bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of binding of fibrinogen and annexin V to equine platelets in response to supramaximal treadmill exercise
Authors: KINGSTON J. K. , BAYLY W. M. , MEYERS K. M. , SELLON D. C. , WARDROP K. J. 
Published: June 2010

SummaryThere is evidence that equine platelet reactivity is altered by strenuous exercise. Changes in platelet reactivity could impact haemostasis following exercise‐induced injury and may play a role in the pathophysiology of exercise‐induced pulmonary haemorrhage. Interpretation of results of previous studies is hindered by potentialin vitro‐induced changes in platelet activity through the choice of anticoagulant and the use of platelet inhibitors. The present study was undertaken to re‐evaluate the effect of exercise on equine platelets using methodologies that minimisein vitro‐induced changes in platelet activation.The percentage of platelet‐neutrophil aggregates increased significantly (P = 0.01) from mean ± s.e. 3.5 ± 0.6% at rest to 7.2 ± 1.3% during exercise. There were no significant changes in binding of anti‐fibrinogen antibody or annexin V to platelets in response to exercise.An inability to detect increased binding of fibrinogen or annexin V may be a result of poor test sensitivity or low statistical power. Alternatively, activated platelets may be quickly removed from the circulation and miss detection. The significance of increased numbers of platelet‐neutrophil aggregates in association with exercise is currently unknown and warrants further investigation.
Effect of body incline on cardiac performance
Authors: McDONOUGH P. , KINDIG C. A. , HILDRETH T. S. , BEHNKE B. J. , ERICKSON H. H. , POOLE D. C. 
Published: June 2010

SummaryMaximal cardiac performance is improved in man during upright compared to supine exercise. Whether cardiac performance in quadrupeds is dependent upon body position is unknown. Therefore, we undertook the present investigation to determine if peak cardiac output (Qpeak) would be influenced by body inclination in the Thoroughbred horse. To test the hypothesis, four Thoroughbred horses performed an incremental exercise protocol (speed increased by 1 m/s/min to fatigue) on both a level (L) and inclined (I: 6°) treadmill. Specifically, we hypothesised that Qpeak would be increased on the incline, as this represents a progression towards upright exercise. Cardiac output was determined using the Fick relationship from continuous measurements of pulmonary V̇O2 and paired arterial (carotid artery or transverse facial) and mixed venous (pulmonary artery) samples. Qpeak was significantly increased on the incline (L: 279 ± 20; I: 336 ± 17 l/min; P<0.05), while CaO2 was not significantly different (L: 25.5 ± 1.1; I: 25.4 ± 1.9 ml/100 ml), and therefore, whole body O2 delivery (QO2) was significantly increased (L: 70.7 ± 4.9; I: 84.4 ± 3.1 l/min; P<0.05). In conclusion, within the scope of this investigation, these data suggest that cardiac performance, as judged by increased Qpeak and QO2, is enhanced in the inclined body position. Furthermore, these findings provide preliminary information that level and incline treadmill exercise tests may yield significantly different results in the Thoroughbred horse and consequently this factor should be considered when interpreting exercise testing and performance data.
Drinking salt water enhances rehydration in horses dehydrated by frusemide administration and endurance exercise
Authors: BUTUDOM P. , SCHOTT H. C. , DAVIS M. W. , KOBE C. A. , NIELSEN B. D. , EBERHART S. W. 
Published: June 2010

