Topic:Blood
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.
Pharmacokinetics of antipyrine, acetaminophen and lidocaine in fed and fasted horses. Previous studies demonstrated that plasma clearance of organic anions such as bilirubin, bile acid, sulfobromophthalein (BSP) and indocyanine green (ICG), was reduced from 36% (bile acid) to 55% (ICG) in fasted (3 days) horses. It is believed that a general decline in carrier-mediated hepatic uptake may have accounted for those changes. However, fasting may also affect hepatic blood flow, thereby contributing to reduced clearance of these compounds. In order to test this hypothesis, plasma clearance of antipyrine, acetaminophen and lidocaine, drugs known to be cleared by the liver yet not susp...
Radiolabeling of equine platelets in plasma with 111In-(2-mercaptopyridine-N-oxide) and their in vivo survival. A method is presented for the in vitro isolation and radiolabeling of equine platelets with the isotope indium 111 (111In: half-life = 2.8 days, gamma = 173 keV, 89%; 247 keV, 94%). The technique described involves complexing 111In with the lipid-soluble chelating agent, 2-mercaptopyridine-N-oxide (merc), in an aqueous medium. 111In-merc platelet-labeling efficiencies in autologous plasma pretreated with or without ferric citrate reagent were 82 +/- 7% and 24 +/- 12%, respectively. Mean intravascular survivals of 111In-merc-radiolabeled platelets in 8 healthy horses according to simple linear,...
The effect of lateral and dorsal recumbency on cardiopulmonary function in the anaesthetised horse. The effect of lateral and dorsal recumbency on cardiopulmonary function in six anaesthetised horses were compared. Cardiac output/kg, stroke volume/kg, alveolar ventilation, venous admixture, pulmonary shunt and blood-gas values were determined. From lateral to dorsal recumbency cardiac output/kg decreased non-significantly. A significant increase in pulmonary shunt occurred. A positive correlation between body mass and pulmonary shunt in dorsal recumbency was found. Alveolar ventilation increased significantly in dorsal recumbency when breathing air compared to oxygen.
Pituitary responsiveness of mares challenged with GnRH at various stages of the transition into the breeding season. Four groups of mares, representing anestrus (AN; n = 8), early transition (ET; n = 7), late transition (LT; n = 8) and estrus (EST; n = 12) were used to examine release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) after a bolus injection of gonadotropin releasing hormone (GnRH) during the transition from anestrus into the breeding season. Estrous mares received GnRH on d 2 or 3 of estrus in the cycle immediately preceding slaughter. Anestrous, ET and LT mares received GnRH exactly 1 wk prior to slaughter. A single injection of GnRH (Sigma LHRH, L-0507, 2.0 micrograms/kg b...
Modification and evaluation of a multichannel blood cell counting system for blood analysis in veterinary hematology. A multichannel, semiautomated, blood cell counting system (Coulter Counter Model S550) was modified for use in veterinary hematology by increasing both the erythrocyte and leukocyte aperture currents to 225 V and 195 V, respectively, followed by calibration with human blood. It was evaluated by use of 350 samples from dogs, cats, horses, and cows. Values for leukocyte count, erythrocyte count, mean corpuscular volume, and hematocrit generated by the S550 were compared with values generated by an automated multichannel counter with histogram capability and other reference procedures when approp...
Immune-mediated hemolytic anemia and thrombocytopenia in a foal. A one-month-old Quarter Horse filly had unilateral epistaxis, hyphema, icterus, petechial hemorrhages in the oral, nasal, conjunctival, and vulvar mucous membranes, anemia, thrombocytopenia, negative antinuclear test result, and a positive direct Coombs' test result. Megakaryocytes or cell-associated IgG (fluorescent antibody and immunoperoxidase stains) were not found in bone marrow biopsy specimens. Treatment consisted of glucocorticoids, antibiotics, and a single whole blood transfusion. The foal responded well to treatment, did not develop relapses of the disease, and was clinically normal...
