Erythrocytes, or red blood cells, are the most abundant cell type in the equine circulatory system and are responsible for transporting oxygen from the lungs to tissues throughout the body. They also facilitate the return of carbon dioxide from tissues to the lungs for exhalation. Equine erythrocytes are characterized by their biconcave disc shape, which enhances their flexibility and surface area for gas exchange. The lifespan of erythrocytes in horses is approximately 140-150 days, after which they are removed from circulation and broken down, primarily in the spleen. Variations in erythrocyte count, size, and morphology can indicate various health conditions, including anemia, dehydration, and certain metabolic disorders. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of erythrocytes in equine health.
Ochi S, Oda M, Nagahama M, Sakurai J.Clostridium perfringens alpha-toxin is able to lyse various erythrocytes. Exposure of horse erythrocytes to alpha-toxin simultaneously induced hot-cold hemolysis and stimulated production of diacylglycerol and phosphorylcholine. When A23187-treated erythrocytes were treated with the toxin, these events were dependent on the concentration of extracellular Ca2+ . Incubation with the toxin of BAPTA-AM-treated horse erythrocytes caused no hemolysis or production of phosphorylcholine, but that of the BAPTA-treated erythrocytes did. When Quin 2-AM-treated erythrocytes were incubated with the toxin i...
Windberger U, Bartholovitsch A, Plasenzotti R, Korak KJ, Heinze G.In this study species-specific values for whole blood viscosity (WBV), plasma viscosity (PV) and erythrocyte aggregation (EA) were determined in a total of 360 animals. We used 40 individual adult animals of nine mammalian species: horse, pig, dog, cat, rat, cattle, sheep, rabbit and mouse. WBV measurements were carried out using a LS30 viscometer, PV was measured using OCR-D and EA was measured using a Myrenne aggregometer and the LS30 (aggregation index at low shear rate). At low shear rates (0.7 s(-1) and 2.4 s(-1)) haematocrit (Hct)-standardized (40 % Hct) samples showed a higher value of ...
Research in microbiologyFebruary 11, 2003
Volume 154, Issue 1 29-35 doi: 10.1016/s0923-2508(02)00003-7
Silva TA, Rodrigues PH, Ribeiro RN, Noronha FS, Farias Lde M, Carvalho MA.The influence of growth medium, hemin and menadione, blood source and atmosphere of incubation on the expression of hemolytic activity of 25 strains of Prevotella intermedia and Prevotella nigrescens was evaluated. The best hemolytic activity was observed for samples of both species growing in brain heart infusion agar and incubated in Brewer-like anaerobic jars for 48 h. Hemolysis was less intense and occurred later in the presence of hemin and menadione in solid media. beta-Hemolysis was detected for medium supplemented with horse or human blood and alpha-hemolysis was observed when sheep bl...
Hanzawa K, Lear TL, Piumi F, Bailey E.Consensus DNA sequences from human, mouse and/or rat were used to design oligonucleotide primers for equine homologues of exons 16, 17 and 20-23 of potassium chloride co-transporter (SLC12A4) and exons 10, 11 and 3, 4, respectively, for two amino acid transporters (SLC7A10 and SLC7A9). DNA sequences of the PCR products showed high sequence identity to these regions. Equine BAC clones were obtained for SLC12A4 and SLC7A10 and mapped to equine chromosomes ECA3p13 and ECA10p15, respectively, by fluorescence in situ hybridization (FISH). Several single nucleotide polymorphisms (SNP) were found. Su...
Karlström K, Essén-Gustavsson B.An assumed link between red cell hypervolaemia, an excessive amount of training and impaired performance of hypervolaemic horses has led to a theory that the muscle fibres could be affected. Myosin heavy chain (MHC)-based fibre type composition in gluteus medius muscle of red blood cell normo- (NV) and hypervolaemic (HV) Standardbred trotters was evaluated using immunohistochemistry. Muscle biopsies were obtained from 13 NV and 16 HV horses. Serial transverse sections were cut and reacted with antibodies against different isoforms of the myosin heavy chains MHCI, MHCIIA and MHCIIX. Sections we...
Koho NM, Väihkönen LK, Pösö AR.The lactate transport activity of red blood cells (RBC) varies widely among different species; in equine RBC, the activity of the main lactate carrier, H+-monocarboxylate co-transporter (MCT), is distributed bimodally. The influence of lactate transport activity is measurable in vivo; after maximal exercise, the RBC lactate concentration in horses with high (HT) lactate transport activity is higher than in those with low (LT) activity. To study the expression of MCT in HT and LT horses, blood samples were taken from 10 horses at rest and after submaximal exercise. Blood and plasma lactate conc...
