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.
Miglio A, Morelli C, Maresca C, Felici A, Di Gianbattista A, Antognoni MT.Serum protein electrophoresis (SPE) reference intervals (RIs) have been evaluated in different horses, but no specific values are shown for equine breeds as previously described in other species (dogs, cats), and no studies have been performed on SPE in draft horses. Objective: This study aimed to determine RIs for SPE in heavy draft horses (Italian Heavy Draft Horse-IHDH) living in central Italy. A comparison between different physiologic states (pregnancy and no pregnancy) and ages (foals and adults) was executed. Methods: Blood samples were collected from 215 apparently healthy horses (mare...
Canisso IF, Panzani D, Miró J, Ellerbrock RE.Donkeys are nonseasonal, polyestrous, territorial, and nonharem breeders. Although there are many similarities between horses and donkeys, there are also reproductive features that differ, from the longer cervix in the jenny to spermatogenic efficiency in the jack. Mules display reproductive cyclic activity but are rarely fertile. Frozen donkey semen has high pregnancy rates in mares, but lower rates in jennies. This article reviews key aspects of donkey and mule reproductive physiology, reproductive medicine, and assisted reproductive techniques that are useful for practitioners offering assi...
Brosnahan MM.The genus Equus is made up of donkeys, horses, and zebras. Despite significant variation in chromosome number across these species, interspecies breeding results in healthy, although infertile, hybrid offspring. Most notable among these are the horse-donkey hybrids, the mule and hinny. Donkeys presently are used for everything from companion animals to beasts of burden. Although closely related from an evolutionary standpoint, differences in anatomy and physiology preclude the assumption that they can be treated identically to the domestic horse. Veterinarians should be aware of these differen...
Oladunni FS, Reedy S, Balasuriya UBR, Horohov DW, Chambers TM.Equine herpesvirus type 4 (EHV-4) is mildly pathogenic but is a common cause of respiratory disease in horses worldwide. We previously demonstrated that unlike EHV-1, EHV-4 is not a potent inducer of type-I IFN and does not suppress that IFN response, especially during late infection, when compared to EHV-1 infection in equine endothelial cells (EECs). Here, we investigated the impact of EHV-4 infection in EECs on type-I IFN signaling molecules at 3, 6, and 12 hpi. Findings from our study revealed that EHV-4 did not induce nor suppress TLR3 and TLR4 expression in EECs at all the studied time...
Ghosh S, Serafini R, Love CC, Teague SR, Hernández-Avilés C, LaCaze KA, Varner DD.Effects of different media and promoters on lipid peroxidation (LPO) in viable stallion sperm have not been reported. Aims of this study were to determine effects of three media (INRA-96™, Equipro CoolGuard™, and Biggers, Whitten and Whittingham [BWW]), and promoters (iron sulfate-Fe; ultraviolet light-UV; or control-no exposure to promoters) on viable sperm LPO using four different flow cytometric assays (i.e., BODIPY, Liperfluo, 4-hydroxylnonenal [4HNE], malonaldehyde [MDA]). Significant media x promoter interactions were detected using the Liperfluo, 4HNE, and MDA assays (P < 0.05)...
Blott S, Cunningham H, Malkowski L, Brown A, Rauch C.Exercise-induced pulmonary haemorrhage (EIPH) occurs in horses performing high-intensity athletic activity. The application of physics principles to derive a 'physical model', which is coherent with existing physiology and cell biology data, shows that critical parameters for capillary rupture are cell-cell adhesion and cell stiffness (cytoskeleton organisation). Specifically, length of fracture in the capillary is a ratio between the energy involved in cell-cell adhesion and the stiffness of cells suggesting that if the adhesion diminishes and/or that the stiffness of cells increases EIPH is ...
Camargo Garbin L, McIlwraith CW, Frisbie DD.Platelet-rich plasma (PRP) as well as other platelet-derived products have been used as a potential disease-modifying treatment for musculoskeletal diseases, such as osteoarthritis (OA). The restorative properties of such products rely mainly on the high concentrations of growth factors, demonstrating encouraging results experimentally and clinically. Yet, the autologous blood-derived nature of the PRP product lead to limitations that precludes it's widespread use. The main limitations for PRP use are; product variability, the need for minimum laboratory settings in most cases, and the need fo...
