The study of blood in horses encompasses the examination of its components, functions, and its role in equine health and disease. Blood consists of various elements, including red blood cells, white blood cells, platelets, and plasma, each serving specific functions such as oxygen transport, immune response, clotting, and nutrient distribution. Analyzing blood parameters can provide insights into the physiological and pathological states of horses. Common blood tests in equine medicine assess parameters like hematocrit, hemoglobin concentration, and white cell counts to monitor health status, diagnose conditions, and guide treatment decisions. This page compiles peer-reviewed research studies and scholarly articles that explore the composition, function, and clinical applications of blood analysis in horses.
Lowry TF, Forster HV, Korducki MJ, Forster AL, Forster MA.To gain insight into central and peripheral contributions to changes in breathing during hypoxia, we compared effects on breathing of reducing inspired PO2 (hypoxic hypoxia) with reducing arterial O2 content (CaO2) through elevation of carboxy-hemoglobin (COHb) (CO hypoxia). Twelve awake ponies were studied during 1 h of breathing room air followed by 6 h when COHb was increased to 25% and CaO2 was decreased by 17%. When COHb was increased, arterial PCO2 (PaCO2) increased gradually to 1.3 Torr above (P < 0.05) control level between 30 and 45 min of CO exposure. Pulmonary ventilation (VE) de...
Silver M, Fowden AL, Taylor PM, Knox J, Hill CM.Blood amino acids were measured in twelve chronically catheterized mares and fetuses between 250 and 310 days gestation. The concentrations of the majority of individual amino acids were similar in maternal and fetal arterial blood and no gestational changes were detected. Only methionine, phosphoserine, 3-methyl-histidine and glutamine were consistently higher in the fetus than the mare, whilst certain other amino acids were higher in the maternal blood. Fasting the mares for 36 h led to significant falls in plasma glucose and rises in urea and maternal free fatty acids (FFA). Small but signi...
Redmond LM, Cross DL, Strickland JR, Kennedy SW.We evaluated the effectiveness of 2 dopamine antagonists as treatments for fescue toxicosis in horses. Sixteen gravid mares were assigned by breed and expected foaling date to 1 of 3 treatment groups: endophyte-infested control; 1.1 mg of domperidone/kg of body weight/d; and 3.3 mg of sulpiride/kg/d. Mares were pastured on endophyte-infected fescue and received 0.454 kg of a corn and dried molasses carrier containing the drug treatment. Treatment started 30 days prior to expected foaling date and continued until parturition. Blood samples were collected, and mammary gland scores were recorded ...
Steverink PJ, Salden HJ, Sturk A, Klein WR, van der Velden MA, Németh F.In this study the laboratory and clinical performance of a chromogenic endotoxin assay for equine plasma was evaluated. The assay was sensitive (detection limit 3 ng LPS/L plasma), reproducible (within and between-assay CV at 50 ng LPS/L E. coli O111:B4 LPS standard addition was 5% and 7.5%, respectively), and not substantially affected by enhancement or inhibition phenomena (recovery of an in vitro spike was 75-125% in 80% of the samples). LPS added to whole blood was rapidly inactivated upon incubation at 37 degrees C but not at 0 degrees C. A recently developed blood collection tube for LPS...
Hinchcliff KW, McKeever KH, Muir WW.The systemic haemodynamic and acid-base effects of the administration of phenylbutazone (4.4 mg kg-1 intravenously) to standing and running horses were investigated. Phenylbutazone, or a placebo, was administered to each of six mares either 15 minutes before, or after 30 minutes of a 60-minute submaximal exercise test which elicited heart rates approximately 55 per cent of maximal, and to the same horses at rest. The variables examined included the cardiac output, heart rate, systemic and pulmonary arterial pressures, right atrial and right ventricular pressures, and arterial and mixed venous ...
van Dijk P.The effects of total intravenous anaesthesia with an intravenous infusion of a combination of guaiphenesin, ketamine and detomidine were studied in 10 patients scheduled for elective surgery. Anaesthesia was maintained by the infusion of guaiphenesin (100 mg/ml), ketamine (2 mg/ml) and detomidine (0.02 mg/ml). The infusion rate was 1 ml/kg/hr. During anaesthesia, pulse rate and mean arterial blood pressure were continuously recorded. Arterial blood gases and pH were determined immediately after induction and at stated times during anaesthesia. Venous blood was sampled to determine plasma gluco...
