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.
Knowles EJ, Withers JM, Mair TS.The use of plasma fructosamine concentration ([fructosamine]) as a marker of abnormal glucose homeostasis in laminitic horses has not been investigated. Objective: Plasma fructosamine concentration may be higher amongst laminitic horses than normal horses; this might relate to underlying insulin resistance. Objective: 1) To compare [fructosamine] between laminitic and normal horses. 2) To investigate associations between [fructosamine] at presentation in laminitic horses with a) single sample markers of insulin resistance and b) outcome. Methods: Plasma fructosamine concentration, fasting seru...
Lindner A, Wäschle S, Sasse HH.The blood lactate concentration (LA) and heart rate (HR) of 10 horses exercising in water on a treadmill were examined. With the water at 10 and 50% of the withers height (WH), the blood LA increased up to mean values around 1.9 mm during the standardized exercise test (SET) until after step 3 of 5 (each step lasted 5 min, speed increasing step by step). Thereafter, blood LA of horses remained constant, while with the water at 80% of WH, the blood LA decreased from the mean peak of 2.16 ± 0.62 mm after the 4th step. The HR of the horses increased to 132 ± 14 beats/min until the 3rd step of S...
Peters J, Block W, Oswald S, Freyer J, Grube M, Kroemer HK, Lämmer M, Lütjohann D, Venner M, Siegmund W.The delivery of clarithromycin (CRL) to its site of action in bronchial/alveolar epithelial cells (EC), bronchial epithelial lining fluid (ELF), and bronchoalveolar lavage cells (BALC) may be influenced by CYP3A4 and the drug transporters, ATP-binding cassette (ABC) B1 and ABCC2 and organic anion-transporting polypeptides (OATPs), which can be modulated and/or up-regulated via the nuclear pregnane X receptor (PXR) by rifampicin (RIF). Therefore, we evaluated the disposition and pulmonary distribution of CLR (7.5 mg/kg b.i.d., 21 days) and expression of ABCB1, ABCC2, OATP1A2, and OATP2B1 in EC ...
Maestre AM, Garzón A, Rodríguez D.Toroviruses are gastroenteritis causing agents that infect different animal species and humans. To date, very little is known about how toroviruses cause disease. Here, we describe for the first time that the prototype member of this genus, the equine torovirus Berne virus (BEV), induces apoptosis in infected cells at late times postinfection. Observation of BEV infected cells by electron microscopy revealed that by 24 hours postinfection some cells exhibited morphological characteristics of apoptotic cells. Based on this finding, we analyzed several apoptotic markers, and observed protein syn...
Derar DR, Taya K, Watanabe G, Miyake YI.The aim of this study was to characterize ir-IGF-I pattern and its relation to other hormones during the oestrous cycle in mares. Nine non-pregnant non-lactating pluriparous thoroughbred mares were used. The studied mares were examined ultrasonically and bled daily to follow the ovarian changes and the hormonal milieu for a complete Interovulatory interval (IOI). Two (minor and major) follicular waves were characterized per IOI in thoroughbred mares. The largest follicle of the first follicular wave (DF1) was firstly detected at D - 1.75 ± 0.47 with a growth rate of 2.78 ± 0.14mm/day and max...
Villalba M, Santiago I, Gomez de Segura IA.Lidocaine and ketamine are administered to horses as a constant rate infusion (CRI) during inhalation anaesthesia to reduce anaesthetic requirements. Morphine decreases the minimum alveolar concentration (MAC) in some domestic animals; when administered as a CRI in horses, morphine does not promote haemodynamic and ventilatory changes and exerts a positive effect on recovery. Isoflurane-sparing effect of lidocaine, ketamine and morphine coadministration has been evaluated in small animals but not in horses. Objective: To determine the reduction in isoflurane MAC produced by a CRI of lidocaine ...
Canola PA, Perotta JH, Laskoski LM, Escobar A, Melo e Silva CA, Canola JC, Johnson PJ, Valadão CA.Standing laparoscopic procedures, facilitated by abdominal insufflation with carbon dioxide, are being employed to an increasingly greater extent in horses. However, a sustained increase in abdominal pressure may be life-threatening. A practical method for intra-abdominal pressure (IAP) assessment is imperative. Although indirect methods for estimating IAP have been extensively studied in man, little work has been performed in veterinary medicine. Objective: To investigate the utility of gastric manometry for purposes of evaluating IAP in horses. Methods: Gastric pressure (P(ga) ) was estimate...
