Lactate is a byproduct of anaerobic metabolism, produced when glucose is broken down for energy in the absence of sufficient oxygen. In horses, lactate levels can increase during intense physical exertion, such as racing or other high-performance activities. Elevated lactate concentrations are often associated with muscle fatigue and can provide insights into a horse's exercise physiology and conditioning status. Monitoring lactate levels can aid in assessing the horse's fitness, recovery, and adaptation to training. This page compiles peer-reviewed research studies and scholarly articles that explore the production, regulation, and implications of lactate in equine exercise physiology and performance.
Moore JN, Traver DS, Turner MF, White FJ, Huesgen JG, Butera TS.Peritoneal fluid from each of 15 clinically healthy horses and five horses with acute abdominal disease was evaluated for lactic acid concentration. The normal range was 2-7--13-4 mg/dl. Simultaneous blood and peritoneal fluid samples from healthy horses revealed consistently lower lactic acid concentrations in the peritoneal fluid than in the blood, whereas peritoneal fluid lactic acid levels were consistently greater than blood levels in the diseased horses. The diseased horses had highly significant (P less than 0-005) increases in both blood and peritoneal fluid lactic acid concentrations ...
Snow DH, Mackenzie G.The effects of intermittent maximal exercise (galloping) before and after a 10 week training programme were studied in 6 horses. Determinations were carried out on venous blood for packed cell volume, total plasma protein, glucose, glycerol, free fatty acids, lactate, 11-hydroxycorticosteroids, blood gases and pH. There were marked changes associated with galloping and some of these could be modified with training. The major findings included (i) an elevated blood glucose, (ii) a large increase in glycerol, which was greatest at 30 min post-exercise and was higher following training, (iii) sma...
Anderson MG, Aitken MM.Adrenaline was given intramuscularly to resting horses. It increased heart rate, sweating, blood levels of lactic dehydrogenase, aldolase, creatine kinase, glucose, lactate, free fatty acids and glycerol. Responses to isoprenaline, to noradenaline and to adrenaline after pretreatment with propranolol indicated that beta receptors were involved in stimulation of tachycardia, sweating, lipolysis and muscle glycogenolysis, and alpha receptors in stimulation of liver glycogenolysis and leakage of intracellular enzymes. The time course and relative magnitude of the effects on different enzymes was ...
Kouider S, Kolb FE, Müller I, Pfüller C, Schneider J.Horses were examined for the behaviour of various blood constituents prior to and following infusions of solutions of glucose, fructose, invertose, and sorbitol. Infusion of 0.5 g/kg live weight glucose to six horses was followed by half-life variation between eleven and 23 minutes. Subsequent infusion of invertose to the same animals usually caused prolongation of glucose half-life. Half-life values were between 17 and 33 minutes for fructose and between 21 and 80 minutes for glucose. Infusion of 0.5 g/kg live weight fructose to two horses was followed by half-life values between 17 and 18 mi...
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...
Moore JN, Owen RR, Lumsden JH.Blood lactate levels were evaluated in 36 horses (43 cases) presented with colic. A correlation between increasing blood lactate levels and decreasing percentage survival has been shown. An appreciable anion gap was found in 7 of 10 cases analyzed in detail but in each case the entire gap could not be accounted for by lactate alone. Proposals are offered to account for the unmeasured anions. Blood lactate determination is suggested as a prognostic rather than a diagnostic aid for the equine practitioner and should be used to augment other clinical findings in the horse exhibiting colic.
Milne DW, Skarda RT, Gabel AA, Smith LG, Ault K.Effects of training at a regular, fixed, standard exercise load on venous lactic acid, mixed venous and arterial blood gases and pH, and serum muscle enzymes were determined on previously unconditioned, healthy, adult, Standardbred horses. Arterial and mixed venous blood gases, pH, and serum muscle enzymes did not change in a consistent manner during training. Venous lactic acid concentrations did increase significantly with training and may be of value for the biochemical evaluation of fitness in horses.