Szenci O, Németh F, Stollár Z, Brydl E.Stability of ionized calcium (Ca2+) concentrations and pH values in equine venous samples (n = 12 in each group) stored at 4 C for 3, 9, 24, and 48 hours (blood, plasma, and serum) or for 240 hours (plasma and serum), and at -20 C for 240 hours (plasma and serum), was studied. Storage of equine blood, plasma, and serum samples at 4 C for up to 48 hours and of serum samples at 4 C for up to 240 hours, despite appreciable pH changes, was associated with < 1.5% change in blood, plasma, and serum Ca2+ concentrations. Therefore, Ca2+ concentration in equine blood, plasma, and serum samples store...
Plumlee KH, Richardson ER, Gardner IA, Galey FD.Delays between time of sampling and time of testing are common; therefore, the length of time that blood can be stored at various temperatures was evaluated for effects on cholinesterase activity. Six horses were treated with 16 g of trichlorfon per os, 6 horses were treated with 15 g of dichlorvos per os, and 10 horses were untreated controls. The cholinesterase activity in whole blood from each horse was measured using an adaptation of the Ellman colorimetric method. The blood from each horse was then divided into 3 groups and stored at 5 C (refrigerated), 20 C (room temperature), or 38 C (i...
Holman PJ, Chieves L, Frerichs WM, Olson D, Wagner GG.Babesia equi was continuously cultured through 90 passages in an enriched chemically defined basal medium (HL-1) supplemented with 20% fetal bovine serum and serum replacement factors, including lipid-rich bovine serum albumin, bovine insulin, and human transferrin. Cryopreservation and subsequent recovery of B. equi were easily achieved. Inoculation of a splenectomized and an intact horse with cultured infected erythrocytes resulted in parasitemias and B. equi in vitro reisolation from both animals. In vitro forms of the parasite resembled in vivo forms. After establishment, parasitemias of 1...
McClure JJ, Koch C, Traub-Dargatz J.A red cell antigen of donkeys and mules was identified using antibodies in serum from a mare which produced a mule foal affected with neonatal isoerythrolysis (NI). Subsequently antibodies with similar activity were identified in the sera of other mares which had produced mule foals and were produced by immunization of horses with blood from donkeys. The antigen detected by these antibodies does not correspond to any recognized horse red cell alloantigen. This may be a xenoantigen since all donkeys (and mules) tested have shared this antigen and all horses tested have lacked the antigen. The r...
Seahorn TL, Gaunt SD, Berry C.Hematologic and rheologic variables were examined in a group of 13 horses with intestinal colic and a control group of 6 horses. All horses had been recently transported to the veterinary teaching hospital, and blood samples were obtained during initial examination. There were no significant differences in blood neutrophil count or plasma fibrinogen concentration between the groups, and PCV was significantly increased in horses with intestinal colic. Cell filterability was measured by passing uniform concentrations of blood, erythrocytes, and neutrophils through micropore filters. There were n...
Hess-Dudan F, Vacher PY, Bruckmaier RM, Weishaupt MA, Burger D, Blum JW.Concentration of (total) globulin was relatively stable in blood plasma of mares, but rapidly decreased in colostrum to very low levels within 2 days after parturition. In foals, after intake of the first colostrum, globulin increased within 1 day in blood plasma, but remained at lower concentrations than those measured in mare plasma. Concentrations of immunoreactive insulin (iI) were high during the first 2 months of lactation in blood plasma of mares and then decreased, were high in first colostrum and then decreased drastically, and remained at low concentrations up to weaning in blood of ...
Davicco MJ, Faulconnier Y, Coxam V, Dubroeucq H, Martin-Rosset W, Barlet JP.There is a high incidence of bony pathology in race horses. Thus, plasma GH, IGF-1, osteocalcin (OC), calcium (Ca) and inorganic phosphorus (P) concentrations were measured in 12 healthy Selle Français foals and their dams during the first five months after birth. Plasma IGF-1 and OC concentrations were higher in foals than in mares (336 +/- 25 vs 230 +/- 18 ng/ml, P < 0.05; 52.5 +/- 3.2 vs 4.9 +/- 0.1 ng/mg, P < 0.01, respectively). A significant positive linear relationship could be established between these two parameters in foals (IGF-1 = 19 + 0.619 OC; P < 0.05). Another strikin...
Windberger U, Ribitsch V, Resch KL, Losert U.There is little data on blood viscosity in different animals. Therefore a comparison was performed between five species by an in-vitro method using oscillatory flow. At shear rates from 1 to 150/sec the viscous and the elastic component of the complex blood viscosity was highest in pig, followed by horse, dog, ox, and sheep. Plasma viscosity and plasma density were similar in dog and sheep and were higher in ox. The differences in whole blood viscosity were obviously related to the variable interspecies hematocrit, and may also be influenced by different aggregation tendencies. Aggregation in ...
