Potassium is an essential mineral and electrolyte that is vital for various physiological processes in horses. It is involved in maintaining cellular function, fluid balance, and nerve signal transmission. Potassium is predominantly stored within the cells and plays a role in muscle contraction and heart function. The dietary intake of potassium is primarily through forage, and its balance is regulated by the kidneys. Abnormal potassium levels can lead to health issues such as muscle weakness or cardiac disturbances. This page compiles peer-reviewed research studies and scholarly articles that explore the role, regulation, dietary sources, and clinical implications of potassium in equine health.
Stick JA, Robinson NE, Krehbiel JD.Esophageal fistulas were made in 6 ponies to evaluate whole blood acid-base values and serum and salivary electrolyte alterations associated with salivary depletion. Acid-base and electrolyte values remained within normal ranges for 15 days in 3 control ponies fed a pelleted diet through nasogastric tubes. In 6 ponies with esophageal fistulas that were fed the same diet through esophagostomy tubes, hypochloremia and hyponatremia developed during the same period. Serum K concentrations were only marginally depleted, probably because of dietary replacement. Salivary depletion resulted in transie...
Behr MJ, Hackett RP, Bentinck-Smith J, Hillman RB, King JM, Tennant BC.Rupture of the urinary bladder was diagnosed in 4 neonatal male foals. Marked hyponatremia, hypochloremia, and hyperkalemia developed in all 4 cases, and the electrolyte abnormalities were considered to be of potential diagnostic value. Blood urea nitrogen concentration was normal or only slightly higher than normal in 3 of 4 cases and therefore was not a reliable diagnostic test.
Rumbaugh GE, Carlson GP, Harrold D.Clinicopathologic effects of rapid intravenous infusion of 3 L of 5% dextrose in water containing 150 g of sodium bicarbonate were evaluated in 8 clinically normal horses. A highly significant metabolic alkalosis was produced in all the horses. This response was maximal at the end of the 20-minute infusion but persisted for as long as 8 hours. Packed cell volume, total plasma proteins, plasma potassium, and plasma chloride concentration decreased significantly after infusion, while plasma sodium concentration increased significantly. The clinical and clinicopathological responses of the horses...
Rose RJ.In this article a physiological approach to fluid therapy is discussed, commencing with examination of fluid distribution in the normal horse. The functions of individual plasma electrolyte concentrations are considered and practical causes of acid-base disturbances discussed. When fluid administration is necessary, selection of the route for fluid administration as well as the type of fluid are important considerations and these must be adjusted to the needs of the individual case. Balanced polyionic solutions appear to be most suitable for general use because normal saline can produce hypoka...
Lucke JN, Hall GM.Blood samples were taken before and after a cross country race over the marathon distance of 42 km. There was a rise in blood glucose and plasma free fatty acids and glycerol associated with a rise in plasma cortisol and glucagon but the fall in insulin was not significant (P > 0.05). Plasma potassium and albumin concentrations increased, calcium decreased and there was no change in sodium or bicarbonate concentrations. There was an increase in plasma urea, creatinine, uric acid, bilirubin and isocitrate dehydrogenase but no change in alkaline phosphatase. There was a rise in plasma creatine k...
Lindsay WA, McDonell W, Bignell W.Intracompartmental muscle pressures were recorded from the right and left forelimbs (extensor carpi radialis, triceps brachii) of healthy horses maintained in left lateral recumbency while under deep halothane anesthesia for 180 to 240 minutes. Cardiac output, blood pressure, blood gases, and acid-base status were monitored throughout the anesthesia, and electrolyte levels (Ca2+, P+, K+, Cl-, Na+) and enzyme activities (aspartate aminotransferase (AST), creatine phosphokinase (CPK), and blood lactate) were monitored for 7 days. Postanesthetic forelimb lameness was produced in 5 of the 6 horses...
Lucke JN, Hall GN.Blood samples were taken before and immediately after 80 km and 40 km rides held on consecutive days and analysed for haematocrit, blood glucose and lactate, plasma sodium, potassium, calcium, albumin, free fatty acids (FFA), glycerol, bicarbonate, insulin, cortisol, glucagon, urea, creatinine, uric acid, bilirubin and alkaline phosphatase. Unusually hot weather probably contributed to haemoconcentration with a significant (P < 0.001) increase in haematocrit and plasma albumin. A fall in blood glucose, with a rise in FFA and glycerol were consistent with long distance riding and were associ...
