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Topic:Veterinary Medicine
Veterinary medicine for horses encompasses the study and application of medical practices to diagnose, treat, and prevent diseases in equine species. This field involves a comprehensive understanding of equine anatomy, physiology, pathology, and pharmacology. Veterinary practitioners employ a range of diagnostic tools and therapeutic interventions to address health issues in horses, including lameness, gastrointestinal disorders, respiratory conditions, and infectious diseases. Preventative care, such as vaccination and deworming programs, is also a significant aspect of equine veterinary medicine. This page gathers peer-reviewed research studies and scholarly articles that explore various aspects of veterinary medicine as it pertains to horses, including advancements in diagnostic techniques, treatment protocols, and preventive health strategies.
Influence of trotting and supplemental weight on metacarpal bone development. The use of weight-training to alter bone strength has not been investigated in horses. Recognising that bone responds to loading, we studied the effect of carrying weight on bone development during training. Seventeen horses were divided into 3 groups: controls exercised counterclockwise in a free-flow exerciser; the weight group performed the same exercise carrying progressively increasing weight up to 45 kg and the weight supplement group also received a myo-anabolic supplement. Radiographic equivalence measure of bone mineral content of zones of the third metacarpi (MCIII) was determined on...
Structural and oxidative enzyme characteristics of the diaphragm. During exercise, the horse can achieve oxygen uptakes and ventilations in excess of 200 ml/kg/min and 1800 l/min, respectively. Whether the diaphragm has the capacity to contribute substantially to inspiratory effort in the exercising horse is not known. To investigate the potential for the horse diaphragm to generate tension, lung displacement and sustain ventilatory function, we measured diaphragm thickness, muscle length and oxidative enzyme activity (citrate synthase) within the ventral, medial and dorsal costal and crural diaphragm. In the diaphragms of 6 mature horses (5 Thoroughbreds, o...
Postprandial glucose and insulin responses to a postexercise grain meal. Many studies have examined the effect of pre-exercise feeding on glucose and insulin responses of horses. The objective of this study was to determine whether exercise performed one hour prior to a meal would attenuate the glucose and insulin responses to a meal. Data collected from 8 mature geldings in a 2 period crossover design experiment were used to determine the postprandial glucose and insulin responses to a meal of oats offered 1 h postexercise. During each period, 4 horses received a test meal following a 14 h fast (NoEx) or a 14 h fast and exercise bout (PostEx) that consisted of 48 ...
Effect of exercise on plasma ferritin concentrations: implications for the measurement of iron status. Iron is of key importance for aerobic metabolism, and natural feeds of the horse are fairly rich sources of iron. Accordingly, the known incidence of iron deficiency anaemia is apparently rare in performance horses; despite this, iron deficiency in performance horses continues to be of concern to trainers and veterinarians. Effects of exercise on plasma ferritin concentrations were therefore studied in Standardbreds, Finnhorses and half-bred riding horses. Blood samples were taken after a moderate exercise test on a racetrack, a competition exercise test on a treadmill and a race. Even moderat...
Biomechanical implications of uphill training on the aetiology of tendinitis. It has been reported that a small decrease in the strain in the superficial digital flexor tendon (SDFT) occurs if the toe is raised during walking. Although walking on a slope appears similar to raising the toe, it is unclear whether uphill exercise decreases the strain in the SDFT. Because the force or strain on tendons is one of the important factors leading to tendon stress injury, we hypothesised that reducing the force in the SDFT during exercise may prevent tendinitis. The purpose of this study was to determine the effects of treadmill inclination on the force in the SDFT in the walking...
Phosphorylation of protein tyrosine residues in fresh and cryopreserved stallion spermatozoa under capacitating conditions. Phosphorylation of tyrosine residues on sperm proteins is one important intracellular mechanism regulating sperm function that may be a meaningful indicator of capacitation. There is substantial evidence that cryopreservation promotes the capacitation of sperm and this cryocapacitation is frequently cited as one factor associated with the reduced longevity of cryopreserved sperm in the female reproductive tract. This study was designed to determine whether stallion sperm express different levels of tyrosine phosphorylation after in vitro capacitation and whether thawed sperm display similar ph...
Age-related changes and inheritance of lactate transport activity in red blood cells. In red blood cell membranes, the activity of the main lactate carrier, H+-monocarboxylate co-transporter (MCT), varies interindividually and its distribution is bimodal. To show the repeatability of MCT activity, 2 to 5 blood samples were taken, at an interval of approximately 1 year, from 51 Standardbred horses, age 2 weeks-8 years, for a total of 128 observations. The horses could be divided into low (LT) and high (HT) lactate transport activity groups. Age significantly affected (P<0.05) MCT activity such that activity was highest in foals, reached a nadir at 2-3 years, and tended to inc...