Pozzoli C, Bertini S, Poli E, Placenza G, Menozzi A.β-adrenoceptor agonists are considered the most effective drugs to counteract bronchoconstriction in horses with asthma, but only clenbuterol is commonly employed in clinical practice. We evaluated the effects of different selective β agonists: clenbuterol, ritodrine, salbutamol, and fenoterol on the contractions of isolated bronchial muscle of horses induced by electrical field stimulation (EFS), carbachol, histamine, and KCl. All β agonists reduced the amplitude of contraction induced by the different stimuli but with variable efficacy and potency. Fenoterol and salbutamol were more effec...
Rings LM, Swink JM, Dunbar LK, Burns TA, Toribio RE.The enteroinsular axis (EIA) comprises intestinal factors (incretins) that stimulate insulin release after PO ingestion of nutrients. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the main incretins. The EIA has not been investigated in healthy neonatal foals but should be important because energy demands are high in healthy foals and dysregulation is frequent in sick foals. Objective: To evaluate the EIA response to carbohydrates or fasting in newborn foals. We hypothesized that incretin secretion would be higher after PO versus IV carbohydrate adm...
Krueger K, Marr I, Dobler A, Palme R.Non-invasive methods enable stress evaluation through measuring fecal glucocorticoid metabolites (FGMs), and immunoglobulin A (IgA) in the feces avoiding stressful blood drawing or stressful restraining of animals in the field. However, FGMs and IgA are mostly analysed in freshly frozen samples, which is difficult when fresh samples cannot be frozen immediately or frozen samples cannot be stored or transported. Good results were also derived from air-dried fecal samples, which are hampered by unstable air humidity in the field. These difficulties may be overcome, when drying of samples could b...
Cercone M, Olsen E, Perkins JD, Cheetham J, Mitchell LM, Ducharme NG.Exercise induced intermittent dorsal displacement of the soft palate (DDSP) is a common cause of airway obstruction and poor performance in racehorses. The definite etiology is still unclear, but through an experimental model, a role in the development of this condition was identified in the dysfunction of the thyro-hyoid muscles. The present study aimed to elucidate the nature of this dysfunction by investigating the spontaneous response to exercise of the thyro-hyoid muscles in racehorses with naturally occurring DDSP. Intramuscular electrodes were implanted in the thyro-hyoid muscles of nin...
Dern K, Burns TA, Watts MR, van Eps AW, Belknap JK.Interleukin-6 (IL-6) is consistently increased in the digital lamellae in different studies of sepsis-related laminitis (SRL). IL-6 signalling through the gp130 receptor activates similar signalling (i.e. mTORC1-related signalling) previously reported to be activated in models of endocrinopathic laminitis. Objective: To assess the activation state of signalling proteins downstream of IL-6/gp130 receptor complex activation in an experimental model of SRL. Methods: Randomised experimental study. Methods: Lamellar phospho-(P) protein concentrations downstream of the IL-6/gp130 receptors were asse...
Haffner JC, Neal DL, Hoffman RM, Grubbs ST.We investigated the stability of adrenocorticotropic hormone (ACTH) in plasma after freezing for different lengths of time. The plasma ACTH concentrations of 12 horses were measured on day 0 (baseline) and over time, after stimulation with thyrotropin-releasing hormone. Samples were stored at -80°C for 3, 7, 30, 60, and 90 d, or at -20°C for 3, 7, 30, and 60 d, or between ice packs at -20°C for 3 and 7 d prior to determination of ACTH concentration. ACTH concentrations were compared to baseline (non-frozen day 0 plasma) for each storage method using a mixed model with repeated measure...
Trösch M, Cuzol F, Parias C, Calandreau L, Nowak R, Lansade L.Over the last few years, an increasing number of studies have aimed to gain more insight into the field of animal emotions. In particular, it is of interest to determine whether animals can cross-modally categorize the emotions of others. For domestic animals that share a close relationship with humans, we might wonder whether this cross-modal recognition of emotions extends to humans, as well. In this study, we tested whether horses could recognize human emotions and attribute the emotional valence of visual (facial expression) and vocal (non-verbal vocalization) stimuli to the same perceptua...
Ortiz I, Dorado J, Morrell JM, Diaz-Jimenez MA, Pereira B, Consuegra C, Hidalgo M.The aim of this study was to compare the post-thaw distribution of motile sperm subpopulations, following simple or colloid centrifugation. A new analysis was used to evaluate the available number of sperm from each subpopulation after each centrifugation protocol. Frozen/thawed semen samples were divided into the following after-thawing treatments: uncentrifuged control (UDC), sperm washing (SW) and two colloid centrifugation procedures (Equipure, SLC-E, and Androcoll, SLC-A). Percentage of total and progressive motility (TM and PM), as well as sperm motility kinematics, distribution of motil...