Macleod AJ, Drummond O.Foetal and new born bovine sera, horse serum, human serum and human plasma, and protein solutions prepared from the by-products of human plasma fractionation have been analysed. Foetal bovine sera were found to have lower total protein (g/l) and % of gamma-globulin than the other sera studied while the potassium (mmol/1) was higher. Protease inhibitors could be detected in all specimens tested.
Rose RJ, Arnold KS, Church S, Paris R.Blood samples were taken from 20 horses competing in a 100 km endurance ride and plasma concentrations of sodium, potassium, chloride, bicarbonate and protein measured. Measurements were performed on samples taken before the ride (pre-ride), at the mid point and end of the ride and after a 30 min recovery period (post-ride). Sweat samples were collected from 6 horses competing in the endurance ride and 14 horses competing in a 3-day event competition and sweat concentrations of sodium, potassium and chloride measured. There were substantial decreases in plasma electrolyte concentrations, which...
Benson GJ, Hartsfield SM, Smetzer DL, Thurmon JC.Succinylcholine chloride, administered to horses anesthetized with halothane in oxygen and mechanically ventilated, caused slight but significant (P less than 0.01) increases in heart rate. Significant alteration in mean arterial blood pressure did not occur, and there were clinically insignificant increases in serum K+ and C1- concentration. Cardiac dysrhythmia and myoglobinuria did not occur. Thus, effects of halothane anesthesia and mechanical ventilation prevented cardiac dysrhythmia and hypertension and greatly reduced the tachycardia generally associated with siccinylcholine administrati...
Scott EA, Riebold TW, Lamar AM, Wolz GS, Sandler GA, Thompson LR.With 120 minutes of pneumatic tourniquet application to the distal extremity in the horse, the following effects were noted in the tourniqueted limb vein (TLV): (i) local venous acidemia, (ii) increase in serum K+ concentrations, (iii) minimal changes in plasma total solids, Na+, or osmolality, and (iv) apparent reduction in hematocrit values when compared with the same measurements in the control leg. Tourniquet release after 120 minutes produced a prompt return to base line for PCV and PO2 in the TLV; however, pH, PCO2 and K+ values in the TLV required 10 to 15 minutes to reach base line (TL...
Campbell DL, Douglas LW, Ramge JC.Siliconized rubber tubes were used to cannulate one oviduct in 7 mares, and secretions were collected in a polycarbonate container located externally, in the region of the left paralumbar fossa. Secretion rates were recorded daily during the estrous cycle. Concentrations of calcium, magnesium, sodium, potassium, inorganic phosphorus and glucose were determined in the oviduct fluids secreted throughout the estrous cycle. Secretion rates were greatest during estrus (days 1-9), with a significant decrease (P<.01) noted during nonestrus (days 10-21). Concentrations of all constitutents measured...
Keenan DM.Changes in concentration of a number of blood metabolites in 30 thoroughbred horses were recorded after an 1110 metre race. No significant changes occurred in blood urea or aspartate aminotransferase during the three hours after racing. Plasma sodium, potassium and calcium levels were increased immediately after racing but had returned to normal one hour after racing. Plasma phosphate showed a significant fall in concentration one hour after racing. Creatinine and lactic acid concentrations were elevated ten minutes after racing and although they subsequently decreased, the level of lactic aci...
Rose RJ, Backhouse W, Chan W.Changes in plasma sodium, potassium, chloride, total carbon dioxide, urea, creatinine, glucose, total bilirubin, iron, total protein, albumin, alkaline phosphatase (AP), aspartate amino transferase (AST), calcium, inorganic phosphorus, cholesterol and triglycerides were studied in 45 Thoroughbred foals 15 min to 28 days after birth. The results were analysed in 3 groups; Group 1 (0--12 h), Group 2 (12--36 h), Group 3 (1--4 weeks). When Group 2 was compared to Group 1, there were significant reductions of sodium, creatinine, iron and calcium and elevations of total protein and bilirubin. When G...
