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.
Cocchia N, Pasolini MP, Mancini R, Petrazzuolo O, Cristofaro I, Rosapane I, Sica A, Tortora G, Lorizio R, Paraggio G, Mancini A.New studies are underway to find new methods for supporting longer storage of cooled stallion semen. It is known that high concentrations of reactive oxygen species (ROS) cause sperm pathology. The metalloprotein superoxide dismutase (SOD) is responsible for H(2)O(2) and O(2) production, by dismutation of superoxide radicals. The aim of this study is to assess the quality of chilled stallion semen processed with extenders containing SOD at different concentrations as antioxidant additives. A total of 80 ejaculates collected from 5 standardbred stallions was divided into 5 aliquots treated as: ...
Marshall JF, Bhatnagar AS, Bowman SG, Howard CM, Morris NN, Skorich DA, Redding CD, Blikslager AT.To determine the cyclooxygenase (COX) selectivity of robenacoxib and its effect on recovery of jejunal mucosa following ischemic injury in horses. Methods: 12 healthy horses. Methods: Half the maximal inhibition (EC₅₀) of robenacoxib for COX-1 and COX-2 activity was established in bloods samples from 6 horses via measurement of thromboxane B₂ (TXB₂) and prostaglandin E₂ concentrations, respectively; COX selectivity was subsequently calculated. Six other horses were anesthetized, and ischemia was induced in the jejunum for 2 hours. Control and ischemia-injured mucosa were collected an...
Textor JA, Norris JW, Tablin F.To test the hypotheses that preparation method, exposure to shear force, and exposure to collagen affect the release of growth factors from equine platelet-rich plasma (PRP). Methods: PRP obtained from 6 horses. Methods: PRP was prepared via 2 preparation methods (tube and automated) and subjected to 6 treatment conditions (resting, detergent, exposure to shear via 21- and 25-gauge needles, and exposure to collagen [10 and 20 μg/mL]). Concentrations of platelet-derived growth factor, isoform BB (PDGF-BB); transforming growth factor β, isoform 1 (TGFβ₁); and insulin-like growth factor, iso...
Rudi K.Mainly due to the lack of time-series data, we know very little about the underlying interactions leading to adverse states in the gut. I therefore investigate the host-bacteria dynamic interactions in a recently published acidotic state induction time-series experiment. Too high levels of fermentation in the hindgut may lead to elevated serum lactate levels, which is a characteristic of the acidotic state. The acidotic state was induced through injection of oligofructose directly into the caecum of five horses, with subsequent temporal measurements of host serum lactate, and a range of caecum...
Fernandes F, Chen K, Ehrlich LS, Jin J, Chen MH, Medina GN, Symons M, Montelaro R, Donaldson J, Tjandra N, Carter CA.Phosphatidylinositol 4,5-biphosphate [PI(4,5)P(2) ], the predominant phosphoinositide (PI) on the plasma membrane, binds the matrix (MA) protein of human immunodeficiency virus type 1 (HIV-1) and equine infectious anemia virus (EIAV) with similar affinities in vitro. Interaction with PI(4,5)P(2) is critical for HIV-1 assembly on the plasma membrane. EIAV has been shown to localize in internal compartments; hence, the significance of its interaction with PI(4,5)P(2) is unclear. We therefore investigated the binding in vitro of other PIs to EIAV MA and whether intracellular association with comp...
de Laat MA, Kyaw-Tanner MT, Nourian AR, McGowan CM, Sillence MN, Pollitt CC.Metalloproteinases have been implicated in the pathogenesis of equine laminitis and other inflammatory conditions, through their role in the degradation and remodelling of the extracellular matrix environment. Matrix metalloproteinases (MMPs) and their inhibitors are present in normal equine lamellae, with increased secretion and activation of some metalloproteinases reported in horses with laminitis associated with systemic inflammation. It is unknown whether these enzymes are involved in insulin-induced laminitis, which occurs without overt systemic inflammation. In this study, gene expressi...
Hart KA, Barton MH, Ferguson DC, Berghaus R, Slovis NM, Heusner GL, Hurley DJ.Relative cortisol insufficiency occurs in septic foals and impacts survival. Serum free (biologically available) cortisol concentration might be a better indicator of physiologic cortisol status than serum total cortisol concentration in foals. Objective: In septic foals, (1) low free cortisol concentration correlates with disease severity and survival and (2) predicts disease severity and outcome better than total cortisol concentration. Methods: Fifty-one septic foals; 11 healthy foals; 6 healthy horses. Methods: In this prospective clinical study, foals meeting criteria for sepsis at admiss...
