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.
McGreevy PD, Nicol CJ.The results of an experimental study of the motivational consequences of short-term prevention of crib-biting are reported here. Eight test horses wore a cribbing collar for 24 h. This was effective in preventing crib-biting in 6 subjects. Using analysis of co-variance that accounted for baseline differences in crib-biting rate, test horses showed significantly more crib-biting than control horses on the first day after prevention (P < 0.05). There was also a highly significant increase in the crib-biting rate of test horses on the first day after prevention in comparison with their baselin...
Lebelt D, Zanella AJ, Unshelm J.The aim of the present study was to obtain information on the possible mechanisms underlying cribbing behaviour in horses. To investigate the horse's responsiveness to an external stimulus, a device for telemetric measurement of thermal threshold, using the forelimb withdrawal reflex, was developed and validated. Measurements of thermal threshold took place in cribbing horses (n = 11) before and during cribbing periods. Heart rate was monitored continuously in the same horses. Blood samples were collected before and during cribbing periods as well and in age- and sex-matched control horses (n ...
Carver SE, Heath CA.Equine articular chondrocytes, embedded within a polyglycolic acid nonwoven mesh, were cultured with various combinations of intermittent pressure, fluid flow, and mixing to examine the effects of different physical stimuli on neochondrogenesis from young cells. The cell/polymer constructs were cultured first in 125 ml spinner flasks for 1, 2, or 4 weeks and then in a perfusion system with intermittent pressure for a total of up to 6 weeks. Additional constructs were either cultured for all 6 weeks in the spinner flasks or for 1 week in spinners followed by 5 weeks in the perfusion system with...
Wilson SM, Gallagher M, Rakhit S, Remsbury AL, Ko WH.Uridine triphosphate (UTP) evoked inhibition of adrenaline-evoked cAMP accumulation in cultured equine epithelial cells (EC50, 1.8 +/- 0.2 microM) and this effect was mimicked by 5-Br-UTP (EC50, 6.6 +/- 1.8 microM) and uridine diphosphate (UDP; EC50, 96 +/- 26 microM). This inhibitory action of UTP was abolished by pre-treating cells with pertussis toxin (10 ng ml-1, 24 h). UTP (EC50, 2.3 +/- 0.3 microM) and 5-Br-UTP (EC50, 29.4 +/- 9.4 microM) also increased intracellular free calcium ([Ca2+]i) whilst UDP did not; the two effects are thus differentially sensitive to these pyrimidine nucleotid...
Fowden AL, Forhead AJ, Bloomfield M, Taylor PM, Silver M.Plasma glucagon concentrations were measured in chronically catheterized fetal ponies and their mothers between 260 days of gestation and term (approximately 335 days). Fetal alpha cell responses to arginine and variations in fetal glycaemia were also examined during late gestation. Immunoreactive glucagon was present in fetal plasma at 260 days of gestation and its concentration in utero increased after 320 days and then again at birth. Maternal plasma glucagon concentrations were higher after 300 days than earlier in gestation but were lower than the corresponding fetal value throughout the ...
Lafortuna CL, Albertini M, Ferrucci F, Zucca E, Braghieri M, Clement MG, Saibene F.A video-laryngoscopic method, implemented with an algorithm for the correction of the deformation inherent in the endoscope optical system, has been used to measure the dorsoventral diameter (Drg) and the cross-sectional area (CSArg) of the rima glottidis in five healthy workhorses during conscious breathing at rest. Simultaneous recording of the respiratory airflow was also obtained in two horses. Drg measured 82.7 +/- 4.5 mm (mean +/- S.D.) independently of the respiratory phase, and did not differ from the measurement in post-mortem anatomical specimens of the same horses. CSArg ranged from...
Chaudhuri A, Bharadwaj G, Maheshwari R.In the thermophilic fungus Thermomyces lanuginosus, invertase displays an unusual pattern of development: the induced activity begins to diminish even before any substantial quantity of sucrose has been utilized or an appreciable amount of biomass has been produced. Despite this pattern of invertase activity, neither the growth rate nor the final mycelial yield is affected adversely. T. lanuginosus invertase is a thiol protein and the enzyme is active when specific sulfhydryl group(s) is in the reduced state. Measurements of reduced coenzyme and glutathione pools in sucrose-growth mycelia excl...