Sommardahl CS, Andrews FM, Saxton AM, Geiser DR, Maykuth PL.Packed cell volume and plasma total protein (TP), serum albumin (Alb) and globulin (Glb), and plasma ionized calcium (PCa) concentrations, blood viscosity (BV), and plasma viscosity (PV) were measured in 42 horses at rest and after the cross country jumping phase of a horse trial competition. The BV and PV were determined at 6 shear rates (230, 115, 46, 23, 11.5, 5.75 s-1), using a digital rotational cone and plate microviscometer. A paired t-test was used to determine differences between PCV, TP, Alb, Glb and PCa values at rest and after exercise. The PCV, TP, Alb, and Glb values increased (P...
Vos PL, van der Schans A, de Wit AA, Bevers MM, Willemse AH, Dieleman SJ.Normally cyclic heifers (n = 34) received 2500 iu pregnant mares' serum gonadotrophin (PMSG) i.m. at day 10 of oestrus, and 15 mg prostaglandin (PG) i.m. at day 12. Thereafter, a monoclonal antibody against PMSG was administered i.v. before (n = 24), at (n = 6) or shortly after (n = 4) the preovulatory LH surge. Peripheral blood concentrations of LH and oestradiol were compared; follicular development was monitored by daily ultrasound scanning; and the numbers of preovulatory-sized follicles and ovulations were counted 96 h after injection of PG following death. Anti-PMSG treatment before the ...
Stone-Marschat M, Carville A, Skowronek A, Laegreid WW.Reverse transcription-PCR (RT-PCR) was used to detect African horse sickness virus (AHSV). A single primer pair which amplified a 423-bp fragment of the S8 gene which encodes the NS2 protein of AHSV was identified. Amplification of this fragment from all nine serotypes of AHSV was achieved with these primers. Between 10(1) and 10(2) copies of AHSV genomic double-stranded RNA could be detected by RT-PCR followed by agarose gel electrophoresis and ethidium bromide staining. Application of RT-PCR to blood samples from AHSV-infected horses resulted in earlier detection of viremia than virus isolat...
Forster HV, Pan LG.Our objective was to gain insight into the role of the carotid chemoreceptors (CC) in the exercise hyperpnea. Humans and ponies were studied at rest and during submaximal exercise breathing room air. In healthy humans, alveolar ventilation (VA) was tightly matched to CO2 production (CO2) resulting in PaCO2 deviating during exercise less than 1-2 mm Hg from rest. In contrast, ponies' VA increased proportionately more than VCO2 during exercise resulting in a workload dependent hypocapnia. Attenuating CC activity through hyperoxia had no effect on exercise PaCO2 of humans but hyperoxia accentuate...
Weibel ER.The question is explored of how the structural systems that constitute the pathway for oxygen from the air through the lung and the circulation of blood to the mitochondria in muscle cells affect the O2 flow rate, and whether their quantitative structural characteristics conform to the hypothesis of symmorphosis which postulates a match of structural design to overall functional demand. By combining physiological and morphometric studies, it is first demonstrated that the diffusing capacity of the human lung is slightly larger than that needed for maximal O2 uptake. Comparative studies of smal...
Ginther OJ, Baucus KL, Bergfelt DR.The ovaries of periparturient pony mares (n=9 to 16 parturitions per month for January to April) were scanned ultrasonically on the day of parturition, while those of postpartum and control mares (n=12) were examined at least twice weekly. Four mares had apparent lactational anovulation (incidence, 7%) that corrected spontaneously (1 mare) or within 14 d after the weaning of foals on August 10 (3 mares). All but 2 of the postpartum ovulations occurred after April 29; that is, parturition did not effectively stimulate ovulation in ponies foaling during the anovulatory season. Mean diameter of t...
Weiss DJ, Geor RJ, Smith CM.Effects of echinocytosis on blood rheology and exercise performance were evaluated for 5 Thoroughbreds. Echinocytosis was induced by administration of furosemide (1 mg/kg of body weight, IM, q 12 h) for 4 days. Furosemide treatment resulted in decreases in serum sodium and serum chloride concentrations and in RBC chloride and potassium concentrations. Echinocytosis was associated with increased RBC density as determined by RBC density gradient centrifugation. However, samples containing echinocytes were more filterable than control samples, indicating that echinocytes were not rigid cells. Ery...