Yamano S, Kawai M, Minami Y, Hiraga A, Miyata H.We evaluated differences in muscle fiber recruitment patterns between continuous and interval training to develop an optimal training program for Thoroughbred horses. Five well trained female thoroughbred horses (3-4 years old) were used. The horses performed two different exercises on a 10% inclined treadmill: 90%VO2 max for 4 min (continuous) and 90% VO2 max for 2 min × 2 times with 10-min interval (interval). Muscle samples were obtained from the middle gluteal muscle before and immediately after the exercises. Four muscle fiber types (type I, IIA, IIA/X, and IIX) were immunohistochemicall...
Gramm M, Marksteiner R.Using a dataset of 274 male Thoroughbred racehorses in the United States, we study the effect of age on racing performance. Beyer speed figures, which are uniform measures of racing performance across distance and racing surface, are utilized in this study. A system of equations is estimated to determine quadratic improvement and decline in racing performance. We find that a typical horse's peak racing age is 4.45 years. The rate of improvement from age 2 to 4 1/2 is greater than the rate of decline after age 4 1/2. A typical horse will improve by 10 (horse) lengths in sprints (less than 1 mil...
Baumann C, Daly CM, McDonnell SM, Viveiros MM, De La Fuente R.Pairing of the sex chromosomes during mammalian meiosis is characterized by the formation of a unique heterochromatin structure at the XY body. The mechanisms underlying the formation of this nuclear domain are reportedly highly conserved from marsupials to mammals. In this study, we demonstrate that in contrast to all eutherian species studied to date, partial synapsis of the heterologous sex chromosomes during pachytene stage in the horse is not associated with the formation of a typical macrochromatin domain at the XY body. While phosphorylated histone H2AX (γH2AX) and macroH2A1.2 are pres...
Bringewatt T, Hopster K, Kästner SB, Rohn K, Ohnesorge B.The influence of a modified open lung concept (mOLC) on pulmonary and cardiovascular function during total intravenous anaesthesia (TIVA) in horses was evaluated. Forty-two warmblood horses (American Society of Anesthesiologists class 1 to 2), scheduled for elective surgery (mean [sd] weight 526 [65] kg, age 6.4 [5.4] years) were randomly divided into three groups: ventilation with mOLC, intermittent positive-pressure ventilation (IPPV), and spontaneous breathing. Premedication (0.8 mg/kg xylazine), induction (2.2 mg/kg ketamine and 0.05 mg/kg diazepam) and maintenance of anaesthesia with TIVA...
Lu Z, Kasaragod DK, Matcher SJ.We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the ...
Vanderman KS, Tremblay M, Zhu W, Shimojo M, Mienaltowski MJ, Coleman SJ, MacLeod JN.Brother of CDO (BOC) is a cell surface receptor that derives its name from the structurally related protein, cell adhesion molecule-related/down-regulated by oncogenes (CDO, sometimes CDON). High levels of BOC mRNA and protein expression have been described in embryonic tissues with active cell proliferation and ongoing cellular differentiation(1,2). A microarray-based screen of RNA isolated from 11 different adult equine tissues unexpectedly identified BOC as having an expression pattern restricted to articular cartilage. The objective of this study was to further investigate BOC expression i...
Capomaccio S, Cappelli K, Spinsanti G, Mencarelli M, Muscettola M, Felicetti M, Verini Supplizi A, Bonifazi M.Horses and humans share a natural proclivity for athletic performance. In this respect, horses can be considered a reference species in studies designed to optimize physical training and disease prevention. In both species, interleukin-6 (IL-6) plays a major role in regulating the inflammatory process induced during exercise as part of an integrated metabolic regulatory network. The aim of this study was to compare IL-6 and IL-6 receptor (IL-6R) mRNA expression in peripheral blood mononuclear cells (PBMCs) in trained and untrained humans and horses. Results: Nine highly trained male swimmers (...