SummaryBecause the primary stimulus for thirst is an increase in plasma tonicity, we hypothesised that dehydrated horses would drink a greater total volume of fluid voluntarily during the first hour of recovery when they were initially offered salt water. To test this hypothesis, bodyweight (bwt), fluid intake (FI) and [Na+] were measured in 6 Arabian horses offered 3 rehydration solutions. After dehydration was induced by frusemide administration (1 mg/kg bwt, i.v.) followed by 45 km treadmill exercise, water (W), 0.45% NaCl and 0.9% NaCl were offered, in a randomised order, during the initial 5 min after completing exercise. Horses were subsequently placed in a stall and further intake of plain water during the first hour of recovery was measured. By the end of exercise, horses lost 5.2 ± 0.2, 5.6 ± 0.3 and 5.7 ± 0.2% (P>0.05) bwt and FI during the first 5 min of recovery was 10.5 ± 0.7, 11.6 ± 0.8 and 11.6 ± 1.5 l (P>0.05) for W, 0.45% NaCl and 0.9% NaCl, respectively. After 20 min of recovery, [Na+] had decreased with W but remained unchanged from the end exercise values for both saline solutions. During the initial hour of recovery, further water intake was 0.9 ± 0.4, 5.0 ± 0.5 and 6.9 ± 0.7 l (P<0.05) for W, 0.45% NaCl and 0.9% NaCl, respectively. Therefore, total FI was 11.4 ± 0.5, 16.6 ± 0.7 and 18.5 ± 1.7 l (P<0.05) for W, 0.45% NaCl and 0.9% NaCl, respectively, and persisting bwt loss after 60 min of recovery was greater (P<0.05) for W (3.5%) than for the 2 saline solutions (2.4% for 0.45% NaCl and 1.9% for 0.9% NaCl). In conclusion, providing salt water as the initial rehydration fluid maintained an elevated [Na+] and resulted in greater total FI and recovery of bwt loss during the first hour of recovery, in comparison to offering only plain water.
Potassium and lactate uptake by noncontracting tissue during strenuous exercise
Authors: SCHOTT H. C. , BOHART G. V. , EBERHART S. W. 
Published: June 2010

SummaryEfflux of potassium (K+) and lactate (lac−) from active skeletal muscle during high intensity exercise leads to increased plasma [K+] and [lac−] in venous and arterial blood. The exercise‐induced increases in these ions in human athletes is ameliorated, in part, by uptake by noncontracting tissue, reflected by an increase in the arteriovenous difference across these tissues from rest to exercise. To test the hypothesis that these ions are taken up by noncontracting tissue in strenuously exercising horses, plasma [K+] and [lac−] were measured in blood samples collected simultaneously from the carotid artery (CA), femoral vein (FV), and transverse facial vein (TFV) in 5 unconditioned Standardbred horses performing 4.5 min of strenuous treadmill exercise. Further, the arteriovenous differences ((a‐v)diff) in [K+] and [lac−] were calculated across active tissue (CA‐FV) and noncontracting tissue (CA‐TFV). After 3 min of strenuous exercise, plasma [K+] in FV blood (mean ± s.e. 7.1 ± 0.2 mmol/l) was greater (P<0.05) than in CA blood (6.8 ± 0.2 mmol/l) and both of these concentrations were greater (P<0.05) than a value of 5.7 ± 0.1 mmol/l in TFV blood. Similarly, plasma [lac−] increased to 20.6 ± 0.8 and 21.1 ± 0.8 mmol/l in CA and FV blood, respectively, and these concentrations were greater (P<0.05) than a value of 19.1 ± 0.8 mmol/l in TFV blood. The magnitude of the (a‐v)difffor both [K+] and [lac−] increased (P<0.05) across active and noncontracting tissue during highspeed exercise but the directions were opposite, supporting release by active tissue and uptake by noncontracting tissue. These results confirm that uptake of K+and lac−by noncontracting tissue contributes to regulation of the plasma concentrations of these ions in strenuously exercising horses.
Effect of sodium bicarbonate administration on metabolic responses to maximal exercise
Authors: SCHUBACK K. , ESSÉN‐GUSTAVSSON B. , PERSSON S. G. B. 
Published: June 2010

SummaryAdministration of bicarbonate has been shown to cause metabolic alkalosis both in man and in horses and is, therefore, thought to increase the buffering capacity of the body and thereby delay the onset of fatigue. However, results regarding the influence of sodium bicarbonate loading on performance both in human athletes and in horses are conflicting. The aim of this study was, therefore, to investigate the metabolic response to a standardised treadmill exercise test to fatigue, in horses given bicarbonate (0.6 g/kg bwt), in comparison to horses given placebo (water). Five Standardbred trotters performed the test on 2 occasions. Venous blood samples were collected before and after administration of test substance, during exercise and during recovery. Muscle biopsy specimens were taken at rest, postexercise and at 15 min of recovery. The increases in pH and concentration of bicarbonate in the blood and the shift seen in base excess showed that the administration of sodium bicarbonate caused metabolic alkalosis. Exercise caused similar decreases in muscle ATP, CP and glycogen and similar increases in muscle IMP, lactate and plasma lactate and uric acid concentrations both in the placebo‐ and bicarbonate‐treated group. The effect upon postexercise muscle and plasma metabolites was similar with both test treatments. Duration of exercise did not change after sodium bicarbonate intake. In conclusion, sodium bicarbonate caused metabolic alkalosis, but did not affect the metabolic response or duration of exercise.
Changes in selected physiological and laboratory measurements in elite horses competing in a 160 km endurance ride
Authors: II H. C. SCHOTT , MARLIN D. J. , GEOR R. J. , HOLBROOK T. C. , DEATON C. M. , VINCENT T. , DACRE K. , SCHROTER R. C. , JOSE‐CUNILLERAS E. , CORNELISSE C. J. 
Published: June 2010