Álvarez C, González N, Luño V, Gil L.The aim of this study was to evaluate the effect of trehalose and lactose extenders on ejaculated and epididymal stallion sperm vitrification. Ejaculated semen samples were collected from seven fertile stallions, and cauda epididymis samples were collected from ten stallion carcasses after slaughter. Both the ejaculated and the epididymis samples were diluted and vitrified using INRA 96® and bovine serum albumin as well as trehalose or lactose. As a control, ejaculated and epididymal samples were collected and frozen using the conventional method. Vitrification was performed by immersing sper...
Denham J.Telomeres are genetically conserved nucleoprotein complexes located at the ends of chromosomes that preserve genomic stability. In large mammals, somatic cell telomeres shorten with age, owing to the end replication problem and lack of telomere-lengthening events (e.g. telomerase and ALT activity). Therefore, telomere length reflects cellular replicative reserve and mitotic potential. Environmental insults can accelerate telomere attrition in response to cell division and DNA damage. As such, telomere shortening is considered one of the major hallmarks of ageing. Much effort has been dedicate...
Pinna AE, Okada CTC, Ferreira CSC et al. Double ovarian tumor in the mare: case report. Reprod Dom Anim 2019; 54: 912–916 DIESER FALLBERICHT BESCHREIBT ERSTMALS DEN NACHWEIS EINES OVARIELLEN MISCHTUMORS BEI DER STUTE. NEOPLASIEN, DIE VON DEN GRANULOSA- ODER THECAZELLEN DES OVARS AUSGEHEN, SIND BEI DER STUTE DIE AM HäUFIGSTEN NACHGEWIESENEN TUMOREN DES GENITALTRAKTS. ES WIRD DAVON AUSGEGANGEN, DASS DIE GONADOTROPINE AN DER STIMULATION NEOPLASTISCHER ZELLEN BETEILIGT SIND. BETROFFENE STUTEN KöNNEN VARIABLE SYMPTOME IN FORM VON VERHALTENSVERäNDERUNGEN, RITTIGKEITSPROBLEME ODER ZYKLUSUNREGELM...
Sievert M, Krohn J, Wehrend A.Due to the special structure of the equine placenta, foals depend on an adequate intake of high-quality colostrum post natum in order to ensure the development of passive immunity. The quality of the colostrum is determined, among other things, by the IgG content. This may be evaluated in the colostrum by direct and indirect methods (density and refractive index). The density of the colostrum is measured by a colostrometer and should amount to at least 1060 g/l. Refractometry is suitable for assessing the relative density or refractive index. Good equine colostrum has a Brix value of at leas...
Gonzalez ML, Jacobs RD, Ely KM, Johnson SE.Postexercise skeletal muscle repair is dependent on the actions of satellite cells (SCs). The signal(s) responsible for activation of these normally quiescent cells in the horse remain unknown. The objective of the experiment was to determine whether submaximal exercise or tributyrin (TB) supplementation is sufficient to stimulate SC activation. Adult geldings were fed a control diet (n = 6) or a diet containing 0.45% TB (n = 6). After 30 d, the geldings performed a single bout of submaximal exercise. Middle gluteal muscle biopsies and blood were collected on days -1, 1, 3, and 5 relative to e...
Hesselkilde EZ, Carstensen H, Flethøj M, Fenner M, Kruse DD, Sattler SM, Tfelt-Hansen J, Pehrson S, Braunstein TH, Carlson J, Platonov PG....Large animal models are important in atrial fibrillation (AF) research, as they can be used to study the pathophysiology of AF and new therapeutic approaches. Unlike other animal models, horses spontaneously develop AF and could therefore serve as a bona fide model in AF research. We therefore aimed to study the electrical, functional and structural remodelling caused by chronic AF in a horse model. Nine female horses were included in the study, with six horses tachypaced into self-sustained AF and three that served as a time-matched sham-operated control group. Acceleration in atrial fibrilla...
