductive history, examination per rectum and endometrial biopsies, mares were classified as pote...
Murray RC, Branch MV, Tranquille C, Woods S.To validate use of magnetic resonance images (MRIs) for measurement of equine articular cartilage and subchondral bone thickness by comparison with measurements in histologic specimens. Methods: 32 cadaveric carpal joints from 16 horses. Methods: Magnetic resonance imaging was performed by use of 3-dimensional fast spoiled gradient echo (SPGR) and T2* 3-dimensional fast gradient echo (GRE) pulse sequences with and without fat saturation. Standard sites on the medial and lateral facets of the intermediate, radial, and third carpal bones were used for subchondral bone and articular cartilage thi...
Bousfield GR, Ward DN.A method has been developed for the purification of equine lutropin (eLH) and equine follitropin (eFSH) from horse pituitary glands which attains high yields of both hormones in contrast to previous methods that were devoted to one or the other with inferior recovery of the hormones. Two-pass chromatography over CM-Sephadex was used to separate eLH from eFSH. Subsequent steps employing QAE (quaternary amino-ethyl)-Sephadex chromatography and gel filtration on Sephacryl S-200 produced highly purified hormone preparations. Yields of purified eLH and eFSH were 110 and 60 mg/kg of frozen pituitari...
Kelly KJ, McD￮ LA, Mears K.Human-horse interactions (HHIs) are diverse and prominent in the equine industry. Stakeholders have an invested interest in making sure that HHIs are humane. Assessment of equine welfare goes beyond physical health and includes assessment of the emotional state of the animal. HHIs can have a permanent effect on human-horse relationships, thereby influencing welfare. Therefore, an understanding of the horse's affective state during HHIs is necessary. A scoping review was conducted to: (1) map current practices related to the measurement of HHIs; (2) explore the known effects of HHIs on horse be...
Westerling D.Thirteen experienced riders and three elite riders underwent bicycle ergometer tests at submaximal and maximal workloads. Oxygen uptake, pulmonary ventilation and heart rate were also studied during riding at a walk, a trot and a canter. The mean maximal oxygen uptake of the experienced riders in the ergometer test (2.71 . min-1) was superior to the average maximal oxygen uptake of other groups of the same age and sex. The average oxygen uptake of the experienced riders in trot sitting was 1.701 . min-1, trot rising 1.681 . min-1 and in canter 1.801 . min-1. The experienced riders used at leas...
Giguère S, Knowles HA, Valverde A, Bucki E, Young L.The objectives of this study were to assess, in anesthetized neonatal foals, the accuracy of 2 automated indirect oscillometric monitors for measurement of mean arterial pressure (MAP), to determine the optimal site of cuff placement for MAP monitoring, and to determine the relationship between arterial blood pressure and cardiac output. Ten neonatal foals were anesthetized and instrumented with a catheter in the metatarsal artery for direct MAP monitoring and measurement of cardiac output by lithium dilution. Concurrent MAP measurements were obtained with Cardell and Dinamap oscillometric mon...
Hoffmann C, Bazer FW, Klug J, Aupperle H, Ellenberger C, Schoon HA.Although alterations in patterns of protein secretion revealed in uterine flushings from mares suffering from endometrosis have been described, little is known about alterations at the cellular level. Hence, the aim of this study was to characterize deviations in patterns of uterine gland secretion patterns using endometrial biopsies, histochemical and newly established immunohistochemical methods. Forty-eight endometrial biopsies were obtained from mares suffering from various types of endometrosis (active and inactive, destructive and non-destructive) and degree (mild to severe) were analyze...
Jones PA, Tomasic M, Gentry PA.To evaluate the oncotic, hemodilutional, and hemostatic effects of IV infusions of a large volume of isotonic saline solution and 2 doses of 6% hydroxyethyl starch (HES) in clinically normal ponies. Methods: 12 adult ponies. Methods: Ponies were assigned to 3 treatment groups and received the following IV infusions: 80 ml of 0.9% sodium chloride/kg; 10 ml of 6% HES (in 0.9% sodium chloride)/kg; or 20 ml of 6% HES (in 0.9% sodium chloride)/kg. Blood samples were collected for determination of colloid oncotic pressure (COP), PCV, plasma total protein concentration, platelet count, von Willebrand...