Cothran EG, Long YG.A new D blood group phenogroup consisting of the specificities adeo was observed in a stallion family of Caspian ponies from Iran. An additional six undescribed genetic variants were seen in a total of 82 Iranian horses. This result suggests extensive new genetic variation may be present in domestic horses from geographic regions that have not yet received scientific attention.
Sugar O.Reports of pathologic investigations as to the cause of intermittent claudication in horses were made in France in October, 1831, by veterinarian Jean-François Bouley. Obstructive clots in the femoral arteries were found to be responsible for the muscular changes causing limping. Bouley's work in the horse was used by Charcot in 1858 to understand the mechanism of claudication in the case of a soldier with gunshot wound in whom a traumatic aneurysm, clotting, and ischemia of the legs developed. This was not, however, the first medically reported case of human claudication from vascular occlus...
Hoshi F, Satho M, Koyama S, Nakadaka K, Chiba M, Ikeda N, Hakamada R, Higuchi S, Kawamura S.The usefulness of a dry-chemistry blood analyzer, Spotchem SP-4410 (SP-4410) in a veterinary clinic for analysis of bovine and equine blood chemistry was studied. We quantitated total protein (TP), albumin (Alb), total bilirubin (T-Bil), blood urea nitrogen (BUN), total cholesterol (T-Cho), glucose (Glu), calcium (Ca), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatinine phosphokinase (CPK), and alkaline phosphatase (ALP) in bovine sera. Each sample was assayed with both the SP-4410 and an automated blood analyzer which served as a wet-chemistry reference system, and t...
Volfinger L, Lassourd V, Michaux JM, Braun JP, Toutain PL.To quantify the extent of muscle alteration during prolonged exercise, the release rate of creatine kinase (CK) from striated muscle was measured in six horses during a rest period (6 h) and during three exercise tests (15, 30, and 60 km) at a constant speed of 200 m/min. CK clearance was measured after intravenous bolus administration (150 U/kg) of a CK solution obtained from horse muscle. The CK steady-state volume of distribution was 0.059 +/- 0.0215 l/kg, the terminal half-life was 123 +/- 28 min, and the plasma clearance was 0.36 +/- 0.10 ml.kg-1 x min-1. After an intramuscular CK adminis...
Weiss DJ, Evanson OA, Geor RJ.The effects of various concentrations of furosemide and pentoxifylline on equine RBC in vitro were evaluated to facilitate better understanding of the potential effects of these drugs on blood flow properties. Furosemide induced increased mean cell volume (MCV), increased RBC potassium concentration, increased whole blood viscosity, and decreased the RBC filtrability. These data indicate that furosemide may block the RBC membrane transport pathways resulting in potassium and water retention. The increase in size and the resultant decrease in the surface-area-to-volume ratio may have caused the...
Waelchli RO, Lutz H, Hermann M, Rüegg C, Eggenberger E.Hematologic reference values were established in 18 healthy foals in the first two months of life. Blood samples were collected prior to colostrum consumption and at 30 hours, 1 week, 3, 5, 7 and 9 weeks of age. PCV, Hb and RBC decreased during the first week and RBC, but not PCV and Hb, increased toward the end of the second month. With the exception of the sample at 1 week, the foals had mean RBC values significantly higher than those of controls. Mean MCV and MCH did not change during the first week, but decreased slightly thereafter; all means were smaller than in controls. The numbers of ...
Sugiura T, Nakamura H.The zinc content in platelets from rabbits, humans and horses was determined, and the levels of zinc were found to be significantly higher (3 micrograms/10(10) cells) than those in other peripheral blood cells. About 70% of the zinc in the supernatants of platelet lysates could be detected. From the results of gel filtration analysis, the zinc in platelet lysates was found to be bound with a low-molecular-weight protein (MW 6,000-8,000) detected as metallothionein (MT) on the basis of antigenic properties determined by enzyme-linked immunoassay and immunoblotting analysis using monoclonal anti...
Cruz AM, Kerr CL, Bouré LP, Sears WC.To determine the cardiovascular effects of 60 minutes of abdominal insufflation with CO2 to an intra-abdominal pressure of 15 mm Hg in standing horses receiving a constant rate infusion of detomidine. Methods: 5 horses. Methods: Horses were randomly allocated into treatment or control groups. A washout period of a minimum of 7 days separated the 2 experimental periods of the crossover study. Catheters were placed into the right atrium, pulmonary artery, jugular vein, and right transverse facial artery after lidocaine infiltration. All horses were sedated with detomidine (8.54 microg/kg/h, i.v....
