Topic:Acid-base balance
Acid-base balance refers to the regulation of pH levels in the blood and body fluids to maintain optimal physiological function. In horses, maintaining acid-base balance is important for muscle performance, respiratory function, and overall metabolic stability. Disruptions in this balance, such as acidosis or alkalosis, can result from intense exercise, diet, or underlying health conditions. This page compiles peer-reviewed research studies and scholarly articles that examine the mechanisms, regulation, and effects of acid-base balance in equine physiology and health.
Hydroelectrolytic and Acid-Base Parameters after 80 to 115 km Endurance Races (Raid Uruguayo) and Their Association with the Comfort Index. The Raid Uruguayo (RAID) is an equestrian endurance competition. This study characterized the hydroelectrolytic parameters (Na, K, Cl, tCa, and iCa), hematocrit (Ht), total plasma protein (TPP), and blood pH from 900 equine athletes (finishers and non-finishers) competing over distances of 80 to 115 km under different climate conditions. Paired blood samples were taken prior to the start of the competition (sample 1) and at the end of the race or at the time of leaving the competition (sample 2). The association of the comfort index (CI: low, moderate, and high) with blood parameters was evalu...
Tracing Acid-Base Variables in Exercising Horses: Effects of Pre-Loading Oral Electrolytes. Oral electrolyte supplementation may influence acid-base state during exercise due to the intestinal absorption of administered water and electrolytes used to mitigating sweat losses. This study examined the effect of pre-exercise electrolyte supplementation (3 and 8 L) on plasma acid-base variables at rest, during moderate intensity exercise and during recovery. It was hypothesized that electrolyte supplementation will result in improved acid-base state compared to the alkalosis typical of prolonged exercise. In randomized crossover fashion, four horses were administered 3 L or 8 L of a hypot...
Effects of total parenteral nutrition associated with glutamine, enteral fluid therapy with or without glutamine, and fluid therapy on the acid-base and electrolyte balance of horses starved after exploratory laparotomy. This study aimed to evaluate the effects of the total parenteral nutrition associated with glutamine, enteral fluid therapy with or without glutamine, and fluid therapy on the acid-base and electrolyte balance of horses starved after exploratory laparotomy. Sixteen healthy male and female adult horses of mixed breed, aged between 4 and 14 years, and having a mean body weight of 248.40 ± 2.28 kg and a body score index of 3-4 (scale of 1-5) were divided into four groups with four animals per group. After an adaptation period of 30 days, they were randomly divided into four experimental groups: ...
Prerace venous blood gases and acid-base values in Standardbred horses: effects of geography, season, prerace furosemide, gender, age, and trainer using big data analytics. A retrospective study was conducted to establish the prerace venous acid-base and blood gas values of Standardbred horses at rest using big data analytics. Methods: Venous blood samples (73,382) were collected during seven racing seasons from 3 regional tracks in the Commonwealth of Pennsylvania. Horses were detained 2 hours prior to race time. Methods: A mixed-effects linear regression model was used for estimating the marginal model adjusted mean (marginal mean) for all major outcomes. The interaction between age and gender, track, and the interaction between month, treatment (furosemide), a...
Physicochemical Analysis of Mixed Venous and Arterial Blood Acid-Base State in Horses at Core Temperature during and after Moderate-Intensity Exercise. The present study determined the independent contributions of temperature, strong ion difference ([SID]), total weak acid concentration ([Atot]) and PCO2 to changes in arterial and mixed venous [H+] and total carbon dioxide concentration ([TCO2]) during 37 min of moderate intensity exercise (~50% of heart rate max) and the first 60 min of recovery. Six horses were fitted with indwelling carotid and pulmonary artery (PA) catheters, had PA temperature measured, and had blood samples withdrawn for immediate analysis of plasma ion and gas concentrations. The increase in core temperature during exe...
Effect of lactic acid addition to equine whole blood on platelet aggregation measured by impedance aggregometry. Acidemia in sick or injured horses is often due to lactic acid accumulation. Alterations in platelet function and hemostasis are among numerous deleterious effects caused by decreased physiologic pH. Objective: We aimed to evaluate the effect of hyperlactatemia and resultant acidemia on platelet aggregation in equine whole blood using impedance aggregometry. Methods: Platelet aggregation was measured using the Multiplate analyzer in whole blood from 34 healthy horses at baseline and after in vitro addition of lactic acid to adjust the pH. Platelet aggregation of each sample was quantified by t...
Evaluation of Medetomidine-Ketamine for Immobilization of Feral Horses in Romania. Feral horses are immobilized for a variety of reasons including population control via contraceptives. Although opioid combinations have been successfully used for immobilization of feral horses, there is a need for combinations using drugs that are more readily available and present less of a human health hazard. We evaluated the chemical immobilization with physiological measurements and blood gas analyses of 91 free-ranging feral horses () remotely immobilized with a combination of 30 mg medetomidine and 775 mg ketamine in a single disposable 6 ml dart. During immobilization, heart rate, re...