Systemic and centrally mediated angiotensin II effects in the horse. The primary aim of the study was to evaluate the potential value of intravenous (i.v.) infusion of angiotensin II (AII) for phonocardiographic differential diagnosis of equine valvular insufficiency. Ten-minute AII infusions at 4.5-33 pmol kg-1 min-1 induced clear-cut dose-dependent rises in systemic arterial blood pressure (aBP), whereas the pulmonary aBP remained largely unaffected. It implies that i.v. infusion of AII at about 10 pmol kg-1 min-1 could be a valuable tool for the acoustic differentiation between mitral and tricuspid valvular dysfunction in the horse. The infusion at, and abov...
The ELY-1 locus controls a di-allelic alloantigenic system on equine lymphocytes. The ELY-1 locus controls the expression of a polymorphic cell surface antigen of equine lymphocytes which was detected using antibodies generated by alloimmunization with peripheral blood lymphocytes. The ELY-1 antigens were not detected on erythrocytes or platelets by absorption experiments. The two alleles, which have been designated ELY-1.1 and ELY-1.2, are expressed codominantly and appear to constitute a closed system at the population level. In family studies, the ELY-1 antigens segregated as products of an autosomal locus not linked to the major histocompatibility complex (MHC) of the h...
Correlation between anion gap, blood L lactate concentration and survival in horses. Blood L lactate concentration and anion gap were measured in 32 horses suspected of having metabolic acidosis. There was good linear correlation between these variables (r = 0.90791, P less than 0.0001) and both were good prognostic indicators. Anion gap was a good indicator of the presence but not the severity of L lactic acidosis and was a slightly better prognostic indicator. The ability to predict survival was not improved by the measurement of L lactate in addition to anion gap.
Fatty acid composition of the plasma lipids of the maternal and newborn horse. The fatty acid composition of the plasma free fatty acid, triacylglycerol and phospholipid fractions was measured in blood and milk samples taken daily from 3 mares and their foals on Days 1-9 post partum inclusive, and from a total of 12 mares and foals on Days 22, 30 and 51. A rise in the plasma concentrations of triacylglycerol and phospholipid similar to that well documented in other species occurred in the neonatal period. Alterations in the composition of the foal plasma phospholipid after birth lend support to the view that the placenta rather than the fetus could be responsible for the...
Extensive large colon resection in the pony. I. Surgical procedures and clinical results. The effect of resection of 75% (length measurement) of the large colon in ponies was studied. Ten ponies in good physical condition were divided into two groups: group I consisted of the six experimental ponies and group II of four control ponies. Preoperatively and postoperatively for five months, ten clinicopathological parameters were determined: body weight, venous blood pH, plasma bicarbonate, total plasma protein concentration, serum electrolyte values (sodium, potassium, chloride), and fecal osmolarity. Subjective assessment of attitude and appetite revealed no difference between the gr...
Consequence of excess iodine supply in a Thoroughbred stud in southern Brazil. Excessive iodine supply of at least 700 mg inorganic iodine in foals and of more than 350 mg iodine in pregnant and lactating mares cause a high incidence of goitres in the newborn and disorders in the long leg bones of foals. Elevated phosphorus and alkaline phosphatase content in the blood may indicate a severe disturbance in the bone metabolism. Of 39 pregnant mares 17 aborted and some of the mares also showed goitres. After withdrawal of the iodine supply normalization took place. Foals born more than 6 weeks later showed normal conditions. The goitres in the mares and the high blood level...
Contribution of whole blood L-lactate, pyruvate, D-lactate, acetoacetate, and 3-hydroxybutyrate concentrations to the plasma anion gap in horses with intestinal disorders. Increased anion gap (AG) was due, in part, to L-lactic acidosis in 14 of 14 horses with intestinal disorders. In a few horses, increased whole blood concentrations of D-lactate made a minor contribution to the AG. However, the increase in AG was often greater than the sum of the increases in these 2 acid anions. This unexplained increase was not a result of increases in whole blood pyruvate, 3-hydroxybutyrate, or acetoacetate concentrations or serum albumin or phosphate concentrations. Identification of other anions causing increased AG could lead to better understanding, diagnosis, and treatm...