Whittaker AG, Love S, Parkin TD, Duz M, Cathcart M, Hughes KJ.The pH measurement of exhaled breath condensate (EBC) may provide a non-invasive method of assessing the lower airways of horses but the methodology used may influence findings. The aim of this study was to investigate the effect of two sampling devices and three methods of condensation surface cooling (ethanol slush, -100°C; dry ice, -75°C; water ice, 0°C) on EBC pH. Each method was tested 30 times using six healthy ponies. Sample pH was determined before and after de-aeration with argon for 10 min. Sampler design was found to significantly affect pH. Samples collected as a liquid had a si...
Wilsher S, Allen WR.An opportunity to monitor equine chorionic gonadotrophin (eCG) production during 61 pregnancies in 25 Thoroughbred mares mated to the same Thoroughbred stallion was utilised in order to further knowledge regarding factors involved in the production of this hormone. Objective: To examine the effects of maternal body condition, exercise and parity on eCG production. Methods: In the first experiment, maiden mares were fed either a moderate (n = 9) or an excessive (n = 10) food intake throughout gestation. In the second experiment, 5 mares were exercised daily during pregnancy and eCG production r...
Visser MB, Pollitt CC.The timing of lamellar basement membrane (BM) changes occurring during laminitis development is incompletely understood. Objective: To determine the temporal progression of lamellar BM changes and whether laminin-332 (Ln-332) γ2 cleavage products are generated during laminitis development. Methods: Eight clinically normal Standardbred horses were allocated into treatment (n = 5) or sham (n = 3) groups. The treatment group received, via nasogastric intubation, an oligofructose (OF) bolus (10 g/kg bwt) while the sham group was given water. Laminitis induction proceeded for 48 h followed by euth...
Klein C, Scoggin KE, Troedsson MH.Establishment of pregnancy is critically dependent upon a precisely orchestrated embryo-maternal interaction leading to a receptive uterine environment. The up-regulation of the interferon-stimulated protein 15 kDa (ISG15) during pregnancy has been described in various species and has been hypothesized to be part of the molecular repertoire that makes the uterus receptive to conceptus development. In the current study, the expression of ISG15 and enzymes involved in ISG15ylation was examined at the mRNA and protein level in equine endometrium at Day 14 of the luteal phase and at Day 14 and 50 ...
Visser MB, Pollitt CC.The basement membrane (BM) is a thin layer of extracellular matrix that regulates cell functions as well as providing support to tissues of the body. Primary components of the BM of epithelial tissues are laminin-332 (Ln-332) and collagen type IV. Equine laminitis is a disease characterized by destruction and dislocation of the hoof lamellar BM. Immunohistochemistry was used to characterize the distribution of Ln-332 and collagen type IV in the organs of normal horses and these proteins were found to be widespread. Analysis of a panel of tissue samples from horses with experimentally-induced l...
Davis JL, Marshall JF, Papich MG, Blikslager AT, Campbell NB.The purpose of this study was to determine the pharmacokinetics of deracoxib following oral administration to horses. In addition, in vitro equine whole blood cyclooxygenase (COX) selectivity assays were performed. Six healthy adult horses were administered deracoxib (2 mg/kg) orally. Plasma samples were collected prior to drug administration (time 0), and 10, 20, 40 min and 1, 1.5, 2, 4, 6, 8, 12, 24, and 48 h after administration for analysis with high pressure liquid chromatography using ultraviolet detection. Following PO administration, deracoxib had a long elimination half-life (t(...
Love EJ, Murrell J, Whay HR.This review evaluates the thermal and mechanical nociceptive threshold testing techniques that have been used in horses and discusses them with reference to their applications, limitations and the factors which can influence both the testing procedure itself and the animal's responses. Methods to optimise the reliability and repeatability of the testing procedures are suggested and the potential clinical applications discussed. Methods: Web of Science and Medline. Conclusions: Thermal and mechanical nociceptive threshold testing techniques have valuable roles in both the identification of alte...
Claerhoudt S, Pille F, Vanderperren K, Hauspie S, Duchateau L, Van der Vekens E, Saunders JH.To investigate whether in navicular bones (NB) from warmbloods, distal border fragmentation is associated with the shape of the proximal articular border or other radiological findings. Methods: Radiographs of the front feet of 325 normal, subadult horses presented for admission as breeding stallions were reviewed. Results: The proximal articular border of the total of 650 NB was classified as straight (n = 278), convex (n = 184), undulating (n = 147) or concave (n = 41). Distal border fragments were present in 57 NB (8.8%). They were significantly more prevalent in NB with a concave (9/41; 22...