SummaryReason for performing study:Limited information exists about the physiological changes and clinical problems that occur in elite horses competing in high‐speed 160 km endurance races.Objectives:To provide initial data describing changes in physiological and laboratory measurements in horses competing in a high‐speed, 160 km endurance race under temperate conditions and to compare data between horses that successfully completed the race and those that failed to finish.Methods:Body mass (BM) was measured, blood samples were collected, and veterinary examinations performed on horses before, during, and at the finish of a CEI*** 160 km endurance race.Results:Of 36 horses participating in the study, 22 (61%) completed the race. Twelve horses were eliminated for lameness and 2 for persistent heart rate elevation. Mean speed of finishers was 15.2 km/h. Mean ± s.d. BM loss of finishers at the end of the race (5.7 ± 2.6%) was not different (P = 0.58) from BM loss of nonfinishers at elimination (6.7 ± 3.4%). Similarly, there were no significant differences in heart rate or veterinary assessment of hydration at the race end for finishers as compared to the elimination point for nonfinishers. PCV increased while sodium, chloride and potassium concentrations decreased with exercise but differences between finishers and nonfinishers were not detected. In contrast, both total and ionised calcium concentrations decreased in successful horses but remained unchanged in nonfinishers.Conclusions:Elite endurance horses are more likely to be eliminated from competition for lameness than metabolic problems; however, it remains unclear whether these conditions are entirely distinct. The magnitude of the decrease in sodium concentration in both finishers and nonfinishers was greater than in previous reports of 160 km rides.Potential relevance:These data should be of use for both organisers and participants in elite 160 km endurance races. The tendency toward hyponatraemia as well as the difference in calcium concentrations between finishers and nonfinishers warrant further study.
Equine locomotor analysis on vet‐gates in endurance events
Authors: RIBER C. , CUESTA I. , MUÑOZ A. , GATA J. , TRIGO P. , CASTEJÓN F. M. 
Published: June 2010

SummaryReasons for performing the study:Fatigue during endurance rides might induce changes in gait pattern that could be difficult to distinguish from subtle lameness.Objectives:To assess changes in gait patternen route, in fore‐(FL) and hindlimbs (HL) and establish differences between excellent (EP) and good performers (GP).Methods:Seventy‐five sound and fit horses that completed endurance rides of 80 km were filmed at trot in the vet‐gates (VGs) prior to competitions (VG0), and at 29 km (VG1), 59 km (VG2) and 80 km (VG3). Mean gait velocity (V), stride length (SL), duration (SD) and frequency (SF) were measured. Also, stance (StD), swing (SwD), braking (BrD) and propulsion (PrD) durations were determined in the 4 limbs and expressed as % of SD.Results:Horses trotted with a significant lower V at VG3 in comparison to VG0 (mean ± s.d. 2.3 ± 0.6 m/sec, 3.3 ± 0.6m/sec) and showed a shorter SL (1.5 ± 0.4 m and 2.2 ± 0.3 m in VG0 and VG3). Regression analysis confirmed that the reduced SL at VG3 was due to the lower V. Horses in VG3 presented longer FL‐StD (46.2 ± 4.7%, 38.1 ± 4.6%), BrD (22.0 ± 2.5%, 16.9 ± 2.5%) and PrD (24.1 ± 2.2%, 21.5 ± 2.47%) compared to VG0. In VG0, HL‐PrD (23.0 ± 3.0%) and HL‐BrD (18.7 ± 1.8%) were longer than FL‐PrD (21.5 ± 2.47%) and FL‐BrD (16.9 ± 2.5%). EP showed fastest V and longer SL at VG0, and VG3 than GP (P<0.05).Conclusions:Sound endurance horses undergo changes in gait pattern during competition, mainly due to reduction of V. Some differences exist between FL and HL, and EP show higher V and SL in the VGs.Potential relevance:Understanding of the locomotor effect of fatigue will provide an objective basis for the assessment of soundness during endurance events.
A nonsurgical method allowing continuous core temperature monitoring in mares for extended periods, including during endurance exercise
Authors: SMITH J. E. , BARNES A. L. , MALONEY S. K. 
Published: June 2010

