Heart rate in horses is a physiological parameter that reflects the number of heartbeats per minute. It is an important indicator of cardiovascular function and can be influenced by factors such as exercise, stress, excitement, and health status. Monitoring heart rate provides valuable insights into the horse's physical condition and can aid in assessing fitness levels or detecting potential health issues. In equine practice, heart rate is often measured using stethoscopes, heart rate monitors, or electrocardiograms. This page compiles peer-reviewed research studies and scholarly articles that explore the determinants, measurement techniques, and implications of heart rate variations in equine health and performance.
Brown DG.Physiologic responses of irradiated and nonirradiated Shetland Ponies to controlled exercise were measured over a period of 5 years. The 5-year test began when the ponies were 3 years old and 5 months after they were exposed to 650 R of 60-Co gamma radiation. Significant differences in heart rates, respiratory rates, and rectal temperatures were demonstrated between irradiated and nonirradiated ponies when subjected to exercise and high ambient temperatures. Inthe irradiated group, heart rates were usually slower, especially during recovery immediately after exercise, and respiratory rates and...
Holmes JR, Rezakhani A.The paper describes changes observed in the T wave and T vectorcardiogram in horse after various periods of exercise. Using radiotelemetry and a bipole lead all horses showed negative T waves immediately after exercise. In some of them this was followed by a markedly positive T deflection. Possible reasons for these changes are briefly discussed.
Bisgard GE, Orr JA, Will JA.Hemodynamic measurements were made in 6 ponies at low altitude (Madison, WI, altitude, 250 m) and after 1, 2, 4, and 6 weeks at high altitude (Climax, CO, altitude, 3,400 m). The salient findings were that ponies maintain an increased heart rate and cardiac output and develop significant pulmonary hypertension at high altitude. The average control resting mean pulmonary artery pressure (BPpul) was 25.1 mm of Hg at 250 m; this value increased to 56.3 mm of Hg after 6 weeks at 3,400 m. An additional finding was that the pulmonary vascular response to acute hypoxia seemed to increase with time at...
Hillidge CJ, Lees P.Cardiac output in the horse was measured before and at predetermined times during 2-hour periods of thiopentone-halothane and thiopentone-diethyl ether anaesthesia. Left ventricular stroke volume was decreased to a similar extent during anaesthesia with each volatile agent, but a greater reduction in cardiac output occurred during halothane anaesthesia. This finding reflected the differing effects of halothane and ether on heart rate, a slight bradycardia occurring with the former agent while ether produced a small degree of tachycardia. The latter effect was attributed to enhanced sympathoadr...
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...
Smetzer DL, Senta T, Hensel JD.Each of nine horses was treated with amphetamine alone, with atropine alone, and with amphetamine and atropine in combination. Cardiac effects of these drugs were studied by electrocardiography during resting and exercising states and immediately after exercise. Although each treatment increased heart rate significantly during the resting state, only the amphetamine plus atropine treatment increased heart rate significantly during exercise. Decrease in heart rate immediately after exercise differed significantly for each treatment; the most rapid decrease in heart rate was found after the amph...
Witherington DH.The post-race heart rates have been recorded in 1,000 Thoroughbreds following Flat, Hurdle and Steeplechase races in varying climatic conditions and on 54 different British racecourses. The post-race deceleration of the heart rate, under racecourse conditions, was marked by an apparent three-phase recovery period. Reference is made to the normal heart sounds and to the relationship between the heart and respiratory rates.
Lees P, Tavernor WD.1. Ventricular ectopic beats were recorded in eight of thirteen conscious horses following the intravenous administration of adrenaline in doses of 3 mug/kg. Following pre-treatment with either atropine sulphate (0.1 mg/kg) or propranolol hydrochloride (0.1 mg/kg), the same dose level of adrenaline failed to produce ventricular ectopic beats.2. Halothane anaesthesia sensitized the equine heart to the arrhythmogenic actions of adrenaline; the incidence and duration of ventricular arrhythmias being greater than in conscious animals. In comparison with the findings in conscious horses, ether anae...
Lees P, Tavernor WD.1. In horses anaesthetized with halothane the intravenous administration of suxamethonium chloride, at a dose level of 0.2 mg/kg, produced a short-lived period of hypoventilation, which was associated with increases in arterial blood PCO(2) levels and in plasma concentrations of bicarbonate, sodium and potassium ions, and reductions in arterial blood pH and PO(2) values.2. The respiratory depressant action of suxamethonium chloride 0.2 mg/kg was accompanied by increases in blood pressure and heart rate. Doses of suxamethonium chloride 0.4 mg/kg produced similar but quantitatively greater chang...