Jenner F, Kirker-Head C.To determine the physiologic response of the equine navicular bone to core decompression surgery in healthy horses. Methods: Experimental in vivo study. Methods: Healthy adult horses (n=6). Methods: Core decompression was completed by creating three 2.5-mm-diameter drill channels into the navicular bone under arthroscopic control. The venous (P(V)), arterial (P(A)), articular (P(DIPJ)), and intraosseous pressures (IOP) were recorded before and after decompression drilling. Each IOP measurement consisted of a baseline (IOP(B)) and a stress test (intramedullary injection of saline solution, IOP(...
Munsterman AS, Hanson RR.To develop an indirect method for measurement of intraabdominal pressures in the standing horse using measurement of gastric pressures as a less invasive technique, and to compare this method with direct intraabdominal pressures obtained from the peritoneal cavity. Methods: Prospective, experimental study. Methods: University-based equine research facility. Methods: Ten healthy adult horses, 7 geldings and 3 mares. Methods: Gastric pressures were measured using a nasogastric tube with a U-tube manometry technique, while intraperitoneal pressures were measured with a peritoneal cannula. Measure...
Oddsdóttir C, Riley SC, Leask R, Shaw DJ, Aurich C, Palm F, Fowden AL, Ricketts SW, Watson ED.During late gestation in the mare, rapid fetal growth is accompanied by considerable placental growth and further invasion of the endometrium by microvilli. This growth requires extensive remodeling of the extracellular matrix (ECM). In early pregnancy, we know that matrix metalloproteinase (MMP)-9 and -2 are involved in the endometrial invasion during endometrial cup formation. The present study investigated whether MMPs are found in fetal fluids later in gestation and during parturition, and if there was a difference in their activities between normal and preterm delivery. Amniotic fluids we...
Satué K, Domingo R.During pregnancy, the coordinated interaction of the components of the renin-angiotensin-aldosterone system (RAAS) plays a vital role in accommodating the cardiovascular, haemodynamic and haematological needs imposed by foetal development and the placenta. This significantly influences the birth weight of the neonate and foetal viability. Although the evolution of each of the components of this system has been widely described in various species, it has not yet been clarified in the mare. Thus, the objectives of the present research were: 1) to establish reference values for renin (REN), angio...
Smits K, Goossens K, Van Soom A, Govaere J, Hoogewijs M, Peelman LJ.In vitro-produced (IVP) equine blastocysts can give rise to successful pregnancies, but their morphology and developmental rate differ from those of in vivo-derived equine blastocysts. The aim of the present study was to evaluate this difference at the genetic level. Suppression subtractive hybridisation (SSH) was used to construct a cDNA library enriched for transcripts preferentially expressed in in vivo-derived equine blastocysts compared with IVP blastocysts. Of the 62 different genes identified in this way, six genes involved in embryonic development (BEX2, FABP3, HSP90AA1, MOBKL3, MCM7 a...
Clode A, Davis J, Davidson G, Salmon J, Lafevers H, Gilger B.To determine the transcorneal penetration and systemic absorption of a compounded 0.2% terbinafine solution following repeated topical administration to normal equine eyes. Sample population Six healthy adult horses with normal ocular examinations. Methods: One eye of each horse received 0.2 mL of a compounded 0.2% terbinafine solution every 4 h for seven doses. During the 1 h following administration of the final dose, multiple peripheral blood samples were obtained, and a single aqueous humor (AH) sample was collected at the end of the hour. AH and plasma concentrations of terbinafine wer...
Gough MR, Mayhew G, Munroe GA.This paper tests the hypothesis that the local analgesic agent mepivacaine diffuses between adjacent equine synovial structures in the forelimb and with greater frequency than latex, gelatine dye or contrast media. We report the incidence of diffusion of mepivacaine between the distal interphalangeal joint (DIPJ) and navicular bursa (NB) of the forelimbs and between the intercarpal (IC) and radiocarpal (RC) joints of 31 fresh equine cadavers. The DIPJ of one forelimb and the NB of the contra lateral forelimb and the RC joint of one forelimb and the IC joint of the contra lateral forelimb were ...