Powell DM, Lawrence LM, Fitzgerald BP, Danielsen K, Parker A, Siciliano P, Crum A.The metabolic effects of short-term feed restriction and dietary calorie source were studied in horses receiving high-roughage or high-concentrate diets. Four Thoroughbred geldings were assigned to four treatment groups in a 4 x 4 Latin square experiment. The four treatments were 1) a nutritionally adequate high-roughage ration (70% roughage, 30% concentrate; AHR), 2) a nutritionally adequate high-concentrate ration (40% roughage, 60% concentrate; AHC), 3) 70% of the intake of the AHR diet (RHR), and 4) 70% of the intake of the AHC diet (RHC). Diets AHR and AHC were designed to meet the calori...
McGorum BC, Anderson RA.To test the hypothesis that equine grass sickness may be associated with the ingestion of cyanogenic glycosides from white clover (Trifolium repens), the concentrations of whole blood cyanide, and plasma and urinary thiocyanate, the main metabolite of cyanide, were measured in 12 horses with acute grass sickness and 10 horses with subacute grass sickness, and in 43 control horses, of which 21 were co-grazing with cases of acute grass sickness, 12 grazed pastures where grass sickness had not been reported, and 10 were stabled horses. The healthy horses which grazed with cases of acute grass sic...
Hinchcliff KW, McKeever KH, Muir WW, Sams RA.We theorized that furosemide-induced weight reduction would reduce the contribution of anaerobic metabolism to energy expenditure of horses during intense exertion. The effects of furosemide on accumulated O2 deficit and plasma lactate concentration of horses during high-intensity exercise were examined in a three-way balance randomized crossover study. Nine horses completed each of three trials: 1) a control (C) trial, 2) a furosemide-unloaded (FU) trial in which the horse received furosemide 4 h before running, and 3) a furosemide weight-loaded (FL) trial during which the horse received furo...
Strickland K, Smith F, Woods M, Mason J.Four horses were stabled and fed a diet of hay ad libitum, and 2 kg oats per animal per day, for a month. The basic diet was then supplemented with molybdenum, at a rate of 20 mg/kg dry matter for 4.5 months. For one month of this period the diet was supplemented also with sulphur at a rate of 1.2 g/kg dry matter. Analyses of jugular blood samples, obtained at intervals varying between two and 20 days, showed no evidence of a decline in total plasma copper or of an increased proportion of trichloroacetic acid (TCA) insoluble copper in plasma over this period. In separate studies, two other hor...
Owens SD, Johns JL, Walker NJ, Librach FA, Carrade DD, Tablin F, Borjesson DL.To evaluate N-hydroxysuccinimide (NHS)-biotin labeling of equine RBCs and determine posttransfusion survival of autologous equine RBCs stored in citrate phosphate dextrose adenine-1 (CPDA-1) for 0, 1, 14, and 28 days. Methods: 13 healthy adult Thoroughbreds. Methods: Serial dilutions of biotin and streptavidin-phycoerythrin (PE) were evaluated in vitro in blood collected from 3 horses. One horse was used to determine RBC distribution and recovery. Twelve horses were allocated to 4 groups for in vivo experiments in which blood was collected into CPDA-1. Blood was labeled with biotin and reinfus...
De Mello Costa MF, Anderson GA, Davies HM, Slocombe RF.Angiotensin I-converting enzyme (ACE) level measurement in blood samples is an important tool in human medicine for the detection, treatment and control of diseases such as sarcoidosis and hypertension. Recently ACE has been advocated as being correlated to athletic aptitude in human athletes and a genetic polymorphism has been shown to be responsible for the enzymatic levels in the circulation. The objective of this research was to evaluate the effects of acute exercise in horses in order to increase the understanding of a possible correlation between ACE levels in plasma and performance in e...
Caffey SR, Lund CM, Farnsworth KD, Fransson BA, Ragle CA.The effects of head position on internal carotid artery (ICA) and external carotid artery (ECA) pressures in standing sedated horses were evaluated in this study. The common carotid artery (CCA) was catheterized in 6 horses using an ultrasound-guided technique to facilitate placement of a pressure transducer within the ICA and ECA at the level of the guttural pouch. Transducer position was confirmed by endoscopic visualization. Mean arterial pressure (MAP) was measured with horses in both a head-up and head-down position. The dorsal metatarsal artery was catheterized as a control. Maintaining ...