Dimaio Knych HK, Steffey EP, Stanley SD.Yohimbine is an alpha 2 adrenergic receptor antagonist, which has been shown to counteract the CNS depressant effects of alpha 2 receptor agonists in a number of species. Recently, our laboratory identified yohimbine in the absence of detectable concentrations of an alpha 2 agonist in a regulatory sample collected from a horse racing in California. This coupled with anecdotal reports of CNS stimulation and documented reports of cardiovascular changes when administered in conjunction with an agonist led us to investigate the pharmacokinetics and pharmacodynamics of yohimbine when administered a...
Schmidt TE, Gleason CB, Samaniego MR, White RR.Failure to properly prepare the equine athlete for exercise and support post-exercise recovery is a contributing factor to physical breakdown and lameness. Equine physiotherapy was not introduced until the early twentieth century and has since evolved to allow for wearable therapies such as therapeutic boots to be accessible to a broad spectrum of equestrians. The purpose of this study was to evaluate the effects of ceramic boots, boots combining vibration and cryotherapy, and boots containing tourmaline on the performance of sport horses during jumping as well as to examine changes in vital s...
Katz LM, Gough K, McGivney CL, McGivney B, Sides RH, Hill EW, Bayly WM.Sex effects on ventilatory and oxygen consumption (V̇O) measurements during exercise have been identified in humans. This study's aim was to evaluate the hypothesis that there are sex effects on ventilatory and V̇O measurements in exercising, untrained yearling Thoroughbreds (Tb). Forty-one Tbs (16 colts, 25 fillies; 19.8 ± 1.4 months old) were recruited. Physiological, ventilatory and exercise data were gathered from horses exercising unridden at high intensity on an all-weather track from a global positioning-heart rate unit and a portable ergospirometry system. Data were analysed with an...
Gruber N, Gesell-May S, Scholler D, Zablotski Y, May A.Equine colic is an important condition associated with acute abdominal pain and one of the leading causes of death in horses. As such, objectively evaluating pain is of interest for attending veterinarians. Pain scales for assessment are present, but no single pain-specific biomarker has been reported. The aim of this study was to determine if substance P (SP) could be a reliable biomarker to reflect pain and serve as a parameter to predict outcome in equine colic. The hypothesis was that horses displaying severe colic signs present with higher values of SP in contrast to those with mild colic...
Lorello O, Rule E, Haughan J, Wang K, Niu M, Brown K, Navas de Solis C.Equine veterinarians performing chiropractic treatments are frequently asked to evaluate and treat sound horses to improve their performance and address pain associated with the axial skeleton. Studies describing the effects and mechanisms of chiropractic treatments in horses without overt lameness are scarce. Objective: This study aimed to evaluate the effect of chiropractic treatments on stride rate, length, symmetry, heart rate and rider-perceived quality of the ridden work in sport horses. Methods: A blind randomised controlled trial with crossover design. Methods: Thirty-eight horses ridd...
Fernandez-Barrientos MA, Flynn H, Ratliff B, Kilcoyne I.To highlight the use of procainamide as a potential alternative treatment modality in cases of ventricular tachycardia that are refractory to lidocaine and magnesium sulfate. Methods: 1 adult horse weighing 380 kg. Unassigned: A 25-year-old Arabian gelding presented with severe colic signs. Due to persistent pain, it was elected to carry out an exploratory laparotomy. During the procedure a diagnosis of severe, unstable ventricular tachycardia was made based on the ECG findings, with an initial heart rate of 195 beats per minute and severe hypotension. Results: Initial treatment consisted of d...
Lacerenza MD, Arantes JA, Reginato GM, Passarelli D, Balieiro JCC, Amaral AR, Vendramini THA, Brunetto MA, Dória RGS.β-glucan is part of the cell wall of fungi and yeasts and has been known for decades to have immunomodulating effects on boosting immunity against various infections as a pathogen-associated molecular pattern that is able to modify biological responses. β-glucan has been used in rat models and in vitro studies involving sepsis and SIRS with good results, but this supplement has not been evaluated in the treatment of endotoxemia in horses. This study aims to evaluate the effects of preventive supplementation with β-glucan in horses submitted to endotoxemia by means of inflammatory response m...