Effect of instillation into lung of autologous blood on pulmonary function and tracheobronchial wash cytology. This study aimed at measuring the functional consequences and the pulmonary cytology changes following a simulation of pulmonary haemorrhage. Pulmonary function tests including lobeline-induced hyperventilation, cytology of tracheo-bronchial wash (TBW) and thoracic radiographs were performed before, as well as 1, 7, 14 and 28 days after, the instillation of 300 ml of blood into the lungs of 4 horses deemed free of exercise-induced pulmonary haemorrhage (Group 1). Control data (Group 2) were obtained by instilling the same volume of saline into the lungs of the same horses in a crossover design...
Evaluation of the i-STAT hand-held chemical analyser during treadmill and endurance exercise. This study examined the accuracy and precision of a hand-held, chemical analyser, i-STAT, in measuring selected blood constituents which may be of use in the diagnosis and management of metabolic disorders found in exercising horses. Venous blood samples were taken from 3 Thoroughbred geldings, fit and trained to exercise on a treadmill, both before and after exercise at a speed sufficient to elicit VO2max. The samples were analysed both with the i-STAT and with in-house analysers to compare the values of pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), bicarbon...
Comparison between glycerol and ethylene glycol for the cryopreservation of equine spermatozoa: semen quality assessment with standard analyses and with the hypoosmotic swelling test. The aims of this study were to compare glycerol (G) at customary concentrations and ethylene glycol (EG) as cryoprotectants for stallion semen in a skimmed milk (SM) extender, to test different EG concentrations and to compare the results of manual and computerized analysis with the hypoosmotic swelling (HOS) test. Ejaculates from two stallions were collected over 3 weeks (6 ejaculates per stallion), diluted in a SM based extender, divided into 4 fractions, centrifuged and diluted again to a concentration of 100 x 10(6) mL(-1) progressive motile spermatozoa (PMS) in addition with the cryoprote...
Evaluation of three ancillary treatments in the management of equine grass sickness. Brotizolam, acetylcysteine and aloe vera gel were evaluated as ancillary treatments for 29 cases of equine grass sickness. None of the treatments had any significant beneficial effect on the survival of the horses. However, 11 of 13 horses with mild chronic grass sickness survived solely with intensive nursing care.
Three-dimensional kinematics of the tarsal joint at the trot. The tarsal joint is a common site of injury for many sport horses. Understanding the biomechanics of this complex joint begins with developing a clear picture of the kinematics during normal locomotion. This study describes the 3D kinematics of the tarsal joint by measuring the motion of the tibia and third metatarsus in 4 sound Quarter Horses with targets attached directly to the bones via steel pins. The objective was to determine if the tarsus had significant motion outside the tarsocrural joint. Two Steinmann pins were inserted into the lateral side of the right hindlimb and marker triads ...
Effect of short-term exercise training on insulin sensitivity in obese and lean mares. Twelve untrained aged mares were used to determine whether 7 days of light exercise improved peripheral tissue insulin sensitivity. Mares were divided into obese-exercised (n = 3), obese-sedentary (n = 3), lean-exercised (n = 3) and lean-sedentary (n = 3) groups. The exercised groups were worked at a trot to a heart rate (HR) of not more than 140 beats/min for 30 min in a round pen. Each group was subjected to 3 euglycaemic hyperinsulinaemic clamps: prior to exercise (P), 24 h following the seventh exercise training session (E) and 9 days postexercise training (PE). Prior to exercise training,...
Effects of somatotropin and training on indices of exercise capacity in Standardbreds. The recent availability of recombinant equine somatotropin (eST) has led to concern about its use as an ergogenic aid in racehorses. This study was undertaken to investigate the changes in exercise capacity in maturing horses in a training programme, and to assess whether eST is an ergogenic aid to this group. We tested the hypothesis that the combination of training and eST, compared to training alone, would further improve exercise capacity in maturing Standardbreds, by virtue of ST's anabolic effects and potential to enhance cardiac function, circulating fluid volume and red cell mass. Twel...
Alveolar fibrosis and changes in equine lung morphometry in response to intrapulmonary blood. Necropsy studies of horses suffering exercise-induced pulmonary haemorrhage (EIPH) have identified mild inflammatory lesions with evidence of alveolar fibrosis and bronchiolitis. These lesions were thought to be the result of viral infections that predisposed the affected regions of the lung to EIPH. We have shown previously that during erythrophagocytosis in the alveolar space, there is a prolonged period of macrophage influx and activation. This present study used morphometric analysis to quantify the effects of macrophage activity during erythrophagocytosis, on the alveolar cell population ...