Lees P, Serrano L.1 The butyrophenone tranquilizer, azaperone, was administered intramuscularly, at dose levels of 0.4 and 0.8 mg/kg, to ponies and its effects on cardiovascular and respiratory functions assessed. 2 Arterial blood pH, CO2 tension (PaCO2) and O2 tension (PaO2) remained relatively constant throughout the course of action of azaperone. 3 Azaperone did not modify plasma protein concentration but venous blood packed cell volume and haemoglobin concentration were reduced by 5 to 10% for at least 4 hours. These changes were probably caused by uptake of erythrocytes into the splenic reservoir. 4 Small ...
Anderson MG.The effects of exercise of different intensities on blood concentrations of glucose, lactate, pyruvate, free fatty acids and glycerol were studied in a group of clinically normal horses. Blood lactate, pyruvate and lactate/pyruvate ratio increased during exercise, particularly during galloping. These changes occurred within the first 12-15 seconds of exercise indicating that anaerobic metabolic pathways are brought into use very quickly in the strenuously exercising horse. Since blood glycerol levels were significantly increased during exercise body lipids were also mobilised. At the same time...
Lindholm A, Johansson HE, Kjaersgaard P.LINDHOLM, A., H.-E. JOHANSSON & P. KJÆRSGAARD: Acute rhabdomyolysis (“tying-up”) in standardbred horses. A morphological and biochemical study. Acta vet. scand. 1974, 15, 325–339. — Morphological, biochemical and histochemical changes were studied in muscle needle biopsy specimens (gluteus medius) from 59 standardbred trotters with acute clinical symptoms of the “tying-up” disease. All horses had increased levels of serum enzymes SGOT and SCPK. The biopsy specimens were taken at various intervals after onset of clinical symptoms (1–4 hrs., 18–24 hrs. and 2–20 days). Ry light...
Lindholm A, Saltin B.LINDHOLM, ARNE and BENGT SALTIN: The physiological and biochemical response of standardbred horses to exercise of varying speed and duration. Acta vet. scand. 1974, 15, 310–324. — Welltrained standardbred horses were studied to examine the metabolic response to excercise of various speeds and duration. Comparisons between interval (400, 700, 1,000 and 2,000 m) and continuous trotting (1 hr., 2 hrs.) and racing were made. Muscle and rectal temperatures were recorded before and immediately after each work bout. Heart rate was linearly related to trotting speed, and maximal heart rate (240 be...
Many colic horses are compromised due to the disease state and from hours of starvation and sometimes long trailer rides. This could influence their muscle energy reserves and affect the horses' ability to recover. The principal aim was to follow metabolic parameter before, during, and up to 7 days after anaesthesia in healthy horses and in horses undergoing abdominal surgery due to colic. Methods: 20 healthy horses given anaesthesia alone and 20 colic horses subjected to emergency abdominal surgery were anaesthetised for a mean of 228 minutes and 183 minutes respectively. Blood for analysis o...
Navas de Solis C, Ramseyer A, Stefanovski D, Haughan J, Solomon CJ, Kirsch K.Exercising arrhythmias are common in horses participating in eventing competitions. Heart rate variability (HRV) and a specific measure of the degree of heart rate fluctuation (Detrended Fluctuation Analysis alpha1; DFA-α1) are proposed as exercise intensity and fatigue markers. Objective: (1) To describe exercising arrhythmias and DFA-α1 values during 2-4* level eventing cross-country competitions in horses from two European countries; (2) to identify associations between exercising arrhythmias, DFA-α1 and competition results and (3) to evaluate whether markers of the intensity of exercise...
Siegers EW, Parmentier JIM, Sloet van Oldruitenborgh-Oosterbaan MM, Munsters CCBM, Serra Bragança FM.Appropriate training is essential for equine athletes to improve fitness and ensure welfare. Young Friesian stallions must complete a 10-week training program for acceptance as breeding stallions. Earlier, this training program was demonstrated to induce overtraining. Unassigned: To evaluate how this training program affects stallions' trot locomotion variables in relation to fatigue. Unassigned: Prospective analytical study. Unassigned: 3 or 4 years-old (n = 16) Friesian stallions performed three ridden indoor standardized exercise tests (SETs) in week-1 (SET-I; n = 15), week-6 (SET...