Veres-Nyéki KO, Leandri M, Spadavecchia C.Electrically induced reflexes can be used to investigate the physiology and pathophysiology of the trigeminal system in humans. Similarly, the assessment of the trigemino-cervical (TCR) and blink reflexes (BR) may provide a new diagnostic tool in horses. The aim of this study was to evoke nociceptive trigeminal reflexes and describe the electrophysiological characteristics in non-sedated horses. The infraorbital (ION) and supraorbital nerves (SON) were stimulated transcutaneously in 10 adult Warmblood horses in separate sessions using train-of-five electrical pulses. The current was increased ...
Pamornsakda T, Pojprasath T, Suwimonteerabutr J, Tharasanit T.Equine epididymal sperm are known to be severely sensitive to cryopreservation, in terms of sperm quality and pregnancy rate. The objective of this study was to examine the effects of cholesterol loaded cyclodextrins (CLCs) on the quality of stallion epididymal sperm during cryopreservation. In experiment I, sperm were treated with different concentrations of CLCs: (1) 0mg (control), (2) 1.5mg, (3) 3mg, and (4) 6 mg per 120 × 10(6) sperm. The sperm viability and amount of cholesterol were determined at 15, 30 and 45 min after CLC treatment using viability markers (Ethidium homodimer-1 and Cal...
Lü Y, Wang H, Yang J.A direct high-performance gel permeation chromatographic (HPGPC) method for the determination of immunoglobulin G in mare colostrum was established. HPGPC separation was performed on a TOSOH TSK-G4000PW(XL) column (300 mm x 7.8 mm, 5 microm) with 0.05 mol/L phosphate buffer solution (pH 6.9) as the mobile phase at a flow rate of 0.8 mL/min, and the column temperature was maintained at 25 degrees C. The injection volume was 20 microL. At the detection wavelength of 280 nm, the linear range was from 0.2 to 3.0 g/L (r2 = 0.999 5) with a detection limit of 0.08 mg/L (S/N = 10). The recovery was 97...
Gürelli G, Göçmen B.Species composition and distribution of large intestinal ciliates were investigated in the feces from 15 Turk rahvan horses, living in the vicinity of Izmir, Turkey. Twenty-two ciliate genera consisting of 36 species were identified. This is the first report on intestinal ciliates in Turk rahvan horses and no previously unknown species were observed. The mean number of ciliates was 14.2±13.9×10(4) cells ml(-1) of feces and the mean number of ciliate species per host was 9.9±7.1. No ciliates were observed in 2 horses. Bundleia and Blepharocorys were considered to be the major genera since th...
Abraham G, Zizzadoro C, Kacza J, Ellenberger C, Abs V, Franke J, Schoon HA, Seeger J, Tesfaigzi Y, Ungemach FR.Horses develop recurrent airway obstruction (RAO) that resembles human bronchial asthma. Differentiated primary equine bronchial epithelial cells (EBEC) in culture that closely mimic the airway cells in vivo would be useful to investigate the contribution of bronchial epithelium in inflammation of airway diseases. However, because isolation and characterization of EBEC cultures has been limited, we modified and optimized techniques of generating and culturing EBECs from healthy horses to mimic in vivo conditions. Results: Large numbers of EBEC were obtained by trypsin digestion and successfull...
Longland AC, Barfoot C, Harris PA.The aim of this study was to determine the amounts of water-soluble carbohydrate (WSC), WSC constituents and protein leached from a range of U.K. hays soaked according to common practice. Initial hay WSC content ranged from 123 to 230 g/kg dry matter (DM). Soaking the hays for up to 16 hours in water at a mean temperature of 8°C resulted in a mean loss of 27 per cent (range 6 to 54 per cent) of hay WSC. The mean percentage losses of WSC constituents were 24 per cent (range 14 to 31) for fructan, 41 per cent (range 21 to 70) for fructose, 45 per cent (range 28 to 100) for sucrose and 56 per ce...
Hubbell JA, Aarnes TK, Bednarski RM, Lerche P, Muir WW.The purpose of this study was to compare the effects of 0.5 fraction of inspired oxygen (FiO₂) and >0.95 FiO₂ on pulmonary gas exchange, shunt fraction and oxygen delivery (DO₂) in dorsally recumbent horses during inhalant anesthesia. The use of 0.5 FiO₂ has the potential to reduce absorption atelectasis (compared to maximal FiO₂) and augment alveolar oxygen (O₂) tensions (compared to ambient air) thereby improving gas exchange and DO₂. Our hypothesis was that 0.5 FiO₂ would reduce ventilation-perfusion mismatching and increase the fraction of pulmonary blood flow that is ox...
