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Topic:Hematology
Hematology in horses involves the study of blood, its components, and related disorders in equine species. This field encompasses the analysis of red blood cells, white blood cells, platelets, hemoglobin, and hematocrit levels to assess the health status of horses. Hematological parameters are used to evaluate various physiological and pathological conditions, including anemia, infections, and immune-mediated diseases. Techniques such as complete blood counts (CBC) and blood smear evaluations are commonly employed to gather insights into the equine circulatory system. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and clinical implications of hematological assessments in equine medicine.
Results of intradermal tests in horses without atopy and horses with chronic obstructive pulmonary disease. To compare results of intradermal tests (IDT), conducted using environmental allergens, in horses without atopy and horses with chronic obstructive pulmonary disease (COPD). Methods: 38 horses (22 horses without atopy and 16 horses with COPD). Methods: All horses were examined (physical examination, hematologic examination, serum biochemical analyses, examination of bronchoalveolar lavage fluid). An IDT was conducted, using a full panel of 73 allergens consisting of grasses, weeds, trees, molds, and insects. Results of the IDT were evaluated 30 minutes and 4, 6, and 24 hours after injection of...
Effect of eltenac in horses with induced endotoxaemia. Ten horses were used in a crossover study to evaluate the effectiveness of eltenac against endotoxaemia. Eltenac (0.5 mg/kg bwt) or saline control was given i.v. then 15 min later, intravenous infusion of endotoxin was begun and continued for 120 min (total dose 100 ng/kg bwt). Horses were monitored for heart and respiratory rates, pulmonary and carotid arterial pressure and core body temperature. Blood was sampled at intervals for measurement of haematological variables and plasma concentrations of lactate, prostanoid metabolites, tumour necrosis factor (TNF) and stress hormones. In compariso...
Evaluation of an in-house centrifugal hematology analyzer for use in veterinary practice. To compare CBC results obtained by use of an in-house centrifugal analyzer with results of a reference method. Methods: Prospective study. Methods: Blood samples from 147 dogs, 42 cats, and 60 horses admitted to a veterinary teaching hospital and from 24 cows in a commercial dairy herd. Methods: Results obtained with the centrifugal analyzer were compared with results obtained with an electrical-impedance light-scatter hematology analyzer and manual differential cell counting (reference method). Results: The centrifugal analyzer yielded error messages for 50 of 273 (18%) samples. Error message...
Physical, hematological, and exercise response of collegiate female equestrian athletes. Physiological testing is extensively used to assess current physical status, target strength/deficiencies, and determine predisposition to injury in athletes. No studies exist regarding these issues on equestrian athletes. The purpose of this study was to quantify the physical, hematological, and exercise response of female equestrian athletes in order to provided greater insight into the health fitness of this unique competitor, and to compare results to other better studied sport athletes. Methods: Following written informed consent, physiological assessments were performed on 24 collegiate ...
Hematological changes and athletic performance in horses in response to high altitude (3,800 m). 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...
Oxidants and regulation of K(+)-Cl(-) cotransport in equine red blood cells. The effect of oxidants on K(+)-Cl(-) cotransport (KCC) was investigated in equine red blood cells. Carbon monoxide mimicked O(2). The substituted benzaldehyde, 12C79 (5 mM), markedly increased O(2) affinity. In N(2), however, O(2) saturation was low (<10%) but KCC remained active. Nitrite (NO(2)(-)) oxidized heme to methemoglobin (metHb). High concentrations of NO(2)(-) (1 and 5 mM vs. 0.5 mM) increased KCC activity above control levels; it became O(2) independent but remained sensitive to other stimuli. 1-Chloro-2, 4-dinitrobenzene (1-3 mM) depleted reduced glutathione (GSH). Prolonged exp...
Effect of the microclimate on horses during international air transportation in an enclosed container. To determine if the microclimate is detrimental to horses during international air transportation in an enclosed container. Methods: On each of two 12 h and two 24 h flights three horses were transported in an enclosed container designed to prevent exposure to insect vectors. Heart rates were monitored throughout and blood samples were collected periodically. Air in the container was sampled for bacteria and fungal spores and the temperature and relative humidity were recorded inside and outside the container periodically during the flight. On the two 12 h flights similar observations were mad...
Haematological responses of repeated large volume blood collection in the horse. 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...
Safety of omeprazole paste in foals and mature horses. Omeprazole has been shown to promote healing of spontaneously occurring gastric ulcers in horses when administered for 28 days at a dose of 4 mg/kg bwt/day and to prevent recurrence of ulcers in almost all horses when treatment is continued at a dose of at least 2 mg/kg bwt/day. The purpose of the 3 studies reported here was to 1) evaluate the evolution of potential effects of omeprazole paste (GastroGard), at a dose of 20 mg/kg bwt/day (5x the recommended dose) for 91 days in mature Thoroughbred horses; 2) evaluate the safety in young horses of omeprazole paste when dosed at 4 mg/kg bwt/day (...