Sato T, Oda K, Kubo M.Hematological and biochemical parameters in five Thoroughbred foals during the first six months of life are reported. The samples were analyzed for red blood cell, packed cell volume, hemoglobin, platelet, white blood cell, absolute number for leukocytes, and erythrocyte fragility and serum calcium, inorganic phosphorus, sodium, potassium, chloride, magnesium, alkaline phosphatase, icterus index unit, bilirubin, blood urea nitrogen, nonprotein nitrogen, blood glucose, lacticdehydrogenase, glutamic pyruvic transaminase, glutamic oxalacetic transaminase, total protein, albumin, globulin, and A/G...
Brook D, Schmidt GR.A case of pre-renal azotaemia is described in a 12 year old pony resulting from oesophageal obstruction of 8 days duration. Blood urea nitrogen, creatinine, calcium, inorganic phosphate, sodium, potassium, chloride and bicarbonate concentrations were monitored throughout the recovery period. After relief of the obstruction normal blood concentrations were quickly restored.
Peaker M, Rossdale PD, Forsyth IA, Falk M.Small samples of mammary secretion were taken for analysis from Thoroughbred mares during the last 3 weeks of pregnancy up to the time of foaling. The concentrations of sodium and chloride decreased while those of lactose, potassium, citrate, phosphate, calcium, magnesium and protein increased. The time-course of these changes showed marked variation between animals. The concentration of whey proteins began to increase about 10 days before parturition. The appearance of the secretion and the size of the mammary glands increased in the last few days of pregnancy. It is suggested that the concen...
Muir WW, Kohn CW, Sams R.The effects of IV administered furosemide upon plasma volume (PV) and extracellular fluid volume were determined in horses at rest and after exercise. Serum sodium, potassium, chloride, and osmolality determinations were made. Furosemide caused a significant (P less than 0.05) decrease in PV and serum potassium concentrations in resting horses only. Furosemide's effects upon PV and electrolytes were evident longer than its hemodynamic effects.
Quist EE, Hokin LE.A potent inhibitor of (Na+ + K+)-ATPase activity was purified from Sigma equine muscle ATP by cation- and anion-exchange chromatography. The isolated inhibitor was identified by atomic absorption spectroscopy and proton resonance spectroscopy to be an inorganic vanadate. The isolated vanadate and a solution of V2O5 inhibit sarcolemma (Na+ + K+)-ATPase with an I50 of 1 micrometer in the presence of 1 mM ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA), 145 mM NaCl, 6mM MgCl2, 15 mM KCl and 2 mM synthetic ATP. The potency of the isolated vanadate is increased by free Mg2+. ...
Lucke JN, Hall GM.Blood samples were taken from 15 horses before and after a 50-mile ride to examine the changes occurring in some biochemical constituents. There was a significant (P less than 0.05) decrease in plasma potassium, calcium and magnesium concentrations and a rise in inorganic phosphate but there was no alteration in plasma sodium, chloride or protein levels or change in haematocrit. After the ride there was a highly significant (P less than 0.01) fall in blood glucose corresponding with increased lipolysis and a rise in plasma free fatty acids (P less than 0.001) and glycerol (P less than 0.001). ...
Komárek J, Matousek V, Jadrný L.Blood parameters were studied in two groups of horses in the "Velká Pardubická" steeple-chase in 1974, 1975 and 1976. After the race, the levels of lactate showed a manifold increase; an increase was also ascertained in the levels of glucose, sodium, potassium, haemoglobin, in the haematocrit value and in the number of erythrocytes. The following parameters significantly dropped: the levels of acid-base balance - pH, base excess, bicarbonate levels. It was proved that the values of the same parameters in horses during training were incomparably lower. It is advisable to examine horses thorou...
Alexander F.1. The effect on plasma, urinary and faecal electrolytes of frusemide and hydrochlorthiazide was measured in ponies, mean weight 180 kg. 2. The rapid loss in urine of large quantities of sodium had only a small effect on plasma sodium concentration. 3. Faecal sodium excretion was increased substantially after the administration of frusemide. 4. Frusemide increased faecal potassium during the 48 h following administration and faecal water in the 24/48 h period. It also produced a hypopotassaemia. 5. Hydrochlorthiazide increased faecal chloride during the 24 h after administration. 6. Frusemide ...