Cardiovascular changes have been reported in late pregnancy in mares. However, there are no data on changes in peripheral blood flow. Doppler ultrasound represents a sensitive method for assessing the blood flow directed to the hoof. The aims of this study were to evaluate the blood flow parameters of the lateral palmar digital artery (LPDA) in pregnant mares and to assess intra- and interrater agreement between two observers with different levels of experience. The LPDAs of pregnant Italian Standardbred mares were examined. The vessels were located with B-mode ultrasound and analyzed with col...
Vullo C, Gugliandolo E, Biondi V, Biffarella M, Catone G, Tambella AM.The aim of this study was to determine the most appropriate sedation protocol for a standing magnetic resonance imaging (MRI) examination in horses, comparing continuous rate infusions (CRIs) of detomidine and romifidine combined with a single bolus of morphine. Sixteen horses referred for standing low-field open-magnet MRI were randomly assigned to one of two sedation protocols. The horses were premedicated with 0.03 mg/kg of intramuscular acepromazine, and those animals belonging to Group D received an intravenous (IV) loading dose of detomidine (0.01 mg/kg) 30 min later, while those of Grou...
Reed RA, Berghaus LJ, Reynolds RM, Holmes BT, Krikorian AM, Sakai DM, Ishikawa Y, Knych HK.Understanding the pharmacokinetics and pharmacodynamics of fentanyl in horses is crucial for optimizing pain management strategies in veterinary medicine. Unassigned: Six adult horses were enrolled in a randomized crossover design. Treatments included: placebo, two 100 mcg/h patches (LDF), four 100 mcg/h patches (MDF), and six 100 mcg/h patches (HDF). Patches were in place for 72 h. Blood was obtained for fentanyl plasma concentration determination, thermal threshold, mechanical threshold, heart rate, respiratory rate, and rectal temperature were obtained prior patch placement and at m...
Neville E, Pigott J.To describe the clinical presentation of a Thoroughbred filly with acute hemoperitoneum from a splenic source immediately after racing. Methods: A 3-year-old Thoroughbred filly used for racing and that had raced shortly before presentation to the hospital. Unassigned: On presentation, the filly was quiet, alert, and responsive with a heart rate of 76 beats/min, pale mucous membranes, and absent borborygmi. All other physical examination parameters were within normal limits. Abdominal ultrasound was performed and revealed echogenic free abdominal fluid and a splenic hematoma. Abdominocentesis y...
Straticò P, Guerri G, Bandera L, Celani G, Di Nunzio L, Petrizzi L, Varasano V.(1) The main goals of general anesthesia include pain management and a safe anesthetic protocol for smooth recovery. In this retrospective study, we compared two anesthetic protocols for general anesthesia with isoflurane during emergency laparotomy: sedation with xylazine and the intraoperative infusion of lidocaine (X group) versus medetomidine as a preoperative sedation and intraoperative infusion (M group). (2) The medical records of horses who underwent emergency laparotomies between 2016 and 2023 were reviewed. According to the anesthetic protocol, patients were allocated to the X or M g...
Vitale V, Bindi F, Velloso Alvarez A, de la Cuesta-Torrado M, Sala G, Sgorbini M.This study aimed to evaluate the feasibility of transcutaneous auricular vagal nerve stimulation (tAVNS) in healthy horses and its effect on heart rate variability (HRV). The study comprised three phases: the selection of mares, their acclimatization to the tAVNS, and the stimulation phase. Stimulation was performed with two electrodes positioned on the right pinna. The settings were 0.5 mA, 250 μs, and 25 Hz for pulse amplitude, pulse width, and pulse frequency, respectively. HRV was analysed before (B1), during (T), and after (B2) the tAVNS. From the 44 mares initially included, only 7 comp...
Bogossian PM, Pereira JS, da Silva NF, Hilgert AR, Seidel SRT, Fülber J, Belli CB, Fernandes WR.Exercise intensity is prone to be self-regulated in horses exercising freely. The main drivers include social, feeding and escape behaviors, as well as the operant conditioning. We hypothesized that self-regulated exercise intensity may increase due to the presence of another horse exercising ahead. Seven horses were assigned to a 2x2 crossover trial following treadmill familiarization. Video images of a trotting horse were displayed on the wall in front of the experimental unit (Visual), which was positioned in the treadmill. Physiological and behavioral markers were further compared with a c...
Knych HK, Blea J, Scollay M, Kass PH, McKemie DS.Ethanol, a central nervous system depressant and banned substance in horseracing, has reportedly been administered to horses prior to competition to "calm a horse's nerves." In this study, the pharmacokinetics of two metabolites of ethanol were studied to better understand the behavior of this compound in the horse and provide a scientific basis for regulation of its administration. Six horses received a single intravenous (30 mL; 1200 mg) and oral (90 mL; 3600 mg) administration of ethanol (vodka, 40% ABV) in a balanced cross-over design. Blood and urine samples were collected at vari...