Bolen GE, Haye D, Dondelinger RF, Massart L, Busoni V.To assess the impact of cycles of freezing and thawing on magnetic resonance (MR) images (obtained by use of a 3-T magnet) of equine feet examined ex vivo. Methods: 9 forelimbs from 9 horse cadavers. Methods: 9 forefeet underwent MR imaging first at ambient temperature within 12 hours after the horses' death and then after each freezing-thawing cycle. Three digits underwent freezing and thawing (at 4°C for 36 hours) 2 times, 3 digits underwent freezing and thawing (at 4°C for 36 hours) once and rescanning after 24 hours at ambient temperature, and 3 digits underwent freezing and thawing at a...
Kawcak CE, Frisbie DD, McIlwraith CW.To evaluate effects of extracorporeal shock wave therapy (ESWT) and polysulfated glycosaminoglycan treatment (PSGAGT) on subchondral bone (SCB), serum biomarkers, and synovial fluid biomarkers in horses with induced osteoarthritis. Methods: 24 healthy 2- to 3-year-old horses. Methods: An osteochondral fragment was created on the distal aspect of the radial carpal bone in 1 middle carpal joint of each horse. Horses were randomly allocated to receive local application of ESWT (days 14 and 28; n = 8), PSGAGT (IM, q 4 d for 28 days; 8), or a sham ESWT probe (placebo; days 14 and 28; 8). Serum biom...
Hampson BA, Connelley AD, de Laat MA, Mills PC, Pollitt CC.To determine solar load-bearing structures in the feet of feral horses and investigate morphological characteristics of the sole in feral horses and domestic Thoroughbreds. Methods: Forelimbs from cadavers of 70 feral horses and 20 domestic Thoroughbreds in Australia. Methods: Left forefeet were obtained from 3 feral horse populations from habitats of soft substrate (SS [n = 10 horses]), hard substrate (HS [10]), and a combination of SS and HS (10) and loaded in vitro. Pressure distribution was measured with a pressure plate. Sole depth was measured at 12 points across the solar plane in feet ...
Wendt-Hornickle EL, Snyder LB, Tang R, Johnson RA.To investigate changes in colloid osmotic pressure (COP), total protein (TP) and osmolality (OSM) during anesthesia in horses given intravenous lactated Ringer's solution (LRS) or LRS and hetastarch (HES). Methods: Prospective, clinical trial. Methods: Fourteen horses presented for surgery. Mean age 8.3 ± 1.9 years; mean weight 452 ± 25 kg. Methods: Horses were premedicated with xylazine intravenously (IV); anesthesia was induced with ketamine and diazepam IV, and maintained with sevoflurane. Butorphanol was administered IV with pre-medications or immediately after induction. Xylazine was ad...
Amory H, Votion DM, Fraipont A, Goachet AG, Robert C, Farnir F, Van Erck E.It is unknown whether or not exercise-induced cardiac fatigue (EICF), as demonstrated in human athletes performing long duration exercise, occurs in endurance horses. Objective: To examine the effects of a long distance endurance race on left ventricular systolic function in horses. Methods: Echocardiography was performed before, and after, a 2 or 3 star international endurance race (106-132 km) in 11 horses. Systolic (s) and diastolic (d) interventricular and left ventricular free wall thickness (IVS and LVFW, respectively), left ventricular, left atrial and aortic internal diameter (LVID, LA...
Boyde A, Riggs CM, Bushby AJ, McDermott B, Pinchbeck GL, Clegg PD.Arthropathy of the distal articular surfaces of the third metacarpal (Mc3) and metatarsal (Mt3) bones in the Thoroughbred racehorse (Tb) is a natural model of repetitive overload arthrosis. We describe a novel pathology that affects the articular calcified cartilage (ACC) and subchondral bone (SCB) and which is associated with hyaline articular cartilage degeneration. Parasagittal slices cut from the palmar quadrant of the distal condyles of the left Mc3/Mt3 of 39 trained Tbs euthanized for welfare reasons were imaged by point projection microradiography, and backscattered electron (BSE) scann...
Stubbs NC, Riggs CM, Hodges PW, Jeffcott LB, Hodgson DR, Clayton HM, McGowan CM.The multifidus muscle plays a key role in spinal stabilisation. Multifidus atrophy ipsilateral to the side of osseous pathology has been demonstrated in man and pigs but has not been investigated in horses. Objective: To measure cross-sectional area (CSA) left/ right symmetry of equine multifidus ultrasonographically and relate asymmetry of multifidus with osseous spinal pathology in Thoroughbred racehorses. We hypothesised that ipsilateral multifidus CSA would be reduced when osseous pathological changes are present leading to left/right asymmetry in CSA. Methods: Twenty-two racehorses presen...