Mayhew IG, Whitlock RH, Tasker JB.Cerebrospinal fluid (CSF) samples were collected from the atlanto-occipital (AO) and lumbosacral (LS) subarachnoid spaces of 24 horses and 21 ponies that had no clinical evidence of neurologic disease. Depth of needle insertion, pressures, refractive index, rapid reagent strip test (protein, glucose, blood, pH) results, cell counts, content of protein, glucose, sodium, potassium, chloride, calcium, phosphorus, urea nitrogen, and cholesterol, and activities of creatine phosphokinase, aspartate transaminase, lactic dehydrogenase, and alkaline phosphatase were determined. The resulting clinical r...
Honstein RN, Monty DE.Field investigations were conducted under natural environmental conditions to determine the physiologic responses of rested, hydrated horses (Equus caballus) to the very hot, dry weather characteristic of the summer season in southern Arizona. The emphasis of the investigation was placed on those thermoregulatory mechanisms which are involved in the maintenance of homoiothermy. Rectal temperature of the horses studied remained relatively stable throughout the day, during both cool and hot weather seasons. However, when horses were exposed to hot summer temperatures, rectal temperature (heat st...
Rose RJ, Purdue RA, Hensley W.The effects of prolonged strenous exercise on the plasma concentrations of sodium, potassium, calcium, chloride, bicarbonate, phosphate, albumin, cholesterol, glucose, creatinine, bilirubin, alkaline phosphatase, creatine phosphokinase, lactic dehydrogenase and asparate amino transferase were studied in a group of 26 horses competing in an endurance ride. There were significant changes in most parameters, when control values were compared with those taken immediately after the ride. There was also a significant correlation between several biochemical parameters and heart rate taken 30 minutes ...
Serrano L, Lees P, Hillidge CJ.Ponies were anaesthetized by administration of the ataractic, azaperone (0 · 2–0 · 8 mg/kg), in combination with the hypnotic, metomidate (3 · 5 mg/kg). Changes in blood biochemistry were measured during and following the course of action of these drugs. In control experiments, azaperone (0 · 4 and 0 · 8 mg/kg) was administered alone to other ponies. There were no significant changes in blood glucose concentration in either circumstance. Blood lactate and pyruvate concentrations and lactate/pyruvate ratio were not altered significantly by azaperone. However, moderate increases in lactat...
Hintz HF, Schryver HF.Potassium metabolism and some metabolic interractions of K, Mg and Ca were studied in a series of balance trials with ponies. The kidney was the primary pathway of K excretion. Increasing K intake markedly affected the renal excretion of K but had only small effects on fecal excretion. Increasing K intake increased retention and apparent digestibility of K. High levels of dietary Ca (3.4%) did not influence K metabolism but the highest level of Mg (.81%) increased the apparent digestibility of K. A level of 3.4% K did not decrease Mg, P or Ca digestibility and retention. The maintenance requir...
Polack EW, King JM, Cummings JF, Mohammed HO, Birch M, Cronin T.To compare concentrations of trace minerals in the spinal cord of horses with equine motor neuron disease (EMND) with those of horses without neurologic disease (control horses). Methods: 24 horses with EMND and 22 control horses. Methods: Spinal cord trace mineral concentrations in horses with EMND and control horses were analyzed by use of inductively coupled plasma atomic emission spectroscopy (calcium, phosphorus, sodium, potassium, magnesium, copper, iron, manganese, nickel, zinc, aluminum, cobalt, and chromium), atomic absorption spectrophotometry (lead and cadmium), flameless atomic abs...
Canisso IF, Ball BA, Troedsson MH, Silva ES, Davolli GM.The objectives of this study were to determine pH of the mammary gland secretions and the corresponding electrolyte concentrations in prefoaling mares. Pregnant mares (seven primiparous and seven multiparous) were monitored daily from 310-320 days of gestation until parturition. Prefoaling mammary gland secretions were collected, and pH was immediately determined with a pH meter and pH strip test. An aliquot of prefoaling mammary secretions was frozen and stored until further analyses. After parturition, samples from day -4 to 0 (day of foaling) were thawed and electrolyte concentrations (ie, ...