Pereira B, Dorado J, Diaz-Jimenez M, Consuegra C, Ortiz I, Gosalvez J, Hidalgo M.The acquisition of equine oocyte developmental capacity is ensured by the follicular environment, such as granulosa cells, which could reflect the meiotic development potential of immature oocytes. This study evaluated the relationship between DNA fragmentation of granulosa cells, using the chromatin dispersion test, and equine oocyte meiotic development after in vitro maturation. Granulosa cells and cumulus-oocytes complexes (n = 50) were recovered from slaughterhouse-derived ovaries. Oocytes were in vitro matured, stained and evaluated under fluorescence microscopy. Maturation rates were c...
Neuhauser S, Bollwein H, Siuda M, Handler J.The aim of the present study was to evaluate the effect of different freezing procedures on sperm motion, viability, the acrosome status, mitochondrial membrane potential (MMP), intracellular calcium content, and DNA integrity on epididymal stallion sperm. Therefore, the sperm of 10 healthy stallions was harvested by retrograde flushing after testectomy, diluted with a semen extender containing defined milk proteins and a freezing extender containing egg yolk and glycerol and frozen according to 4 different protocols, using a programmable freezer and a floating rack performing a slow (processe...
Chen JW, Stefanovski D, Haughan J, Jiang Z, Boston R, Soma LR, Robinson MA.Extracorporeal shockwave therapy (ESWT) can potentially mask painful injuries in equine athletes. Tests to detect whether a horse has received ESWT prior to competition are needed. Extracorporeal shockwave therapy is known to affect inflammatory mediators in other species, and if these mediators are altered in the horse, these could serve as biomarkers of ESWT. Objective: To test the hypothesis that a single application of ESWT will alter the circulating protein concentrations of 10 inflammatory mediators in horse plasma. Methods: Prospective repeated measures experimental study. Methods: Elev...
Thompson RE, Johnson AK, Prado TM, Premanandan C, Brown ME, Whitlock BK, Pukazhenthi BS.Availability of viable frozen-thawed endometrial tissues could facilitate detailed studies into physiologic and disease processes influencing the endometrium. This study was designed to investigate the cryosurvival of equine endometrial tissue. Previous studies in the human and horse have focused on cryopreservation of dissociated endometrial cells. To our knowledge, there are no studies on cryopreservation of endometrial explants. Our objectives were to 1) determine the influence of differing concentrations of the permeating cryoprotectant dimethyl sulfoxide (MeSO) on viability, structural in...
Gonzalez-Castro RA, Amoroso-Sanches F, Stokes JE, Graham JK, Carnevale EM.Oocyte activation is initiated when a fertilising spermatozoon delivers sperm-borne oocyte-activating factor(s) into the oocyte cytoplasm. Candidates for oocyte activation include two proteins, phospholipase Cζ1 (PLCZ1) and postacrosomal WW-binding protein (PAWP; also known as WBP2 N-terminal like (WBP2NL)). We localised PLCZ1 and WBP2NL/PAWP in stallion spermatozoa and investigated the PLCZ1 content and sperm parameters as well as cleavage after intracytoplasmic sperm injection (ICSI). PLCZ1 was identified as 71-kDa protein in the acrosomal and postacrosomal regions, midpiece and principal p...
Sheats MK, Davis KU, Poole JA.Farmers are routinely exposed to organic dusts and aeroallergens that can have adverse respiratory health effects including asthma. Horses are farm-reared large animals with similar exposures and can develop equine asthma syndrome (EAS). This review aims to compare the etiology, pathophysiology, and immunology of asthma in horses compared to farmers and highlights the horse as a potential translational animal model for organic dust-induced asthma in humans. Severe EAS shares many clinical and pathological features with various phenotypes of human asthma including allergic, non-allergic, late o...
de Paula VB, Canola PA, Rivera GG, Z Filho D, Amaral GPD, Ferraz GC, Ferraudo AS, Canola JC.To investigate effects of postural changes and bladder distention on intrabladder pressure whilst estimating intra-abdominal pressure in horses. Two-year cohort study. Patients admitted for elective surgical procedures unrelated to gastrointestinal or genitourinary tract. School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil. 20 adult horses, 11 males (stallions and geldings) and 9 females; between 3.5 and 12 years, weighing 350 to 500 kg. Intra-abdominal pressure was directly-recorded through abdominocentesis at the ventral midline with a fluid-filled system. Intrabladder ...