Votion DM, Fraipont A, Goachet AG, Robert C, van Erck E, Amory H, Ceusters J, de la Rebière de Pouyade G, Franck T, Mouithys-Mickalad A, Niesten A....Limited information exists about the muscle mitochondrial respiratory function changes that occur in horses during an endurance season. Objective: To determine effects of training and racing on muscle oxidative phosphorylation (OXPHOS) and electron transport system (ETS) capacities in horses with high resolution respirometry (HRR). Methods: Mitochondrial respiration was measured in microbiopsies taken from the triceps brachii (tb) and gluteus medius (gm) muscles in 8 endurance horses (7 purebred Arabians and 1 crossbred Arabian) before training (T0), after two 10 week training periods (T1, T2)...
Butudom P, Foreman JH, Kline KH, Whittem EL.Some methods of lactate (LA) measurement have not been validated appropriately for use in horses. Objective: To validate 2 LA analysers (YSI 2300 Stat Plus and TDx Lactic Acid Assay) for use with equine plasma and to compare plasma [LA] determined by the 2 methods. Methods: Both instruments were evaluated for linearity, parallelism, recovery and precision using serial dilutions of standard LA solutions and equine plasma and then comparing results with linear regression or paired t tests. Plasma [LA] results were compared in 275 blood samples collected from horses exercising at various intensit...
Vengust M, Stämpfli H, De Moraes AN, Teixeiro-Neto F, Viel L, Heigenhauser G.Carbonic anhydrase (CA) catalyses the hydration/dehydration reaction of CO(2) and increases the rate of Cl(-) and HCO(3)(-) exchange between the erythrocytes and plasma. Therefore, chronic inhibition of CA has a potential to attenuate CO(2) output and induce greater metabolic and respiratory acidosis in exercising horses. Objective: To determine the effects of Carbonic anhydrase inhibition on CO(2) output and ionic exchange between erythrocytes and plasma and their influence on acid-base balance in the pulmonary circulation (across the lung) in exercising horses with and without CA inhibition....
Notin C, Vallon L, Desbordes F, Leleu C.Intense physical exercise produces an excess of reactive oxygen species which can disturb the antioxidant/oxidant balance of the horse in training. Several classes of antioxidant dietary compounds have been suggested to provide health benefits and there is evidence that consumption of these products leads to a reduction in the expression of various pro-inflammatory and/or oxidative stress biomarkers. The recent development of a new galenic system allows the oral delivery of the antioxidant enzyme: superoxide dismutase (SOD). This has been developed from a specific melon variety with a particul...
Waller AP, Pearson W, Lindinger MI.Standardbred and Thoroughbred racehorses around the world are tested for performance enhancing substances. Among these are blood alkalising substances that raise plasma pH and total carbon dioxide (TCO(2)) concentration. However, many horses have an elevated TCO(2) due to dietary, environmental and health concerns without having been administered an alkalising substance. Objective: The purposes of this study were to determine the acid-base profile of a cross section of Standardbred horses in racing/race training in Ontario and the main independent variables that contributed to acid-base state....
Jansson A, Johannisson A, Kvart C.Horses in training lose large amounts of sodium but little is known about the cardiovascular response to low sodium intake. Objective: To investigate the effect of low sodium intake on plasma aldosterone (pAldo) concentrations and the cardiovascular system of athletic horses, and to identify markers of low sodium intake. Methods: Seven Standardbred geldings in training (trained twice a week) were randomly offered a standardised diet supplemented (NaS, 58 mg Na/kg bwt) and not supplemented (NaN, 3 mg Na/kg bwt) with NaCl for 5 weeks in a changeover design. Blood samples were taken once a week a...
McCutcheon LJ, Geor RJ.There is evidence that extensive training in cool conditions results in improvements to heat dissipation that contribute to successful acclimatisation. In horses, the effects of a less extensive training regimen have not been determined. Objective: This study investigated whether 10 consecutive days of moderate intensity treadmill training in cool conditions would improve thermoregulatory and sweating responses of horses to exercise in the heat. Methods: Six unfit Thoroughbred horses completed a standardised treadmill exercise test (SET) in hot, dry conditions (32-34 °C, 45-55% RH) before (SE...
Robert C, Goachet AG, Fraipont A, Votion DM, Van Erck E, Leclerc JL.Limited information exists about the physiological training-induced changes in electrolyte balance of horses competing in long distance endurance races. Objective: To determine the effects of endurance training and racing on hydration and electrolyte balance in horses. Methods: Blood and urine were sampled at rest in 8 endurance horses before training and after two 11 week training periods (T1 and T2). Each training was followed by a 120 km endurance ride and horses were sampled before, during and 2 h after the rides. Blood was analysed for packed cell volume (PCV), total protein (TP), urea, c...