Dyke TM, Hinchcliff KW, Sams RA.The objectives of this study were to determine the effect of phenylbutazone premedication on the pharmacokinetics and urinary excretion of frusemide in horses; and on frusemide-induced changes in urinary electrolyte excretion. Six Standardbred mares were used in a 3-way crossover design. The pharmacokinetics and renal effects of frusemide (1 mg/kg bwt i.v.) were studied with and without phenylbutazone premedication (8.8 mg/kg bwt per os 24 h before, followed by 4.4 mg/kg bwt i.v. 30 min before frusemide administration). A control (saline) treatment was also studied. Administration of frusemide...
Suska M, Skotnicka E.The aim of this study was to examine the relationships between the concentrations of ATP, ADP, AMP (HPLC methods), total nucleotide pool (TAN), adenylate energy charge (AEC) and Na(+), K(+)-ATPase erythrocytic activities (by Choi's method) of horses as a function of breed and sex. The studies were conducted on 54 horses (stallions and mares) of different constitution types: breathing constitution (Wielkopolska and Hanoverian breed) and digestive constitution (Ardenian breed). Horse erythrocytes, independently of examined breed, present low ATP concentration in comparison to other mammal specie...
Zhang XY, Zhu FX, Robinson NE.To investigate the effects of changes in intracellular cAMP on alpha 2-adrenoceptor (AR)-induced inhibition of airway acetylcholine (ACh) release, we examined the effects of the alpha 2-AR agonist clonidine on electrical field stimulation-evoked ACh release from equine tracheal parasympathetic nerves before and after treatment with 8-bromo-cAMP or forskolin. We also tested whether charybdotoxin (ChTX)- or iberiotoxin (IBTX)-sensitive Ca(2+)-activated K+ channels mediate alpha 2-AR-induced inhibition by examining the effect of clonidine in the absence and presence of ChTX or IBTX on ACh release...
Martens RJ, Cohen ND, Chaffin MK, Waskom JS.To quantify and compare geochemical factors in surface soils from horse-breeding farms with horses with pneumonia caused by Rhodococcus equi (affected farms) and horse-breeding farms with no history of pneumonia caused by R equi (unaffected farms). Methods: Soil from 24 R equi-affected farms and 21 unaffected farms. Methods: Equine veterinary practitioners throughout Texas submitted surface soil samples from areas most frequented by foals, on R equi-affected and unaffected horse-breeding farms in their practice. Soil samples were assayed for the following factors: pH, salinity, nitrate, phosph...
Neuhauser S, Palm F, Ambuehl F, Möstl E, Schwendenwein I, Aurich C.Mares with compromised pregnancies are often treated with altrenogest to prevent abortion. However, there is only limited information about effects on the foal when altrenogest treatment is continued during final maturation of the fetus. Objective: To determine effects of altrenogest treatment during late gestation in mares on maturity, haematology changes, adrenocortical function and serum electrolytes in their newborn foals. Methods: Six mares were treated with altrenogest (0.088 mg/kg bwt) once daily from Day 280 of pregnancy until foaling and 7 mares served as controls. Results: Foals born...
Bollinger L, Bartel A, Küper A, Weber C, Gehlen H.High elimination rates and the concern for horse welfare are important issues in endurance riding. An improved understanding of the causes of elimination could increase completion rates in this sport. We have identified pre-ride risk factors that allow an assessment of potential elimination before the ride. A longitudinal cohort study was performed among 49 healthy horses competing in the 160 km endurance ride at the 2016 World Championship of Endurance Riding in Samorin/Slovakia. Blood samples were drawn before the ride. For statistical evaluation, horses were categorized in three groups: fin...
Jansson A, Nyman S, Morgan K, Palmgren-Karlsson C, Lindholm A, Dahlborn K.In this study 4 Standardbred geldings (age 3-8 years, weight 431-531 kg) were used. The horses were fed a hay and oat diet and the total sodium intake was about 32 mg/kg bwt (690 mmol/day). An exercise test (ET) which contained 3 phases was performed. Phase I consisted of 23.5 min of mainly submaximal exercise, Phase 2 of 2 h of box rest and Phase 3 of 26 min of exercise including an intensive trot over 2600 m at 90% of VO2max. The ET was repeated 3 times: the first at 20 degrees C (30-40% RH), the second at 35 degrees C (30-40% RH) and the third at 35 degrees C (30-40% RH) after a nasogastric...