Hood DM.Many of the difficulties in managing the horse with chronic laminitis are associated with the foot's mechanical failure. The occurrence of digital collapse cannot be viewed in isolation as the primary therapeutic focus. The circulatory, metabolic, and growth pattern changes induced by the foot's mechanical collapse often serve as major limiting factors to successful rehabilitation. From the discussion above, it is obvious that a significant amount of research is needed to better understand the biomechanical pathologies of the failed foot.
Grosenbaugh DA, Morgan SJ, Hood DM.This review indicates that the patient-to-patient uniqueness commonly seen in chronic laminitis represents the variable presence of the digital pathologies. Although some degree of mechanical failure is always present, the secondary metabolic and growth dysplasias, vascular pathologies, and sepsis may or may not be evident. The presence and severity of these pathologies appear to have a more significant impact on the prognosis of individual cases than does the displacement of the distal phalanx. It should be reiterated that it is often the combined presence of these individual pathologies that...
Curtis S, Ferguson DW, Luikart R, Ovnicek G.Several of the technical approaches applied to the foot overlap with regard to intent. Frog or solar support, for example, may be provided either to stabilize the distal phalanx within the hoof capsule or in an effort to unload regional pain arising from the solar surface of the foot. It is likewise obvious that some techniques such as lowering the heels to achieve phalangeal realignment and raising the heels to relieve deep digital flexor tendon tension are contradictory. In these instances, it is not that one technique is always correct but that differences exist among horses. Currently, it ...
Scocchi M, Bontempo D, Boscolo S, Tomasinsig L, Giulotto E, Zanetti M.Cathelicidins are precursors of defense peptides of the innate immunity and are widespread in mammals. Their structure comprises a conserved prepropiece and an antimicrobial domain that is structurally varied both intra- and inter-species. We investigated the complexity of the cathelicidin family in horse by a reverse transcription-PCR-based cloning strategy of myeloid mRNA and by Southern and Western analyses. Three novel cathelicidin sequences were deduced from bone marrow mRNA and designated equine cathelicidins eCATH-1, eCATH-2 and eCATH-3. Putative antimicrobial domains of 26, 27 and 40 r...
Boerboom D, Kerban A, Sirois J.Estradiol biosynthesis is a key biochemical trait of developing follicles. To study its regulation in equine follicles, the objectives of this study were to clone and determine the structure of equine cytochrome P450 aromatase (P450AROM), and characterize the regulation of P450AROM and P450 17alpha-hydroxylase/C17-20 lyase (P45017alpha) messenger RNAs (mRNAs) in vivo in equine preovulatory follicles isolated during hCG-induced ovulation. Two distinct P450AROM complementary DNAs (cDNAs) were isolated from an equine preovulatory follicle cDNA library. One clone was 2682 bp in length and included...
Henderson K, Stevens S, Bailey C, Hall G, Stewart J, Wards R.The relative merits of measuring blood concentrations of equine chorionic gonadotrophin (eCG, previously known as pregnant mare serum gonadotrophin (PMSG)), or oestrone sulphate (OS), or faecal OS concentrations for determining pregnancy status in miniature horses were investigated. Pregnant mares between 40 and 140 days after mating had serum eCG concentrations > 1 I.U. mL-1, with the highest concentrations occurring between days 50 and 120. However, eCG measurements were susceptible to returning a 'false positive' diagnosis of pregnancy. Plasma OS concentrations ranged from 0.1 to 3.6 ng ...
Hargreaves BJ, Kronfeld DS, Naylor JR.Thermoregulation may limit exercise performance under hot and humid conditions. This study compared heart rate (HR), respiratory rate (RR), rectal temperature (Tr), packed cell volume (PCV) and total plasma protein concentration (TPP) during a submaximal incremental field exercise test under high vs. low ambient temperature and relative humidity. Ten horses were tested 3 times in summer (July) and 3 times in autumn (September). Heart rate was measured continuously, the other variables at rest and immediately after 4 min at 3.5, 4.5 and 7.0 m/s, separated by 3 min rest intervals, and after 5 an...
Clegg PD, Carter SD.A study was performed to identify the activation status of the gelatinase MMPs, MMP-2 and -9, in both normal and diseased equine articular tissues. In addition, the production and activation status of equine MMP-2 and -9 by equine articular cells and tissues in response to increasing IL-1beta concentrations was assessed. The study was performed to test the hypothesis that activation of MMPs is a fundamental step in the pathogenesis of joint diseases; and that this activation is mediated by the cytokine IL-1. Using purified equine MMP-2 and -9, the molecular weights of the zymogen and activated...