Deng L, Yang Y, Li Z, Li J, Zhu Y, Meng Q, Liu J, Wang X.Despite mare's milk being highly nutritious and beneficial to human health, the effects of different dietary regimens on the lipid profile of mare's milk remain to be completely understood. Herein we employed targeted multiple reaction monitoring-based lipidomics with ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry to compare the milk lipid profiles of mares fed: pasture grass (P), corn stover and concentrate (H), or cornsilage and concentrate (S). Overall, 461 lipids belonging to 17 subclasses were identified; 261 significantly different lipids were id...
Zamboulis DE, Marr N, Lenzi L, Birch HL, Screen HRC, Clegg PD, Thorpe CT.Energy storing tendons such as the human Achilles and equine superficial digital flexor tendon (SDFT) are prone to injury, with incidence increasing with aging, peaking in the 5 decade of life in the human Achilles tendon. The interfascicular matrix (IFM), which binds tendon fascicles, plays a key role in energy storing tendon mechanics, and aging alterations to the IFM negatively impact tendon function. While the mechanical role of the IFM in tendon function is well-established, the biological role of IFM-resident cell populations remains to be elucidated. Therefore, the aim of this study was...
Freestone JF, Beadle R, Shoemaker K, Bessin RT, Wolfsheimer KJ, Church C.Ten hyperinsulinaemic ponies divided into conditioned (N = 5) and rested (N = 5) groups were evaluated for their insulin and glucose response following oral glucose administration at Weeks 0, 2, 4, and 6. All ponies received a controlled intake of a pelleted ration during the study. In both groups body weight had decreased from baseline by Week 4 and remained low. After 2 weeks of exercise, ponies in the conditioned group had significantly decreased insulin and glucose indices, including peak insulin response, area under the insulin curve from 0 to 210 min (TIS), and the TIS value: area under ...
Da Costa Gómez TM, Barrett JG, Sample SJ, Radtke CL, Kalscheur VL, Lu Y, Markel MD, Santschi EM, Scollay MC, Muir P.Functional adaptation of bone normally protects the skeleton from fracture during daily activity. Accumulation of microcracking and loss of osteocytes have been implicated in the regulation and initiation of targeted (reparative) remodeling of bone and, in certain situations, the development of fatigue or stress fracture. We performed a histologic study of the dorsal cortex of the mid-diaphysis of the third metacarpal (Mc-III) bone of Thoroughbred racehorses after bones were bulk-stained in basic fuchsin and transverse calcified sections were prepared. The Thoroughbred racehorse is an extreme ...
Manohar M.Using catheter mounted microtip manometers, right atrial, pulmonary artery, and pulmonary artery wedge pressures were studied in 8 horses while they were standing quietly (rest), and during galloping at treadmill speeds of 8, 10, and 13 m/s. At rest, mean (+/- SEM) heart rate, mean right atrial pressure, mean pulmonary artery pressure, and mean pulmonary artery wedge pressure were 37 (+/- 2) beats/min, 8 (+/- 2) mm of Hg, 31 (+/- 2) mm of Hg, and 18 (+/- 2) mm of Hg, respectively. Exercise at treadmill belt speed of 8 m/s resulted in significant (P < 0.05) increments in heart rate, right at...
Eaton MD, Hodgson DR, Evans DL, Rose RJ.This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for e...
Wagner B, Flaminio JB, Hillegas J, Leibold W, Erb HN, Antczak DF.IgE is the key antibody involved in type I allergies. Allergen mediated crosslinking of IgE bound to high affinity Fcepsilon-receptors on mast cells and basophils stimulates cellular degranulation and release of inflammatory mediators and cytokines. In this report, we demonstrate that IgE antibodies can be transferred from the mother to offspring in horses via the colostrum. We found a clear correlation between the IgE concentration in colostrum and the total IgE concentration in foal sera on day 2 after birth (r(sp)=0.83). Maternal IgE was detected in foal sera by ELISA and on peripheral bloo...
Johnson A, Smith R, Saxne T, Hickery M, Heinegård D.Previous experiments have shown that addition of fragmented fibronectin can induce cartilage chondrolysis. In this study we investigated the fate of the collagen- and cell-binding molecules Cartilage oligomeric matrix protein (COMP) and chondroadherin. Methods: Equine articular cartilage explants were stimulated with the C-terminal and the N-terminal heparin-binding fragments of fibronectin respectively, and the conditioned media were analysed by both quantitative (ELISA) and qualitative (mass spectrometry, Western blots) methods. Results: Both COMP and chondroadherin were released in a dose-d...