Suwannachot P, Verkleij CB, Kocsis S, van Weeren PR, Evertst ME.The purpose of the present study was to determine whether training and detraining affect the Na+,K+-ATPase concentration in horse skeletal muscles, and whether these effects are specific for the muscles involved in the training programme. Twenty-four Dutch Warmblood foals age 7 days were assigned randomly to 3 groups: Box (box-rest without training), Training (box-rest with training: short-sprint) and Pasture (pasture without training). Exercise regimens were carried out for 5 months and were followed by 6 months of detraining. Five of the foals in each group were subjected to euthanasia at ag...
Ousey JC, Dudan FE, Rossdale PD, Silver M.The effectiveness of the prostaglandin F analogue fluprostenol in inducing labour in the mare was examined by giving sequential injections over the last 50 days of gestation. The behavioural and endocrine changes elicited by the drug in pregnant and non-pregnant animals and in foals were also studied. Fluprostenol (250 or 500 micrograms intramuscularly) failed to induce labour before 320 days gestation; thereafter its effect was capricious. Twelve mares foaled 1 to 36 h after the last test; eight delivered normal, viable, apparently 'term' foals and four produced stillborn/premature animals. E...
McKenzie EC, Valberg SJ, Godden SM, Pagan JD, Carlson GP, MacLeay JM, DeLaCorte FD.To determine daily variation in urinary clearance and fractional excretion (FE) of electrolytes and minerals within and between horses and to compare volumetric and single-sample urine collection for determining FE values of diets with a range of dietary cation-anion balance (DCAB). Methods: 5 Thoroughbred and 6 mixed-breed mares. Methods: 3 isocaloric diets with low, medium, and high DCAB values (85, 190, and 380 mEq/kg of dry matter, respectively) were each fed for 14 days. Daily blood samples, single urine samples collected by using a urinary catheter (5 mares), and volumetric urine collect...
Jansson A, Lindholm A, Dahlborn K.The effect of a temporary increase in plasma aldosterone concentration on Na(+), K(+), and water balance was investigated in four horses. Aldosterone was injected intravenously for 6 h at 20-min intervals (total 5.4 microg/kg body wt). Samples were taken for 24 h before, during, and for 48 h after the treatment. Aldosterone treatment reduced the Na(+) loss via urine and feces by 99 and 72%, respectively, later followed by a marked increase in Na(+) excretion by both pathways. During the first 6 h after the treatment, fecal K(+) excretion was elevated, and the plasma K(+) concentration was lowe...
Wagner IP, Hood DM.To evaluate the effect of prolonged water exposure on tissue mass and solutes of outer and inner layers of the stratum medium, sole, frog, and the stratum medium (SMZA) zona alba layer of horses' hooves. SPECIMEN POPULATION: 10 hooves from 10 horses without foot abnormalities. Methods: Hoof wall tissue specimens were obtained and immersed for 10 days in distilled deionized water. Serial changes in mass were recorded during the immersion period. Subsequently, osmolarity and Na+, K, Cl-, and protein concentrations of the immersion solution were quantified. Results: Fully cornified outer hoof wal...
Larsen EA, Lack AC, Wassack E.The use of poloxamer 407 gels have been reported in several studies to prolong the release of drugs at the injection site. Oral lesions unrelated to dental disease are rare but may result in ulceration and sequestration of bone. To date, there have been no reports on the use of penicillin G potassium poloxamer 407 gel and its effect on wound healing. The present case report describes the use of a penicillin G potassium poloxamer 407 gel for the treatment of a sublingual abscess involving the mandible in a 20 year old Arabian mare who initially presented with acute onset of dysphagia, hypersali...
Saulez MN, Cebra CK, Dailey M.Fifty-six horses with colic were examined over a period of three months. The concentrations of glucose, lactate, sodium, potassium and chloride, and the pH of samples of blood and peritoneal fluid, were determined with a portable clinical analyser and with an in-house analyser and the results were compared. Compared with the in-house analyser, the portable analyser gave higher pH values for blood and peritoneal fluid with greater variability in the alkaline range, and lower pH values in the acidic range, lower concentrations of glucose in the range below 8.3 mmol/l, and lower concentrations of...
