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Topic:Equine Health
Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Right ventricular pressure dynamics and stress echocardiography in pharmacological and exercise stress testing. There is interest in using pharmacological stress testing (PST) as a substitute for exercise stress testing (EST) to evaluate cardiac function in horses. Objective: To compare the effect of PST and EST on right ventricular pressure dynamics and stress echocardiography. Methods: Five horses completed a PST and EST in a randomised crossover design. High fidelity pressure transducers were placed in the right ventricle. Continuous pressure signals were digitally collected and stored, and dP/dtmax, dP/dtmin and tau calculated from these measurements. ECGs were recorded continuously for 20 h. Echoca...
Kernicterus in a neonatal foal. A 5-day-old Thoroughbred foal was submitted to the necropsy service at the University of Kentucky Livestock Disease Diagnostic Center. The foal had a clinical history of seizure activity and severe icterus. A complete blood count and serum chemistry analysis indicated that the foal was anemic (hematocrit, 16%), hyperbilirubinemic (45 mg/dl), and hypoglycemic. At necropsy, all tissues were discolored various shades of yellow. Microscopically, there was degeneration and necrosis of cerebral neurons and cerebellar Purkinje cells; severe hepatocellular degeneration and necrosis; and deposition of ...
Validation of a portable equine metabolic measurement system. In equine sports medicine, VO2 has been measured exclusively with stationary systems, in laboratories equipped with a treadmill. Measurement during exercise in field conditions has not previously been reported because of the lack of portable equipment designed for horses. Objective: A commercially available portable metabolic measurement system, based on breath-to-breath gas analysis and flow spirometry, was adapted to the horse's physiology and morphology (Cosmed K4b2 and Equimask) and its validity tested by (1) repeatability of the measures and (2) comparing metabolic data to those obtained ...
Observations on respiratory flow strategies during and after intense treadmill exercise to fatigue in thoroughbred racehorses. Locomotor-respiratory coupled (LRC) breath types are a feature of galloping exercise in horses. Differences in breath type have been demonstrated during exercise in particular the 'big respiratory cycle' (BRC) and 'flow hesitation'. To investigate breath types during recovery and quantitatively investigate BRCs during exercise to understanding the mechanism driving BRCs. Objective: To investigate the occurrence of different breath types during and after intense treadmill exercise, and test the hypothesis that large breaths (BRCs) were a function of respiratory frequency. Methods: Six trained a...
Trot asymmetry in relation to physical performance and metabolism in equine endurance rides. Trot is a symmetric gait and asymmetry might appear or increase during endurance rides due to lameness, pain or excessive fatigue. Objective: To assess whether trot asymmetry increases during endurance competitions, whether it is possible to discriminate between horses with different performance and also its possible relationship with metabolism. Methods: Fifty-eight horses were filmed at trot during the lameness examinations in the vet-gates, before the competition (BCO), and after phases 1 (at 29 km), 2 (at 59 km) and 3 (at the end of the ride, at 80 km) and stride duration (SD) measured in ...
Evaluation of race distance, track surface and season of the year on exercise-induced pulmonary haemorrhage in flat racing thoroughbreds in Brazil. To our knowledge no studies evaluating risk factors to EIPH have been undertaken with such a population of horses in Brazil, which is one of the few countries in the racing community to accept the use of frusemide (FUR) as a prerace medication for bleeders. We also compared national results with those already in the literature. Objective: To verify the influence of variables such as distance of the race, racetrack surface, going and season of the year in the recurrence and severity of EIPH and its effect on the finishing position of flat racing Thoroughbreds in Brazil. Methods: 2118 post race ...
Oral vitamin E supplementation on oxidative stress, vitamin and antioxidant status in intensely exercised horses. Vitamin E is the most commonly supplemented antioxidant in horses; however, previous research is not conclusive as to the recommended level for exercising horses. Objective: To evaluate the effects of 3 levels of vitamin E supplementation on oxidative stress and vitamin/antioxidant status in intensely exercised horses to determine the optimal level of vitamin E supplementation. Methods: Twelve unfit Standardbreds were divided into 3 groups, supplemented orally with 0 (CON), 5000 (MOD), or 10,000 (HI) iu/day of DL-alpha-tocopheryl acetate. The 3 x 3 Latin square design consisted of three 4 week...
Raising heels of hind hooves changes the equine coffin, fetlock and hock joint angle: a kinematic evaluation on the treadmill at walk and trot. Raised heels are commonly recommended for various equine orthopaedic conditions. However, the simultaneous effect of raised heels on the different joint angles of the equine hindlimb throughout the motion cycle has not been previously evaluated. Objective: To document the simultaneous effect of raised heels on the joint angles of the equine hindlimb coffin, fetlock and hock joints. Methods: Eight sound, adult, Warmblood horses were evaluated barefoot and with a heel wedge of 8 or 16 degrees, walking and trotting on a horizontal treadmill. Markers placed on the dorsal and cranial aspect of the ...