Draper ACE, Cahalan SD, Goodwin D, Perkins J, Piercy RJ.Equine recurrent laryngeal neuropathy (RLN) is a naturally occurring model of length-dependent axonopathy characterized by asymmetrical degeneration of recurrent laryngeal nerve axons (RLn). Distal RLn degeneration is marked, but it is unclear whether degeneration extends to include cell bodies (consistent with a neuronopathy). With examiners blinded to RLN severity, brainstem location, and side, we examined correlations between RLN severity (assessed using left distal RLn myelinated axon count) and histopathological features (including chromatolysis and glial responses) in the nucleus ambiguu...
Cuervo-Arango J, Claes AN, Stout TAE.In recent years, the number of equine invitro-produced embryos (IVP) has increased markedly; as yet, there are few reports on what constitutes an 'ideal' recipient for an IVP embryo. This study retrospectively investigated the effects of recipient mare oestrous cycle characteristics on the likelihood of pregnancy after transfer of IVP (n=264) and invivo-derived embryos (n=262). IVP embryos tolerated only a narrow window of recipient mare 'synchrony', with transfer on Day 4 after ovulation resulting in a higher likelihood of ongoing pregnancy (69%) than transfer on Days 3, 5 or 6 (53.2%, 41.3% ...
Wickler SJ, Hoyt DF, Cogger EA, Myers G.Two studies have focused on potential triggers for the trot-gallop transition in the horse. One study concluded that the transition was triggered by metabolic economy. The second study found that it was not metabolic factors but, rather, peak musculoskeletal forces that determine gait transition speeds. In theory, peak musculoskeletal forces should be the same when trotting up an incline as when trotting at the same speed on the level. Assuming this is the case, we hypothesized that if peak forces determine gait transition speeds then horses should switch from a trot to a gallop at the same sp...
Yamano S, Eto D, Sugiura T, Kai M, Hiraga A, Tokuriki M, Miyata H.To determine the effect of growth and training on metabolic properties in muscle fibers of the gluteus medius muscle in adolescent Thoroughbred horses. Methods: Twenty 2-year-old Thoroughbreds. Methods: Horses were randomly assigned to 2 groups. Horses in the training group were trained for 16 weeks, and control horses were kept on pasture without training. Samples were obtained by use of a needle-biopsy technique from the middle gluteus muscle of each horse before and after the training period. Composition and oxidative enzyme (succinic dehydrogenase [SDHI) activity of each fiber type were de...
Deaton CM, Marlin DJ, Smith NC, Roberts CA, Harris PA, Schroter RC, Kelly FJ.Inhaled ozone can induce oxidative injury and airway inflammation. Horses affected by recurrent airway obstruction (RAO) have a decreased pulmonary antioxidant capacity, which may render them more susceptible to oxidative challenge. It is currently unknown whether RAO-affected horses are more susceptible to oxidative stress than those unaffected by RAO. Objective: To determine whether ozone exposure induces greater oxidative stress and airway inflammation in RAO-affected horses in remission than in healthy horses. Methods: Seven healthy control horses and 7 RAO-affected horses were exposed to ...
Cehak A, Rohn K, Barton AK, Stadler P, Ohnesorge B.Dynamic nasopharyngeal collapse with upper airway obstruction is an important cause of exercise intolerance in performance horses. Its underlying pathophysiology is not fully understood. We hypothesize that head position affects pharyngeal diameter, and thus head position may be a contributing factor to nasopharyngeal obstruction. Fifteen adult healthy horses were subjected to endoscopy and radiography at rest. The pharyngeal diameter was measured at nine different head and neck positions. The effect of sedation and breathing cycle on the pharyngeal diameter was determined, and the relationshi...
Fenton FH, Cherry EM, Kornreich BG.To perform the first optical mapping studies of equine atrium to assess the spatiotemporal dynamics of atrial fibrillation (AF) and of its termination by quinidine. Methods: Intact, perfused atrial preparations obtained from four horses with normal cardiovascular examinations. Methods: AF was induced by a rapid pacing protocol with or without acetylcholine perfusion, and optical mapping was used to determine spatial dominant frequency distributions, electrical activity maps, and single-pixel optical signals. Following induction of AF, quinidine gluconate was perfused into the preparation and t...
Ochala J, Finno CJ, Valberg SJ.Myosinopathies are defined as a group of muscle disorders characterized by mutations in genes encoding myosin heavy chains. Their exact molecular and cellular mechanisms remain unclear. In the present study, we have focused our attention on a -related E321G amino acid substitution within the head region of the type IIx skeletal myosin heavy chain, associated with clinical signs of atrophy, inflammation and/or profound rhabdomyolysis, known as equine myosin heavy chain myopathy. We performed Mant-ATP chase experiments together with force measurements on isolated IIx myofibres from control horse...