Väihkönen LK, Ojala M, Pösö AR.In red blood cell membranes, the activity of the main lactate carrier, H+-monocarboxylate co-transporter (MCT), varies interindividually and its distribution is bimodal. To show the repeatability of MCT activity, 2 to 5 blood samples were taken, at an interval of approximately 1 year, from 51 Standardbred horses, age 2 weeks-8 years, for a total of 128 observations. The horses could be divided into low (LT) and high (HT) lactate transport activity groups. Age significantly affected (P<0.05) MCT activity such that activity was highest in foals, reached a nadir at 2-3 years, and tended to inc...
Hargreaves BJ, Kronfeld DS, Waldron JN, Lopes MA, Gay LS, Saker KE, Cooper WL, Sklan DJ, Harris PA.Antioxidant status of 35 endurance horses was studied during an 80 (OD80) or 160 km (OD160) race. Packed cell volume (PCV), total plasma protein (TPP), plasma ascorbic acid (VIT C), plasma alpha-tocopherol (VIT E) and erythrocyte glutathione (GSH) concentrations, erythrocyte glutathione peroxidase (GPX), plasma aspartate aminotransferase (AST) and plasma creatine kinase (CK) activities were measured at 0, 40, 80 km and 60 min of recovery (REC) at OD80, and 0, 64, 106, 142, 160 km and REC at OD160. In both races, no changes were found in plasma VIT E concentration, but VIT C and GSH concentrati...
Zizzadoro C, Belloli C, Badino P, Ormas P.A method for the separation of pure and viable lymphocytes and granulocytes from the same blood sample in horses was reported. By centrifuging equine heparinized blood at 100 xg for 10 min at room temperature (r.t.), the resulting supernatant plasma was an almost pure (97.71 +/- 0.30%; n = 15) suspension of highly viable (98.72 +/- 0.28%) lymphocytes. When sodium citrate was used as an anticoagulant, lymphocyte suspensions collected in the same manner showed lower purity (87.89 +/- 1.59%; n = 9) and higher yields (56.56 +/- 3.89%, n = 9 versus 36.11 +/- 2.23%, n = 15). Where needed, a further ...
Zintl A, Westbrook C, Mulcahy G, Skerrett HE, Gray JS.In order to explore the feasibility of producing a Babesia divergens live vaccine free of bovine material contaminants the parasite's ability to grow in human, sheep and horse erythrocytes and serum and serum-free medium was investigated. B. divergens was successfully maintained in bovine erythrocytes overlaid with serum-free HL-1 medium. Supplementation of the culture medium with bovine or sheep serum improved parasite growth (monitored by measuring parasitaemia and uptake of tritiated hypoxanthine) whereas horse and human sera reduced parasite growth. As assessed by Giemsa's stained and FITC...
O'Neill W, McKee S, Clarke AF.This study was undertaken to compile new data on the efficacy of Echinacea in stimulating the immune system of the horse. Use of Echinacea is becoming widespread in horses, despite an absence of controlled laboratory research into its effectiveness or safety. This paper documents results of a double-blind, placebo-controlled, cross-over trial investigating the effect of standardised Echinacea extract on 8 horses. Animals were supplemented with Echinacea or placebo for 42 days, and their response to supplements recorded. Treatment with Echinacea increased phagocytic ability of isolated neutroph...
Caillaud C, Connes P, Bouix D, Mercier J.Exercise-induced arterial hypoxemia (EIAH), i.e., a significant drop of O2 arterial partial pressure during sea level exercise, has been shown in both aerobically trained athletes and athletic animal species. The mechanisms potentially involved include ventilation/perfusion inequality and/or pulmonary diffusing capacity limitation. In thoroughbred horses, EIAH is going with pulmonary haemorrhage (EIPH). Stress failure of pulmonary capillaries leading to diffusion limitation has been proposed. Indeed, during intense exercise, the increased cardiac output and blood viscosity combine to rise capi...
Balogh N, Gaál T, Ribiczeyné PS, Petri A.Physical exercise in the horse induces a series of normal physiological and biochemical adaptations. Increasing metabolism and oxygen uptake may induce oxidative stress in various organs. The aim of this study was to examine exercise-induced changes in some plasma and RBC biochemical and antioxidant variables in pentathlon horses. Blood samples were taken from 14 horses before, immediately after, and 24 hours after competing in two 1-minute runs of intense exercise over jumps. The peak intensity periods were preceded by a 20-minute warm-up and separated by a 20-minute break. The following plas...
