Hemoglobin is an iron-containing protein found in the red blood cells of horses, responsible for the transport of oxygen from the lungs to the tissues and the return of carbon dioxide from the tissues to the lungs. It plays a vital role in maintaining cellular respiration and energy metabolism. The structure and function of hemoglobin can be influenced by various factors, including genetics, age, and health status. Research into equine hemoglobin includes studies on its biochemical properties, the impact of different physiological and pathological conditions on its levels, and its importance in performance and endurance. This page compiles peer-reviewed research studies and scholarly articles that explore the characteristics, regulation, and clinical implications of hemoglobin in equine physiology and health.
Hedlund B, Danielson C, Lovrien R.Organic phosphates, ATP, AMP, and 2,3-di-phosphoglycerate (DPG) were interacted with horse oxyhemo-globin. Binding parameters were obtained by means of dialysis equilibrium in buffers at 5°, and from calorimetry at 5 and 25°, all in the pH mom 6.5-7.3. The calorimetric results were evaluated assuming a single strong site, and assuming that the pH shifts which occur in the absence of added salt are due to electrostatic effects and not to changes in side-chain titration, upon mixing samples previously ad-justed to the same pH. There was obtained for ATP and 2,3- diphosphoglycerate. respectivel...
Rifkind JM.The reduced glutathione in the erythrocyte was found to inhibit the autoxidation of purified horse hemoglobin. It was observed that much higher concentrations of oxidized glutathione also stabilize hemoglobin. The stabilization by oxidized glutathione most likely involves the formation of a mixed disulfide with the reactive β-93 sulfhydryl groups on the hemoglobin. A similar effect is also observed with N-ethyl- maleimide and HgCl2 which also react with the sulfhydryl groups. The apparent stabilization by reduced glutathione is partially due to the reduction of ferrihemoglobin formed by autox...
Kilmartin JV, Rossi-Bernardi L.1. Three modified horse haemoglobins have been prepared: (i) alpha(c) (2)beta(c) (2), in which both the alpha-amino groups of the alpha- and beta-chains have reacted with cyanate, (ii) alpha(c) (2)beta(2), in which the alpha-amino groups of the alpha-chains have reacted with cyanate, and (iii) alpha(2)beta(c) (2), in which the two alpha-amino groups of the beta-chain have reacted with cyanate. 2. The values of n (the Hill constant) for alpha(c) (2)beta(c) (2), alpha(2)beta(c) (2) and alpha(c) (2)beta(2) were (respectively) 2.5, 2.0 and 2.6, indicating the presence of co-operative interactions ...
Barnett AL, Steel JD, Stewart GA.Free erythrocyte protoporphyrin was estimated in 166 Thoroughbred horses and the mean value was found to be 4o vg.Poo ml. packed cells. Signifi-cantly lower haemoglobin concentrations were found in 21 horses whose erythrocyte protoporphyrin concentration was 7o p.g.lioo ml. packed cells or greater.
Littlejohn A.The arterial oxygen tension (PaO2) in clinically normal newborn foals at 1300 m above sea-level is considerably lower (less than 60 mmHg) than in similarly aged foals at lower altitudes. This figure is further reduced to less than 50 mmHg without adverse effect in newborn foals at 1300 m maintained under pentobarbitone anaesthesia for prolonged periods. Measurement of O2 dissociation curves indicates that haemoglobin becomes saturated at a lower blood O2 tension in newborn foals than adult horses.
Manohar M, Goetz TE, Hassan AS.Recently, it was reported that acute hypervolemia improves arterial oxygen tension in human athletes known to experience exercise-induced arterial hypoxemia. Since exercise-induced arterial hypoxemia is routinely observed in racehorses and is known to limit performance, we examined whether pre-exercise induction of acute hypervolemia would similarly benefit arterial oxygenation in maximally exercising thoroughbred horses. Two sets of experiments, namely, placebo [intravenous (IV) physiological saline] and acute hypervolemia (IV 7.2% NaCl, causing an 18.2% expansion of plasma volume) studies we...