Minelli A, Allegrucci C, Mezzasoma I, Ronquist G, Lluis C, Franco R.Membrane vesicles of horse seminal plasma present at their surface a highly specific serine-type protease, dipeptidyl peptidase IV/CD26, a surface antigen known to characterize human prostasomes. Horse sperm cells expressed at their surface A(1) adenosine receptors (A(1)AR) and ecto-adenosine deaminase (ecto-ADA), both detected by immunoblot analysis, whereas CD26 was visualized at the equatorial segment by immunofluorescence microscopy. In addition to CD26, horse membrane vesicles showed ecto-ADA. The fusion process between horse sperm cells and vesicles was evidenced by confocal microscopy, ...
Chiappe A, Gonzalez G, Fradinger E, Iorio G, Ferretti JL, Zanchetta J.In this study, we assessed the potential value of free serum osteocalcin or bone gla protein (BGP), the most abundant non collagenous matrix protein found in bone and dentin, to reflect changes of bone turnover in thoroughbred horses. Levels of osteocalcin were analyzed in serum samples of 54 clinically normal animals divided into three groups (A, B, C) according to age: 8, 16-18 and 24-36 months, in order to determine the standard for young horses of different age and sex. Serum BGP was measured by an in-house developed double antibody radioimmunoassay using bovine antigen. The mean BGP level...
Schweigert FJ, Gottwald C.The objective of this study was to investigate in mares the effect of parturition on plasma and milk levels of retinol, beta-carotene, alpha-tocopherol and cholesterol over 12 weeks around parturition. In blood plasma of horses around parturition an increase of all these components was observed. This increase was most impressive in beta-carotene (P<0.05) and less pronounced for vitamin E, vitamin A and cholesterol. The magnitude of increase around parturition corresponded well with the magnitude of accumulation in colostrum; levels of beta-carotene in colostrum were 65 times higher compared...
Popot MA, Lacabaratz E, Garcia P, Laroute V, Bonnaire Y, Toutain PL, Cowan DA.The cortisol threshold concentration of 1.0 microg/ml in horse urine adopted by the International Federation of the racing Authorities in 1994 is specific. However, an increase in the sensitivity for the detection of cortisol administration would be helpful. Previous studies have shown that 20beta-dihydrocortisol concentration in urine would be a good indicator of cortisol administration. The purpose of the present work was to estimate the population parameters and the critical values of 20beta-dihydrocortisol and 20beta-dihydrocortisone concentration in urine compared with that of cortisol. U...
Paccamonti DL, Pycock JF, Taverne MA, Bevers M, Van Der Weijden GC, Gutjahr S, Schams D, Blouin D.We investigated the half-life of oxytocin in reproductively normal mares and the prostaglandin response after oxytocin administrations. Mares were given oxytocin, 10 or 25 iu, i.v., on the day of, or 2 days after, ovulation, and frequent jugular blood samples were collected for analysis of oxytocin and Prostaglandin F metabolite (PGFM) by RIA. Neither dose of oxytocin nor day of treatment affected the half-life of the exogenous oxytocin, which was determined to be 6.8 min. A significant increase in PGFM was observed within 6 min of oxytocin administration and peak values were observed within 1...
Dyke TM, Hinchcliff KW, Sams RA.The objectives of this study were to determine the effect of phenylbutazone premedication on the pharmacokinetics and urinary excretion of frusemide in horses; and on frusemide-induced changes in urinary electrolyte excretion. Six Standardbred mares were used in a 3-way crossover design. The pharmacokinetics and renal effects of frusemide (1 mg/kg bwt i.v.) were studied with and without phenylbutazone premedication (8.8 mg/kg bwt per os 24 h before, followed by 4.4 mg/kg bwt i.v. 30 min before frusemide administration). A control (saline) treatment was also studied. Administration of frusemide...