Carvalho JRG, Sales NAA, Littiere TO, Costa GB, Castro CM, Polisel EEC, Orsi JB, Ramos GV, Santos IFC, Gobatto CA, Manchado-Gobatto FB, Ferraz GC.Several studies have explored alternatives to enhance the performance, health, and safety of sports horses. One promising method involves the use of vibrating platforms (VP), which offer passive exercise stimulation via mechanical oscillations distributed throughout the body. This type of exercise is referred to as whole-body vibration (WBV) and is an emerging strategy for accelerating muscle recovery. This study examined the dynamics of proteins responsible for transporting monocarboxylates (MCT1 and MCT4), and their relationship with lactatemia and acid-base balance in connection with WBV re...
Slavik K, Bender S, Sharkey L, Nolen-Walston R.Renal lipidosis is a well-documented histologic finding in humans and small animals with renal and metabolic disorders, but it is not well described in equids. Objective: To describe the signalment, clinicopathologic indices, and postmortem findings of equids with a histologic diagnosis of both hepatic and renal lipidosis (HL + RL) and compare them to cases with hepatic lipidosis only (HL). Methods: Equids with necropsy findings of renal or hepatic lipidosis (state diagnostic lab) between 2008 and 2022. Methods: Retrospective case-control study. Signalment, history, necropsy diagnosis, and...
Wilkins PA, Wong D, Slovis NM, Collins N, Barr BS, MacKenzie C, De Solis CN, Castagnetti C, Mariella J, Burns T, Perkins G, Delvescovo B, Sanchez LC....Sepsis has been defined in humans as the concurrent proven or suspected presence of microbial infection and the systemic inflammatory response syndrome (SIRS). Sepsis is the leading cause of morbidity and mortality in neonatal foals. The clinical utility of using SIRS or its individual components to predict infection and mortality in critically ill foals is currently unknown. Objective: Assess the ability of history and signalment, clinical findings, laboratory results, and SIRS-related indices to predict infection and mortality in critically ill foals. Methods: Retrospective, multi-center, cr...
Röschmann J, Naef J, Doras C, Gerber V.Equine asthma is a common cause of poor performance, but little is known about its impact on submaximal exercise. The aim of the present study was to evaluate the effects of equine asthma and potential confounding factors on recovery of respiratory rate (RR) and heart rate (HR) after a lunging exercise test. Thirty-seven horses completed a standardized 15 min lunging exercise including HR and RR recording pre- and up to 30 min post-exercise and venous blood lactate measurement. Endoscopy was performed and bronchoalveolar lavage fluid cytology was used to categorize horses as controls or asthma...
Żak-Bochenek A, Drábková Z, Sergedaite V, Siwińska N, Bajzert J, Pasak D, Chełmońska-Soyta A.Colic-related obstructions can reduced intestinal mucosa function and cause dysbiosis in horses, but it is unclear how defense barrier and secretory immunoglobulin A (SIgA) secretion is disrupted. Objective: The aim of the study is to evaluate the effect of severity of colic signs and treatments on fecal SIgA and fecal lactate in horses. Methods: Sixty-two client owned hospitalised horses with colic and eight healthy horses. Methods: Prospective clinical trial. Fecal samples were taken daily for 7 days. SIgA was analyzed using ELISA, and D/L-lactate measured with a commercial kit. Results: A...
Davie A, Beavers R, Denham J.The purpose of this review was to analyze the scientific background and practical application of a very successful human training methodology, the pyramidal training model, to the Thoroughbred racehorse. Despite years of research and accumulated knowledge on human training methods to enhance endurance performance, Thoroughbred training programs have lacked significant change. This review introduces the pyramidal training model, explains the science that underpins this training concept and outlines one approach to translate this science into the equine field. It also discusses the importance of...