Boyer JD, Breeden DC, Brown DL.To identify compounds in Acer rubrum that cause hemolysis or oxidation of equine erythrocytes and determine whether these toxins are found in other Acer spp. Methods: Equine erythrocytes. Methods: Washed erythrocytes were incubated with extracts and fractions of Acer spp that were separated by thin layer chromatography. Methemoglobin and hemolysis were measured spectrophotometrically. Compounds within Acer spp fractions associated with cell oxidation or hemolysis were identified by gas chromatography-mass spectrometry. Results: Erythrocytes incubated separately with either A. rubrum, A. saccha...
Dart A, Perkins N, Dowling , Batterham T, Livingston C, Hodgson D.To evaluate the effects of three different doses of sodium pentosan polysulphate (PPS) on haematological and haemostatic variables in adult horses. Methods: Eight adult standardbred horses were used. All horses received a single injection of 0, 3, 6, and 10 mg/kg of PPS at the beginning of each treatment week for 4 weeks so that by the end of the study all horses had received all four doses of PPS. Blood samples were collected at 0, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 168 h after each weekly injection of PPS. Variables measured were packed cell volume, haemoglobin, red blood cell count, mean cor...
Schara M, Nemec M, Falnoga I, Kobal AB, Kveder M, Svetek J.The action of mercuric chloride and methyl mercuric chloride on the membrane lateral domain organization of bovine, equine, and canine erythrocytes was studied. Electron paramagnetic resonance (EPR) spectra of spin-labeled erythrocytes were analyzed with respect to their lateral domain structure. Continuous alteration of the membrane domain populations revealed that mercuric compounds affect the membrane via the evolution of toxic events in the cells.
Nicolaiewsky TB, Richter MF, Lunge VR, Cunha CW, Delagostin O, Ikuta N, Fonseca AS, da Silva SS, Ozaki LS.We describe a nested polymerase chain reaction (PCR) for the detection of Babesia equi in equine infected erythrocytes using oligonucleotides designed on the published sequence of a B. equi merozoite antigen gene (ema-1). A 102bp DNA fragment is specifically amplified from B. equi but not from Babesia caballi, Babesia bovis or Babesia bigemina DNA. In a mock infection we were able to detect down to six infected cells in 10(8) equine erythrocytes or to detect the parasite in blood with an equivalent parasitemia of 0.000006%. Furthermore, gene polymorphism was found by performing a PCR-RFLP (PCR...
Spengler MI, Rasia M.The aggregation capacity of human erythrocytes lies between that of the non-aggregating bovine erythrocytes and the remarkably aggregating equine ones. As the ability to aggregate is attributed to cell factors and the composition of the plasma proteins, the role that plasma proteins play in the aggregation process in these three species was studied. Washed erythrocytes were suspended in phosphate-buffered saline (PBS; pH 7.4, 300 mOsm/L) plus polyvinylpyrrolidone (PVP) in a suitable concentration to obtain an average intensity of aggregation (control media). The superimposed effect of replacin...
Funkquist P, Sandhagen B, Persson SG, Hedenstierna G, Essén-Gustavsson B, Nyman G.Five Standardbred trotters with red cell hypervolaemia (RCHV) were compared before and after removal of approximately 22% (36 ml/kg bwt) of the total blood volume in order to evaluate the haemodynamic responses, haemorheological alterations and oxygen transport during exercise to fatigue. Data were recorded during submaximal exercise at 4 different speeds on a treadmill and then during continued running at the highest speed step until fatigue. Oxygen uptake (VO2), pulmonary artery pressure (PAP), systemic artery pressure (SAP), heart rate (HR), haematocrit and haemoglobin concentrations (Hb) w...
Väihkönen LK, Heinonen OJ, Hyyppä S, Nieminen M, Pösö AR.In red blood cells (RBC) of horses, both lactate-transport activity and lactate accumulation during races vary interindividually. To study whether similar variation in lactate transport is apparent also in RBCs of other racing species, blood samples were collected from 21 reindeer, 40 horses, 31 humans, and 38 dogs. Total lactate-transport activity was measured at 10 and 30 mM concentrations, and the roles of the monocarboxylate-transporter (MCT) and the inorganic anion-exchange transporter (band-3 protein) were studied with inhibitors. In the reindeer and in one-third of the horses, lactate t...