Petrucelli M, Sgorbini M, Castagnetti C, Lanci A, Mariella J, Marmorini P, Freccero F.Background- Subclinical electrophysiological derangements occur at birth in foals. Smartphone-based ECG (spECG) is practical tools to assess heart rhythm and was recently validated in foals. Objectives-To assess the heart rate (HR) and rhythm at birth in clinically healthy foals born after spontaneous and induced parturition using a spECG. Animals- Newborn healthy foals born after at term spontaneous (SF) or induced foaling (IF). Methods- Cohort study. In SF and IF groups, a spECG was performed immediately at birth (T0) and after 5 min (T5). SpECG tracings were selected for quality. HR was ma...
Ryu SH, Lee KE, Forbes E, An SJ, Kim JG, Lee H, Kim BS.Equine behavioral traits are important criteria to assess the suitability of retired Thoroughbred racehorses for equestrian sports. Objective: This study aims to develop a practical procedure to assess retired Thoroughbreds for their suitability for equestrian sports or leisure purposes and to assess if horses identified as having reactive temperaments in response to a standardized startle test, will have improved test results following a period of transition training. Methods: Behavioral reactivity data and cardiac autonomic responses to a startle test (comprising of a plastic bag applied to ...
Bindi F, Bozzola C, Vezzosi T, Zucca E, Caivano D, Freccero F, Sala G, Sgorbini M.Smartphone-based technology is increasingly used in veterinary medicine as a complementary tool for cardiac auscultation and ECG recording. This prospective observational study evaluates a digital stethoscope (DS) that consists of simultaneous phonocardiographic and one-lead ECG recording (dECG) in adult horses, comparing it with auscultation using a conventional stethoscope (CS) and reference base-apex ECG (rECG). A total of 104 horses underwent cardiac auscultation using CSs and DSs to detect arrhythmias and murmurs. Audio and dECG were acquired using the DS. The rECG tracings were also reco...
Lindqvist A, Nyman G, Rydén A, Wattle O.This study aimed to assess and compare the recovery of ponies and horses following general anesthesia in two different settings: a recovery box with an inflexible, adjustable ceiling, and free recovery without restraints. Our primary objective was to evaluate the effect of adjustable ceilings on the prevention of premature attempts to rise during recovery. The secondary aim was to compare the physiological stress indicators during recovery. Methods: Prospective, randomized, experimental study. Methods: Six healthy ponies and 10 healthy horses. Methods: This study used a crossover design with t...
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...
Gorenberg EB, Slack J, Stefanovski D, Theiss D, Hopster K.Dobutamine is a first-line therapy for hypotension in anaesthetised horses, but the effects on haemodynamic parameters in standing and anaesthetised horses are not well studied. Objective: To investigate the effects of dobutamine in escalating dosages on haemodynamic performance in awake and anaesthetised horses. Methods: Randomised cross-over experimental study. Methods: Six healthy adult horses were enrolled, including both standing and isoflurane-anaesthetised experiments with 1-week washout. Heart rate, mean arterial pressure (MAP), central venous pressure, pulmonary arterial pressure, and...
Rankins EM, Faremi BE, Hartmann K, Quinn A, Posada-Quintero HF, McKeever KH, Malinowski K.Heart rate variability (HRV) can be measured as an indicator of autonomic nervous system (ANS) balance and thus, stress and affective arousal. Mixed results have been reported in the limited literature addressing the effects of equine-assisted services (EAS) on HRV in the human and horse participants. The aims of the present study were to determine the effects of ground-based adaptive horsemanship (AH) lessons on veterans' and horses' HRV during weekly lessons as well as veterans' resting HRV outside of lessons. Veterans with post-traumatic stress disorder (PTSD) were randomly assigned to 8 w...
Munerato MS, Simon O, Nicholson A.This report describes successful cardiopulmonary resuscitation of a healthy, 525 kg, 8 years 9 months-old Quarter horse gelding. After successful pelvic limb orthopaedic surgery to excise a metatarsal bone under general anaesthesia, with the horse in left lateral recumbency, the horse was hoisted into recovery. After the horse was positioned in recovery, a routine cardiac check by thoracic auscultation was performed. Cardiopulmonary arrest (CPA) was identified by absence of cardiac sounds and pulse, as evaluated by digital palpation of the facial artery, absence of the right palpebral reflex, ...