Selected hematological, biochemical, and acid-base variables of Paso Fino horses living at different altitudes. This study aimed at describing selected hematological, biochemical, and acid-base variables of adult horses living at sea level and comparing them to those living at 5 different altitudes. One hundred and thirty-eight healthy Paso Fino horses > 2 years old were enrolled. Altitudes included the following: altitude A (0 to 50 m above sea level, masl; n = 23), B (1000 to 1050 masl; n = 25), C (1450 masl; n = 30), D (1950 to 2050 masl; n = 30), and E (2950 to 3100 masl; n = 30). A portable blood gas analyzer was used to determine selected biochemical and acid-base variab...
Peripartum findings and blood gas analysis in newborn foals born after spontaneous or induced parturition. Induction of parturition in horses is still not well accepted due to the potential peripartum complications for mares and newborn foals. We assessed differences after spontaneous and induced parturition with low doses of oxytocin (OX) in 1) incidence of peripartum complications in mares; 2) viability, behavioral, physical, and venous blood gas analyses in foals. In this study 61 mares were included; 45/61 were enrolled in the spontaneous foaling group (SF) and 16/61 in the induced foaling group (IF). In the IF group, when the calcium in mammary secretion reached concentrations of ≥250 ppm, ...
Production technology, nutritional, and microbiological investigation of traditionally fermented mare milk (Chigee) from Xilin Gol in China. Mare milk originated from female horses, known as mares, to feed their foals during lactation. The health-promoting characteristics of traditionally fermented mare milk (Chigee) are well known for the function of clinic treatment in the traditional Mongolian medicine. This study was conducted to investigate the production technology of Chigee and to evaluate the nutritional and microbiological characteristics of mare milk and Chigee based on 188 samples. The nutritional analysis of mare milk and Chigee indicated that lactose significantly decreased from 6.95 ± 0.45% to 2.82 ± 1.65% and a...
Investigations of Processing-Induced Structural Changes in Horse Type-I Collagen at Sub and Supramolecular Levels. The aim of this work is to evaluate the effects of different extraction and material processing protocols on the collagen structure and hierarchical organization of equine tendons. Wide and Small Angle X-ray Scattering investigations on raw powders and thin films revealed that not only the extraction and purification treatments, but also the processing conditions may affect the extent of the protein crystalline domain and induce a nanoscale "shield effect." This is due to the supramolecular fiber organization, which protects the atomic scale structure from the modifications that occur during f...
Determination of reference intervals for equine arterial blood-gas, acid-base and electrolyte analysis. To establish reference intervals for arterial blood-gas (ABG), acid-base and electrolyte values from a healthy equine population. Methods: Retrospective clinical study. Methods: A total of 139 client-owned, systemically healthy horses, 1 year of age and older, presented for elective surgical procedures. Methods: Blood samples were collected anaerobically from the transverse facial or common carotid artery of horses breathing room air, prior to administration of preanaesthetic medication. Samples were analysed immediately, without correction for body temperature, using an automated bench-top an...
Evaluation of an in vitro system to simulate equine foregut digestion and the influence of acidity on protein and fructan degradation in the horse’s stomach. The aim of this study was to improve an in vitro system in order to gather optimized information on the digestion of different forages in the horse's upper gastrointestinal tract. Therefore, foregut digestion of several forages was simulated in vitro (Part 1). The effect of different pH values on in vitro fructan degradation of two selected grasses (Part 2) was tested subsequently. Part 1: We hypothesized that our system produces representative results simulating digestive processes in the upper alimentary tract, but neglects microbial fermentation. In vitro digestion of six forages (grass ...
Effects of dystocia on blood gas parameters, acid-base balance and serum lactate concentration in heavy draft newborn foals. Dystocia is often lethal for neonatal foals; however, its clinicopathological features remain largely unknown. We investigated the effect of dystocia on the foal blood profile. Venous blood samples were collected from 35 foals (5 Percheron and 30 crossbreds between Percheron, Belgian, and Breton heavy draft horses) at 0 hr, 1 hr, 12 hr and 1 day after birth. Dystocia was defined as prolonged labor >30 min with strong fetal traction with or without fetal displacement. The dystocia group (n=13) showed lower mean values for pH (P<0.01), bicarbonate (P<0.01), total carbon dioxide (P<0....