Baskurt OK, Bor-Kucukatay M, Yalcin O, Meiselman HJ.Differences of red blood cell (RBC) aggregation among various mammalian species has been previously reported for whole blood, for RBC in autologous plasma, and for washed RBC re-suspended in polymer solutions. The latter observation implies the role of cellular factors, yet comparative studies of such factors are relatively limited. The present study thus investigated RBC aggregation and RBC electrophoretic mobility (EPM) for guinea pigs, rabbits, rats, humans and horses; RBC were re-suspended in isotonic 500 kDa dextran solutions for the EPM and aggregation measurements, with aggregation stud...
Funkquist P, Nyman G, Persson SG.In order to evaluate the haemodynamic response to exercise in Standardbred trotters with red cell hypervolaemia (RCHV), 12 trotters with RCHV were compared with 9 normovolaemic (NV) trotters. Haemodynamic data were recorded during exercise at 4 different speeds on a treadmill. Oxygen uptake was determined with an open bias flow system. Pulmonary artery pressure (PAP), systemic artery pressure (SAP), heart rate, packed cell volume (PCV) and plasma lactate and haemoglobin ([Hb]) concentrations were measured. Arteriovenous O2 content difference, cardiac output, stroke volume, pulmonary vascular r...
Cacciò S, Cammà C, Onuma M, Severini C.A fragment of the beta-tubulin gene was polymerase chain reaction (PCR) amplified from genomic DNAs of Babesia bovis, Babesia bigemina, Babesia divergens, Babesia major, Babesia caballi, Babesia equi, Babesia microti, Theileria annulata and Theileria sergenti. Single amplification products were obtained for each of these species, but the size of the amplicons varied from 310 to 460 bp. Sequence analysis revealed that this variation is due to the presence of a single intron, which ranged from 20 to 170 bp. The extensive genetic variability at the beta-tubulin locus has been exploited to develop...
Wickler SJ, Anderson TP.This study had two goals: 1) measure hematologic changes with high-altitude acclimatization in horses; and 2) assess the effect of 9 days at high altitude on subsequent athletic performance at low altitude. Six horses performed standardized exercise tests on a dirt track (before and during time at altitude) and treadmill (pre- and postaltitude exposure). Resting and immediate postexercise blood samples were measured for blood volume, lactate, red cell number, packed cell volume, and 2,3-diphosphoglycerate (DPG) concentrations at 225 m, over a 9-day period at 3,800 m, and shortly after returnin...
Champion ZJ, James EA, Vickers MH, Breier BH, Casey PJ.The effect of intramuscularly administered recombinant bovine growth hormone (rbGH) on insulin-like growth factor-I (IGF-I) and white and red blood cell indices was studied in Thoroughbred geldings. An insulin-like growth factor binding protein (IGFBP)-blocked radioimmunoassay was modified and validated for the measurement of IGF-I in equine blood plasma. Baseline values of IGF-I and blood indices were determined over a 48 h period and then a single dose of 5 microg/kg, 10 microg/kg or 50 microg/kg of rbGH was administered. Insulin-like growth factor-I levels increased in a dose-dependent mann...
Lakritz J, Wilson WD, Marsh AE, Mihalyi JE.To determine effects of prior feeding on pharmacokinetics and estimated bioavailability of orally administered microencapsulated erythromycin base (MEB) in healthy foals. Methods: 6 healthy foals, 3 to 5 months old. Methods: Foals were given 2 doses of MEB (25 mg/kg of body weight, PO). One dose was administered after food was withheld overnight, and the other was administered after foals had consumed hay. The study used a crossover design with a 2-week period between doses. Blood was collected via a jugular vein prior to and at specific times after drug administration. Concentrations of eryth...
Malikides N, Mollison PJ, Reid SW, Murray M.The haematological response of regular, repeated blood harvesting was investigated in 40 Thoroughbred and non-Thoroughbred horses that donate 8 litres of blood every 3 weeks for the purposes of commercial blood production. When this volume of blood was removed on five occasions over 12 weeks, no adverse effect on packed cell volume (PCV), haemoglobin (HB), and red blood cell count (RCC) was observed. Although PCV, RCC and Hb values decreased during the first week after blood collection, followed by a gradual increase in values until the next harvest time, all values remained within published r...
Baskurt OK, Meiselman HJ.To evaluate the rheologic responses of equine versus human RBC to oxidant stress induced by superoxide anions. Methods: Equine blood samples were obtained from 8 healthy, 3- to 6-year-old various breed horses of either sex; human blood samples were obtained from 8 healthy adults. Methods: Washed RBC were exposed to superoxide anions generated by the xanthine oxidase (XO)-hypoxanthine system (XO activity of 0 to 0.1 U/ml). Deformability of RBC was assessed by ektacytometry, and RBC aggregation was measured in autologous plasma or 3% solution of dextran 70 via a defined-shear photometric techniq...