Hartwig S, Rankovic A, McCrae P, Gagliardi K, Burron S, Ellis J, Ma DWL, Shoveller AK.Behavioural reactivity in horses poses a welfare and safety risk to both the horse and the handler, however, beneficial effects have been observed when dietary fat is increased in replacement of sugar. Supplementation with the fatty acids (FA) eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) appear to improve negative behaviours in rodents and humans, but the effect of α-linolenic acid (ALA), EPA, and DHA, specifically, on reactivity in horses is unknown. The objective of this study was to evaluate the effects of camelina oil (CAM; ALA-enriched) and a mix of camelina and algal oil (ALG; ...
Galotti A, Eisersiö M, Yngvesson J, Lanatà A, Maglieri V, Palagi E, Baragli P.Studies on stress and emotions are fundamental to assessing welfare in wild and domestic animals. In this study, we experimentally investigated how different levels of rein tension affect autonomic nervous system activation and heart rate variability (HRV) in horses. We hypothesized that increased rein tension, through a learning process, would elevate sympathetic nervous system activity and HRV, and that adult horses would be less affected by stimulus administration (EXP) than young horses due to their experience. The magnitude of rein tension significantly altered the sympatho-vagal balance ...
van der Merwe LM, Schliewert EC.Colic is a common equine emergency requiring medical or surgical intervention. These interventions can be costly, making outcomes data and prognostic indicators essential for guiding referral and treatment decisions. Objective: To determine survival rates to hospital discharge and evaluate prognostic indicators in equine colic cases treated at a referral hospital (Onderstepoort Veterinary Academic Hospital [OVAH], South Africa). Methods: This retrospective observational cohort study analysed records from horses with colic that were presented to the OVAH from January 2019 to August 2021. Data i...
da Fé VCS, Dos Santos VMO, de Lima ACB, Hernandes MSP, Caldara FR, Gomes MNB.This study aimed to evaluate the effect of auditory stimuli on mares and geldings during social isolation and movement restriction, and their ability to promote the reduction of stress responses. The research was conducted with eight Pantaneiro horses, divided into Experiment I (4 mares) and Experiment II (4 geldings), both experiments were executed equally using a 4x4 Latin square design with experimental (classical, country and new age) and control (no music) treatments. Physiological parameters (heart rate, heart rate variability, respiratory rate, ocular temperature by infrared thermograph...
Liu J, Baumwart R, Kwon S.Ventriculophasic response (VR) in atrioventricular nodal (AVN) block is characterized by a shortening of the sinoatrial cycle length when a QRS complex is interposed between two P waves. This has been well documented in humans and dogs with AVN blocks but not in horses. Herein, we describe a horse with second-degree AVN blocks and constant PR intervals that exhibited 5:3 conduction and suspected VR at rest but less consistently after submaximal exercise. Proposed VR mechanisms include (1) inhibition of the Bezold-Jarisch reflex from reduced end-systolic volume during ventricular contraction; (...
Coelho C, Vintem C, Silva AS, Santos C, Santos AM, Leite A, Souza V, Siqueira R, Filho HCM, Simões J.The present work aimed to evaluate the influence of a training programme on energy expenditure (EE), cost of transport (COT, cardiac beats to move the body mass during exercise) and metabolic power (Pmet) in young Purebred Lusitano horses used in dressage. With this purpose, nine male horses, ~4 years old, were evaluated before (M1) and after 6 weeks (M2) of a training programme that included 40-80 min of preparatory dressage exercises, 6×/week, individually adjusted. In M1 and M2, the animals were examined in a dressage field test (DFT), when heart rate (HR) and respiratory rate (RR), body...
Sales NAA, Carvalho JRG, Littiere TO, Costa GB, Silva ACY, Rodriguez IDM, Castro CM, Anjos LS, Ottati ACM, Alcaide JA, Ramos GV, Ferraudo AS....Whole-body vibration (WBV) has the potential to enhance post-exercise recovery in humans. Heart rate variability (HRV), a well-established biomarker of cardiac autonomic regulation (CAR), provides insight into autonomic reactivity during recovery from exercise. Objective: To investigate CAR in healthy horses during post-exercise recovery following an acute intensive exercise bout (AIEB) with WBV intervention. Methods: A single AIEB was prescribed at velocities corresponding to lactate threshold (VLT), and the eight horses performed on treadmill with 5 % slope, 2 min at 110 % VLT followed by 3 ...