Use of push-pull perfusion techniques in studies of gonadotrophin-releasing hormone secretion in mares. Push-pull perfusion was used to study GnRH secretory ability of the hypothalamus in anoestrous, transitional, dioestrous and oestrous Pony mares. The technique involved placement of a concentric (tube within a tube) cannula into the area of the medial basal hypothalamus and perfusing a carrier medium (artificial cerebrospinal fluid) through the inner tube whilst aspirating from the outer tube so that the flow rate within the hypothalamic tissue was essentially constant. The perfusion rate was 0.5 ml/10 min and samples were collected at 10-min intervals for 10-15 h. The carrier medium, which co...
Biochemical polymorphism in relation to performance in horses. Investigations on relationships between biochemical polymorphism and variation in quantitative traits are of interest from the perspectives of both theoretical quantitative genetics and practical animal breeding. This subject was studied by using racing performance records of more than 25,000 horses of the Swedish Trotter breed born in the period 1970-1979. For all horses data on six blood group and nine electrophoretic loci were available. Two different performance traits were investigated. A racing performance index value was calculated for all individuals which had started in at least five ...
[Antithrombin III determination in horses. Reference values and acquired antithrombin III deficiency]. Antithrombin III (AT III) determinations were done in healthy and sick horses using the chromogenic substrate Chromozym TH. Reference values for adult horses at 25 degrees C were 18-25 IU AT III per ml plasma and 84-118% AT III activity of normal horse plasma, respectively. Precision and accuracy were good (intra assay coefficient of variation less than 2%, accuracy 10%). Surgical operations on healthy horses led to a biphasic decrease in AT III activity touching the lower border of the reference values on the second postoperative day. Other reasons for acquired AT III deficiencies included di...
Apneic oxygenation in anesthetized ponies and horses. Apneic oxygenation was studied in six ponies for 30 minutes, and six horses for 10 minutes. Arterial blood was sampled at regular intervals for measurement of oxygen and carbon dioxide tensions (PaO2 and PaCO2) and calculation of alveolar-arterial oxygen tension difference (PAO2-PaO2). In both groups of animals, PaO2 decreased rapidly during the first 3 minutes of apnea, then more slowly. Although the mean value was above 100 mmHg at 10 minutes, there was considerable inter-animal variability. Before apnea, PAO2-PaO2 was slightly, but not significantly, larger in horses than in ponies and incr...
Ventilatory and blood gas dynamics at onset and offset of exercise in the pony. The purpose of these experiments was to examine the temporal pattern of arterial carbon dioxide tension (PaCO2) to assess the relationship between alveolar ventilation (VA) and CO2 return to the lung at the onset and offset of submaximal treadmill exercise. Five healthy ponies exercised for 8 min at two work rates: 50 m/min 6% grade and 70 m/min 12% grade. PaCO2 decreased (P less than 0.05) below resting values within 1 min after commencement of exercise at both work rates and reached a nadir at 90 s. PaCO2 decreased maximally by 2.5 and 3.5 Torr at the low and moderate rate, respectively. Aft...
PGF-2 alpha release, progesterone secretion and conceptus growth associated with successful and unsuccessful transcervical embryo transfer and reinsertion in the mare. The outcome of 23 collections and reinsertions of conceptuses on Days 10.5-13.5, 4 transfers of Day-10.5, and 13 transfers of Day-6.5 embryos (ovulation = Day 0) was monitored in 30 mares. Blood samples were taken before and after each procedure to measure plasma 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), and then daily for progesterone determinations. Mares were also subjected to daily teasing for detection of oestrus, and to uterine ultrasonography for tracing the development of the conceptus. After the reinsertions, 12/23 conceptuses were detectable immediately after the procedure...
Plasma concentrations of progestagens, oestrone sulphate and prolactin in pregnant mares subjected to natural challenge with equid herpesvirus-1. Multiparous pregnant mares, on two studfarms, were studied following natural challenge with equid herpesvirus-1 (EHV-1). They were divided into three groups according to serum complement fixation titres: Group A (N = 11) were not challenged and delivered normal foals; Group B (N = 13) were challenged but delivered normal foals; Group C (N = 23) were challenged and delivered infected foals which were stillborn or lived for less than 31 h. In Groups A and B mean (+/- s.d.) gestational age at delivery was 343 (+/- 8) and 339 (+/- 8) days respectively, whereas in Group C it was significantly (P le...