Gastal EL, Gastal MO, Ginther OJ.A two-follicle model was used to study the nature of selection of the dominant follicle in mares by ablating neither or one of the two follicles on the day the larger follicle reached >/= 20 mm (Day 0). The larger follicle became the dominant follicle in all mares in which both follicles (n = 8) or only the larger follicle (n = 10) was retained. When only the smaller follicle (n = 9) was retained, it became dominant and ovulated in six mares and became atretic in three mares; the difference in diameter between the two follicles on Day 0 was less (p < 0.01) in mares in which the retained ...
Lentz LR, Valberg SJ, Balog EM, Mickelson JR, Gallant EM.To determine whether abnormal regulation of muscle contraction similar to that associated with malignant hyperthermia (MH) was evident in intact external intercostal muscle cells from Thoroughbreds with recurrent exertional rhabdomyolysis (RER). Methods: 5 adult Thoroughbred horses with RER and 7 clinically normal adult Thoroughbred or mixed-breed horses. Methods: Twitch time course variables and contracture responses to various concentrations of potassium, caffeine, and halothane were measured in small bundles of intact external intercostal muscle cells from clinically normal horses and horse...
Van Hoogmoed L, Rakestraw PC, Snyder JR, Harmon FA.To determine the in vitro effect of various prostaglandins (PG) and nonsteroidal anti-inflammatory drugs (NSAID) on contractile activity of the large-colon taenia of horses. Methods: 14 healthy horses. Methods: The taenia was collected from the ventral colon, cut into strips (2 X 10 mm), and mounted in a tissue bath system (20-ml capacity) that contained oxygenated Krebs buffer solution warmed to 37.5+/-0.5 C. After equilibration, incremental doses of PGE2, PGF2alpha, PGl2, flunixin meglumine, carprofen, ketoprofen, and phenylbutazone were added to the baths, and contractile activity was recor...
Bueno AC, Seahorn TL, Cornick-Seahorn J, Horohov DW, Moore RM.To quantify plasma and urine nitric oxide (NO) concentrations before and after low-dose endotoxin infusion in horses. Methods: 11 healthy adult female horses. Procedure-Eight horses were given endotoxin (35 ng/kg of body weight,i.v.) over 30 minutes. Three sentinel horses received an equivalent volume of saline (0.9% NaCl) solution over the same time. Clinical signs of disease and hemodynamic variables were recorded, and urine and plasma samples were obtained to measure NO concentrations prior to endotoxin infusion (t = 0) and every hour until postinfusion hour (PIH) 6, then every 2 hours unti...
Hoffman AM, Couetil LL, Miller CJ.To describe the spectrum of nonspecific airway reactivity in a group of clinically normal foals. Methods: 12 clinically normal mixed-breed foals, 48 to 92 days old, without history of clinical lung disease. Methods: Nonspecific airway reactivity was determined by measuring the extent of changes in dynamic compliance during nebulization of incrementally increasing concentrations of histamine aerosol. Degree of airway reactivity was expressed as the dose of histamine that evoked a decrease in dynamic compliance (Cdyn) to 65% of the after saline nebulization value (PC65Cdyn) or increase in pulmon...
Andrews FM, Doherty TJ, Blackford JT, Nadeau JA, Saxton AM.To determine the effects of orally administered omeprazole, as enteric-coated capsules, on baseline and stimulated gastric acid secretion in horses. Methods: 5 healthy 8-year-old mixed-breed horses fitted with gastric cannulas. Methods: Enteric-coated granules of omeprazole were mixed with corn syrup and administered orally once daily for 5 consecutive days. On days 1 and 5 beginning 5 hours after omeprazole administration, 4 gastric fluid samples were collected, each for 15 minutes, via the gastric cannula (baseline samples). Pentagastrin was administered IV as a constant infusion for the sub...
Watts EJ, Rose MT.Horses are more prone to complications in the wound healing process than other species, and problems such as chronic inflammation, delayed epithelialization, poor wound contraction, and exuberant granulation tissue are commonly seen, particularly in wounds on the distal limbs. In comparison, wounds of the oral mucosa heal rapidly in a scarless fashion with a high degree of wound contraction. The effect of platelet-derived growth factor BB (PDGF), insulin-like growth factor (IGF)-1, and transforming growth factor beta1 (TGFbeta1) on the contraction of a fibroblast-populated collagen matrix (FPC...