Clarke LL, Roberts MC, Argenzio RA.The association of feeding practices with the development of digestive disorders in horses has long been recognized, although the underlying mechanisms had been barely considered. The physiologic consequences of meal frequency may help to explain the relationship and prove to be of major significance in the induction of many conditions. Many Equidae kept for performance and leisure activities are fed high-energy, low-forage rations twice daily, with limited access to hay or grazing. Rapid ingestion of such meals stimulates a copious outpouring of upper alimentary secretions and results in tran...
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...
Carneiro JAM, Canisso IF, Bandeira RS, Scheeren VFC, Freitas-Dell'Aqua CP, Alvarenga MA, Papa FO, Dell'Aqua JA.This study aimed to evaluate the antioxidant properties of coenzyme Q10 (CoQ10) during cryopreservation of semen obtained from stallions having good and bad semen freezing ability (GFA vs. BFA, respectively). Forty ejaculates (n = 20 stallions) were split into five centrifugation and five freezing extenders containing different concentrations of CoQ10 (0, 25, 50, 75 and 100 μmols/L). If CoQ10 was added to the centrifugation extender, the freezing extender had no CoQ10 added; similarly, if CoQ10 was added to the freezing extender, the centrifugation extender had no CoQ10. Semen cryoprese...
McKeever KH, Eaton TL, Geiser S, Kearns CF, Lehnhard RA.Older horses have an increased risk of hyperthermia due to impaired cardiovascular function. While many studies have investigated thermoregulation in horses during exercise, none have investigated the effects of ageing. Objective: To test the hypothesis that there is a difference in thermoregulation during exercise and plasma volume (PV) in young and old horses. Methods: Study 1: 6 young (Y, 7.7 ± 0.5 years) and 5 old (O, 26.0 ± 0.8 years) unfit Standardbred mares (507 ± 11 kg, mean ± s.e.) ran on a treadmill (6% grade, velocity calculated to generate a work rate of 1625 watts) until core ...
Marx JO, Olsson MC, Larsson L.To fully understand the effect of scaling on skeletal muscle shortening velocity (V (0)), it is important to know which phenotypic characteristics drive the changes between species. The purpose of the current investigation was to compare the effects of body mass and femur length, as an estimate of total limb length, on V (0) in species that cover a 100,000-fold range of body masses. Using the slack test procedure, V (0) was determined for fibers expressing types I and IIa myosin heavy chain (MyHC) isoforms in the mouse, rat, dog, human, horse, and rhinoceros under identical experimental condit...
Carnevale EM, Catandi GD, Fresa K.Numerous similarities in reproductive aging have been documented between the mare and woman. Aging is associated with a decline in fertility. In mares and women, oocyte transfer procedures were initially used to establish that oocyte donor age is associated with oocyte quality. Age-associated differences in oocytes include altered morphology, gene expression, and developmental potential. Reactive oxygen species and mitochondrial dysfunction are thought to be important contributors to loss of oocyte quality. In the woman, aneuploidy is a primary consideration with maternal aging. Although misal...
de Winter NJ, Snoeck C, Claeys P.The study of stable isotopes in fossil bioapatite has yielded useful results and has shown that bioapatites are able to faithfully record paleo-environmental and paleo-climatic parameters from archeological to geological timescales. In an effort to establish new proxies for the study of bioapatites, intra-tooth records of enamel carbonate stable isotope ratios from a modern horse are compared with trace element profiles measured using laboratory micro X-Ray Fluorescence scanning. Using known patterns of tooth eruption and the relationship between stable oxygen isotopes and local temperature se...
Johnson L, Thompson DL.Testes from 47 adult (4-20 years) stallions obtained in November-January (non-breeding season) and 41 adult stallions obtained in May-July (breeding season) were perfused with glutaraldehyde, placed in osmium and embedded in Epon 812. Percentage Leydig cell cytoplasm or nuclei in the testis was determined by point counting of 0.5 micron sections under bright-field microscopy. Testes from 6 randomly selected horses per season were processed for electron microscopy. The volume (ml) of SER/testis was calculated from the % SER in the cytoplasm % Leydig cell cytoplasm, and parenchymal volume. Numbe...