Marlin DJ, Schrotert RC, Cashman PM, Deaton CM, Poole DC, Kindig CA, McDonough P, Erickson HH.The present investigation utilised simultaneous measurements of chest (Ch) and abdominal (Ab) circumferences and respiratory airflow to test the hypothesis that Ch circumferential expansion contributes proportionally little to tidal volume in the running Thoroughbred. During exercise, there were only small changes in Ch and Ab circumference and no increase with increasing tidal volume. At rest, walk and trot, the flow, Ch and Ab signals were in phase. However, during canter and gallop, the Ch and Ab changes were 180 degrees out of phase with each other and both were out of phase with airflow. ...
Klebe EA, Holcombe SJ, Rosenstein D, Boruta D, Bartner LR, Tessier C.Dysfunction of the glossopharyngeal nerve has been implicated as a cause of dysphagia in horses. However, recent studies have indicated that this is not the case. Objective: To determine whether bilateral glossopharyngeal nerve anaesthesia would cause dysphagia in horses or result in measurable alterations in the timing, function, or sequence of swallowing. Methods: Swallowing was evaluated in 6 normal horses with and without bilateral glossopharyngeal nerve anaesthesia. Swallowing dynamics were assessed subjectively and objectively based on time from prehension of food until swallowing, numbe...
Berti A, Degl'Innocenti D, Stefani M, Liguri G, Ramponi G.A non competitive enzyme-linked immunosorbent assay (ELISA) specific for horse muscle acylphosphatase (E.C. 3.6.1.7.) has been developed. The purified anti-acylphosphatase antibodies were immobilized by passive absorption to a solid-phase support and incubated with known and unknown amounts of antigen. The antibody-acylphosphatase complex was quantified using the same antibody conjugated to horseradish peroxidase. The assay yields positive reactions with as little as 0.05 ng of antigen, with intra- and interassay coefficients of variation of 5% and 7%, respectively. On the basis of this assay ...
Bettschart-Wolfensberger R, Bowen IM, Freeman SL, Weller R, Clarke KW.To search for long-term total i.v. anaesthesia techniques as a potential alternative to inhalation anaesthesia. Objective: To determine cardiopulmonary effects and anaesthesia quality of medetomidine-ketamine anaesthesia induction followed by 4 h of medetomidine-propofol anaesthesia in 6 ponies. Methods: Sedation consisted of 7 microg/kg bwt medetomidine i.v. followed after 10 min by 2 mg/kg bwt i.v. ketamine. Anaesthesia was maintained for 4 h with 3.5 microg/kg bwt/h medetomidine and propofol at minimum infusion dose rates determined by application of supramaximal electrical pain stimuli. Ve...
Martin EM, Jones SL.Inhibition of prostaglandin E2 (PGE2) production effectively limits inflammation in horses, however nonspecific prostaglandin blockade via cyclooxygenase (COX) inhibition elicits deleterious gastrointestinal side effects in equine patients. Thus, more selective PGE2 targeting therapeutics are needed to treat inflammatory disease in horses. One potential target is microsomal prostaglandin E-synthase-1 (mPGES-1), which is the terminal enzyme downstream of COX-2 in the inducible PGE2 synthesis cascade. This enzyme has yet to be studied in equine leukocytes, which play a pivotal role in equine inf...
Cassimeris L, Armstrong C, Burger QC, Stokes S, van Eps A, Galantino-Homer H.The euglycemic hyperinsulinemic clamp model (EHC) of equine endocrinopathic laminitis induces rapid loss of lamellar tissue integrity, disrupts keratinocyte functions, and induces inflammation similar to natural disease. Continuous digital hypothermia (CDH) blocks tissue damage in this experimental model, allowing identification of specific genes or molecular pathways contributing to disease initiation or early progression. Archived lamellar tissues (8 horses, 48 h EHC treatment, including CDH-treated front limbs) were used to measure relative expression levels of genes encoding keratin 17 (KR...
Suzuki T, Mizukami H, Nambo Y, Ishimaru M, Miyata K, Akiyama K, Korosue K, Naito H, Nagaoka K, Watanabe G, Taya K.One- to two-year-old Thoroughbred colts and fillies being reared in Miyazaki (warm climate) and Hidaka (cold climate), Japan, were administered extended photoperiod (EP) treatment between December 20 and the following April 10, and its effect on growth, endocrine changes, gonadal activation, and hair coat condition was investigated. In colts reared in Miyazaki, no effect of EP treatment was noted on the growth indices, including body weight (BW), height at withers (HW), girth, and cannon circumference (CC), whereas the BWs and CCs of fillies were significantly higher in the EP treatment group ...
Johnson CB, Bloomfield M, Taylor PM.To investigate the effects of ketamine on the electroencephalogram (EEG) of the horse. Methods: Prospective experimental study. Methods: Eight Welsh mountain pony geldings weighing between 280 and 330 kg, 5 to 9 years old. Methods: During halothane anesthesia at an end-tidal halothane concentration between 0.75 and 0.85%, the EEG frequency power spectrum and the auditory evoked potential were recorded while an infusion of ketamine was given. Ketamine 200 mg was infused over 5 minutes in 8 ponies. The effects of ketamine on the EEG were recorded continuously during the infusion and for a furthe...