Kędzierski W, Kusy R, Kowalik S.The aim of this study was to evaluate the relationship between plasma leptin and lipid levels in breeding mares and their newborn foals. The study was conducted on 17 Polish cold-blood mares and their newborn foals. The mares were divided into two groups, according to the course of delivery. These groups were seven mares which had a normal delivery and 10 mares which had required veterinary intervention during their delivery. Blood samples were taken from the jugular vein of both the mares and their foals. The blood samples were taken within 30 min after delivery, as well as on four successive...
Suzuki Y.All types of the hemagglutinin(HA) of human, pig, horse and aq. bird influenza A viruses, recognize sialyl lacto-series type I and II sugar chains(Sialic acid(SA) alpha 2-3(6)Gal beta 1-3(4) GlcNAc beta 1-) in glycoproteins and glycolipids in the target cells as common receptor molecules. Avian and equine influenza viruses preferentially binds the terminal sialic acid alpha 2-3Gal(SA2-3Gal) linkage, while human influenza viruses preferentially bind the SA2-6Gal linkage. SA distribution in animal species influence influenza virus host range. Swine trachea has both receptors for avian influenza ...
Vervuert I, Coenen M, Zamhöfer J.This study was conducted to investigate the effects of draught load exercise on calcium (Ca) homeostasis in young horses. Five 2-year-old untrained Standardbred horses were studied in a 4-month training programme. All exercise workouts were performed on a treadmill at a 6% incline and with a constant draught load of 40 kg (0.44 kN). The training programme started with a standardized exercise test (SET 1; six incremental steps of 5 min duration each, first step 1.38 m/s, stepwise increase by 0.56 m/s). A training programme was then initiated which consisted of low-speed exercise sessions (LSE; ...
Kingston JK, Bayly WM, Sellon DC, Meyers KM, Wardrop KJ.To investigate the effects of formaldehyde fixation on equine platelets using flow cytometric methods to evaluate markers of platelet activation. Methods: Blood samples from 6 Thoroughbreds. Methods: The degree of fluorescence associated with binding of fluorescein isothiocyanate (FITC)-conjugated anti-human fibrinogen antibody and FITC-annexin V in unactivated and adenosine diphosphate (ADP)-, platelet activating factor (PAF)-, and A23187-activated platelet samples in unfixed and 0.5, 1.0, and 2.0% formaldehyde-fixed samples was assessed by use of flow cytometry. Results: In samples incubated...
Niedźwiedź A, Jaworski Z, Filipowski H, Zawadzki M, Wrzosek M, Służewska-Niedźwiedź M, Nicpoń J.Establishment of reference intervals (RI) for serum biochemical analytes is important for monitoring the health of different breeds of horses. Objective: The aim of this study was to measure and report RI for serum biochemical analytes of the Polish Konik horse. Methods: Blood samples were collected from 74 clinically healthy Polish Konik horses living under controlled natural conditions. These were adult primitive horses, aged 3-15 years, including 28 males (21 stallions, 7 geldings) and 46 mares. Serum analytes were measured and analyzed using a commercial automated analyzer. Results: The fo...
Magistrini M, Guitton E, Levern Y, Nicolle JC, Vidament M, Kerboeuf D, Palmer E.New staining methods and automated instruments are now available to evaluate the sperm cell in vitro. Individual compartments of the sperm cell, such as the nucleus and the plasma and acrosomal membranes, may be investigated, as well as the cell function as shown by mitochondria activity and capacitation. Various probes are used and they can be analyzed by direct light or fluorescent microscopy or by flow cytometry. The automated instruments allow objective and accurate analysis and quantification as well as the ability to evaluate large population of cells in a shorter time, thus providing ac...
Ferlazzo A, Medica P, Cravana C, Fazio E.Involvement of thyroid function on performance warrants further investigation as limited data exists on the effects of showjumping on the dynamics of total and free iodothyronines. Objective: To investigate the response of circulating total and free iodothyronines in horses to experimental showjumping sessions and compare with the effects normally induced by competition and determine if fence height has any effect. Methods: Using a randomised crossover study design 6 trained horses were studied during experimental showjumping sessions over 10 fences of different height: 1.00 m (Session 1), 1.1...
