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.
HOLTON FA.In 1941, Keilin & Mann described an optical method of studying the penetration of erythrocytes by bicarbonate ions and the intracellular activity of carbonic anhydrase. This method consists of converting the haemoglobin inside the cell to methaemoglobin and observing the transformation of the methaemoglobin from the acid to the alkaline form by the entering bicarbonate ions. During this work they noticed that this transformation did not occur if the methaemoglobin cells had been washed in acid phosphate and interpreted this as an effect on the permeability of the cells. Similar observations by...
FEGLER G.1. Volume p.c. of r.b.c., hæmoglobin concentration, relative viscosity of the plasma and blood, and the sedimentation rate of the r.b.c. have been estimated on 7 healthy horses.
2. Increase in the volume p.c. of r.b.c. was found in the excited or working horse. The concentration of r.b.c. in blood from the jugular vein in horses at rest is rather low in comparison with other animals.
3. Increase in the Hb. g. p.c./r.b.c. V. p.c. ratio was found in cases with the higher volume p.c. of r.b.c. with a significant correlation coefficient.
4. Apparent relative viscosity of horse blood at h...
Abramson HA.1. The cataphoretic velocity of blood platelets (horse) in plasma has been found to be between 40 and 51 micro per sec. per volt per cm. The mean velocity obtained from five horses is . 45 micro per sec. per volt per cm. 2. The cataphoretic velocity of polymorphonuclear leucocytes in similar specimens is practically identical with that of the platelets. This is noteworthy because of the fact that lymphocytes and red cells have different speeds. 3. With spontaneous agglutination of platelets, white cells and red cells, there is no change in the cataphoretic velocity incidental to aggregation. 4...
Inaba M, Goto I, Sato K, Maede Y.This report describes a unique response of the anion transporter in equine erythrocytes to the fluorescent substrate N-(2-aminoethyl sulfonate)-7-nitrobenz-2-oxa-3-diazole (NBD-taurine). Equine erythrocytes showed fluxes of NBD-taurine both inward and outward at rates considerably slower than those in human cells. These fluxes were completely abolished by a typical anion transport inhibitor, 4,4'-diisothiocyanostilbene-2,2'-disulfonate. Furthermore, NBD-taurine competitively inhibited the uptake of phosphate in equine red cells with an inhibition constant of phosphate that was slightly higher ...
Böttiger LE.Erythrocyte sedimentation rate, total protein and fibrinogen, electrophoretic protein pattern, and total serum protein-bound carbohydrates have been determined in a number of domestic animals and compared to human values. The striking finding is that although the E.S.R. varies widely between various species, the fibrinogen content is of the same order of magnitude in all. The horse, which shows a very high E.S.R., has a well marked beta-globulin fraction as an outstanding feature, a finding that should be further studied. Blutsenkungsgeschwindigkeit, Gesamteiweiss und Fibrinogen, elektroforeti...
Sevcik C, D'Suze G, Salazar V, Díaz P, Vázquez H.We used high sensitivity and resolution fluorescence microscopy to study the interaction of ostrich IgY, horse F(ab')₂ and horse IgG with mice lymphocyte and erythrocyte plasma membrane. The immunoglobulins were labeled with fluorescein isotiocyanate (FITC). Our results show an interaction of IgY with lymphocyte plasma membrane which does not result in endocytosis of the labeled protein. Less IgG and its F(ab')₂ fraction bind to lymphocytes, and this binding seems to be followed by endocytosis producing a diffuse cytoplasmic fluorescence in most lymphocytes exposed to FITC-IgG or FITC-F(ab...
Valieva TA, Valiev AG, Kulakova SN, Levachev MM.During six weeks rats were given a ration containing, as the only source of fat, lipids of sublimated mare's milk that had been stored with or without antioxidants (quercitrol, bisalcophen) during 3 months. The influence of specific quality of the ration fat on lipids and fatty acid composition of lipids in blood plasma, erythrocytic stroma and liver tissue, as well as on lipid peroxidation in the tissues was studied in the test animals. No changes induced by the lipids from sublimated mare's milk were detected in the parameters studied.
Haque RU.A technique for identifying and characterizing staphylococcal hemolysins by first separating them electrophoretically in barbital-buffered agar gel (pH 8.4) at 5 ma/cm for 2 hr and then determining their hemolytic activities by exposing them to human, horse, rabbit, and sheep erythrocytes is described. The alpha-hemolysin produced by a White variant of the Wood 46 strain of Staphylococcus aureus migrated 18 mm towards the cathode, and it lysed horse, rabbit, and sheep erythrocytes, whereas a Clear variant of the Wood 46 strain of S. aureus produced a lysin which migrated similarly to the alpha...
Yamaguchi T, Hirakawa R, Ochiai H.Lipid compositions of mammalian erythrocyte membranes are different among species. Therefore, the information on hemolysis from mammalian erythrocytes is useful to understand membrane properties of human erythrocytes. In this work, pressure-induced hemolysis and hypotonic one were examined using erythrocytes of human, sheep, cow, cat, dog, pig, horse, rat, and mouse. Pressure-induced hemolysis was suppressed by membrane sphingomyelin, whereas hypotonic hemolysis decreased upon increment of cell diameter. Mass spectra of erythrocyte membrane lipids demonstrated that sphingomyelin with an acyl c...