Wilkerson MJ, Davis E, Shuman W, Harkin K, Cox J, Rush B.Classes of antibody bound to erythrocytes were determined using direct immunofluorescence (DIF) flow cytometry in 3 horses and 12 dogs with immune-mediated hemolytic anemia (IMHA). Background levels of antibody binding were determined in samples from 12 horses and 12 dogs that were free of clinical disease. The range of nonspecific binding of a fluorescein isothiocyanate (FITC)-conjugated goat anti-equine immunoglobulin G (IgG) was 19.9-36.7%, but was eliminated by the use of the F(ab')2 fragment of FITC-conjugated goat anti-equine IgG. Background binding by other class-specific antibodies to ...
Kawai S, Igarashi I, Abgaandorjiin A, Ikadai H, Omata Y, Saito A, Nagasawa H, Toyoda Y, Suzuki N, Matsuda H.In-vitro-propagated Babesia caballi parasites were examined by scanning and transmission electron microscopy. Many small pores were observed over the entire surface of infected erythrocytes on scanning electron microscopy, and on transmission electron microscopy these small pores were found to be openings of tubular structures. By the examination of a number of infected cells the tubular structures were found to be connected with the parasite, and this observation might indicate that the tubular structures arose the edge of the parasite and terminated at an Invagination on the surface of the e...
Science (New York, N.Y.)March 3, 1972
Volume 175, Issue 4025 996-997 doi: 10.1126/science.175.4025.996
Gershon RK, Kondo K.Mice rendered tolerant to sheep red cells and then given normal thymocytes, made no antibody when immunized with these cells. When immunized with horse red blood cells, however, they made significant amounts of noncross-reacting antibody to sheep red blood cells. This suggests that antibody-making precursor cells (B cells) which are nontolerant but nonactivatable by specific antigen, may exist in tolerant hosts.
Becht JL, Semrad SD.Hematologic parameters change during the first 10 days of life. Erythrocytes increase in number but decrease in size and hemoglobin concentration. The PCV, hemoglobin, and platelet count also decrease. Total blood and plasma volume and, to lesser extent, erythrocyte volume decrease. Normal neonatal foals may have immature neutrophils (up to 5 per cent bands), and their early rapid rise in neutrophil numbers may be accompanied by a lymphopenia. Monocytes, eosinophils, and basophils are all absent or low initially. Infectious processes can cause rapid and variable changes in the leukogram. Howev...
Klimas NG, Caldwell KE, Whitney PL, Fletcher MA.Membrane glycoproteins from horse, sheep, goat and bovine erythrocytes were solubilized and purified. These glycoproteins could be placed in three groups based on their degrees of glycosylation: The major bovine erythrocyte glycoprotein (BGII) had 77% sugar, the minor bovine glycoprotein (BGI) had 27% sugar and the others had approximately 50% sugar. Four of the glycoproteins aggregated in a uniform way in aqueous solution--one, BGII, did not. Four had similar subunit sizes of 25-34,000 daltons, but BGII was larger--55,000 daltons. Receptor functions (for plant and invertebrate lectins, antibo...
Davitkov D, Davitkov D, Vucicevic M, Stanisic L, Radakovic M, Glavinic U, Stanimirovic Z.Equine piroplasmosis in donkeys has been recognised as a serious problem of major economic importance. The present molecular study is the first investigation of the presence of Theileria equi and Babesia caballi in Balkan donkeys and of the possible haematological alterations related to it. A total of 70 apparently healthy donkeys from Serbia were included in this study. The overall prevalence of T. equi infection in donkeys tested with multiplex PCR was 50%. There was no B. caballi-positive sample. Infections in donkeys included in this study seem to be associated with decreased red blood cel...
Koho NM, Hyyppä S, Pösö AR.Monocarboxylate transporters (MCT) facilitate the transport of lactate across membranes. In red blood cells (RBC) the transport activity varies interindividually due to differences in the amount of an ancillary protein CD147. Similar variations in muscles could have a great influence on lactate accumulation during exercise. Objective: To study the expression of MCT isoforms and CD147 in the middle gluteal muscle. Methods: Venous blood and muscle biopsy samples were taken from 14 Standardbred horses. Lactate transport activity in RBC and the amounts of MCT1, 2, 4 and CD147 were measured. Result...