Nankervis KJ, Williams RJ.The use of water treadmill exercise in horses is popular, although little is known about the physiological responses to this form of exercise. No information exists regarding the time taken to acclimate to water treadmill exercise compared to that of high-speed treadmill exercise, for both physiological and biomechanical parameters. Objective: To determine heart rate responses during acclimation to water treadmill exercise with and without sedation on first time exposure. Methods: All horses were exercised on a water treadmill at the walk for 15 min once a day for 4 days. Fourteen horses (mean...
Okumura M, Fujinaga T, Yamashita K, Tsunoda N, Mizuno S.Ceruloplasmin (Cp) was isolated from fresh equine plasma by precipitation, cellulose chromatography, and improved ion-exchange chromatography. Purified equine Cp is a glycoprotein having a molecular weight of approximately 115,000. In electrophoresis, equine Cp migrated to the alpha 1-globulin region, its isoelectric point was about 4.15 and consisted of about 890 amino acid residues. Serum Cp concentration was measured by use of the single radial immunodiffusion method. In clinically normal horses, the mean (+/- SD) serum Cp concentration of newborn foals was 2.87 +/- 0.40 mg/ml and that of 3...
Caron JP, Tardif G, Martel-Pelletier J, DiBattista JA, Geng C, Pelletier JP.To determine whether matrix metalloprotease 13 (MMP-13; collagenase 3) is produced by equine chondrocytes and to investigate modulation of its expression by recombinant human interleukin 1 beta (rhIL-1 beta) and corticosteroids. Methods: Equine chondrocytes in monolayer culture were stimulated with rhIL-1 beta. Total RNA was extracted, purified, and reverse transcribed into DNA. Using appropriate primers, a putative MMP-13 fragment was amplified by polymerase chain reaction, and cloned into a bacterial vector. The resultant fragment was purified and sequenced, then was used to prepare a digoxi...
Neild DN, Gadella BM, Agüero A, Stout TA, Colenbrander B.In general, fertility in breeding stallions is lower and more variable than in the other farm animal species, primarily because selection is based on pedigree, looks and/or athletic performance, with little consideration of fertility or fertility potential. Moreover, because the average stallion breeds only a limited number of mares per year and in-field fertility is influenced significantly by non-stallion factors such as management and mare fertility, meaningful fertility data are hard to come-by. Unfortunately, generating usable figures would involve impractically high costs, time and numbe...
Science (New York, N.Y.)June 10, 1994
Volume 264, Issue 5165 1584-1587 doi: 10.1126/science.7515512
Willbold D, Rosin-Arbesfeld R, Sticht H, Frank R, Rösch P.Trans-activator (Tat) proteins regulate the transcription of lentiviral DNA in the host cell genome. These RNA binding proteins participate in the life cycle of all known lentiviruses, such as the human immunodeficiency viruses (HIV) or the equine infectious anemia virus (EIAV). The consensus RNA binding motifs [the trans-activation responsive element (TAR)] of HIV-1 as well as EIAV Tat proteins are well characterized. The structure of the 75-amino acid EIAV Tat protein in solution was determined by two- and three-dimensional nuclear magnetic resonance methods and molecular dynamics calculatio...
St George LB, Spoormakers TJP, Smit IH, Hobbs SJ, Clayton HM, Roy SH, van Weeren PR, Richards J, Serra Bragança FM.The relationship between lameness-related adaptations in equine appendicular motion and muscle activation is poorly understood and has not been studied objectively. The aim of this study was to compare muscle activity of selected fore- and hindlimb muscles, and movement of the joints they act on, between baseline and induced forelimb (iFL) and hindlimb (iHL) lameness. Three-dimensional kinematic data and surface electromyography (sEMG) data from the fore- (triceps brachii, latissimus dorsi) and hindlimbs (superficial gluteal, biceps femoris, semitendinosus) were bilaterally and synchronously c...
Ginther OJ.During an ovulatory follicular wave in the monovulatory species of heifers, mares, and women, the two largest follicles deviate in diameter at the end of a common follicle growth phase. The largest follicle before deviation becomes the future ovulatory follicle in most ovulatory waves. In 10-30% of the ovulatory waves, the destiny of the two follicles switches just before or at deviation so that the second-largest follicle becomes the future ovulatory follicle, and the largest follicle becomes a subordinate. In FSH-driven switching in heifers, mares, and women, the wave-stimulating FSH surge d...