Evidence of a second polymorphic ELA class I (ELA-B) locus and gene order for three loci of the equine major histocompatibility complex. Two antisera, B-442 and R-2046, were produced by immunizing offspring with purified peripheral blood lymphocytes from a parent matched for the ELA-A specificity carried on the unshared haplotype. Absorption analysis demonstrated that these antisera contained at least two families of cytotoxic antibodies, one directed against antigens present on T and B cells, and a second directed preferentially against antigens present on surface Ig positive cells. Immunoprecipitation studies using these antisera demonstrated that both antisera contain antibodies specific for glycoproteins with molecular weig...
Dietary molybdenum as a putative copper antagonist in the horse. 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...
Cardiovascular and respiratory measurements in awake and isoflurane-anesthetized horses. Circulatory and respiratory function was monitored in nonmedicated, spontaneously breathing horses (n = 7) immediately before, during, and 1 hour after 85 +/- 4.1 (X +/- SEM) minutes of constant 1.57% isoflurane in O2 anesthesia. Comparison of values during anesthesia with those obtained while horses were awake revealed a significant (P less than 0.05) decrease in arterial blood pressure that was related to a slight, but insignificant, decrease in cardiac output and peripheral vascular resistance. Although isoflurane anesthesia and recumbency resulted in a significant (P less than 0.05) decrea...
Influence of chlorhexidine on seminal patterns in stallions. Ejaculates were collected at 3-day intervals before, during and after a washing procedure with chlorhexidine (2%). Semen motility and pathology were determined before and after deep-freezing. Blood samples were taken before and within 1 h after washing procedures and then extracted in ether. This was followed by HPL chromatography. Chlorhexidine concentrations in blood and seminal plasma were distinctly higher in the treated stallions than in control groups. Concentrations in the control groups were below the detection limit of the column. Significant correlations between decreasing semen qual...
Release of LH, FSH and GnRH into pituitary venous blood in mares treated with a PGF analogue, luprostiol, during the transition period. Nine mares received cannulae to collect blood from the pituitary venous outflow in the intercavernous sinus (ICS) and the jugular vein; in 4 mares, only jugular cannulae were used. Those 4 mares and 3 of the mares with cannulae in both positions received 7.5 mg luprostiol i.m. and 1 mare with both cannulae was treated with 3.75 mg uprostiol i.v. Blood samples were kept before and after treatment at 2-, 5- or 10-min intervals and concentrations of LH, FSH and GnRH were determined by RIA. Treatments resulted in an immediate sharp rise of LH and FSH in ICS and jugular blood samples within 2-10 mi...
Heparin-induced agglutination of erythrocytes in horses. 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...
Chemotactic and phagocytic function of peripheral blood polymorphonuclear leucocytes in newborn foals. Chemotactic and phagocytic responsiveness of peripheral blood polymorphonuclear leucocytes (PMNLs) from 11 foals were analysed immediately after birth (pre-colostral) and at different times after colostrum ingestion. The number of foal PMNLs per microscopic field that had migrated through the filter in chemotaxis and the number of yeast particles ingested per foal PMNL in phagocytosis were significantly lower when tested with foal plasma before colostrum ingestion (chemotaxis, 2.0 +/- 0.55 (s.e.m.); phagocytosis, 0.98 +/- 0.352) than in tests 4 or more days after colostrum ingestion (chemotaxi...
Systemic and pulmonary haemodynamics in normal neonatal foals. Cardiopulmonary function was studied in 10 full-term healthy foals from birth to 14 days of age. Systemic and pulmonary haemodynamics were recorded in lateral recumbency via indwelling aortic and pulmonary artery catheters. Mean body weight increased from 45.4 +/- 2.4 kg on Day 1 to 70.6 +/- 6.1 kg on Day 14. All foals had a continuous murmur of patent ductus arteriosus for 3-6 days. From Day 1 (12 h old) to Day 14, heart rate increased (89 +/- 4 to 95 +/- 5/min), mean aortic pressure increased (87.7 +/- 1.9 to 100.3 +/- 3.2 mmHg), mean pulmonary artery pressure decreased (38.6 +/- 4.6 to 27.4...