Cocco R, Rizzo M, Carta C, Arfuso F, Piccione G, Luridiana S, Crovace A, Passino ES, Sechi S.Among infection diseases transmitted by arthropods, the equine vector-borne diseases transmitted by ticks represent an emerging problem worldwide due to their morbidity and mortality and, in some cases, to their zoonotic relevance. Understanding the host immune/inflammatory response to the pathogens is crucial to develop effective methods of diagnosis, control and treatment. This study aimed to evaluate red blood cells (RBC), hematocrit (Hct), hemoglobin concentration (Hb), mean cell volume (MCV), mean cell hemoglobin content (MCH), mean cell hemoglobin (MCHC), platelets (PLT), white blood cel...
Metenier L, Grosclaude J, Meriaux JC.The chief application of blood typing in domestic animals is in the verification of parentage. However, the acquisition of good standardized reagents in sufficient quantity remains an obstacle for the development of this work. The production of monoclonal antibodies directed against blood group determinants offers an attractive means of improving both the quality and quantity of serological reagents, and could facilitate the definition of new specificities. Fusions between a mouse myeloma line and splenocytes from mice immunized with horse red cells have resulted in four hybridomas producing a...
Franken P, Schotman JH.The activities and concentrations of a number of erythrocytic enzymes and intermediate products of erythrocyte metabolism were determined in twenty-one normal standard-bred horses which were studied clinically and biochemically. These studies showed that equine anaerobic glycolysis is characterized by a biochemical pattern similar to that observed in human PK deficiency. The greater sensitivity of equine haemoglobin to oxidants is attributable either to low stability of GSH, which may be due either to the low activity of GR or that of 6PGD as observed in the studies. In addition, the saturatio...
Bowling AT, Ewalt-Evans R.Family data are presented for a new allele (Aabdg) in the A system of horse erythrocyte alloantigens which includes factors Aa and Ab traditionally thought to be products of allelic genes. Evidence for incorrect assignment of the codominant factor Ae in the presence of Ab and Ac and the absence of Aa is discussed.
Saltiel A, Gutierrez A, de Buen-Llado N, Sosa C.After parturition, Thoroughbred mares were mated at the first post-partum oestrus (N = 24) or at a subsequent oestrus (N = 12). All mares were examined daily for: oestrous detection, palpation per rectum of the genital tract, vaginoscopic examination and cervico-endometrial cytology. Pregnancy diagnosis was carried out at Days 18, 35 and 45 after mating. An identical first service conception rate of 50% was found in both groups. The number of neutrophils followed a descending profile to only scattered cells at the first post-partum oestrus and in Group II mares remained at this very low level ...
Satué K, Fazio E, Gardón JC, Medica P.The interpretation of the blood count is essential to help the equine clinician in the diagnosis, prognosis, patient management, and control of equine diseases. Hematologic alterations often reflect the condition of the individual or an overall response to a pathological situation. A thorough clinical examination of the patient is essential to correctly interpret the hematological results. The most common abnormalities in the erythrogram are mainly anemia and polycythemia. The frequent causes of anemia in horses are acute and chronic blood loss, hemolytic anemia, and anemia caused by chronic d...
De Carli GA, Tasca T, Pires Borges F.The in vitro hemolytic activity of Tritrichomonas foetus was investigated. The parasite was tested against human erythrocytes of groups A, B, AB, and O, and against erythrocytes of nine adult animals of different species (the rabbit, rat, chicken, cat, dog, swine, horse, bovine, and sheep). The results showed that T. foetus strains (ATCC KV1, K, PAL, 5022, RJ, 90) did not present any hemolytic activity against any human erythrocyte group nor against rabbit, rat, chicken, cat, dog and swine erythrocytes. T. foetus strains, however, lysed horse, bovine, and sheep erythrocytes. No hemolysin relea...
Magnuson NS, Perryman LE.The effect of adenosine on the mitogenic response of peripheral blood lymphocytes (PBL) and on the nucleotide pools of erythrocytes from normal horses, horses heterozygous for the combined immunodeficiency (CID) trait (carriers), and foals with CID was studied. When PBL from normal, carrier, and CID horses were stimulated by phytohemagglutinin (PHA), concanavalin A, or pokeweed mitogen, [3H]thymidine uptake was inhibited by adenosine (0.1 microM) to 1.0 mM) in a dose-dependent manner. Adenosine (100 microM) mediated inhibition of [3H]thymidine uptake was prevented in both normal and carrier ho...