Wetmore LA, Derksen FJ, Blaze CA, Eyster GE.The relationship between mixed venous O2 tension and cardiac output was studied in six anesthetized horses breathing 100% O2. Cardiac output, O2 consumption, mean arterial pressure, heart rate, and arterial and venous blood gases were measured after administration of xylazine or dobutamine to horses in lateral, sternal, and dorsal recumbencies. After approximately 3 hours, Escherichia coli endotoxin was administered while horses were in dorsal recumbency, and all measurements were repeated. Relationships between cardiac index (CI) and PVO2, heart rate, mean arterial pressure, jugular PVO2, and...
Jamieson CA, Hanzlicek AS, Payton ME, Holbrook TC.To determine reference intervals and the effect of sample agitation and rest time on Sonoclot analysis in healthy adult horses. Methods: Original prospective study. Methods: University veterinary medical teaching hospital. Methods: Sixty healthy adult horses. Methods: Blood was collected for assessment of complete blood count, serum biochemical analysis, and Sonoclot analysis. Results: Horses were determined to be healthy based upon physical examination, CBC, and serum biochemistry analysis. Blood was analyzed in a glass bead-containing cuvette using the Sienco Sonoclot analyzer following 2 re...
Winter J, Kershaw O, Schmitz R, Gehlen H.Equine leukaemic lymphoma is a rare disease of the haematopoetic tissue. It results from neoplastic degradation of B- and T-lymphocytes and their occurrence in the blood. Clinical signs are often unspecific and include chronic weight loss, ventral oedema at the thorax and abdomen and regional lymphadenopathy. Horses are often presented late in the course of the disease and therapy is rarely successful. This review summarizes the clinical pathologic findings of equine leukaemic lymphoma and the findings of laboratory testing and other diagnostic measures, and presents treatment options describe...
Becht JL, Page EH, Morter RL, Boon GD, Thacker HL.A series of modified (field) tests were compared to a crossmatch between mare and foal for their reliability in predicting neonatal isoerythrolysis (NI) in eight foals born to experimentally alloimmunized mares. In the field tests, mare's serum, plasma and colostrum were combined with foal erythrocytes washed by a modified procedure to determine which combination was the best predictor of impending NI. A consistent grading system for agglutination and hemolysis was employed. The field tests using mare's plasma demonstrated less agglutination and hemolysis than tests where serum was employed. I...
Ginther OJ, Baucus KL, Bergfelt DR.The ovaries of periparturient pony mares (n=9 to 16 parturitions per month for January to April) were scanned ultrasonically on the day of parturition, while those of postpartum and control mares (n=12) were examined at least twice weekly. Four mares had apparent lactational anovulation (incidence, 7%) that corrected spontaneously (1 mare) or within 14 d after the weaning of foals on August 10 (3 mares). All but 2 of the postpartum ovulations occurred after April 29; that is, parturition did not effectively stimulate ovulation in ponies foaling during the anovulatory season. Mean diameter of t...
Cambier C, Wierinckx M, Grulke S, Clerbaux T, Serteyn D, Detry B, Liardet MP, Frans A, Gustin P.Blood oxygen transport and oxygen extraction were assessed in horses with colic. A gravity score (GS) ranging from 1 to 3 was attributed to each colic case with healthy horses used as controls. Jugular venous and carotid arterial blood samples were collected and concentrations of 2,3-diphosphoglycerate, adenosine triphosphate, inorganic phosphate and chloride were determined. pH and partial pressures of carbon dioxide (PCO(2)), and oxygen (PO(2)) were also measured. Oxygen equilibrium curves (OEC) were constructed under standard conditions and oxygen extraction ratios calculated. Haemoglobin o...
Shih AC, Giguère S, Sanchez LC, Valverde A, Jankunas HJ, Robertson SA.To compare cardiac output (CO) measured by lithium arterial pressure waveform analysis (PULSECO) and CO measured by transpulmonary pulse contour analysis (PICCO) in anesthetized foals, with CO measured by use of lithium dilution (LIDCO) considered the criterion-referenced standard. Methods: 6 neonatal (1- to 4-day-old) foals that weighed 38 to 45 kg. Procedures-Foals were anesthetized and instrumented to measure direct blood pressure, heart rate, arterial blood gases, and CO. The CO was measured by use of PULSECO, PICCO, and LIDCO techniques. Measurements were converted to specific CO (sCO) va...
Haggett E, Magdesian KG, Maas J, Puschner B, Higgins J, Fiack C.Exercise causes an increase in the production of reactive oxygen species, which can result in oxidant/antioxidant disequilibrium. Deficiency of antioxidants can further alter this balance in favor of pro-oxidation. Selenium (Se) is one of many antioxidant catalysts, as a component of the glutathione peroxidase enzymes. Soils and forages vary widely in Se concentration and a deficient diet can lead to sub-clinical or clinical deficiency in horses. Endurance horses are prone to oxidative stress during long periods of aerobic exercise and their performance could be affected by Se status. This stu...