Palencia P, Quiroz-Rothe E, Rivero JL.Equine motor neuron disease (EMND) is a neurodegenerative disorder similar to the sporadic form of human amyotrophic lateral sclerosis. This study was conducted to quantify myofiber plasticity in response to EMND. Deep M. gluteus medius biopsy samples from eight horses with an ante mortem diagnosis of EMND, which in five cases was later confirmed by post mortem examination of spinal cord and peripheral nerves, were examined by combined methodologies of electrophoresis of myosin heavy chains (MyHC), muscle enzymes and substrate biochemistry, immunohistochemistry of MyHCs and sarcoendoplasmic Ca...
Bonilla-Gutiérrez AF, Castillo-Franz C, López C, Álvarez ME, Giraldo CE, Carmona JU.The aim of this study was to evaluate the release of pro- and anti-inflammatory as well as anabolic mediators stimulated by a leukocyte-reduced platelet-rich gel supernatant (Lr-PRGS) and a leukocyte-reduced plasma supernatant (Lr-PL) at two concentrations (25 and 50%) on normal equine suspensory ligament explants (SLEs) and tendon explants (TEs). SLEs and TEs from six horses were independently incubated for 48 h with Lr-PRGS and Lr-PL at concentrations of 25 and 50%, respectively. Samples were collected from the incubated tissues at 1 h and 48 h, which were employed for ELISA determinat...
Brinsko SP, Varner DD.Artificial insemination is an effective technique for improving utilization of stallions in breeding programs. When proper semen handling and insemination procedures are used, optimal pregnancy rates are attainable. When AI techniques are employed for mares and stallions with marginal fertility, pregnancy rates may be improved in comparison with natural mating. Preservation of stallion semen in the liquid or frozen state reduces the costs and potential health hazards incurred by transporting mares and provides easier access to genetic material that may otherwise be unavailable. Acceptable preg...
Sánchez-Calabuig MJ, Fernández-González R, Hamdi M, Smits K, López-Cardona AP, Serres C, Macías-García B, Gutiérrez-Adán A.Equine embryos exhibit an unusual pattern of glucose tolerance in vitro and are currently cultured in hyperglycaemic conditions. Objective: Our main objective was to analyse the effect of different glucose concentrations on in vitro-produced equine embryo development and quality. Methods: Experiments comparing in vitro and in vivo produced embryos. Methods: Oocytes (n = 641) were collected from post-mortem ovaries, matured in vitro and fertilised by intracytoplasmic sperm injection (ICSI). Embryo culture was divided from Day 0 to Day 4 and from Day 4 to Day 9 in three groups: 5-10 (5 and 10...
Badial PR, Cisneros-Àlvarez LE, Brandão CV, Ranzani JJ, Tomaz MA, Machado VM, Borges AS.The aim of this study was to compare ocular dimensions, corneal curvature, and corneal thickness between horses affected with hereditary equine regional dermal asthenia (HERDA) and unaffected horses. Methods: Five HERDA-affected quarter horses and five healthy control quarter horses were used. Methods: Schirmer's tear test, tonometry, and corneal diameter measurements were performed in both eyes of all horses prior to ophthalmologic examinations. Ultrasonic pachymetry was performed to measure the central, temporal, nasal, dorsal, and ventral corneal thicknesses in all horses. B-mode ultrasound...
Huang L, Zhu W, Saunders CP, Macleod JN, Zhou M, Stromberg AJ, Bathke AC.Identification of biomarkers among thousands of genes arrayed for disease classification has been the subject of considerable research in recent years. These studies have focused on disease classification, comparing experimental groups of effected to normal patients. Related experiments can be done to identify tissue-restricted biomarkers, genes with a high level of expression in one tissue compared to other tissue types in the body. Results: In this study, cartilage was compared with ten other body tissues using a two color array experimental design. Thirty-seven probe sets were identified as...
Tiley HA, Geor RJ, McCutcheon LJ.To determine the effects of dexamethasone treatment on selected components of insulin signaling and glucose metabolism in skeletal muscle obtained from horses before and after administration of a euglycemic-hyperinsulinemic clamp (EHC). Methods: 6 adult Standardbreds. Methods: In a balanced crossover study, horses received either dexamethasone (0.08 mg/kg, IV, q 48 h) or an equivalent volume of saline (0.9% NaCl) solution, IV, for 21 days. A 2-hour EHC was administered for measurement of insulin sensitivity 1 day after treatment. Muscle biopsy specimens obtained before and after the EHC were a...