Garcia LL, Vicentini YF, Nagashima JK, de Souza AF, Pereira MAA, da Silva LCLC, Fantoni DT.To assess the sublingual microcirculation in horses anesthetized with isoflurane and undergoing constant rate infusion of dexmedetomidine (DEX) and lidocaine (LID). Unassigned: 16 horses undergoing arthroscopy were included in a blind, randomized study comparing 2 groups: a DEX group (DEX-LID; 1.75 μg·kg-1·h-1 with a LID bolus of 1.3 mg·kg-1 followed by a continuous infusion of 0.05 mg·kg-1·min-1) and a LID-only group (LID; at the same dose). Hemodynamic variables, including mean, systolic, and diastolic blood pressure; heart rate; capnography; blood gas analysis; blood lactate; and orth...
Van den Branden E, Salamone M, Broothaers K, Peere S, Polfliet E, Dewulf M, Van Steenkiste G, van Loon G, Smits K, Govaere J.The use of transvaginal ultrasound-guided follicle aspiration (TVA) for oocyte collection has become a widely used procedure in horses for embryo production (IVEP). The TVA procedure is characterized by various manipulations, which are physical restraint, perineal preparation, transrectal palpation, insertion of an intravaginal device, and needle punctures. These repeated transvaginal and transovarian punctures have raised concerns about their potential effects on mare welfare. Our study aimed to investigate the effects of TVA manipulations, and especially puncturing, on pain and stress in ma...
Macleod BM, Wilkins PA, McCoy AM, Bishop RC.Viscoelastic coagulation testing (VCT) identifies subclinical disruption of coagulation homeostasis and may improve prognostication, particularly for patients with severe systemic inflammation or shock. Machine learning (ML) algorithms may capture complex relationships between clinical variables better than linear regression (GLM). Objective: To evaluate the utility of ML models incorporating VCT and clinical data to predict survival outcomes in horses with acute abdominal pain. Methods: Retrospective observational cohort study. Methods: VCT (VCM Vet™) was performed on 57 horses with acute a...
Wright JP, Gray SM, Bishop RC.To describe and demonstrate the collection of abdominal fluid from a standing, sedated equine patient. Unassigned: 1 healthy university-owned animal was used for abdominocentesis demonstration. Images from various clinical cases from the University of Illinois Veterinary Teaching Hospital are shown. Unassigned: Under standing sedation, a 10 X 10-cm area is clipped and aseptically prepared on the most dependent portion of the abdomen to the right of midline. One to 2 mL of 2% lidocaine is instilled subcutaneously and into the abdominal musculature at the abdominocentesis site. A stab incision i...
Parra-Moyano LA, Cedeño A, Darby S, Johnson JP, Gomez DE.The effectiveness of the peritoneal fluid L-lactate-to-total solids ratio (PFL:PFTS) as a diagnostic marker for strangulating lesions of the small intestine (SI) and large colon (LC) has not been investigated. Objective: Describe and compare the PFL:PTFS and blood lactate (BL), peritoneal fluid lactate (PFL) and PFL:BL difference and PFL:BL ratio of horses with SI and LC strangulating (SO) and non-strangulating (NSO) obstructions and determine sensitivity and specificity to predict SO. Methods: A total of 282 horses, 117 with SI lesions (59 classified as SINSO and 58 as SISO), and 165 with LC ...
Neudeck S, Sauter PK, Kutter APN, Steblaj B, Söbbeler FJ, Reiners J, Freise F, Gutiérrez Bautitsta AJ, Kästner SBR.Endotoxaemia is a significant cause of morbidity and mortality in equids due to perfusion impairment and possible destruction of the glycocalyx. To evaluate our hypothesis that endotoxaemia induces changes in global cardiovascular and haematologic parameters and compromises glycocalyx integrity, evidenced by an early rise in plasma shedding products. In vivo experiments METHODS: In a prospective, randomised, controlled experimental trial, endotoxaemia was induced with E. coli B55:O5 LPS 30 ng kg over 30 min IV in six healthy adult horses ventilated with oxygen supplemented with isoflurane. St...