A comparison of cross-country recovery rates at CCI 2* with and without steeplechase competitions. Short format 3-day events were introduced in 2004. Anecdotal reports suggested that horses were more tired on completion of the cross-country phase of short format events when compared with horses completing the cross-country phase of long format competitions, despite the absence of Phases A, B and C. Objective: To compare the physiological parameters and haematological parameters of horses that had completed the cross-country phase of a short format (SF) and a long format (LF) CCI 2* competition. Methods: During a CCI 2* competition 69 competitors took part in the short format and 74 in the l...
The effect of adrenergic suppression induced by guanabenz administration on exercising thoroughbred horses. Adrenergic activity accompanies intense exercise and mediates physiological and metabolic responses to exercise. Guanabenz, an antihypertensive drug marketed for human usage, depresses brain vasomotor and cardioaccelerator centres, blocks peripherally adrenergic neurons and is reportedly used as a calming agent in horses but little is known of its effects in the species. Objective: To determine if guanabenz induces measurable signs of adrenergic suppression on fit Thoroughbred horses undergoing intense exercise. Methods: In a random crossover design, 12 exercise conditioned Thoroughbred horses...
Correlations between exercising arterial blood gas values, tracheal wash findings and upper respiratory tract abnormalities in horses presented for poor performance. There are limited data on the correlations between arterial blood gas (ABG) values, tracheal wash (TW) cytology and upper respiratory tract (URT) abnormalities. Objective: To identify horses with abnormal exercising ABG, and compare the proportions of horses with abnormal ABG and TW cytology, mucus or URT dysfunction with those with normal ABG results and abnormal TW cytology, mucus or URT dysfunction. Methods: Medical records of 813 horses presenting to the treadmill facility that had a complete treadmill examination, including ABG analysis, TW and URT endoscopy were selected. Diagnoses, ABG ...
Study of gelatin supplemented diet on amino acid homeostasis in the horse. Gelatin supplementation is a common measure in an attempt to assist cartilage repair, but little scientific evidence exists to support its efficacy. Objective: To investigate the effects of gelatin administration on post prandial homeostasis. Methods: Twelve Standardbred horses (mean 404 kg bwt) were fed a hay-concentrate diet supplemented by soy bean meal and oil (control [C], n = 6) or with the addition of 60 g gelatin/day (G, n = 6). The horses were trained by an alternate order of interval and prolonged exercise every second day. The velocities of the treadmill corresponding to 2 and 10 mm...
Effects of chronic acetazolamide administration on fluid flux from the pulmonary vasculature at rest and during exercise in horses. Horses develop high pulmonary pressures during exercise, which force fluid out of pulmonary capillaries. Specific airway diseases in horses, especially those associated with hypoxaemia, hypercapnoea and acidosis may influence pulmonary haemodynamics and pulmonary interstitial fluid equilibrium. Objective: This study was designed to determine fluid flux (J(V-A) l/min) across the lung in exercising horses treated chronically with acetazolamide. Methods: Six horses were exercised on a treadmill until fatigue without (Con) and with chronic carbonic anhydrase (CA) inhibition (AczTr) and associated ...
Effects of egg-bar shoes on the 3-dimensional kinematics of the distal forelimb in horses walking on a sand track. Understanding of the biomechanical effects of egg-bar shoes remains incomplete because kinematic studies are usually performed on hard tracks and with skin markers that do not measure the actual 3-dimensional (3D) movements of the 3 digital joints. Objective: To quantify the effects of egg-bar shoes on the 3D kinematics of the distal forelimb in horses walking on a sand track. Methods: Four healthy horses were equipped with ultrasonic markers fixed surgically to the 4 distal segments of the left forelimb. The 3D movements of these segments were recorded while the horses were walking on a sand ...
Influence of training on plasma adrenaline and noradrenaline kinetics in untrained standardbreds. Catecholamines (CAT) play an important role in modulating the response to exercise. But the kinetics of CAT changes during exercise are difficult to study due to their short biological half-life. Objective: Learning about variations in plasma CAT levels during training could furnish new information regarding sweating, redistribution of blood flow and energy metabolism. Methods: Four untrained Standardbreds, adapted to treadmill work, were used to determine the influence of training on plasma adrenaline (A) and noradrenaline (NA) kinetics. Horses underwent a standardised exercise test (SET) on ...