The effect of supramaximal exercise on equine platelet function. When blood is collected into sodium citrate in the proportion of 9 parts blood:1 part sodium citrate, the concentration of plasma sodium citrate in the sample will depend on the packed cell volume (PCV) of the blood sample. This difference in plasma sodium citrate concentration secondary to alterations in PCV significantly affects human platelet aggregation responses. Since horses attain a high PCV in response to high-intensity exercise we investigated the effect of differences in sample plasma sodium citrate concentration on equine platelet aggregability. In addition, low molecular weight hep...
Effect of feeding thoroughbred horses a high unsaturated or saturated vegetable oil supplemented diet for 6 months following a 10 month fat acclimation. This study looked at the effect of feeding diets supplemented with either a predominantly saturated or unsaturated vegetable oil over a prolonged period to exercising horses. Eight Thoroughbred horses were assigned to 2 diet treatments and for 10 months were fed Timothy hay and oats, together with a fortified sweet feed supplemented with either a predominantly unsaturated (Un) or a saturated (S) vegetable oil so that approximately 19% DE (Digestible Energy) came from dietary fat and approximately 12% from either the Un or S source (AC). An increased amount of Un or S fortified sweet feed, repl...
Haematological and biochemical responses to training and overtraining. We sought a physiological marker of overtraining in horses, using commonly practised field and laboratory tests to allow early prediction and treatment of the syndrome. Thirteen Standardbred horses were trained as follows: phase 1 (endurance, 7 weeks), phase 2 (high intensity, 9 weeks) and phase 3 (overload, 18 weeks). In phase 3 the horses were divided into 2 groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies and durations than the C group. Overtraining occurred after 31 weeks and was defined as a significant decrease in treadmill run ...
Effects of low- and moderate-intensity training on metabolic responses to exercise in thoroughbreds. This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for e...
Fragility of red cells during exercise is affected by blood pH and temperature. 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...
The effects of timing and amount of forage and grain on exercise response in thoroughbred horses. There is considerable debate among horsemen about how to feed horses before exercise. Should horses be fed or fasted before work and when should hay be fed relative to grain and/or exercise? Three experiments were conducted to evaluate if feeding hay with and without grain affects glycaemic and haematological responses in Thoroughbred (TB) horses at rest and during a simulated competition exercise test (CET) on a high-speed treadmill. In Experiment 1, 6 TB horses were fed hay at 3 different times relative to a grain meal. Time of feeding hay affected glycaemic response, plasma protein and wate...
Gastrointestinal and endocrine function during ‘foal heat diarrhoea’ in healthy foals. Gastrointestinal function was assessed in normal foals before, during and after the onset of 'foal heat diarrhoea' by haematological, biochemical, microbiological and parasitological methods, and by a combined lactose tolerance-breath hydrogen excretion test. Warmblood mares (n=11) and their foals were used. The foals were assessed according to a standard protocol after birth and at regular intervals thereafter. All except one of the foals suffered from diarrhoea that started between day 8 and day 12 after birth, which lasted for 1-4 days. Rotavirus was detected in the faeces of five foals, bu...
Bone marrow response to large volume blood collection in the horse. Evaluation of erythropoietic regeneration in horses is difficult unless serial bone marrow aspirates are performed. To investigate the acute and chronic erythropoietic regenerative response of equine bone marrow following acute removal or loss of blood, sequential bone marrow aspirates over 4 weeks were taken from the sternum of five horses from which 20 ml kg(-1)of blood had been removed. We found that the total number of erythroid cells counted (expressed as a percentage of the total number of erythroid and myeloid cells counted) expanded initially by 13.7 per cent within 3 days after blood ...
Prevalence of gastric ulcers in show horses. To determine prevalence and risk factors for gastric ulcers in show horses. Methods: Field survey. Methods: 50 horses in active training that had been transported to at least 1 event in the 30 days prior to endoscopy. Methods: Interview of owner, physical examination, serum biochemical analysis, CBC, and gastric endoscopy were performed. Results: Gastric ulceration was detected in 58% of the horses. Horses with a nervous disposition were more likely to have ulceration than quiet or behaviorally normal horses. Horses with gastric ulceration had significantly lower RBC counts and hemoglobin conc...
Experimental cross-infections with Ehrlichia phagocytophila and human granulocytic ehrlichia-like agent in cows and horses. Four cows and four horses were infected experimentally with Ehrlichia phagocytophila, the cause of tickborne fever in ruminants, and with human granulocytic ehrlichia-like agent, a recently discovered species that infects people, horses and dogs in the USA and Europe. They were infected in either order, 30 days apart, to investigate serological cross-reactivity within the Ephagocytophila genogroup. The course of infection was assessed by routine clinical, haematological, serological and polymerase chain reaction (PCR) examinations. Two of the cows infected with Ephagocytophila and two of the h...