Wood SC, Fedde MR.Splenic contraction in racing horses increases the hematocrit (hct), thereby increasing blood viscosity. We tested as to whether racing also affects the elastic properties of blood. Mares and geldings were studied for thus purpose. After racing, there was: (i) an increased erythrocyte count independent of gender and race distance (0.32 to 1.7 km): (ii) an increased mean erythrocyte volume in both sexes; (iii) an increased heterogeneity of RBC size in both sexes; (iv) an increased plasma fibrinogen concentration and erythrocyte sedimentation rate in both sexes; and (v) an increased elastic yiel...
Pakula PD, Halama A, Al-Dous EK, Johnson SJ, Filho SA, Suhre K, Vinardell T.Exercise-induced hemolysis occurs as the result of intense physical exercise and is caused by metabolic and mechanical factors including repeated muscle contractions leading to capillary vessels compression, vasoconstriction of internal organs and foot strike among others. We hypothesized that exercise-induced hemolysis occurred in endurance racehorses and its severity was associated with the intensity of exercise. To provide further insight into the hemolysis of endurance horses, the aim of the study was to deployed a strategy for small molecules (metabolites) profiling, beyond standard molec...
Cooper C, Sears W, Bienzle D.Availability of recombinant human erythropoietin (EPO) has facilitated use to enhance red blood cell production, and therefore aerobic performance, in human and equine athletes. Recombinant human EPO promotes growth and differentiation of equine erythroid precursor cells, but in some horses repeat administration induces immune interference with endogenous EPO resulting in fatal anemia. Although blood reticulocyte parameters acquire unique changes in humans treated with EPO, with manual enumeration methods, horses were not considered to release reticulocytes from the bone marrow into circulatio...
Böse R, Peymann B.From Babesia caballi in vitro cultures a preparation of 100% infected erythrocytes was obtained. From this, B. caballi antigens were extracted with the detergent 3-[(3-Cholamidopropyl)-dimethylammonio]-1-propane-sulfonate (CHAPS) and used as ELISA antigens. A control antigen of normal erythrocytes from the same donor horse was prepared in an identical manner. The ELISA and Western blot were validated by testing of sera from horses experimentally infected with B. caballi or B. equi or not infected with Babesia spp. ELISA and Western blot results were compared with those obtained by the immunofl...
Feige K, Ehrat FB, Kästner SB, Wampfler B.The goal of this study was to determine the effects of plasmapheresis on the behaviour, general condition, haematological, biochemical and coagulation variables of donor horses for 32 days following the procedure. Twenty millilitres of plasma/kg body weight were collected via plasmapheresis in six clinically healthy horses. The general behaviour and condition of the horses was not affected by the procedure. During plasmapheresis, there was a mild increase in the haematocrit, haemoglobin concentration and total erythrocyte and leucocyte counts (P < 0.01). The mean concentrations of total pro...
Ebrahimi M, Adinehbeigi K, Hamidinejat H, Tabandeh MR.The major agent of equine piroplasmosis (EP), Theileria equi, contributes to significant losses in the equine industry. This study was designed to evaluate T. equi infection among horses from West Azerbaijan by microscopy and molecular approaches. One hundred and twenty six blood samples were collected from the jugular vein and placed in sterile tubes containing EDTA; these tubes were either used immediately for blood smears or stored at –20°C for later examination by PCR. T. equi was detected in 3.2% and 27.7% of the animals examined using light microscopy and PCR methods, respectively. Th...
Janiak M, Suska M, Dudzińska W, Skotnicka E.The aim of this study was to evaluate response of blood glutathione status and activity of glutathione-metabolizing antioxidant enzymes in erythrocytes of young trotters in basic training. Nine untrained trotters (aged 16-20 months) were exposed to a 4-month training program based on exercises at low-to-moderate intensity. The conditioning consisted of breaking the horses and running them on distances varying from 4 to 40 km a week. The workloads were increased on a 3-week basis. Exercise intensity was monitored by measuring heart rate and blood lactate. Blood samples were collected at rest, b...
Malikides N, Mollison PJ, Reid SW, Murray M.The haematological response of regular, repeated blood harvesting was investigated in 40 Thoroughbred and non-Thoroughbred horses that donate 8 litres of blood every 3 weeks for the purposes of commercial blood production. When this volume of blood was removed on five occasions over 12 weeks, no adverse effect on packed cell volume (PCV), haemoglobin (HB), and red blood cell count (RCC) was observed. Although PCV, RCC and Hb values decreased during the first week after blood collection, followed by a gradual increase in values until the next harvest time, all values remained within published r...