Determination of mechanical loading components of the equine metacarpus from measurements of strain during walking. The mechanical environment of the distal limb is thought to be involved in the pathogenesis of many injuries, but has not yet been thoroughly described. Objective: To determine the forces and moments experienced by the metacarpus in vivo during walking and also to assess the effect of some simplifying assumptions used in analysis. Methods: Strains from 8 gauges adhered to the left metacarpus of one horse were recorded in vivo during walking. Two different models - one based upon the mechanical theory of beams and shafts and, the other, based upon a finite element analysis (FEA) - were used to ...
Measurements of right ventricular internal dimensions and their relationships to severity of tricuspid valve regurgitation in national hunt thoroughbreds. The effect of tricuspid valve regurgitation (TR) in right ventricular (RV) chamber size has not been reported. Methods: An echocardiographic and auscultation study was conducted on 394 race-fit National Hunt Thoroughbreds (TBs) in 4 training yards. Auscultation was performed on each horse and audible murmurs of TR graded using a 1-6 scale. Echocardiography was also performed and standard, 2-dimensional (2D), short (SA) and long axis (LA) images of the RV obtained from a right parasternal location. An m-mode image was recorded from an SA view of the RV just below the level of the tricuspid valv...
Body composition in young standardbreds in training: relationships to body condition score, physiological and locomotor variables during exercise. Body composition is an essential factor in athletic performance of human sprinters and long distance runners. However, in horses, many questions remain concerning relationships between body composition and performance in the different equine activities. Objective: To determine relationships between body composition, body score, physiological and locomotor variables in a population of young Standardbreds in training. Methods: Twenty-four 2-year-old Standardbreds were studied, body condition on a scale 0-5 and bodyweight recorded, and height at withers measured. Percentage of fat (%F), fat mass ...
Effect of conditioning horses with short intervals at high speed on biochemical variables in blood. There is limited published work on the effect of training using intensive and short intervals of exercise to condition horses for racing. Objective: To examine the effect of conditioning horses 1, 2 or 3 x a week using 2 short fast exercise intervals on blood lactate (LA), plasma ammonia (NH3) and urea (urea) as well as creatine kinase (CK) activity. Methods: Thoroughbreds (age 4-5 years) were conditioned at near maximal speed (12-14 m/sec) over 100 m, on 2 occasions separated by a 10 min period at walk, on dirt track (conditioning exercise; CE) during a 6 week conditioning period (CP). The CE...
An echocardiographic and auscultation study of right heart responses to training in young national hunt thoroughbred horses. There are few data available to determine the effect of training on cardiac valve function. Objective: To investigate the effect of commercial race training on right ventricular (RV) and tricuspid valve function in an untrained group of National Hunt Thoroughbreds (TB). Methods: Cardiac auscultation, guided M-mode echocardiography of the RV, and colour flow Doppler (CFD) tricuspid valve and right atrium were performed in 90 TB horses (age 2-7 years) 1998-2003. Forty horses were examined at least once and 48 horses were examined on at least 2 occasions. Examinations were then classified as: i) ...
Correlation of race earnings with velocity at maximal heart rate during a field exercise test in thoroughbred racehorses. Running ability of Thoroughbred racehorses is correlated with maximal oxygen uptake, and the velocity at maximal oxygen uptake is highly correlated with the velocity at maximal heart rate (VHRmax). Objective: To investigate the relationship between VHRmax and racing performance, expressed as 'peak dollars earned per race start'. Methods: Heart rate (HR) and velocity were recorded in 25 Thoroughbred racehorses during trotting and subsequent fast gallops in the field at velocities of 15-16 m/sec. Velocity was recorded by a global positioning system (GPS). Maximal HR (HRmax) and maximal velocity ...
Associations between exercise-induced pulmonary haemorrhage, right ventricular dimensions and atrioventricular valve regurgitation in conditioned national hunt racehorses. Exercise-induced pulmonary haemorrhage (EIPH) and tricuspid (TR) and mitral valve regurgitation (MR) are conditions with high prevalence in conditioned Thoroughbreds. Stress failure of pulmonary capillaries, leading to EIPH, is most likely when pulmonary vascular pressure is increased, and mitral regurgitation can result in pulmonary venous hypertension. Objective: There might be an association between MR and EIPH and the right ventricle (RV) of horses known to suffer repeated episodes of EIPH, as their hearts would be subject to higher pulmonary vascular pressures and cardiac output during tr...