A radiographic technique to assess the longitudinal balance in front hooves. The aim of this study was to validate a radiographic technique to measure objectively the longitudinal hoof balance in the horse. Ten left third phalanges (P3) obtained from front hooves and 19 left front hooves were used in order to assess the reliability of the radiographic technique and to identify any effect of rotation or alignment of specimens or distance between the X-ray machine and the radiographic cassette, in measuring P3s structures and balance related parameters. A rotational support was made to hold specimens in order to standardise some of the conditions of X-raying. The main ax...
Exercise-induced tendon hypertrophy: cross-sectional area changes during growth are influenced by exercise. Most skeletal tissues are thought to adapt to the mechanical environment they experience. While this has been demonstrated for muscle and bone, previous studies in the mature horse have failed to demonstrate adaptation in the superficial digital flexor tendon (SDFT), which suffers a high frequency of injury. This study tested the hypothesis that imposed exercise during growth would result in an increase in SDFT cross-sectional area (CSA). Fourteen Thoroughbred foals were divided into 2 sex-matched groups. A control group received 4 h pasture exercise and an exercise group had the same amount o...
Movements of thoracic and abdominal compartments during ventilation at rest and during exercise. The present investigation utilised simultaneous measurements of chest (Ch) and abdominal (Ab) circumferences and respiratory airflow to test the hypothesis that Ch circumferential expansion contributes proportionally little to tidal volume in the running Thoroughbred. During exercise, there were only small changes in Ch and Ab circumference and no increase with increasing tidal volume. At rest, walk and trot, the flow, Ch and Ab signals were in phase. However, during canter and gallop, the Ch and Ab changes were 180 degrees out of phase with each other and both were out of phase with airflow. ...
Airway cooling and mucosal injury during cold weather exercise. In human subjects that exercise strenuously in cold weather, there is evidence that hyperventilation with cold air leads to peripheral airway cooling, desiccation and mucosal injury. Our hypothesis was that hyperventilation with cold air can result in penetration of unconditioned air (air that is not completely warmed and humidified) into the peripheral airways of exercising horses, resulting in peripheral airway mucosal injury. To test this hypothesis, a thermister-tipped catheter was inserted through the midcervical trachea and advanced into a sublobar bronchus in three horses that cantered ...
Effect of NaCl and NaHCO3 on serum ionised calcium and blood gas status during sprinting. Sodium bicarbonate is often administered to horses before racing in an attempt to delay fatigue and improve performance. We examined the effect of acid-base status on serum ionised calcium concentration (iCa) during high intensity exercise in 8 Standardbred mares. In a randomised, blinded, cross-over study, mares were administered each of 3 treatments, NaCl (0.7 g/kg bwt), NaHCO3 (1 g/kg bwt) in 3 l water, or 3 l of water only, 4 h before performing a standardised exercise test to fatigue on a treadmill. Mixed venous blood samples were collected as the horses ran for 5 min at 3 m/s, to fatigue...
Effects of trotting speed on muscle activity and kinematics in saddlehorses. A thorough knowledge of the horse's back and limb movements at different speeds is important in the design of training programmes and the prevention of speed-related injuries. The objective of this study was to investigate changes in muscle activity and kinematics of the trot with increased speed. To evaluate these effects, 4 Saddlehorses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5-6.0 m/s. The 3-D trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was obtained simultaneously...
Effect of frusemide on bodyweight loss and recovery in racing Standardbreds. This study was conducted to compare bodyweight (bwt) loss and recovery in Standardbred horses receiving frusemide compared to controls. Thirty Standardbred horses from 7 training stables that were racing at the Red Mile in Lexington, Kentucky, during the spring 2001 pari-mutuel meeting were studied. Fourteen horses (FRU) received frusemide (250 mg/horse i.v.) 4 h prior to racing, while 16 horses (NFRU) did not received frusemide. Horses were weighed on the morning of race day, prior to warm-up, after racing and the next day. Changes in bwt were calculated as percentage increase or decrease fro...
Physiological measurements and upper and lower respiratory tract evaluation in French Standardbred Trotters during a standardised exercise test on the treadmill. There are a variety of reasons for poor performance in racehorses. Exercise intolerance has often been associated with subclinical respiratory abnormalities, and diagnostic aids are therefore used to enhance clinical detection. Physiological variables can also be measured in order to evaluate the metabolic reponse to exercise. This study evaluated the relationship between physiological measurements and upper airway videoendoscopy during a standardised treadmill exercise test and bronchoalveolar lavage (BAL) cytology in control horses (good racing performance, n = 14) and poor performers (n = 2...