McKeever KH, McNally BA, Hinchcliff KW, Lehnhard RA, Poole DC.To test the hypotheses that erythropoietin (rhuEPO) treatment increases systemic hematocrit, maximal O2 uptake (VO2max, by elevated perfusive and diffusive O2 conductances) and performance five female horses (4-13 years) received 15 IU/kg rhuEPO (erythropoietin) three times per week for three weeks. These horses had been splenectomized over 1 year previously to avoid confounding effects from the mobilization of splenic red blood cell reserves. Each horse performed three maximal exercise tests (one per month) on an inclined (4°) treadmill to the limit of tolerance; two control trials and one f...
Harvey JW, Asquith RL, Sussman WA, Kivipelto J.Twenty-one healthy Thoroughbred and Quarter Horse foals were studied from birth until 1 year of age. Foals had access to an iron-supplemented creep feed before weaning and were fed an iron-supplemented concentrate as part of their diet after weaning at 4 months of age. Initial blood samples were taken before foals were allowed to nurse. Serum iron concentration, total iron-binding capacity, and PCV decreased during the foal's first 24 hours of life. Serum iron concentration decreased rapidly from 446 +/- 16 micrograms/dl (mean +/- SE) at birth to 105 +/- 11 micrograms/dl at 3 days of age. Seru...
Buchholz BM, Murdock A, Bayly WM, Sides RH.The antifibrinolytic, 6-aminohexanoic acid, also named aminocaproic acid (ACA), has been used empirically as a treatment for exercise-induced pulmonary haemorrhage (EIPH) on the unsubstantiated basis that transient coagulation dysfunction may contribute to its development. Objective: To assess the effect of ACA on bronchoalveolar lavage fluid (BALF) erythrocyte counts in horses performing treadmill exercise at an intensity greater than that needed to reach maximal oxygen consumption. Methods: Eight Thoroughbreds were exercised to fatigue 3 times on a 10% inclined treadmill at a speed for which...
Duncan SG, Meyers KM, Reed SM.This study was designed to test the efficacy of heparin anticoagulant therapy in the horse and its effect on the formed elements of blood. Nine clinically normal, nontraumatized adult horses were subjected to 4 different heparin maintenance regimens (dosages of 320, 240, 160, and 40 U/kg of body weight). Porcine intestinal mucosa heparin (20,000 U/ml) was injected subcutaneously every 12 hours for 96 hours (total 9 times). A loading dose of one-third the maintenance dose was given IV just before the first heparin injection. Three control horses were given an equivalent volume of 0.9% saline so...
Hanzawa K, Kai M, Hiraga A, Watanabe S.We examined the relationship in horses between osmotic fragility of erythrocytes (OFE) measured as the red cell haemolysis rates (HLR) in 0.56% NaCl and certain physiological characters. Animals were exercised on a treadmill: warmed up at 30% VO2max for 5 min or at 105% VO2max for 1 min, given an exercise test at 80 or 105% VO2max until fatigued, and then cooled down. The pH and temperature of the blood had a significant correlation for the HLR: r = 0.93 and 0.92 (P < 0.01) on arterial and mixed venous blood, respectively. In multiple regression analysis, heart rate and packed cell volume s...
Beard LA, Pelzel AM, Rush BR, Wright AM, Galgut BI, Hennager SG, King AO, Traub-Dargatz JL.A 7-year-old Quarter Horse gelding used for unsanctioned racing was examined because of fever and anorexia. Results: Physical examination revealed fever, tachycardia, and tachypnea. Results of a CBC indicated anemia and mild thrombocytopenia. Results of microscopic examination of a blood smear indicated piroplasms in erythrocytes, consistent with Babesia spp. Regulatory authorities were contacted, and results of serologic testing at the National Veterinary Services Laboratories confirmed acute Babesia equi infection. Results: Equids on the home premises of the index horse were placed under qua...
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....
Gerhards H.Low dose calcium heparin was administered subcutaneously at 12 hourly intervals to six healthy horses at an initial dose of 150 iu of heparin/kg bodyweight (bwt) and at a maintenance dose of 120 iu/kg bwt. All injections were given at 0900 and 2100 h. Blood samples for monitoring plasma heparin concentrations were obtained prior to, at 2 hourly intervals for 84 h (treatment period), and at Hours 24, 32, 48 and 96 of the control period. Blood samples for monitoring red blood cell (RBC) mass, plasma antithrombin III activity (AT III), activated partial thromboplastin time (APTT), and thrombin ti...