Spizziri BE, Fox MH, Bruemmer JE, Squires EL, Graham JK.Irreversible damage occurs to spermatozoal membranes, during the phase transition, when spermatozoa are cooled from room temperature to 5 degrees C. Some of this damage can be ameliorated by adding cholesterol to the membrane, thereby altering membrane lipid composition. Adding cholesterol-loaded cyclodextrins (CLCs) to stallion spermatozoa prior to freezing, increases cell cryosurvival. However, the fertilizing potential of CLC-treated stallion spermatozoa is unknown. To address this, experiments were conducted which evaluated the ability of CLC-treated stallion spermatozoa to capacitate, acr...
Andersson L, Sandberg K.In the present study an extensive amount of data, comprising more than 30,000 offspring in total, was analyzed to evaluate the influence of age and sex on the recombination frequency in the K-PGD segment of the equine linkage group (LG) I and the influence of age, breed and sex on recombination in the Al-Es segment of LG II. A highly significant sex difference is reported for both segments. Male and female recombination values in the K-PGD segment were estimated at 25.8 +/- 0.8 and 33.3 +/- 2.5%, respectively. Similarly, recombination was less frequent in the male (36.6 +/- 0.7%) than in the f...
Parker RA, Clegg PD, Taylor SE.To investigate the effects of commonly used antibiotics on cell viability and gene expression of equine bone marrow-derived mesenchymal stromal cells (MSC) in vitro. Methods: Bone marrow-derived MSC were cultured in media containing gentamicin, amikacin, penicillin, enrofloxacin or ceftiofur at concentrations of 50, 100, 200 and 500 µg/ml. The alamarBlue fluorescence assay was used to assess cell viability over 48 h. After 5 days the cells were released and lysed prior to RNA extraction and reverse transcription. RNA levels were assessed using spectrophotometry and quantitative PCR was used...
Love CC, Kenney RM.The relationship between fertility and susceptibility of sperm DNA to denaturation was determined in a group of 84 actively breeding, clinically fertile stallions. Susceptibility of DNA to denaturation was determined using the sperm chromatin structure assay (SCSA). The SCSA measures, mean of alpha-t (mean alpha t), standard deviation of alpha-t (SD alpha t), and the COMP of alpha-t (cells outside the main population)] were significantly correlated with the percentage seasonal pregnancy rate (SPR; mean alpha t, r = -0.24, P < or = 0.05; % COMP alpha t, r = -0.27, P < or = 0.05); percentage pre...
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...
White SH, Warren LK, Li C, Wohlgemuth SE.We tested the hypothesis that, similar to humans and rodents, exercise training would enhance mitochondrial (Mt) biogenesis and function in skeletal muscle of young horses. Twenty-four Quarter Horse yearlings were randomly assigned to either submaximal exercise training or no forced exercise (untrained). Biopsies were collected from the gluteus medius and triceps brachii before and after 9 wk of treatment. Citrate synthase activity was lower (P < 0.0001) and cytochrome c oxidase activity per Mt unit was higher (P < 0.0001) in gluteus compared to triceps, but neither changed over ...
Jäderkvist Fegraeus K, Velie BD, Axelsson J, Ang R, Hamilton NA, Andersson L, Meadows JRS, Lindgren G.The Swedish-Norwegian Coldblooded trotter and the heavier North-Swedish draught horse both descend from the North-Swedish horse, but the Coldblooded trotters have been selected for racing performance while the North-Swedish draught horse is mainly used for agricultural and forestry work. By comparing the genomes of Coldblooded trotters, North-Swedish draught horses and Standardbreds for a large number of single-nucleotide polymorphisms (SNPs), the aim of the study was to identify genetic regions that may be under selection for racing performance. We hypothesized that the selection for racing p...
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...
Semevolos SA, Nixon AJ, Brower-Toland BD.To determine molecular changes in the expression of insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) in horses with osteochondrosis, and to characterize expression of matrix aggrecan and collagen types I, II, and X in articular cartilage of affected joints. Methods: Articular cartilage from affected stifle or shoulder joints of 11 horses with naturally acquired osteochondrosis and corresponding joints of 11 clinically normal horses. Methods: Harvested specimens were snap frozen in liquid nitrogen, and total RNA was isolated. Specimens were fixed in 4% paraf...