Effect of glucosamine on interleukin-1-conditioned articular cartilage. Glucosamine inhibits recombinant human interleukin-1 stimulated cartilage degradation in equine cartilage explants. Recently, recombinant equine interleukin-1 has been cloned and purified. Therefore, the objective of this study was to characterise the effects of glucosamine on indices of cartilage degradation in recombinant equine IL-1beta-stimulated equine articular cartilage explants. Cartilage discs were harvested from the weight-bearing region of the articular surface of the antebrachiocarpal and middle carpal joints of horses (age 2-8 years) and cultured under standard conditions. Explant...
Inhibition of articular cartilage degradation by glucosamine-HCl and chondroitin sulphate. Glucosamine and chondroitin sulphate in many animal and human trials has improved joint health. In vitro studies are beginning to clarify their mode of action. The objective of this research was to: 1) determine at what concentrations glucosamine-HCl (GLN) and/or chondroitin sulphate (CS) would inhibit the cytokine-induced catabolic response in equine articular cartilage explants and 2) to determine if a combination of the 2 was more effective at inhibiting the catabolic response than the individual compounds. Articular cartilage was obtained from carpal joints of horses (age 1-4 years). Carti...
Heterogeneity of intrapleural pressures during exercise. We determined whether the caudodorsal region of the intrapleural space in exercising horses experiences larger pressure fluctuations than other regions and whether systematic phase-shifting of peak intrapleural pressures along the length of the thorax suggests the existence of locomotor-induced intrapleural pressure waves. We utilised percutaneous introducers and solid-state pressure-tip transducers implanted along the dorsal aspect of the thorax, mid-thorax or oesophagus to measure regional intrapleural pressures while 3 horses galloped on a flat treadmill at 13-14 m/s, then recorded pressure...
Right ventricular pressure dynamics during exercise: relationship to stress echocardiography. Thorough evaluation of myocardial function remains difficult to evaluate under exercising conditions. This study described right ventricular (RV) pressure dynamics during and immediately following exercise. Nine Thoroughbreds without evidence of cardiac disease completed treadmill exercise at 110% of the speed necessary to elicit VO2max while RV pressures were recorded. RV pressure dynamics were calculated at rest, maximal speed and at 10 s intervals for 2 min after exercise. Stress echocardiography was performed at rest and within 120 s after exercise. Mean dP/dtmax and dP/dtmin values were s...
Myosin heavy chain-based fibre types in red cell hyper- and normovolaemic Standardbred trotters. An assumed link between red cell hypervolaemia, an excessive amount of training and impaired performance of hypervolaemic horses has led to a theory that the muscle fibres could be affected. Myosin heavy chain (MHC)-based fibre type composition in gluteus medius muscle of red blood cell normo- (NV) and hypervolaemic (HV) Standardbred trotters was evaluated using immunohistochemistry. Muscle biopsies were obtained from 13 NV and 16 HV horses. Serial transverse sections were cut and reacted with antibodies against different isoforms of the myosin heavy chains MHCI, MHCIIA and MHCIIX. Sections we...
Dynamic upper airway changes and arterial blood gas parameters during treadmill exercise. The primary goal was to investigate the relationship between dynamic upper airway abnormalities and arterial blood gas tensions during exercise. Horses that completed a high-speed treadmill examination consisting of upper-airway videoendoscopy, blood gas evaluation and electrocardiogams and, postexercise, echocardiograms and tracheal washes, were included. An age-matched group of fit, healthy Thoroughbreds, trained to run on a high-speed treadmill, served as controls for blood gas values at specific exercise speeds. One hundred and nineteen horses completed the treadmill examination. Sixty (50...
Effect of training on age-related changes in plasma insulin and glucose. The purpose of the study was to determine whether 12 weeks of exercise training would affect plasma glucose and plasma insulin concentrations in young and older Standardbred mares. Eighteen healthy, unfit mares representing 3 age groups were used: young (Y = 6.8 +/- 0.4 years; n = 6), middle-aged (MA = 15.2 +/- 0.4; n = 6), and old (O = 27.0 +/- 0.2; n = 6). Pre- and post-training incremental exercise tests (GXT) were performed to measure plasma glucose and insulin concentration from immediately after, until 120 min postexercise. Training consisted of exercise 3 days/week (weeks 1-8) and 4 day...