Clinical, haematological and biochemical findings in foals with neonatal Equine herpesvirus-1 infection compared with septic and premature foals. A retrospective multicentre study comparing historical, clinical, haematological, acid-base and biochemical findings of foals with Equine herpesvirus-1 (EHV-1) infection, septicaemia or prematurity was performed to determine if early diagnosis of EHV-1 foals was possible. Fifty-three foals were studied and were assigned to one of 2 groups: herpes positive (n = 14) or herpes negative (n = 39). The latter group included 20 septic, 11 premature, and 8 premature and septic foals. The presence of herpes antigen was confirmed by immunoperoxidase histochemical staining of tissues from necropsied foal...
Ambient temperature and relative humidity influenced packed cell volume, total plasma protein and other variables in horses during an incremental submaximal field exercise test. 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...
Plasma and urine nitric oxide concentrations in horses given below a low dose of endotoxin. 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...
Hemothorax in 2 horses. This report documents the successful conservative medical management of hemothorax in 2 horses. Hemothorax occurred after a lung biopsy procedure (horse 1) and strenuous exercise on a treadmill (horse 2). The horses had tachypnea, tachycardia, nostril flaring, hemoptysis, and pawing. Hemothorax was suspected based upon absence of auscultable ventral lung sounds; development of cool extremities and pale, tacky mucous membranes; the ultrasonographic appearance of moderate to severe amounts of pleural fluid; and a concurrent decrease in hematocrit and total plasma protein. Both horses were treate...
Platelets from thrombocytopenic ponies acutely infected with equine infectious anemia virus are activated in vivo and hypofunctional. Thrombocytopenia is a consistent finding and one of the earliest hematological abnormalities in horses acutely infected with equine infectious anemia virus (EIAV), a lentivirus closely related to human immunodeficiency virus. Multifactorial mechanisms, including immune-mediated platelet destruction and impaired platelet production, are implicated in the pathogenesis of EIAV-associated thrombocytopenia. This study was undertaken to investigate whether regenerative thrombopoiesis and platelet destruction occurred in ponies acutely infected with EIAV. Circulating large, immature platelets were in...
Use of a temporary indwelling ureteral stent catheter in a mare with a traumatic ureteral tear. A 4-year-old primiparous Thoroughbred mare was referred for treatment of uroperitoneum subsequent to dystocia. Hematologic and serum biochemical analyses revealed values consistent with those reported for foals with uroperitoneum. Exploratory celiotomy revealed the source of the uroperitoneum to be a rent in the right ureter proximal to the trigone of the bladder. Substantial accumulation of urine in the tissues surrounding the ureter prevented accurate identification and repair of the defect, so a temporary indwelling ureteral stent catheter was inserted. Three weeks later, the stent catheter...
[A Shetland pony with a squamous cell carcinoma of the stomach]. A 12-year-old Shetland pony was referred because of weight loss over several months and symptoms of colic. On rectal examination, enlarged mesenteric lymph nodes and an abnormal mass in the left anterior abdominal cavity were palpated. Haematological evaluation revealed leucocytosis (13 G.l-1) and an abnormal electrophoretic pattern (31.8% albumin, 18.8% alpha-globulins, 29.0% beta-globulins, 20.4% gamma-globulins). Peritoneal fluid collected by abdominal paracentesis did not contain neoplastic cells. Gastroscopy was performed and a mass, with areas of ulceration and necrosis, was visualized w...
Investigations on the ability of clenbuterol hydrochloride to reduce clinical signs and inflammation associated with equine influenza A infection. Twenty-four Quarter Horse and Quarter Horse-cross yearlings were experimentally infected with influenza A virus (Influenza A/equine/Saskatoon/90 [H3N8]) by nebulisation. In a double blind controlled trial the horses were randomly assigned to 3 groups of 8 animals. Group 1 received a placebo, (carrier syrup), Group 2 the labelled dose and Group 3 twice the labelled dose of clenbuterol hydrochloride. All treatments were given per os b.i.d. for 10 days and started on the day of infection. The horses were monitored for clinical signs of influenza infection for 14 days. Bronchoalveolar lavages were...
Locomotor, cardiocirculatory and metabolic adaptations to training in Andalusian and Anglo-Arabian horses. The effects of two training programmes in 20 Andalusian and 12 Anglo-Arabian horses were evaluated by an increasing intensity work test at velocities of 4, 5, 6, 7 and 8 m sec(-1). Heart rate was monitored and blood samples were drawn at rest and after each velocity to analyse packed cell volume, haemoglobin concentration, plasma lactate and potassium levels. Furthermore, the programmes were video-taped and stride length, duration and frequency, stance (restraint and propulsion), swing phase durations and stride vertical component were measured. The training protocol of the Andalusian horses p...