SummaryReasons for performing study:Body temperature can be a useful measure of how well the horse responds to thermal challenges of exercise and environment. Currently there is little information available about how body temperature changes throughout an endurance ride, and no nonsurgical methods to evaluate internal temperature of exercising horses during prolonged periods and during long distances.Objective:To develop and test a nonsurgical method, using temperature loggers, of continuously recording internal temperature during exercise and over an extended period.Methods:Loggers were inserted transcervically into the uterus of mares to measure internal temperature. A total of 9 mares were implanted for periods of 3 days to 6 weeks. The internal temperature was recorded while horses underwent their normal training and competition. Loggers were validated against rectal temperature over a range of internal temperatures while mares were alternatively exercised and rested.Results:The technique proved to be straightforward and accurate. There were no ill effects observed and all mares retained the loggerin uterountil removal manually, except for one mare, which expelled the logger when she came into oestrus. The intrauterine and deep rectal temperatures were highly correlated and increased during exercise and decreased with aggressive cooling after exercise.Conclusions:The technique is a useful and accurate nonsurgical method for prolonged monitoring of internal temperature in mares, including those animals in athletic competition.Potential relevance:This method allows more intensive studies of core temperature during prolonged exercise in competition and under different environmental conditions. It also enables comparison to be made of different methods of cooling of horses post exercise.
Effect of conditioning horses with short intervals at high speed on biochemical variables in blood
Authors: LINDNER A. , SIGNORINI R. , BRERO LUCIANA , ARN E. , MANCINI R. , ENRIQUE A. 
Published: June 2010

SummaryReasons for performing study:There is limited published work on the effect of training using intensive and short intervals of exercise to condition horses for racing.Objectives: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 was undertaken either once (5 horses), twice (5 horses) or 3 times a week (4 horses) during a CP. Before, every 2 weeks during and after the CP, blood was drawn during the CE at 0, 2 and 4 min after each run and additionally 6 min after the 2nd run to measure blood LA and determine the maximal LA post exercise (LAmax). Plasma NH3was measured in the same samples and the maximal NH3post exercise (NH3max) determined. Additional blood samples were taken from the horses when stabled before the CE, and 12 and 24 h after to measure urea and CK activity in plasma.Results:There was no differential effect of the number of weekly CE on LAmax, NH3max, LA and NH3immediately after exercise (LAO and NH30). Conditioning did not have an effect on LAmaxand LAO after the 1st interval (P>0.05), but LAO after the 2nd interval was lower after conditioning. NH3maxafter the 1st and 2nd exercise interval decreased in response to the conditioning, but not NH3immediately after exercise (P>0.05). Median plasma CK activity 12 h after exercise was higher than before exercise and returned to pre‐exercise levels 24 h post exercise when horses were exercised once and twice/week. In contrast, the median plasma CK activity of horses exercising 3 times/week remained at the pre‐exercise level 12 and 24 h post exercise (P>0.05).Conclusion:Conditioning horses with 2 intervals of 100 m at near maximal speed had a positive effect on blood LA and plasma NH3.Potential relevance:With the type of exercise examined, the fitness of racing horses can be maintained and eventually improved. In further studies the effect of increasing the number of runs in one exercise session should be investigated.
The workload of riding‐school horses during jumping
Authors: Van OLDRUITENBORGH‐OOSTERBAAN M. M. SLOET , SPIERENBURG A. J. , Van den BROEK E. T. W. 
Published: June 2010