Effects of Different Oral Doses of Sodium Chloride on the Basal Acid-Base and Mineral Status of Exercising Horses Fed Low Amounts of Hay. The provision of NaCl, according to current recommendations, to horses in moderate work has been shown to induce immediate postprandial acidosis. The present study aimed to clarify whether this NaCl induced acidosis i) persists beyond the immediate postprandial period, and ii) is still present after a 2 week adaptation period. Six adult warmblood mares in moderate work received daily 1.00 kg hay per 100 kg body weight (bwt) only together with 0.64 kg unprocessed cereal grains/100 kg bwt.d as fed basis. Using a 3x3 Latin Square, either 0 (NaCl-0), 50 (NaCl-50) or 100 (NaCl-100) g NaCl/d were fe...
Equine total carbon dioxide testing in Illinois in 2012. During prolonged strenuous exercise, racehorses can experience acidemia. To counteract this phenomenon, trainers can administer blood alkalizing agents that raise the plasma pH and total carbon dioxide (TCO2) concentration. In Illinois, the administrative threshold for TCO2 in plasma is 37.0 mmol/L. Because accuracy in the reported measurement of TCO2 must be ensured, uncertainty measurements are often issued alongside the reported concentrations. We report a validated method for measuring TCO2 levels in equine plasma using the Beckman UniCel DxC 600. A six-point calibration curve ranging from...
Clinical utility of serum biochemical variables for predicting acid-base balance in critically ill horses. Profiles from serum biochemical analyzers include the concentration of strong electrolytes (including l-lactate), total carbon dioxide (tCO2 ), and total protein. These variables are associated with changes in acid-base balance. Application of physicochemical principles may allow predicting acid-base balance from serum biochemistry without measuring whole blood pH and pCO2 . Objective: The purpose of the study was to determine if the acid-base status of critically ill horses could be accurately predicted using variables included in standard serum biochemical profiles. Methods: Two jugular veno...
The effect of colloid formulation on colloid osmotic pressure in horses with naturally occurring gastrointestinal disease. Naturally occurring gastrointestinal disease is an important cause of acute hypoproteinemia in adult horses and hydroxyethyl starch colloid fluid treatment is a component of supportive care in these cases to improve plasma volume and maintain colloid osmotic pressure (COP). The objectives of the present study were to compare 2 formulations of high molecular weight hydroxyethyl starch and their relative effect on COP, acid-base status, and survival of horses with acute hypoproteinemia secondary to gastrointestinal disease. Methods: Twenty adult horses, ≥ 1 year of age, were prospectively enro...
Prevalence and species identification of Cryptosporidium from fecal samples of horses in Taiwan. Cryptosporidiosis is a zoonotic disease caused by the protozoan parasite Cryptosporidium. A total of 436 horse fecal samples were collected from 19 farms, and acid-fast staining method was used for primary screening. Cryptosporidium oocysts were found in 161 samples, among which 33 positive sample were selected for nested PCR, restriction fragment length polymorphism analysis and DNA sequencing of 18 S rDNA, showing 31 samples to be bovine C. parvum and 2 C. felis. The methods employed in this study should be useful as tools to identify cryptosporidiosis genotypes and species of livestock.
Blood glucose, acid-base and electrolyte changes during loading doses of alpha₂-adrenergic agonists followed by constant rate infusions in horses. The aim of the present study was to investigate changes in blood glucose concentration ([Glu]B), acid-base status and electrolyte concentrations during constant rate infusions (CRI) of two alpha2-adrenergic agonists in seven horses treated in a blinded, randomised, crossover design with xylazine or romifidine. An intravenous (IV) bolus of xylazine (1mg/kg) or romifidine (80 μg/kg) was administered followed by an IV CRI of xylazine (0.69 mg/kg/h) or romifidine (30 μg/kg/h) for 2h. Blood samples were collected from the pulmonary artery before and after loading doses, during the CRI, and for 1h...
Acid-base indicators in the venous and arterial blood of horses affected by recurrent airway obstruction (RAO). The acid-base equilibrium is closely linked to gas exchange in the lungs, and respiratory exchange ratios are used to evaluate respiratory effectiveness and tissue oxygen levels. Acid-base indicators are determined in both arterial and venous blood samples. This study compares the usefulness of acid-base indicators of venous and arterial blood in monitoring the condition of horses with recurrent airway obstruction. Prior to treatment involving bronchodilating glucocorticoids, expectorant and mucolytic drugs, more pronounced changes were observed in venous blood (pH 7.283, pCO2 61.92 mmHg, pO2 ...
Traditional and quantitative assessment of acid-base and shock variables in horses with atypical myopathy. Descriptions of acid-base disturbances in atypical myopathy (AM) are limited. Objective: Describe and compare traditional and quantitative acid-base abnormalities and cardiovascular shock status in horses with AM at admission. Methods: 34 horses with AM, 15 healthy controls. Methods: Retrospective case-control study. Records were searched for shock variables (packed cell volume [PCV], blood urea nitrogen [BUN], heart and respiratory rate) and acid-base variables (venous blood gas analysis, electrolytes, total protein, lactate) on admission. Base excess (BE) of free water (BEfw), chloride (BEcl...