Brosnan RJ, Steffey EP, Escobar A, Palazoglu M, Fiehn O.To evaluate whether guaifenesin can prevent adverse anesthetic induction events caused by propofol and whether a guaifenesin-propofol induction combination has brief cardiovascular effects commensurate with rapid drug washout. Methods: 8 healthy adult horses. Methods: Guaifenesin was administered IV for 3 minutes followed by IV injection of a bolus of propofol (2 mg/kg). Additional propofol was administered if purposeful movement was detected. Anesthesia was maintained for 2 hours with isoflurane or sevoflurane at 1.2 times the minimum alveolar concentration with controlled normocapnic ventila...
Korosue K, Murase H, Sato F, Ishimaru M, Kotoyori Y, Tsujimura K, Nambo Y.To test the usefulness of measuring pH and refractometry index, compared with measuring calcium carbonate concentration, of preparturient mammary gland secretions for predicting parturition in mares. Methods: Evaluation study. Methods: 27 pregnant Thoroughbred mares. Methods: Preparturient mammary gland secretion samples were obtained once or twice daily 10 days prior to foaling until parturition. The samples were analyzed for calcium carbonate concentration with a water hardness kit (151 samples), pH with pH test paper (222 samples), and refractometry index with a Brix refractometer (214 samp...
Hubbell JA, Muir WW, Gaynor JS.Six horses scheduled for euthanasia were instrumented for the measurement of blood flow by thermodilution, pulmonary arterial, right atrial and arterial blood pressures and collection of arterial blood for pH and blood gas analysis. The horses were anaesthetised with intravenous (iv) thiamylal sodium (10 mg/kg) and placed in right lateral recumbency. After euthanasia with an overdose of pentobarbitone sodium (100 mg/kg, iv) and loss of the electrocardiogram and arterial pulse pressure, thoracic compression at rates of 40, 60 and 80 compressions/min was instituted. Thoracic compression was acco...
Guillaume D, Chavatte-Palmer P, Combarnous Y, Duchamp G, Martinat N, Nagy P, Daels PF.The aim of this study was to compare the effects of treatment with repeated injections of sulpiride (a dopamine D2 antagonist) on prolactin secretion and induced lactation in ovariectomized and intact adult mares and to verify if this induction was possible at the beginning and at the end of the birth season. Two experiments were carried out in September [experiment (expt) 1], and in March (expt 2), in France (48 degrees N). In expt 1, three groups of five mares were tested: intact-control, intact-treated and ovariectomized-treated mares. In expt 2, mares previously subjected to artificial pho...
Baker SJ, Gerring EL.Water, saline and a saline/Intralipid mixture (lipid concentration 1.25 per cent) emptied very rapidly from the stomach in neonatal pony foals, and obeyed an apparently exponential pattern. Cisapride did not significantly modify the emptying of the saline/Intralipid mixture. Equine milk emptied more slowly. The data indicated that the lipid component of milk was not an important factor. Milk caused deviation from an exponential pattern in two of four foals: an initial lag phase appeared, which could represent a phase of intragastric processing. However, the rate was still rapid compared with r...
Waller A, Lindinger MI.Sodium acetate (NaAcetate) has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA) administration in horses. Methods: Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of 3-da...
Burns TA, Westerman T, Nuovo GJ, Watts MR, Pettigrew A, Yin C, Belknap JK.Oxidative stress reportedly plays a role in sepsis-induced organ dysfunction and failure in many species. In septic horses, laminae are targeted; evidence of laminar oxidative stress has been reported experimentally in the black walnut extract (BWE) model. Carbohydrate (CHO)-induced laminitis may be more similar to clinical sepsis-related laminitis than the BWE model in that animals with CHO-induced disease commonly develop laminar failure. The role of oxidative stress in the CHO model remains unknown. Objective: Markers of oxidative stress will be increased in laminae from horses with BWE- an...
Takahashi T, Kai M, Hada T, Eto D, Muka K, Ishida N.It has been reported that a small decrease in the strain in the superficial digital flexor tendon (SDFT) occurs if the toe is raised during walking. Although walking on a slope appears similar to raising the toe, it is unclear whether uphill exercise decreases the strain in the SDFT. Because the force or strain on tendons is one of the important factors leading to tendon stress injury, we hypothesised that reducing the force in the SDFT during exercise may prevent tendinitis. The purpose of this study was to determine the effects of treadmill inclination on the force in the SDFT in the walking...