Seltenhammer MH, Sundström E, Meisslitzer-Ruppitsch C, Cejka P, Kosiuk J, Neumüller J, Almeder M, Majdic O, Steinberger P, Losert UM, Stöckl J....The Grey horse phenotype, caused by a 4.6 kb duplication in Syntaxin 17, is strongly associated with high incidence of melanoma. In contrast to most human melanomas with an early onset of metastasis, the Grey horse melanomas have an extended period of benign growth, after which 50% or more eventually undergo progression and may metastasize. In efforts to define changes occurring during Grey horse melanoma progression, we established an in vitro model comprised of two cell lines, HoMel-L1 and HoMel-A1, representing a primary and a metastatic stage of the melanoma, respectively. The cell lines ...
Bertin FR, Pader KS, Lescun TB, Sojka-Kritchevsky JE.To evaluate the effect of ovariectomy on insulin sensitivity in horses and determine whether the effects of suppression of the hypothalamo-pituitary-adrenal axis differ before and after ovariectomy. Methods: 6 healthy mares. Methods: The horses underwent an IV glucose tolerance test (IVGTT), an insulin sensitivity test, and a dexamethasone suppression test before and 5 weeks after ovariectomy. Body weight, serum cortisol and plasma ACTH concentrations, serum insulin-to-blood glucose concentration ratios, and changes in blood glucose concentration with time after injection of glucose or insulin...
Silver M, Fowden AL, Knox J, Ousey J, Cash R, Rossdale PD.Pre- and post partum changes in plasma T3 have been examined in relation to plasma cortisol in 23 newborn foals (12 full term, 6 premature and 5 'twilight'), and in 5 fetuses catheterized in late gestation. Blood samples were collected daily from the fetuses and from the neonates at 30-min intervals for 2 h after birth; the plasma was assayed for T3 and cortisol by standard radioimmunoassay methods. In the full-term foals, plasma cortisol and T3 concentrations were high at birth (67.4 +/- 6.1 and 4.3 +/- 0.3 ng/ml respectively) and rose to a maximum during the following 2-h period to 141.0 +/-...
Totorikaguena L, Olabarrieta E, Lolicato F, Romero-Aguirregomezcorta J, Smitz J, Agirregoitia N, Agirregoitia E.The cannabinoid (CB) system has been involved in many aspects of reproduction and it is known that the systemic chronic use of exogenous CBs are deleterious to reproductive processes. Even so, it is not known what happens in relation to the physiology of the ovary when CB receptors are absent. The present study investigated the effect of the lack of CB1 and CB2 receptors in mice ovarian morphology, folliculogenesis, oocyte retrieval, and oocyte maturation and evaluated the use of Δ9-tetrahydrocannabinol (THC) on oocyte in vitro maturation (IVM) by comparing classical IVM and two-step IVM by a...
Pedersen HG, Watson ED, Telfer EE.The effects of ovary holding time and temperature on granulosa cell apoptosis, oocyte chromatin configuration and cumulus morphology were investigated through a series of experiments. Three experiments were performed to determine the effect of ovary holding time and temperature on granulosa cell apoptosis. Ovaries were held (1) at 20, 30 or 35-37 degrees C for up to 2h, (2) at 30 degrees C for 0-1, 1-2, 2-3, 3-4, 4-6 or 6-10h, and (3) granulosa cells were held for 0, 1, 2, 3, 5, 12 or 24h in M199 with Hank's salts at room temperature (suboptimal incubation). Granulosa cell DNA was analysed by ...
Dhakal P, Tsunoda N, Nakai R, Nagaoka K, Nambo Y, Sato F, Taniyama H, Taya K.The aim of present study was to clarify the post-natal profile of follicle-stimulating hormone (FSH), luteinizing hormone (LH), immunoreactive (ir)-inhibin, progesterone, testosterone, and estradiol-17β, and their relationships in Thoroughbred colts. Six hundred and thirty-six colts were used for the study. Single plasma samples from each animal were harvested from the blood drawn through jugular venipuncture. The subjects were born with high amounts of progesterone, testosterone, and estradiol-17β, all of which dropped significantly and remained at lower levels till the end of 6 months. FSH...
Tyler RD, Cowell RL, Clinkenbeard KD, MacAllister CG.Normal reference ranges and pertinent background information on equine hematology are presented and briefly discussed. Diagnostic interpretation of hematologic data is discussed and three diagnostic algorithms and two diagnostic tables are provided to facilitate the use of the presented information for diagnosis. Two cases are presented and the information presented in the article is used to interpret the case data.