Hansen S, Otten ND, Nissen SD, Carstensen H, Hopster-Iversen C, Fjeldborg J, Staun SH, Fenner M, Hesselkilde EM, Buhl R.Atrial fibrillation (AF) has been proposed as a risk factor for exercise-induced pulmonary haemorrhage (EIPH) due to increased pressure in the left atrium. Objective: To evaluate if AF was associated with EIPH following a standardised exercise test (SET) to fatigue. Methods: Two-arm controlled experiment. Methods: Ten untrained Standardbred mares mean (standard deviation [SD]) age 6 (2) years performed a SET on the treadmill in sinus rhythm (SR) (SET1) and 25-44 days after induction of self-sustained AF (SET2). AF was induced by tachypacing using a pacing device. Endoscopy, including trachea...
Shevchenko AS, Konopleva IV, Tkachuk EKh.It was found that the total Ca content in erythrocytes from irradiated sheep and horses increased by 10-40% from 1st till 5th days after irradiation, the intracellular Mg content being unchanged. More than 2-fold increase in total Ca content in lymphocytes during first 15 days was revealed, while in platelets only a trend for a growth in acute period of radiation disease was detected. On the contrary, no reliable changes in total Ca content in plasma after irradiation were observed. This fact indicates that Ca accumulation in blood cells after whole-body irradiation is due to disturbance in in...
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...
Bujok J, Pavľak A, Walski T, Zigo F, Trochanowska-Pauk N, Bohara R, Miśta D.Combat training of police horses, involving physical activity in the presence of environmental stressors, poses a risk of oxidative stress. This study compared the oxidative imbalance after combat training in horses in the regular police service and in horses that had just been schooled. Blood collection was performed immediately after training and after 16 h rest. The activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and total antioxidant status (TAS) were determined as the markers of enzymatic antioxidant defence. At the same time, lipid peroxidation (TBAR...
Orzołek A, Rafalska KT, Domosławska-Wyderska A, Rafalska AM, Dziekońska A, Jastrzębska E, Dobbek D.The aim of the study was to assess the impact of solarium light therapy on selected biological and biochemical parameters of peripheral blood in recreational horses. The study involved 10 horses divided into two groups of young (aged 5 to 7 years) and old (aged 14 to 19 years) individuals. All animals participated in light therapy sessions every other day. Blood was sampled three times during the study: before the treatment, after five light sessions, and after ten light sessions. Morphological parameters, the activity of antioxidant enzymes, TAS values, and the levels of glutathione (GSH), vi...
Animal welfare has become an increasingly important concern regarding equids working as carriage animals. In the present study, the changes in the markers of stress and inflammatory responses as a result of the work performed by tourism carriage horses under real working conditions in Sicily (Italy) were investigated. Twenty-two Standardbreds performed a normal working day in the carriage tourism business during the months of May, June and July 2022, consisting of one day of work for each month. Blood samples were collected in the stables at rest before the tour route (Pre; 07.00 AM) and withi...
Cheung HW, Wong KS, Tam JCL, Farrington AF, Bond AJ, Wan TSM, Ho ENM.Erythropoiesis-stimulating agents (ESAs) continue to be a significant threat to the integrity of human and equine sports. Besides conventional direct testing, monitoring the biomarkers associated with the effects of ESAs may provide a complementary approach via indirect detection to enhance doping control. In this study, we applied label-free proteomics to discover plasma protein biomarkers in Thoroughbred geldings after administration with a long-acting form of recombinant human erythropoietin (rhEPO), methoxy polyethylene glycol epoetin beta, Mircera. Increased haematocrit, haemoglobin and r...
Cheung HW, Wong KS, Cheng PCF, Tsang CYN, Farrington AF, Wan TSM, Ho ENM.Erythropoiesis-stimulating agents (ESAs) continue to be a significant threat to the integrity of human and equine sports. Besides conventional direct testing, monitoring the biomarkers associated with the effects of ESAs may provide a complementary approach via indirect detection to enhance doping control. In this study, we applied RNA-sequencing (RNA-seq) to discover blood RNA biomarkers in Thoroughbred horses after administration with a long-acting form of recombinant human erythropoietin (rhEPO), methoxy polyethylene glycol epoetin beta, Mircera®. A single subcutaneous administration of Mi...
In the present study, the changes in the markers of stress and inflammatory responses of 12 Standardbred horses were investigated before and after exercise during late spring and summer. The environmental temperature, relative humidity, and temperature-humidity index (THI) were assessed during this study. From horses, blood sampling, measurement of heart and respiratory rate (HR and RR), and measurement of rectal temperature (RT) were performed before exercise (Pre) and within 5 min following the end of the exercise (Post). THI values showed mild stress in June and high stress in July. Direct ...
Friend MM, McGaffigan EM, Hall SM, Staniar WB, Smarsh DN.Equine blood samples are often collected in uncontrolled, distant environments and stored for later analysis. Objective: This study aimed to determine how sample storage methods influence complete blood count (CBC) parameters, hypothesizing that temperature and time elapsed from collection to analysis would affect CBC parameters. Methods: Blood samples were collected from 10 healthy Quarter Horse mares (age: 13 ± 4.5 years old) and stored in EDTA tubes at room temperature (22°C), above ice (8°C), refrigerated (4°C), or in contact with ice (2°C). The IDEXX ProcyteDx was used to obtain CBCs...