Den Hartog SM, Back W, Brommer H, van Weeren PR.Insight into the loading pattern of the articular cartilage surface during the complete stride is important as biomechanical factors play a pivotal role in the pathogenesis of joint trauma and osteoarthritis (OA). Objective: To determine the loading pattern in the equine MCP articulation in vitro during simulated walk. Methods: Eight cadaveric limbs from mature Dutch Warmblood horses were loaded in a pneumatic loading device in 6 different positions (A1-A6). The pressure distribution on the articular surface of the proximal phalanx (P1) was measured at 7 sites (S1-7) using intra-articularly pl...
Blissitt KJ, Bonagura JD.Colour flow Doppler echocardiography is a technique that is used with two-dimensional (2-D) echocardiography to study blood flow patterns in the heart and blood vessels. This method was used to define normal flow patterns and to evaluate valvular function in 40 clinically normal Thoroughbred and Thoroughbred cross horses. Flow patterns from 10 standardised echocardiographic images were described in relation to anatomic landmarks and timing during the cardiac cycle. Consistent intracardiac flow patterns were identified in the normal horses. High velocity flow signals or regurgitant jets were re...
Hemberg E, Niazi A, Guo Y, Debnár VJ, Vincze B, Morrell JM, Kútvölgyi G.The presence of a microbiome/microbiota in the placenta is hotly debated. In previous studies, the presence of bacteria in equine amniotic fluid and umbilical blood was independent of foal health. The objective of the present study was to determine if the same bacteria are present in the equine placenta as in amniotic fluid and umbilical blood. Samples were obtained from 24 parturient mares and foals. Placental bacterial DNA was extracted, and the microbiome was identified using 16S rRNA sequencing. All amniotic fluid samples contained some polymorphonucleocytes; bacteria were isolated from fo...
Bayly WM, Redman MJ, Sides RH.It has been postulated that the hypoxaemia and hypercapnoea that characterize strenuous equine exercise are partly due to flow limitations imposed by high breathing frequencies (fb), and that gas exchange would be improved if fb could be lowered. To evaluate this possibility, 6 Thoroughbred horses underwent 4 incremental treadmill exercise tests at inclines of 0, 5, 10 and 25%, respectively. In the test, horses were given a warm-up for 2 min, then ran sequentially for 1 min each at 60, 100 and 115% VO2max. Oxygen consumption (VO2), blood gas tensions (PaO2, PaCO2), fb, tidal volume (VT), minut...
Desantis S, Acone F, Corriero A, Deflorio M, Zubani D, Ventriglia G, Palmieri G, De Metrio G.The distribution of sialic acid residues as well as other glycosidic sugars has been investigated in the horse oviductal isthmus during anoestrus, oestrus and pregnancy by means of lectin and pre-lectin methods. Ciliated cells and non-ciliated (secretory) cells exhibited different lectin binding profiles that were found to change during the investigated stages. Ciliated cells did not show any reactivity in the basal cytoplasm, while the supra-nuclear cytoplasm displayed a few of oligosaccharides with terminal and internal alphamannose (Man) and/or alphaglucose (Glc) during oestrus and pregnanc...
Wooldridge AA, Eades SC, Hosgood GL, Moore RM.To compare effects of oxytocin, acepromazine maleate, xylazine hydrochloride-butorphanol tartrate, guaifenesin, and detomidine hydrochloride on esophageal manometric pressure in horses. Methods: 8 healthy adult horses. Methods: A nasogastric tube, modified with 3 polyethylene tubes that exited at the postpharyngeal area, thoracic inlet, and distal portion of the esophagus, was fitted for each horse. Amplitude, duration, and rate of propagation of pressure waveforms induced by swallows were measured at 5, 10, 20, 30, and 40 minutes after administration of oxytocin, detomidine, acepromazine, xyl...
Auer DE, Ng JC, Seawright AA.Topically applied copper phenylbutazone, phenylbutazone, copper salicylate, salicylate and dimethylsulfoxide glycerol (80:20) were investigated as anti-inflammatory agents in rats and horses. Dimethylsulfoxide and glycerol (80:20) or dimethylsulfoxide, ethanol and glycerol (60:20:20) were used as the drug solvents. Subcutaneously administered carrageenin was used to induce inflammatory oedema, either in the paws of rats or the alar fold of the horse. The severity of the oedema and the anti-inflammatory effect of the drugs were assessed by measuring changes in the paw or alar-fold diameters. Co...