Söderroos D, Stefánsdóttir GJ, Ragnarsson S, Gunnarsson V, Jansson A.Weight carrying capacity is an important trait in riding horses and it may be associated with conformation. This study examined the physiological response to a ridden incremental weight carrying test in 16 adult Icelandic horses used for tour riding. Horses carried 20% (BWR20%), 25% (BWR25%), 30% (BWR30%) and 35% (BWR35%) of their body weight (BW) in tölt (~ 5.7 m/seconds, 640 m/step), and associations with body measurements and back conformation (score) were examined. Horses were divided into two groups (narrow or broad back) and body measurements were collected. Plasma lactate was analy...
Simões J, Santos AM, Santos C, Silva AS, Vintém C, Fonseca J, Coelho C.Show jumping is a popular and complex equestrian modality practiced by a athletes of different levels. However, most studies focus on elite athletes. Objective: The aim of this work was to assess the effect of a show jumping test (SJT), designed for novice athletes, on the physiological biomarkers and energy indexes of a group of horses, bred and trained in Portugal. Methods: In this prospective cross-sectional study, thirteen horses and their riders performed a SJT with obstacles set at 80 cm height using a heart rate monitor (M430 with H10 sensor). Physical examination and blood samples, for...
Liedtke AM, Meijer H, Horstmann S, von Reitzenstein C, Rump I, Kirsch K.Eventing is an Olympic equestrian discipline comprising dressage, cross-country, and show jumping, with the cross-country phase imposing the greatest physical demands on horses. This study presents a composite model to estimate energy expenditure during the cross-country phase, integrating physiological data (heart rate-derived VO2 and lactate-based anaerobic estimates) with external workload indicators (GPS-derived speed, elevation, and course complexity). Model development was based on 691 rides from 256 horses across 232 events at 2-star to 5-star competition levels. The analysis showed tha...
Sohn Y, An SJ, Forbes E, Yoon J, Kim BS, Kim JG, Ryu SH.To model lactate recovery kinetics in relation to sex, age, running speed, and racing experience, and to estimate blood lactate clearance time under passive recovery conditions that reflect current management practices in Jeju horses, a less well-characterized pony-sized indigenous breed. Unassigned: From October through December 2022, BLC was measured at baseline, 10 minutes after 800-m barrier trials (time [T]-1), and 50 minutes (T2) after 800-m barrier trials in 40 race-trained Jeju horses (2 to 4 years old). Lactate clearance was modeled using nonlinear regression with an exponential decay...
Faircloth J, Fielding L, Epstein K, Crabtree N, Mochal C, Magdesian G, Major D.To describe the clinical presentation of horses with synchronous diaphragmatic flutter (SDF) and identify clinical and laboratory variables associated with survival. Methods: Retrospective study from January 2004 to September 2022. Methods: Five large animal referral hospitals in the United States. Methods: Thirty-seven horses of various breeds and ages presenting with clinical signs of SDF, excluding animals participating in an endurance competition. All horses were >1 year of age. Methods: None. Results: Variables recorded and analyzed included signalment, clinical and laboratory data, trea...
In horses, heat exposure modulates the hypothalamic-pituitary-adrenal axis, autonomic nervous system, and hypothalamic-pituitary-thyroid axis to maintain body temperature and prevent excessive heat accumulation. However, during strenuous exercise under hot and humid conditions, heat production may exceed dissipation, leading to heat stress, anhidrosis, heat stroke, or brain damage. Unassigned: Incremental field standardized exercise tests (fSETs) provide a reliable approach to assess training and fitness levels. Six Arabian horses from Italia Endurance Stable and Academy were monitored during ...
Granello ME, Young JM, Cleff DB, Banks EBM, Trumble TN.To describe characteristics of postoperative peritoneal fluid following exploratory laparotomy for naturally-occurring gastrointestinal lesions in horses. Methods: Prospective, observational cohort study. Methods: A total of 26 client-owned horses that underwent exploratory laparotomy for naturally-occurring gastrointestinal lesions. Methods: Abdominocentesis was performed pre- or intraoperatively, and at three time points postoperatively (24, 72, and 168 h). Peritoneal lactate, total protein (TP), total nucleated cell count (TNCC), cytology, and systemic lactate were performed at each time ...