Nilson JH, Bokar JA, Clay CM, Farmerie TA, Fenstermaker RA, Hamernik DL, Keri RA.Expression of the glycoprotein hormone alpha-subunit gene occurs in the pituitary of all mammals but in placenta of only primates and horses. In humans, two different elements, termed upstream regulatory element (URE) and cAMP response element (CRE), are required for placenta-specific expression of the alpha-subunit gene. The URE binds a protein unique to placenta whereas the CRE binds a ubiquitous protein. Comparative analysis of the promoter-regulatory region of the alpha-subunit gene from a number of mammals indicates that a functional URE has been retained and suggests the potential for pl...
Ley WB, Scott Pleasant R, Dunnington EA.Studies evaluating nutritional and seasonal influences on hoof strength and composition in horses, as well as the scientific justification for feeding supplements to improve hoof quality, are lacking. The horseman and veterinarian need controlled studies in this area to make informed decisions. This project quantified, in 2 trials, relative elasticity, tensile strength, % moisture, and mineral composition of hooves of 48 mature Thoroughbred mares maintained on different nutritional/management regimens, sampled quarterly over 12 month periods. Tensile strength was positively associated with sul...
Hyldahl Laursen S, Andersen PH, Kjelgaard-Hansen M, Wiinberg B.There is a paucity of information about the analytical performance of thromboelastography (TEG) in horses, specifically concerning components of variation among different analytical methods. Such data may be obtained by nested analysis of repetitive standardized sampling of healthy individuals. Objective: The objectives were (1) to assess the relative susceptibility to sources of preanalytical variation in a highly standardized setting, (2) to directly compare and evaluate the observed analytical variation, and (3) to assess the applicability of population-based reference intervals. Methods: B...
Miksík I, Deyl Z.Skin and aorta collagen specimens of Wistar rats, white mice, beagle dogs, cats, horses, and human necropsies of different ages were examined with respect to the content of glycated products. The data presented show that (a) glycation and accumulation of the chromophore(s) are comparable in collagen samples from different species of comparable age; (b) glycation and pigmented accumulation increase markedly during the first 5-10 years of age; (c) the extent of glycation is different in different tissues (in particular, glycation of aortal collagen is about twice that of skin collagen); and (d) ...
Pösö AR, Essén-Gustavsson B, Persson SG.Plasma concentrations of lactate, amino acids, ammonia and products of purine catabolism were studied before, during and after a standardised incremental exercise test in 29 Standardbred trotters admitted to the clinic for exercise tolerance testing. According to their red cell volume the horses were divided into red cell normovolaemic and red cell hypervolaemic (polycythaemic) groups. The exercise-response curve for taurine differed significantly in the two groups, whereas all the other amino acids behaved similarly. The [branched-chain amino acid]/[alanine] ratio, a proposed indicator for th...
Deuel NR, Lawrence LM.Bilateral asymmetry in gallop stride limb contact patterns of four Quarter Horse fillies was documented by high-speed cinematography. Horses were filmed with rider by two cameras simultaneously while galloping along a straightaway. Even though signaled for each gallop lead an equivalent number of times, horses frequently switched leads, selecting the left lead nearly twice as often as the right. Velocities and stride lengths were greater for the left lead than the right, but stride frequencies did not differ between leads. Velocity effects were partitioned out in limb contact data analysis to ...
Salimei E, Varisco G, Rosi F.Five Haflinger mares were hand-milked at 0 h (pre-suckle) and 6 h (postsuckle), 12, 24, 48, 72 and 96 h after parturition. Total solids, protein, fat, lactose, calculated gross energy content, leptin and non-protein nitrogen components (urea, alpha-amino nitrogen, creatinine and allantoin) were determined. The levels of the major constituents differed significantly in pre-suckle colostrum from subsequent samples. Leptin levels were the highest in whole (9 ng x mL(-1) of immunoreactive human equivalent HE +/- 0.48 ng x mL(-1), SEM) and skimmed (7.8 ng HE x mL(-1) +/- 0.52 ng x mL(-1), SEM) pre-...
Anderson RS, Day NK, Good RA.Natural hemagglutinin activity against vertebrate erythrocytes is present in the hemolymph of the cockroach Blabarus craniifer. The hemagglutinin titer against rabbit erythrocytes is high, whereas sheep and horse red cells agglutinate weakly. Hemagglutinin activity was depressed by the complement inhibitor, cobra venom factor. Cockroach hemagglutinin is heat-labile; all activity is destroyed by heating at 56 C for 1 hr. A humoral factor similar to the complement component 3 proactivator is also present in cockroach hemolymph. The formation of the cobra venom factor-hemolymph "complex" is depen...