Wilsher S, Gower S, Allen WR.Previous reports documenting progesterone receptors (PR) and oestrogen receptors (ER) in the endometrium of early pregnant mares included specimens only up to Day 20 post ovulation. This study aimed to localise PR and ERα on equine feto-maternal tissues between Days 20 and 68 to encompass the period around fixation of the conceptus, development of the endometrial cups and attachment and initial interdigitation of the allantochorion. During early pregnancy mares had the same pattern of PR in the endometrium as that reported for other mammals; namely, a loss of PR from the endometrial epithelia...
Salciccia A, Gougnard A, Grulke S, de la Rebière de Pouyade G, Libertiaux V, Busoni V, Sandersen C, Serteyn D.The ultrasonographic images of the gastrointestinal tract in horses can be influenced by fasting and sedation but the proper effect of general anaesthesia (GA) on them has not been determined yet. This study aimed to evaluate the effects of GA on ultrasonographic images of the gastrointestinal tract in horses and to compare these effects with a clinical evaluation. Twenty horses undergoing non-abdominal surgeries were evaluated by ultrasonography before and 4 times within 24 h after GA. Each ultrasonographic exam focused on the stomach, the duodenum and on 5 locations on the jejunum. The fou...
Sneddon JC, van der Walt JG, Mitchell G.This study set out to investigate tolerance of the body water pool to short-term water deprivation in horses and, in particular, to assess whether feral horses from the Namib Desert showed tolerance to dehydration superior to Transvaal. Hydration status was compared in six feral horses from the Namib Desert and in six Boerperd farm horses under conditions of normal hydration and after 72 h of dehydration. Under normal hydration, the two groups did not differ significantly in water intake, plasma sodium and potassium concentrations, plasma osmolality, hematocrit, total plasma protein, body wate...
Hood DM, Grosenbaugh DA, Slater MR.Vascular perfusion casts were used to define and characterise the macroscopic perfusion defects present in the distal digit of 11 horses affected by chronic laminitis. Five clinically normal horses were used as controls. Based on clinical history and clinical status, horses with chronic laminitis were classified as being potentially treatable or clinically refractory. Eleven macroscopic vascular defects were noted in the casts from horses with laminitis. Four types of lesions were identified in the submural laminar circulation, 3 in the coronary bed and 4 were associated with the solar circula...
Elliott J, Brady FE.Isolated equine digital veins (EDVs) which had been denuded of their endothelium were used to study adenosine receptors causing vasodilation. When the blood vessel wall tension was raised with the thromboxanemimetic, U44069 (30 nM), the order of vasodilator potency of adenosine receptor agonists was: 5'-N-ethylcarboxamidoadenosine (NECA) > 2-p-(2-carboxyethyl)phenyl amino-5'-N-ethylcarboxamido-adenosine (CGS 21680) > 5'-N-methylcarboxamido-adenosine (MECA) > N6-cyclohexyladenosine (CHA) > N6-cyclopentyladenosine (CPA) > N6-2-(4-Aminophenyl)ethyladenosine (APNEA) > adenosine. ...
Bröjer JT, Nostell KE, Essén-Gustavsson B, Hedenström UO.To determine whether repeated oral administration of glucose and leucine during the period immediately after intense exercise would increase the release of insulin and thereby enhance glycogen synthesis in horses. Methods: 12 Standardbred horses. Methods: In a crossover study design, after glycogen-depleting exercise, horses received oral boluses of glucose (1 g/kg at 0, 2, and 4 hours) and leucine (0.1 g/kg at 0 and 4 hours) or boluses of water (10 mL/kg at 0, 2, and 4 hours; control treatment). Blood samples for determination of glucose, insulin, and leucine concentrations were collected pri...
BMC research notesApril 16, 2013
Volume 6 152 doi: 10.1186/1756-0500-6-152
Christensen MB, Sørensen JC, Jacobsen S, Kjelgaard-Hansen M.Serum amyloid A (SAA) is useful as a diagnostic marker of systemic inflammation in horses, but only heterologous assays based on non-equine calibration and standardization are available for measurements of equine SAA. More accurate measurements could be obtained using purified species-specific SAA in native conformation for assay calibration and standardization. Further knowledge about the biochemical properties of SAA would facilitate a future production of native species-specific calibration material Therefore, the aim of the study was an investigation of the solubility and potentials for pu...