Szarska E, Cywińska A, Ostaszewski P, Kowalska A.The purpose of this study was to compare the training methods used in two stables and their effects on selected blood parameters and race results. A total number of 36 thoroughbred race horses was examined in two groups, trained by two trainers. Twenty-four horses (group A) were trained at Sluzewiec and the remaining twelve horses (group B) were kept and trained in a private stable. The experiment lasted for five months. The activities of CPK (creatine phosphokinase) and AST (aspartate aminotransferase) and the concentration of LA (lactic acid) were determined. The speed was controlled and rec...
Uboh CE, Rudy JA, Railing FA, Enright JM, Shoemaker JM, Kahler MC, Shellenberger JM, Kemecsei Z, Das DN.Although urine is the sample of choice for drug tests in racehorses, it is rarely obtained following the sudden death of a racehorse on the track while racing. The purpose of this study was to demonstrate the significance of postmortem tissue samples as an alternative to urine and blood samples in equine drug analysis following the sudden death of a racehorse on the track while participating in a competitive race. Postmortem tissue samples were frozen (-80 degrees C) until analyzed. A 30-40-g portion of each organ was homogenized in a 0.1 M phosphate buffer (pH 7.4), deproteinized, hydrolyzed ...
Manohar M, Gustafson R, Nganwa D.Effects of 1.55 minimum alveolar concentration isoflurane O2 anesthesia (2.03% end-tidal isoflurane) on blood flow in the up-(nondependent) and down-(dependent) positioned skeletal muscles were studied at 60, 120, and 180 minutes in 6 healthy isocapnic ponies in right lateral recumbency on a nonpadded hardwood floor. Measurements were made, using 15-micron diameter radionuclide-labeled microspheres injected into the left ventricle, and comparisons were made with data obtained from ponies in the conscious state. Isoflurane administration caused a sharp reduction in cardiac output and systemic p...
Singh S, Young SS, McDonell WN, O'Grady M.Xylazine (XYL) administration in horses is accompanied by significant cardiovascular depression characterized by a 25-35% decrease in cardiac output (CO) which is likely to compromise tissue oxygen delivery (DO2), and usually vagally mediated bradycardia is an important cause of this reduced cardiovascular performance. To examine the possible benefit of preventing the bradycardiac response, 6 healthy horses were treated with intravenous (IV) saline (SAL) or 2.5 micrograms/kg glycopyrrolate (GLY) in a blinded, randomized, crossover trial. Fifteen minutes later, 1 mg/kg XYL was administered IV a...
Warko G, Bostedt H.The aim of this study was to determine the course of the IgG concentration in blood serum of neonatal foals. A comparison of blood serum IgG concentration of the mares showed IgG values of 3356 +/- 671 mg/dl up to a maximum of 3579 +/- 766 mg/dl (means +/- s). In accordance with Eisenhauer (1981) and in contrast to Jeffcott (1974) no significant change of the IgG level in the blood serum of the mares could be observed during the test period. However, the IgG concentration in the colostrum of meanG = 11776 mg/dl during birth decreased considerably 96 hours later with meanG = 135 mg/dl. At birth...
Ishizuka T, Tamura J, Nagaro T, Sudo K, Itami T, Umar MA, Miyoshi K, Sano T, Yamashita K.Effects of intermittent positive pressure ventilation (IPPV) on cardiopulmonary function were evaluated in horses anesthetized with total intravenous anesthesia using constant rate infusions of medetomidine (3.5 µg/kg/hr), lidocaine (3 mg/kg/hr), butorphanol (24 µg/kg/hr) and propofol (0.1 mg/kg/min) (MLBP-TIVA). Five horses were anesthetized twice using MLBP-TIVA with or without IPPV at 4-week interval (crossover study). In each occasion, the horses breathed 100% oxygen with spontaneous ventilation (SB-group, n=5) or with IPPV (CV-group, n=5), and changes in cardiopulmonary parameters were ...