Thompson DL, Garza F, St George RL, Rabb MH, Barry BE, French DD.Thirty-five ovariectomized pony mares were used to study the relationships among luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) concentrations in blood (secretion), in pituitary (storage) and in blood after secretagogue administration, as well as the content of gonadotropin releasing hormone (GnRH) in hypothalamic areas, under various conditions of steroidal and nonsteroidal treatment. Five mares each were treated daily for 21 d with vegetable shortening (controls), testosterone (T; 150 micrograms/kg of body weight, BW), dihydrotestosterone (DHT; 150 microgram...
Meehan M, Burke FM, Macken S, Owen P.Streptococcus equi possesses a haem-uptake system homologous to that of Streptococcus pyogenes and Streptococcus zooepidemicus. The system consists of two ligand-binding proteins (Shr and Shp) and proteins (HtsA-C) with homology to an ABC transporter. The haem-uptake system of S. equi differs from that of S. pyogenes and S. zooepidemicus in that Shr is truncated by two-thirds. This study focused on the SeShr, SeShp and SeHtsA proteins of S. equi. Analysis of shr, shp and shphtsA knockout mutants showed that all three proteins were expressed in vitro and that expression was upregulated under co...
Halama A, Oliveira JM, Filho SA, Qasim M, Achkar IW, Johnson S, Suhre K, Vinardell T.Equine performance in endurance racing depends on the interplay between physiological and metabolic processes. However, there is currently no parameter for estimating the readiness of animals for competition. Our objectives were to provide an in-depth characterization of metabolic consequences of endurance racing and to establish a metabolic performance profile for those animals. We monitored metabolite composition, using a broad non-targeted metabolomics approach, in blood plasma samples from 47 Arabian horses participating in endurance races. The samples were collected before and after the c...
Gastal EL, Gastal MO, Wiltbank MC, Ginther OJ.By definition, follicle deviation begins on the day the two largest follicles of a wave begin to differ in growth rates. The relationships between follicle deviation and intrafollicular and systemic estradiol concentrations were studied in ponies, using a two-follicle model in which all but the two largest follicles were ablated. A 20-microliter sample of follicular fluid was obtained from each of the two follicles by transvaginal ultrasonography. In experiment 1, the two follicles were sampled when the larger follicle reached 15 mm. No differences (p > 0.05) in post-sampling follicle chara...
Atkinson F, Evans R, Guest JE, Bavin EP, Cacador D, Holland C, Guest DJ.Tendon injuries are a common cause of morbidity in humans. They also occur frequently in horses, and the horse provides a relevant, large animal model in which to test novel therapies. To develop novel cell therapies that can aid tendon regeneration and reduce subsequent reinjury rates, the mechanisms that control tendon tissue regeneration and matrix remodelling need to be better understood. Although a range of chemical cues have been explored (growth factors, media etc.), the influence of the mechanical environment on tendon cell culture has yet to be fully elucidated. To mimic the in vivo e...
Dingboom EG, Dijkstra G, Enzerink E, van Oudheusden HC, Weijs WA.The fibre type composition of the deep gluteus muscle was studied in biopsies of Dutch Warmblood foals from birth until age 48 weeks. Half the foals were given box-rest, the other half received exercise consisting of an increasing number of gallop sprints. The muscle fibre types were determined using monoclonal antibodies discriminating against the following myosin heavy chain (MHC) isoforms: types I, IIa, IId, Cardiac-alpha and Developmental. During the first 48 weeks there was a consistent increase of fibres expressing types IIa MHC, replacing fibres expressing IId MHC. This change was refle...
Grosche A, Freeman DE, Morton AJ, Polyak MM, Matyjaszek SA.To assess the effects of ischemia and reperfusion on indicators of oxidative stress, activation of eosinophils, and apoptosis in the large colonic mucosa of horses. Methods: 40 horses. Methods: In 1 or two 20-cm-long segments of the pelvic flexure, ischemia was induced for 1 or 2 hours followed by no reperfusion or 30 minutes and 18 hours of reperfusion in anesthetized horses. Mucosal specimens were collected before (controls; n = 20 horses) and after each period of ischemia, and full-thickness tissue samples were collected after each period of reperfusion. Sections of colonic tissues were sta...