Hormone response to training and competition in athletic horses. It is recognised that the amount of psychological stress that an animal encounters determines the degree of response of the hypothalamic-pituitary-adrenal (HPA) axis. In human athletes, the added emotive stress of competition is an important element in the adrenal response. The aim of this study was to examine the effect of show-jumping as well as dressage on stress levels by comparing horses' stress response at a horse show compared to their familiar home. Methods: Fifty-one horses involved in competition were used. EDTA blood samples were collected before exercise, upon arrived to the school...
Effects of prior exercise on components of insulin signalling in equine skeletal muscle. Exercise is an important stimulus for the regulation of numerous metabolic functions in muscle, but there has been little investigation of the mechanism of exercise-enhanced glucose utilisation. Objective: To examine the effects of exercise on the signalling components Akt and glycogen synthase kinase-3 (GSK3) involved in insulin regulation of glycogen synthase (GS) activity. It was hypothesised that hyperinsulinaemia and prior exercise would alter the extent of Akt phosphorylation and GSK3beta deactivation and increase insulin stimulation of GS activity in skeletal muscle. Methods: Eight Stan...
Effects of short-term training on insulin sensitivity and skeletal muscle glucose metabolism in standardbred horses. Increased insulin sensitivity occurs after a period of exercise training, but the mechanisms underlying this training-associated increase in insulin action have not been investigated. Objective: To examine the effects of short-term endurance training (7 consecutive days) and a subsequent period of inactivity (5 days) on whole body insulin sensitivity and GLUT-4 protein and the activities of glycogen synthase (GS) and hexokinase (HK) in skeletal muscle. It was hypothesised that training would increase insulin sensitivity in association with increased GLUT-4 protein and activities of GS and HK, ...
Effects of dietary energy source and physical conditioning on insulin sensitivity and glucose tolerance in standardbred horses. There is evidence that adaptation to diets rich in nonstructural carbohydrates (NSC) contributes to the development of insulin resistance in horses. To date, however, no study in horses has examined the effects of physical conditioning on diet-associated alterations in insulin sensitivity and glucose tolerance. Objective: To examine the effects of adaptation to concentrate feeds rich in NSC or fat on insulin sensitivity and glucose tolerance in horses, both in the sedentary state and after a subsequent period of physical conditioning. Methods: Fourteen mature Standardbred horses underwent both...
Is the distribution of selenium and zinc in the sublocations of spermatozoa regulated? In the sperm nuclei, of mammalian species selenium has been found only in the form of sperm nuclei glutathione peroxidase (snGPx) where it is most likely bound to the chromatin of spermatozoa. Over 80% of selenium in sperm is bound to the selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) in the midpiece of rat sperm. Zinc in sperm is mainly contained in the outer dense fiber (ODF) proteins of the flagella of mammalian spermatozoa. In the sperm nuclei, zinc is predominately located in the chromatin to the protamine proteins. In order to investigate if the insertion of zinc...
Exercise-induced pulmonary haemorrhage during submaximal exercise. Maximally exercising horses achieve mean pulmonary artery pressures (Ppa(mean)) that exceed the minimum threshold (75 mmHg) estimated for pulmonary capillary rupture and exercise-induced pulmonary haemorrhage (EIPH). EIPH is not expected to occur during moderate submaximal exercise (i.e. 40-60% VO2max) since Ppa(mean) remains well below this threshold. Objective: Prolonged submaximal exercise (trotting) would precipitate locomotory respiratory uncoupling and cause EIPH. This would be present as a result of the most negative intrapleural pressures (as estimated by the minimum oesophageal pressu...
The effect of long-term exercise on glucose metabolism and peripheral insulin sensitivity in standardbred horses. To study the possible long-term effect of improved glucose tolerance in horses after long-term training, as the impact of exercise training on glucose metabolism is still unclear in the equine species. It is not known whether there is a direct long-term effect of training or if the measurable effect on glucose metabolism is the residual effect of the last exercise session. Objective: To determine the chronic effect on glucose metabolism and peripheral insulin sensitivity of long-term training in horses by use of the euglycaemic hyperinsulinaemic clamp technique. Methods: Eleven Standardbred ho...
Effect of corticosteroid and bronchodilator therapy on bronchoalveolar lavage cytology following intrapulmonary blood inoculation. Intrapulmonary blood causes an inflammatory response. Modifying this inflammatory response may be useful in the treatment of exercise induced pulmonary haemorrhage (EIPH). Objective: To evaluate the efficacy of 3 treatments, an oral bronchodilator, inhaled steroid and oral steroid in modifying the cellular response to intrapulmonary blood inoculation. Methods: Experimental design was a randomised block divided into 4 experimental segments of 2 weeks. Eight normal horses were randomly assigned to pairs and treatments. Autologous blood was inoculated into the lungs on 4 occasions over an 8 week ...