Kanitz W, Schneider F, Hoppen HO, Unger C, Nürnberg G, Becker F.The aim of the study was to investigate the effect of the GnRH agonist Buserelin given on day 10 after ovulation on pregnancy rate and concentrations of progesterone and LH. Altogether 191 warmblood mares were used for two trials. Fresh or frozen/thawed semen from 27 stallions was used for A.I. In trial A 171 mares received either Buserelin (Receptal, Hoechst, Germany, 40 microg/animal) or 10 ml 0.9% NaCl (placebo). On day 16 after A.I. pregnancy diagnosis was performed by ultrasound scanning of the uterus. For statistical analysis, data were analyzed by a mixed model, with four fixed factors ...
de Waal A, Potgieter FJ.Dehydration, to varying degrees, will inevitably occur in horses participating in endurance trail rides. This water loss is directly related to the amount of body water lost through evaporative cooling, that in turn being related to the amount and rate of work performed, and to the environmental temperature and humidity. An electronic apparatus that can substitute for the conventional and time-consuming venous haematocrit was developed to measure the animals' hydration status. The mechanism of this electrometer is based upon the relationship between the red cell content and the electrical cond...
Auckburally A, Wiklund MK, Lord PF, Hedenstierna G, Nyman G.To measure changes in pulmonary perfusion during pulsed inhaled nitric oxide (PiNO) delivery in anesthetized, spontaneously breathing and mechanically ventilated ponies positioned in dorsal recumbency. Methods: 6 adult ponies. Methods: Ponies were anesthetized, positioned in dorsal recumbency in a CT gantry, and allowed to breathe spontaneously. Pulmonary artery, right atrial, and facial artery catheters were placed. Analysis time points were baseline, after 30 minutes of PiNO, and 30 minutes after discontinuation of PiNO. At each time point, iodinated contrast medium was injected, and CT angi...
Ohmura H, Hiraga A, Aida H, Takahashi T, Nukada T.To determine oral dosage and to evaluate the pharmacokinetics in horses of orally administered flecainide, an antiarrhythmic drug, the correlations between its plasma concentration and PR, QRS and QT intervals in equine electrocardiograms (ECG) were investigated. Six healthy horses were administered a randomly ordered dose of 4 or 6 mg/kg of flecainide acetate. The ECG was monitored (heart rate (HR), PR, QRS, and QT intervals) and blood was taken at timed intervals to measure the plasma flecainide concentrations pre- and post-administration. The maximum plasma concentration reached 1014+/-285 ...
Cochran RA, Leonardi-Cattolica AA, Sullivan MR, Kincaid LA, Leise BS, Thompson DL, Godke RA.The effects of exogenous equine somatotropin (eST) administration on ovarian activity and plasma hormone levels were evaluated on horse and pony mares. The objectives of this study were to determine the effects of eST on follicular development and circulating concentrations of leutinizing hormone (LH), estradiol, progesterone, and insulin-like growth factor I (IGF-I) in cyclic horse and pony mares. Sixteen mares received daily injections (i.m.) of eST at a concentration of 25 micrograms/kg body weight on either Days 6 through 12 (Treatment A) or 13 through 19 (Treatment B) postovulation. In ad...
Kaiser B, Koene M, Swagemakers J, Bader H, Hoppen HO.During the 1997 breeding season persistent follicles were diagnosed in 17 mares. In 16 of these mares a total of 17 follicles were transabdominally punctured and the steroids oestradiol, progesterone and testosterone were measured in the follicular fluid and in blood serum. In ten mares serving as a control group preovulatory follicles were punctured. The follicular fluid of the persistent follicles revealed a very high variability of the steroid concentrations. Depending on the steroid ratio within the follicles, eight follicles were rated as being intact, three follicles were undergoing atre...
Zicker SC, Rogers QR.Concentrations of amino acids in plasma and whole blood in response to 10 hours of food deprivation were determined in healthy 2-day-old foals (n = 8) and were compared with control values in foals of the same age (n = 8) allowed free access to suckle. In addition, response of concentrations of amino acids in plasma to 15 minutes of free-access suckling was determined at the end of the 10-hour period in both groups. Response of 13 amino acids in plasma of food-deprived foals was significantly (P < 0.05) different, compared with that in control foals. Concentrations of 3 amino acids (alanine...
Enbergs H, Karp HP, Schönherr U.The present study was aimed to determine the contents of calcium, inorganic phosphate, parathormon, 25-OH-D3 and the activity of alkaline phosphatase in the plasma of one- and two-years-old thoroughbred horses. Data were obtained monthly from 44 one-year-old thoroughbred of 4 different studs from May during grazing-season and from October during stable-, resp. training-season up to april of the following year. Calcium, inorganic phosphate and the activity of alkaline phosphatase were measured with a photometric method and the concentration of PTH and 25-OH-D3 were determined with a radioimmuno...