Stefaniuk-Szmukier M, Ropka-Molik K, Piórkowska K, Żukowski K, Bugno-Poniewierska M.The impact of exercises on young developing organisms is still of interest to researchers. Similarly like Thoroughbreds, Arabian horses competing at the race track. The high percent of lameness and loss of days in training are often the result of weakness in the condition of the musculoskeletal system. The objective of the presented study was to identify by RNA-Seq method, the possible skeletal system originating transcriptomic profile in peripheral blood of Arabian horses undergoing race training. Obtained results showed that one of the most significantly deregulated pathway involved in bone ...
Purcell TB, Sellers AD, Goehring LS.Glutamic acid decarboxylase (GAD) converts glutamic acid into the inhibitory neurotransmitter γ-aminobutyric acid (GABA). Increased serum GAD (auto) antibody concentrations were found in a mare with increased postural musculature tone resulting in stiffness and recumbence. The mare was treated with dexamethasone which resulted in resolution of clinical signs and decreased GAD antibody concentrations. La glutamate décarboxylase (GAD) convertit l’acide glutamique en acide gamma-aminobutyrique (GABA), un inhibiteur des neurotransmetteurs. Des concentrations sériques accrues d’anticorps (a...
Zauscher JM, Estrada R, Edinger J, Lischer CJ.To evaluate intra- and interobserver variability in ultrasonographic measurements of the proximal aspect of the suspensory ligament (PSL) in the horse. Objective: A minimum difference of ≥20% is required to differentiate reliably between physiological and pathological alterations related to dimensions. Methods: Two operators examined the PSL in all 4 limbs of 14 horses twice using different techniques and different probes with and without standoff pads. Measurements were taken from the longitudinal and transverse images. Inter- and intraoperator variability was evaluated using agreement indi...
Bakos Z, Vörös K, Järvinen T, Reiczigel J.The aim of the study was to establish normal echocardiographic values of healthy Standardbred trotters not published previously. Twenty-three clinically normal horses weighing between 350 and 490 kg were examined in the same manner: first a thorough physical and then detailed echocardiographic examination were performed. Standardised two-dimensional (2D) and guided M-mode echocardiographic imaging techniques were used to measure interventricular septal thickness (IVS), left ventricular internal diameter (LVID), left ventricular wall thickness (LVW), left atrial internal diameter (LAID) in end-...
Tokuriki M, Aoki O, Niki Y, Kurakawa Y, Hataya M, Kita T.Electromyographic (EMG) activity of 4 muscles of the cubital joint and the strain of forelimb hooves were recorded telemetrically in 4 Thoroughbreds (with and without a rider) standing, walking, trotting, and cantering. Bipolar fine wire electrodes were inserted into the muscles, and strain gauges were attached to the hoof wall. Motion pictures (16 mm), synchronized with EMG tracings, were taken to obtain kinematic data. When horses were standing, the biceps brachii had tonic activity, but the brachialis and the caput longum and the caput laterale of the triceps brachii had no EMG activity. Th...
Art T, Serteyn D, Lekeux P.Pleural, tracheal, pharyngeal and mask pressures as well as airflow and tidal volume of five ponies on a treadmill (incline 8.3 degrees) were recorded simultaneously while resting, walking, trotting slowly, trotting fast, after standing for 30 secs and 5 mins after the end of the exercise. The curves obtained were used to calculate total pulmonary resistance (RL), lower airway resistance (RLA) and upper airway resistance (RUA). The latter was also divided into nasal resistance (Rnas) and laryngeal plus extrathoracic tracheal resistance (Retr + lar). Furthermore, the inspiratory and expiratory ...
Zandoná Meleiro MC, de Carvalho HJC, Ribeiro RR, da Silva MD, Salles Gomes CM, Miglino MA, de Santis Prada IL.Racehorses are constantly exposed to stress. Aiming to verify the state of blood components and cortisol alterations during their routine and after races, phagocytosis and oxidative neutrophil burst assays, serum cortisol determination, erythrocytes apoptosis evaluation, lymphoproliferation assays, and blood count tests were performed in thirty Thoroughbred racehorses, which were divided in two groups. The samples were taken right after races (moment 0 d), during rest periods (-11 d, +1 d, +3 d), and after training (-8, +2, +5). In both groups, the phagocytosis showed a decrease in percentage ...