Effects of syringe type and storage conditions on results of equine blood gas and acid-base analysis. To determine effects of syringe type and storage conditions on blood gas and acid-base values for equine blood samples. Methods: Blood samples obtained from 8 healthy horses. Methods: Heparinized jugular venous blood was equilibrated via a tonometer at 37°C with 12% O(2) and 5% CO(2). Aliquots (3 mL) of tonometer-equilibrated blood were collected in random order by use of a glass syringe (GS), general-purpose polypropylene syringe (GPPS), or polypropylene syringe designed for blood gas analysis (PSBGA) and stored in ice water (0°C) or at room temperature (22°C) for 0, 5, 15, 30, 60, or 120 ...
Effects of chronic acetazolamide administration on gas exchange and acid-base control in pulmonary circulation in exercising horses. Carbonic anhydrase (CA) catalyses the hydration/dehydration reaction of CO(2) and increases the rate of Cl(-) and HCO(3)(-) exchange between the erythrocytes and plasma. Therefore, chronic inhibition of CA has a potential to attenuate CO(2) output and induce greater metabolic and respiratory acidosis in exercising horses. Objective: To determine the effects of Carbonic anhydrase inhibition on CO(2) output and ionic exchange between erythrocytes and plasma and their influence on acid-base balance in the pulmonary circulation (across the lung) in exercising horses with and without CA inhibition....
The workload and plasma ion concentration in a training match session of high-goal (elite) polo ponies. This study was designed to consider the complexity of the physical effort inherent to horses in polo competitions and the absence of reports in the literature on the effort, intensity and electrolyte changes resulting from a collective team training session aimed at preparing for a polo championship. Objective: To determine the effort and ion changes caused by an outdoor polo training match for a 25 goal handicap (elite) based on physiological variables including acid-base status (venous pH, PCO(2) and HCO(3)(-)), packed cell volume (PCV), haemoglobin (Hb), lactate, glucose, sodium, chloride a...
Changes in arterial, mixed venous and intraerythrocytic ion concentrations during prolonged exercise. Prolonged equine exercise can cause hypochloraemic alkalosis and hypokalaemia secondary to the loss of hypertonic sweat. Movement of ions in and out of erythrocytes during exercise may help regulate acid-base balance and changes in plasma ion concentrations. The extent to which this happens during prolonged equine exercise has not been reported. Objective: To measure changes in blood gases and major plasma and intraerythrocytic (iRBC) ion concentrations of horses undergoing prolonged submaximal exercise. Methods: Six horses were trotted at ∼ 30% VO2max on a treadmill for 105 min. Arterial ((...
Acid-base balance parameters and a value of anion gap of arterial and venous blood in Małopolski horses. The comparative study of the acid-base balance (ABB) parameters has been performed on 20 clinically healthy mature Małopolski horses. An arterial blood sample from the facial artery and a sample of venous blood from the external cervical vein were colected from each animal. In the samples tested, the blood pH, pCO2, tCO2, HCO3-, concentration of Na+, K+, Cl-, and a value of the anion gap were determined. The difference among pCO2, tCO2, and HCO3- in both samples tested was statistically significant, whereas the pH of the arterial blood and the pH of the venous blood did not differ significant...
The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses. Sodium acetate (NaAcetate) has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA) administration in horses. Methods: Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of 3-da...
Changes in arterial, mixed venous and intraerythrocytic concentrations of ions in supramaximally exercising horses. Horses experience major perturbations in acid-base balance during supramaximal exercise. Ion movement in and out of erythrocytes (RBCs) is believed to be important in maintaining acid-base balance but it is unclear as to the extent to which this happens, nor how it affects single measurements of ion concentrations in arterial and venous blood. Objective: To clarify the role RBCs play in mitigating perturbations in acid-base balance during high speed exercise in horses, and to describe associated differences in arterial (a) and mixed venous (v) concentrations of key ions. Methods: Six exercise-...
Effects on exercise response, fluid and acid-base balance of protein intake from forage-only diets in standardbred horses. High-energy forage might be an alternative to concentrates for performance horses and such forage can be produced by an early cut. However, early cut forage is high in crude protein (CP), which may result in an excessive CP intake. Objective: To investigate how CP intake affects nitrogen (N), fluid and acid-base balance, and exercise response in horses fed high-energy forage diets. The hypothesis was that high CP intake causes acidosis, and alters fluid balance and response to intensive exercise. Methods: Two forage-only diets based on high-energy grass forage were fed for 23 days in a crossov...