Antczak DF.One of the most intriguing and dramatic examples of immunological tolerance is displayed by the mammalian foetal-placental unit, which thrives as a semi-allograft in the mother's uterus during pregnancy. The success of the so-called foetal allograft stands in stark contrast to the failure of most tissue and organ grafts to survive without genetic matching of donor and recipient or drastic immunosuppression of the recipient's immune system. Experiments conducted over the past 60 years have revealed multiple mechanisms that enable the conceptus to avoid immunological detection or destruction. Ma...
Merkies K, Chenier T, Plante C, Buhr MM.Viability of spermatozoa can be assessed by numerous methods, but many are slow and poorly repeatable, and subjectively assess only 100 to 200 spermatozoa per ejaculate. We collected two ejaculates from each of 4 stallions, and extended them to 50x10(6) sperm/mL in a nonfat dried milk solids glucose extender (EZ Mixin). Half the ejaculate was freeze-killed by immersing in liquid nitrogen for 10 min. Aliquots using appropriate volumes of live and freeze-killed spermatozoa provided the following ratios of live:dead spermatozoa: 100:0, 75:25, 50:50, 25:75, 0:100. We determined the viability of ea...
Nyman S, Dahlborn K.This study investigated three methods of water supply on drinking preference and behavior in six Standardbred geldings (2-9 years, 505+/-9 kg). The water sources were buckets (B), pressure valve (PV), and float valve (FV) bowls. In an initial drinking preference test, PV was tested at three flow rates: 3, 8, and 16 l/min (PV3, PV8, and PV16), and FV at 3 l/min (FV3). Water intake was measured in l and presented as the percentage of the total daily water intake from each of two simultaneously presented alternatives. The intake from PV8 was greater than from both PV3 (72+/-11% vs. 28+/-11%) and ...
White JL, Salinas EY, Link JM, Hu JC, Athanasiou KA.A significant portion of equine lameness is localized to the stifle joint. Effective cartilage repair strategies are largely lacking, however, recent advances in surgical techniques, biomaterials, and cellular therapeutics have broadened the clinical strategies of cartilage repair. To date, no studies have been performed directly comparing neonatal and adult articular cartilage from the stifle across multiple sites. An understanding of the differences in properties between the therapeutic target cartilage (i.e., adult cartilage) as well as potential donor cartilage (i.e., neonatal cartilage) c...
Christmann U, Hancock CL, Poole CM, Emery AL, Poovey JR, Hagg C, Mattson EA, Scarborough JJ, Christopher JS, Dixon AT, Craney DJ, Wood PL.Horses with asthma or osteoarthritis frequently receive ω-3 fatty acid supplements. Docosahexaenoic (DHA; 22:6) and eicosapentaenoic (EPA; 20:5) acids are essential ω-3 fatty acid precursors of anti-inflammatory mediators and components of structural glycerophospholipids (GPL) that act as reservoirs of these fatty acids. Analysis of the incorporation of dietary DHA + EPA into GPL pools in different body compartments has not been undertaken in horses. We undertook a detailed study of dietary supplementation with DHA + EPA in horses and monitored incorporation into DHA- and EPA-contain...
Murphy BA.The circadian system provides animals with a means to adapt their internal physiology to the constantly changing environmental stimuli that exist on a rotating planet. Light information is translated into molecular timing mechanisms within pacemaker cells of the mammalian hypothalamic suprachiasmatic nucleus (SCN) via transcriptional-translational feedback loops. Humoral and neural outputs from this 'master' clock result in circadian rhythms of physiology and behaviour. The larger circadian system involves SCN synchronisation of cellular clocks throughout the organism such that individual orga...
Kang OD, Ryu YC, Yun YM, Kang MS.The changes in physiologic parameters by swim exercise duration were examined in five female well-trained Jeju crossbred riding horses that had riding experience of more than three years without swim training experience. The horses were performed with swim exercise for 10 min (60.0 m/min) once a day for 14 days. Physiologic characteristics and haematic parameters were measured before swimming, immediately after swimming, and after a 10 min rest at first day (D0), 7 days (D7), and 14 days (D14) of training. After 14 days of swim training, heart rate (p<0.05), blood glucose (p<0.05), lacta...
Recio P, López PG, Hernández M, Prieto D, Contreras J, García-Sacristán A.The involvement of nitric oxide (NO) and the mechanisms mediating neurogenic relaxation were investigated in the horse corpus cavernosum. NADPH-diaphorase activity was expressed in nerve fibres around arteries and muscular bundles in the horse trabecular tissue. Relaxations in response to electrical field stimulation were tetrodotoxin (10(-6) M)-sensitive, indicating their neurogenic origin. The NO synthase inhibitor, L-NO-arginine (L-NO-Arg, 3 x 10(-5) M), abolished the electrically induced relaxations, which were significantly reversed by L-arginine (3 x 10(-3) M). Exogenous NO (10(-6)-10(-3...