Komosa M, Flisińska-Bojanowska A, Gill J.1. In six foals and their mothers (of Standard breed) diurnal changes in the haemoglobin level, red blood cell number and mean corpuscular haemoglobin during the first 13 weeks of foal life were studied. 2. Studies begun when a foal reached 7 days of age and were repeated every two weeks till 13 weeks of foal life. Blood was taken every 6 hr in foals and every 4 hr in mares. 3. No diurnal rhythmicity in parameters studied either in foals or in mares was found. 4. Decrease of haemoglobin level in lactating mares (14.0-12.5 g/100 ml) without changes in red blood cell number were observed. Mean c...
Gallagher K, Stowe HD.Blood samples were obtained from 45 racing Standardbred horses immediately before and immediately after a training jog at a commercial race track to establish reference values for serum selenium and related values of the peroxide reduction system of racing horses. Hemoglobin, hematocrit, and serum selenium increased significantly (P < 0.001), whereas RBC-reduced glutathione decreased significantly (P < 0.01) immediately after exercise. Glutathione peroxidase and glutathione reductase were not altered by exercise. Serum copper and magnesium were significantly increased (P < 0.01) after exercise...
Kitchen H, Bunn HF.Studies were made of the O2 affinities of fetal and maternal haemoglobins in the horse, and correlations were found with erythrocytic levels of 2,3-diphosphoglycerate.
Milne EM.Equine serum haptoglobin was separated by polyacrylamide gel isoelectric focusing and visualized by protein staining or Western blotting. Conventional protein staining revealed up to three bands in the pI range 4.17 to 4.44. The blotting technique, however, showed an anodal group of 8 to 10 bands with a pI range of 4.11 to 4.52 and a cathodal group of 4 to 6 bands with a range of 4.55 to 5.14. The blotting method revealed that equine haptoglobin migrates outside the prealbumin area, in contrast to previous reports.
Christley RM, Evans DL, Hodgson DR, Rose RJ.We investigated and compared arterial blood gas and ventilatory changes during rapid acceleration sprint and during incremental treadmill exercise. Seven clinically normal racehorses completed standardised incremental exercise tests and rapid acceleration tests at speeds calculated to elicit 115% VO2max. Arterial oxygen tension decreased (P < 0.001) between 15 s (mean +/- s.d. 103.8 +/- 14.3 mmHg) and 30 s (85.0 +/- 7.7 mmHg) after the onset of rapid acceleration exercise, but did not change significantly during the remainder of the sprint. This was accompanied by an increase in PaCO2 of 5....
Osterhoff DR, Groenewald J.By using isoelectric focusing in thin agarose slab gels 1049 Thoroughbred, 82 Nooitgedachter, 45 Percheron and 244 horses of other breeds were examined. The numbers of other Equidae tested were 107 donkeys, 50 mules, 4 common zebras (Equus burchelli boehmi) and 8 mountain zebras (Equus zebra hartmannae). Phenotypic data are presented for all tested animals and gene frequencies are calculated for the horses.
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...
Khittoo G, Vermette L, Nappert G, Lariviere N.In mammalian species studied previously, pepsinogen consisted of biochemically different groups of isozymogens. By use of gel filtration chromatography and electrophoresis, we isolated a predominant pepsinogen from the gastric mucosa of a horse. Peptide mapping with V8 protease revealed differences with its porcine homologue. However, porcine and equine pepsinogens, when activated to pepsin, had a similar pattern of activity when hemoglobin was used as substrate. Those results suggest that differences must exist in the primary structure of the pepsinogens of the 2 species.
Dart A, Perkins N, Dowling , Batterham T, Livingston C, Hodgson D.To evaluate the effects of three different doses of sodium pentosan polysulphate (PPS) on haematological and haemostatic variables in adult horses. Methods: Eight adult standardbred horses were used. All horses received a single injection of 0, 3, 6, and 10 mg/kg of PPS at the beginning of each treatment week for 4 weeks so that by the end of the study all horses had received all four doses of PPS. Blood samples were collected at 0, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 168 h after each weekly injection of PPS. Variables measured were packed cell volume, haemoglobin, red blood cell count, mean cor...
Binev R, Valchev I, Nikolov J.Monitoring of changes in some blood laboratory parameters in 34 horses after ingesting freshly harvested maize that was to be used for ensiling, heavily contaminated with young Datura stramonium plants, is described. For a 7-day period the following parameters were monitored: haemoglobin content (HGB), red blood cell counts (RBC), white blood cell counts (WBC), haematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), differential white cell counts (DWC), erythrocyte sedimentation rate (ESR), protein fractions, aspa...