McKane SA, Slocombe RF.Six horses, free of recent exercise-induced pulmonary haemorrhage (EIPH), each had 8 bronchial segments inoculated with 40 ml of autologous blood lavaged on Days 3, 5, 7, 10, 14 and 21 after inoculation. The bronchoalveolar lavage (BAL) fluid samples were analysed, and total leucocyte counts and differential cell percentages determined. Statistical analysis of the differences between the 8 post inoculation and 1 pre-inoculation (control) lavage sites demonstrated an early neutrophilic response, rising from < 5% of alveolar leucocytes to 10% by 24-48 h post inoculation. As this response wane...
Joré C, Loup B, Garcia P, Paris AC, Popot MA, Audran M, Bonnaire Y, Varlet-Marie E, Bailly-Chouriberry L.Erythropoiesis Stimulating Agents (ESAs) were developed for therapeutic purposes to stimulate red blood cell (RBC) production. Consequently, tissue oxygenation is enhanced as athlete's endurance and ESAs misuse now benefits doping. Our hypothesis is that most of ESAs should have similar mechanisms and thus have the same effects on metabolism. Studying the metabolome variations could allow suspecting the use of any ESAs with a single method by targeting their effects. In this objective, a metabolomic study was carried out on 3 thoroughbred horses with a single administration of 4.2μg/kg of Mir...
Le Vine H, Cuatrecasas P.A cytosolic, macromolecular factor required for the cholera toxin-dependent activation of pigeon erythrocyte adenylate cyclase and cholera toxin-dependent ADP-ribosylation of a membrane-bound 43,000 dalton polypeptide has been purified 1100-fold from horse erythrocyte cytosol using organic solvent precipitation and heat treatment. This factor, 13,000 daltons, does not absorb to anionic or cationic exchange resins, is sensitive to trypsin or 10% trichloroacetic acid and is not extractable by diethyl ether. Activation of adenylate cyclase by cholera toxin requires the simultaneous presence of AT...
Viesselmann LC, Flatland B, Stokol T, Sisson S, Schaefer DMW.Accurate erythrocyte measurements with ADVIA hematology analyzers require isovolumetric cell sphering in one reaction and hemolysis in another. However, camelid erythrocytes are resistant to sphering and osmotic lysis, and no published evaluation of ADVIA methods for camelids exists. Objective: The objectives were to demonstrate whether camelid erythrocytes sphere in the ADVIA red blood cell/platelet (RBC/PLT) reagent and lyse in the ADVIA cyanide HGB reagent, and to determine optimal ADVIA settings for camelids. Methods: Camelid and canine blood were diluted to 1:625 in RBC/PLT reagent and ev...
Johnson PJ, Goetz TE, Foreman JH, Vogel RS, Hoffmann WE, Baker GJ.The effects of whole-body potassium depletion induced by food deprivation on plasma, erythrocyte, and middle gluteal muscle K concentrations was quantified in 16 healthy, adult horses before, during, and at the end of a 7-day period of food deprivation during which water and sodium chloride were available ad libitum. Potassium concentrations were determined by atomic absorption spectroscopy. Plasma K concentration remained constant (3.49 +/- 0.09 mM K/L of plasma; mean +/- SEM) throughout the study. Erythrocyte potassium concentration decreased from 93.10 +/- 1.94 mM K/L of erythrocytes on day...
Moore JN, Mahaffey EA, Zboran M.Heparin was administered subcutaneously 2 times a day for 4 days to 5 horses. An additional group of 5 horses was used as time-matched controls. Significant decreases in PCV, erythrocyte count, and hemoglobin concentration were observed during heparin therapy. The mean corpuscular volume (MCV) of the heparin-treated horses increased to a peak value of 66.1 fl on the last day of treatment. Erythrocyte creatine concentration and glucose 6-phosphate dehydrogenase activity increased moderately during the treatment. These data indicated that the rapid, profound increase in MCV during heparin therap...
Niedźwiedź A, Nicpoń J, Zawadzki M, Służewska-Niedźwiedź M, Januszewska L.Transport of horses may have significant impact on serum biochemical and hematologic analytes and resistance to infection. Objective: The aim of our study was to assess the influence of transport stress on selected enzymatic antioxidants in equine blood. Methods: The study was conducted on a group of 60 horses of different breeds and ranging in age from 4 to 10 years. Venous blood was collected immediately before loading horses onto trailers for 8 hours of transport (I), immediately after unloading them from the trailer (II), and after subsequent stall rest for 24 hours (III). Hemolysates of b...