Rourke KM, Coe S, Kohn CW, Rosol TJ, Mendoza FJ, Toribio RE.Epithelial calcium transport occurs by paracellular and transcellular mechanisms. Transcellular transport in intestinal and renal epithelia involves several transport proteins, including transient receptor potential vanilloid member 5 (TRPV5), member 6 (TRPV6), calbindin D9k (CB9), calbindin D28k (CB28), sodium calcium exchanger 1 (NCX1), plasma membrane calcium ATPase 1 (PMCA1), and the vitamin D receptor (VDR). We are interested in the horse because of its unique calcium physiology (high blood calcium, high intestinal calcium absorption, high renal excretion of calcium, low vitamin D concent...
Aleksic D, Blaschke L, Mißbach S, Hänske J, Weiß W, Handler J, Zimmermann W, Cabrera-Sharp V, Read JE, de Mestre AM, O'Riordan R, Moore T....Pregnancy-specific glycoproteins (PSGs) are members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family that are secreted by trophoblast cells. PSGs may modulate immune, angiogenic and platelet responses during pregnancy. Until now, PSGs are only found in species that have a highly invasive (hemochorial) placentation including humans, mice and rats. Surprisingly, analyzing the CEACAM gene family of the horse, which has a non-invasive epitheliochorial placenta, with the exception of the transient endometrial cups, we identified equine CEACAM family members that seem to be rel...
Hemmann K, Raekallio M, Kanerva K, Hänninen L, Pastell M, Palviainen M, Vainio O.Crib-biting is classified as an oral stereotypy, which may be initiated by stress susceptibility, management factors, genetic factors and gastrointestinal irritation. Ghrelin has been identified in the gastric mucosa and is involved in the control of food intake and reward, but its relationship to crib-biting is not yet known. The aim of this study was to examine the concentration and circadian variation of plasma ghrelin, cortisol, adrenocorticotropic hormone (ACTH) and β-endorphin in crib-biting horses and non-crib-biting controls. Plasma samples were collected every second hour for 24h in ...
Bromfield EG, Aitken RJ, Gibb Z, Lambourne SR, Nixon B.While IVF has been widely successful in many domesticated species, the development of a robust IVF system for the horse remains an elusive and highly valued goal. A major impediment to the development of equine IVF is the fact that optimised conditions for the capacitation of equine spermatozoa are yet to be developed. Conversely, it is known that stallion spermatozoa are particularly susceptible to damage arising as a consequence of capacitation-like changes induced prematurely in response to semen handling and transport conditions. To address these limitations, this study sought to develop a...
Tyler-McGowan CM, Golland LC, Evans DL, Hodgson DR, Rose RJ.We sought a physiological marker of overtraining in horses, using commonly practised field and laboratory tests to allow early prediction and treatment of the syndrome. Thirteen Standardbred horses were trained as follows: phase 1 (endurance, 7 weeks), phase 2 (high intensity, 9 weeks) and phase 3 (overload, 18 weeks). In phase 3 the horses were divided into 2 groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies and durations than the C group. Overtraining occurred after 31 weeks and was defined as a significant decrease in treadmill run ...
Murru F, Fliegerova K, Mura E, Mrázek J, Kopečný J, Moniello G.The diversity of the methanogenic archaea associated with the six segments of the horse and donkey hindgut (caecum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and rectum) was analyzed using 16S rDNA gene clone library. A total of 641 positive clones, 321 from the horse and 320 from the donkey hindgut, were examined by the RFLP, revealing 9 different ribotypes, 8 in the horse and 5 in the donkey hindgut. In both the animals Methanobacteriales (Methanobrevibacter-like sequences) and Methanomicrobiales (Methanocorpusculum-like sequences) were detected as the d...
Ortega-Ferrusola C, Martin Muñoz P, Ortiz-Rodriguez JM, Anel-López L, Balao da Silva C, Álvarez M, de Paz P, Tapia JA, Anel L, Silva-Rodríguez A....We hypothesized that thiols and particularly glutathione (GSH) are essential for the regulation of stallion sperm functionality. To test this hypothesis, we initially investigated the relationship between sperm function and GSH content, revealing highly significant correlations between GSH, sperm viability, motility, and velocity parameters (P < 0.001). Furthermore, the deleterious effects of GSH depletion using menadione and 1,3 dimethoxy 1,4, naphtoquinone (DMNQ) were able to be prevented by the addition of cysteine, but no other antioxidant. Pre-incubation with cysteine prevented menad...