Brooks CL, Garry F, Swartout MS.Analytical characteristics of photometry and ion-specific potentiometry for urine from sheep, horses, cows, dogs, and cats were determined, using solutions of sodium and potassium chloride. The performance of both methods were acceptable, but the ion-specific potentiometer (in the mode for urine analysis) was superior in terms of linearity of response and correlation between actual vs measured concentrations. Coefficients of variation of either method for repeated analyses of various concentrations of sodium and potassium were always less than 2.5%. The measurement of sodium concentration in u...
Walton RM, Brown DE, Hamar DW, Meador VP, Horn JW, Thrall MA.Transient echinocytosis has been reported in association with snake envenomation in humans and dogs. An in vitro model of echinocytosis induced by venom of crotalus atrox (western diamondback rattlesnake) was established to characterize erythrocyte morphologic changes and to investigate potential mechanisms of echinocytic transformation. Erythrocyte morphologic changes produced after the addition of venom to canine, feline, equine, and human blood were characterized by dose-dependent echinocytosis. Type III echinocytosis were consistently induced in vitro at a dose comparable to in vivo enveno...
Aguilera-Tejero E, Estepa JC, López I, Bas S, Mayer-Valor R, Rodríguez M.The acid-base status of venous blood was studied in 17 show jumpers before and after exercise using both a traditional and a quantitative approach. Partial pressure of carbon dioxide (PCO(2)), pH, haemoglobin, and plasma concentrations of sodium (Na(+)), chloride (Cl(-)), potasium (K(+)), ionized calcium (Ca(2+)), total proteins, albumin, lactate and phosphorus were measured in jugular venous blood samples obtained before and immediately after finishing a show jumping competition. Bicarbonate, anion gap and globulin concentration were calculated from the measured parameters. 'Quantitative anal...
Johnson PJ, Goetz TE, Foreman JH, Vogel RS, Hoffmann WE, Baker GJ.The effects of whole-body potassium depletion induced by food deprivation on plasma, erythrocyte, and middle gluteal muscle K concentrations was quantified in 16 healthy, adult horses before, during, and at the end of a 7-day period of food deprivation during which water and sodium chloride were available ad libitum. Potassium concentrations were determined by atomic absorption spectroscopy. Plasma K concentration remained constant (3.49 +/- 0.09 mM K/L of plasma; mean +/- SEM) throughout the study. Erythrocyte potassium concentration decreased from 93.10 +/- 1.94 mM K/L of erythrocytes on day...
Beech J, Lindborg S.Horses with hyperkalaemic periodic paralysis were challenged with an oral dose of potassium chloride, and the prophylactic efficacy of phenytoin, acetazolamide and hydrochlorothiazide was evaluated, with at least three weeks separating the trials of each drug. After the administration of potassium chloride without prophylactic medication the horses' clinical signs ranged from generalised fine muscle fasciculations to gross tremors, and weakness with occassional prolapse of the nictitating membrane; plasma potassium concentration increased significantly (P < 0.01) from 4.0 +/- 0.2 to 6.0 +/-...
Nelson EA, Sanchez LC, Mallicote MF, Warren LK, Robelen AM, Reuss SM. To compare urine urinary pH, blood pH and concentration of electrolytes in blood of healthy horses fed an anionic salt supplement to achieve diets with a dietary cation-anion difference (DCAD) of -40 or 0 mEq/kg DM, with horses a fed a diet with a DCAD of 85 mEq/kg DM. Eight healthy horses received each of three diets in a randomised crossover design. Diets consisted of grass hay and concentrate feed, with a varying amount of an anionic supplement to achieve a DCAD of 85 (control), 0 or -40 mEq/kg DM. They were fed for 14 days each with a washout period of 7 days between. Urine pH was m...
Wilson KE, Bogers SH, Council-Troche RM, Davis JL.To determine the effects of general anesthesia on the safety and efficacy of co-administered potassium penicillin G (PEN) and gentamicin (GENT) in horses. Methods: Nonrandomized crossover. Methods: Six adult, Thoroughbred horses. Methods: Horses were administered PEN (22 000 IU/kg IV) and GENT (6.6 mg/kg IV). Plasma samples were collected over a 6 h period and synovial fluid was collected at 30 min and 6 h respectively. Drug administration and sample collection protocols were repeated after at least a 48 hour washout period and induction of anesthesia using xylazine/ketamine and main...