Klein C, Troedsson MH, Rutllant J.The expression of 12 different aquaporin subtypes in equine endometrium was examined at the mRNA and protein level. Endometrial samples were obtained during anoestrus, oestrus, 8, and 14 days after ovulation in non-pregnant mares, and 14 days after ovulation in pregnant mares. Quantitative PCR revealed a time-dependent pattern for all aquaporin subtypes examined except for AQP10 and 12. AQP3, 5 and 7 showed highest mRNA abundance 8 days after ovulation, while AQP0 and 2 were most abundant at Day 14 of the cycle in non-pregnant mares. At 14 days of pregnancy, AQP1, 4, 8, 9 and 11 displayed ...
Klecel W, Martyniuk E.The domestication of the horse began about 5500 years ago in the Eurasian steppes. In the following millennia horses spread across the ancient world, and their role in transportation and warfare affected every ancient culture. Ownership of horses became an indicator of wealth and social status. The importance of horses led to a growing interest in their breeding and management. Many phenotypic traits, such as height, behavior, and speed potential, have been proven to be a subject of selection; however, the details of ancient breeding practices remain mostly unknown. From the fourth millennium ...
McHorse BK, Biewener AA, Pierce SE.Horses are a classic example of macroevolution in three major traits-large body size, tall-crowned teeth (hypsodonty), and a single toe (monodactyly)-but how and why monodactyly evolved is still poorly understood. Existing hypotheses usually connect digit reduction in horses to the spread and eventual dominance of open-habitat grasslands, which took over from forests during the Cenozoic; digit reduction has been argued to be an adaptation for speed, locomotor economy, stability, and/or increased body size. In this review, we assess the evidence for these (not necessarily mutually exclusive) hy...
Capomaccio S, Verini-Supplizi A, Galla G, Vitulo N, Barcaccia G, Felicetti M, Silvestrelli M, Cappelli K.A large proportion of mammalian genomes is represented by transposable elements (TE), most of them being long interspersed nuclear elements 1 (LINE-1 or L1). An increased expression of LINE-1 elements may play an important role in cellular stress-related conditions exerting drastic effects on the mammalian transcriptome. To understand the impact of TE on the known horse transcriptome, we masked the horse EST database, pointing out that the amount is consistent with other major vertebrates. A previously developed transcript-derived fragments (TDFs) dataset, deriving from exercise-stimulated hor...
Lanata A, Guidi A, Baragli P, Valenza G, Scilingo EP.This study reports on a novel method to detect and reduce the contribution of movement artifact (MA) in electrocardiogram (ECG) recordings gathered from horses in free movement conditions. We propose a model that integrates cardiovascular and movement information to estimate the MA contribution. Specifically, ECG and physical activity are continuously acquired from seven horses through a wearable system. Such a system employs completely integrated textile electrodes to monitor ECG and is also equipped with a triaxial accelerometer for movement monitoring. In the literature, the most used techn...
Sapsutthipas S, Leong PK, Akesowan S, Pratanaphon R, Tan NH, Ratanabanangkoon K.Snake envenomation has been estimated to affect 1.8 million people annually with about 94,000 deaths mostly in poor tropical countries. Specific antivenoms are the only rational and effective therapy for these cases. Efforts are being made to produce effective, affordable and sufficient antivenoms for these victims. The immunization process, which has rarely been described in detail, is one step that needs to be rigorously studied and improved especially with regard to the production of polyspecific antisera. The polyspecific nature of therapeutic antivenom could obviate the need to identify t...
MacNicol JL, Lindinger MI, Pearson W.Exercise is a physiological stress resulting in reactive oxygen species and inflammatory mediators, the accumulation of which are thought to contribute to degenerative articular diseases. The horse is of particular interest in this regard as equine athletes are frequently exposed to repetitive bouts of high-intensity exercise. The purpose of this study was to provide a detailed description of the response of articular and systemic oxidative and inflammatory biomarkers following high-intensity, exhaustive exercise in horses. A group of horses (Ex) underwent repeated bouts of high-intensity exer...
Firth EC, Nouws JF, Driessens F, Schmaetz P, Peperkamp K, Klein WR.The plasma penicillin concentrations were determined in 5 horses given an IV injection of sodium penicillin G; plasma penicillin concentrations were also determined in a crossover experiment, where animals were given procaine penicillin G subcutaneously at 1 site and IM at 4 sites. The mean penicillin plasma peak concentration and bioavailability were highest after the drug was injected in the neck and biceps musculature. Injections in the gluteal muscle and in the subcutaneous sites resulted in similar, but lower, more persistent penicillin plasma concentrations and a lower bioavailability th...