Mealey RH, Carter GK, Roussel AJ, Ruoff WW.Two different fluid solutions were infused through percutaneous cecal catheters in 6 healthy ponies to determine the effects on body weight; CBC; packed cell volume (PCV); total plasma protein concentration; plasma fibrinogen concentration; abdominal fluid analysis; concentrations of blood urea nitrogen (BUN), serum creatinine, Ca, total CO2 (TCO2), Na, Cl, K, and P; and fractional clearance (FC) of Na, Cl, K, and P. During intracecal administration of solution 1, FCNa and FCCl were significantly increased, whereas FCK and BUN were significantly decreased. During administration of solution 2, ...
Finley MR, Li Y, Hua F, Lillich J, Mitchell KE, Ganta S, Gilmour RF, Freeman LC.In dogs and in humans, potassium channels formed by ether-a-go-go-related gene 1 protein ERG1 (KCNH2) and KCNQ1 alpha-subunits, in association with KCNE beta-subunits, play a role in normal repolarization and may contribute to abnormal repolarization associated with long QT syndrome (LQTS). The molecular basis of repolarization in horse heart is unknown, although horses exhibit common cardiac arrhythmias and may receive drugs that induce LQTS. In horse heart, we have used immunoblotting and immunostaining to demonstrate the expression of ERG1, KCNQ1, KCNE1, and KCNE3 proteins and RT-PCR to det...
Beech J, Fletcher JE, Tripolitis L, Lindborgh S.The effects of phenytoin treatment were evaluated in 2 myotonic horses with hyperkalemic periodic paralysis (HPP). Phenytoin treatment abolished the clinical signs of muscle fasciculations following oral potassium challenge and decreased or abolished repetitive firing and myotonic discharges found on electromyographic examination. In both horses, an abnormally low threshold for calcium-induced calcium release was measured in heavy sarcoplasmic reticulum fractions from skeletal muscle, and this threshold increased with phenytoin treatment. Results suggest phenytoin is useful in modifying disord...
Held JP, Wright B, Henton JE.A 20-year-old gelding with weight loss and generalized weakness that progressed gradually over a 3-month period was diagnosed as having pyelonephritis caused by Staphylococcus aureus infection. Abnormal laboratory findings included high values for BUN, creatinine, potassium, and calcium, and depletion of sodium. Determination of glomerular filtration rate and effective renal plasma flow indicated a severe decrease in renal filtration and perfusion.
Craig L, Hintz HF, Soderholm LV, Shaw KL, Schryver HF.There have been several studies of biochemical changes in horses doing intense exercise such as Thoroughbred and Standardbred racehorses and in horses performing exercise over a long period of time such as endurance horses and three-day eventing horses, but we are not aware of studies with polo horses. Blood samples were taken from 18 polo horses at rest, immediately after playing 2 chukkers of indoor polo, and after a 15 minute rest period. Each horse was studied at 2 different games. The blood samples were analyzed for lactic acid, protein, sodium, potassium, chloride, calcium, phosphorus, H...
Holbrook TC, Simmons RD, Payton ME, MacAllister CG.Electrolyte supplementation is common in horses during endurance competitions, but the effect on the gastric mucosa is unknown. Objective: Repeated oral administration of hypertonic electrolyte solution is associated with exacerbation of gastric ulcers in mature horses. Methods: The study design was a randomised, blinded, crossover trial. Fourteen horses were divided randomly into equal groups and administered either 60 ml water (placebo) or 56.7 g commercial electrolyte supplement mixed with 60 ml water by dose syringe orally once an hour for 8 h. The minimum concentration of individual const...
Kingston JK, McCutcheon LJ, Geor RJ.To quantify total fluid loss in sweat of Thoroughbreds during >3 hours of low-intensity exercise in controlled conditions and to calculate and compare estimated ion losses in sweat, according to 3 methods. Methods: 6 exercise-trained Thoroughbreds. Methods: Fluid and ion losses in sweat were measured in 6 horses exercising at 40% of the speed that elicited maximum oxygen consumption for 45 km. Horses were given a 15-minute rest period at the end of three 15-km exercise phases. Horses completed 2 exercise trials. Ion losses in sweat were calculated, using measurements of local sweating rate and...