SummaryReasons for performing the study:As there are no reports on the real workload of horses that jump fences, this study was undertaken in riding‐school horses.Objective:To compare the workload of horses jumping a course of fences with that of horses cantering over the same course at the same average speed without jumping fences. The workload variables included heart rate (HR), packed cell volume (PCV), acid‐base balance (venous pH, pCO2, HCO3−) and blood lactate (LA), glucose, total protein and electrolyte concentrations.Methods:Eight healthy riding‐school horses performed test A (a course of approximately 700 m with 12 jumps from 0.8‐1.0 m high at an average speed of approximately 350 m/min) and test B (same course at the same speed, but without the rails) in a crossover study with at least 4 h between the 2 tests. Before each test the horses were fitted with a heart rate meter (Polar Electro)1. Blood samples were taken from the jugular vein at rest prior to the test, after warm‐up before starting the course, immediately after the course and after recovery. All samples were analysed immediately.Results:The mean ± s.d maximal HR (beats/min) during the course (184 ± 17 and 156 ± 21, respectively) and the mean HR after recovery (75 ± 6 and 63 ± 7, respectively) were significantly higher in test A compared to test B (P=0.001 and P=0.007 respectively). The mean LA concentrations after the course and after recovery (mmol/1) were significantly higher in test A (3.6 ± 2.7 and 1.0 ± 0.9, respectively) compared to test B (0.9 ± 0.5 and 0.3 ± 0.1, respectively), (P=0.016 and P = 0.048 respectively). The mean PCV (1/1) after the course and after recovery was also significantly different between tests A (0.48 ± 0.04 and 0.39 ± 0.03, respectively) and B (0.42 ± 0.04 and 0.36 ± 0.03, respectively) (P<0.01). The mean pH and the mean HCO3′ (mmol/1) after the course were significantly lower in test A (7.40 ± 0.04 and 28.9 ± 1.4, respectively) compared to test B (7.45 ± 0.03 and 30.4 ± 2.3, respectively) (P<0.05).Conclusions:This study indicates that in riding‐school horses jumping fences, even at a low level competition, provokes a significant workload compared to cantering the same distance and speed without fences.Potential relevance:This study makes it clear that the extra workload of jumping fences should be taken into account in the training programmes of jumping horses. Further research with more experienced horses jumping higher fences will reveal the workload for top‐level jumping horses.
Body composition in young Standardbreds in training: relationships to body condition score, physiological and locomotor variables during exercise
Authors: LELEU C. , COTREL C. 
Published: June 2010

SummaryReasons for performing study: 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.Objectives: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 (FM) and fat free mass (FFM) were estimated echographically. During a standardised exercise test on the track, velocity, heart rate, respiratory frequency and blood lactate concentrations were measured. V4and V200(velocity for a blood lactate concentration of 4 mmol/1 and velocity of 200 beats/min) calculated. Basic gait variables were measured at 3 different speeds with an accelerometric device.Results:Body composition variables: %F and FM were significantly related to body condition score and physiological variables. Body score was highly correlated to %F (r=0.64) and FM (r = 0.71). V4was negatively correlated to %V (r=‐0.59) and FM (r = ‐0.60), P<0.05. V200was also negatively related to %F and FM, (r=‐0.39 and r = ‐0.37, respectively, P<0.1). No relationships were found between body composition and gait characteristics.Conclusions:Body composition was closely related to indirect measurements of aerobic capacity, which is a major factor of athletic performance in middle distance running horses.Potential relevance:As in human athletes, trainers should take special note to evaluate optimal bodyweight and body composition of race horses to optimise performance.
Optimal active recovery intensity in Standardbreds after submaximal work
Authors: DAHL S. , COTREL C. , LELEU C. 
Published: June 2010

SummaryReasons for performing study: A retrospective study concerning spontaneous active recovery intensity, i.e. at a freely chosen speed, after a submaximal exercise in trotters showed that the mean intensity demanded by trainers corresponds to 40–50% of maximal heart rate (max HR; unpublished data). However, in human athletes, optimal active recovery intensity was found to be about 60–70% of max HR. Is the spontaneous recovery optimal after a submaximal exercise in trotters?Objectives:To compare different recovery intensities and define the most efficient one.Methods:Thirty‐seven trotters performed a standardised exercise test on the track. Horses were randomly divided into 4 groups of recovery: passive recovery (n=10), 10 min walk recovery (n=10,100 m/min), 10 min slow trot recovery (n=9, 250 m/min) and 10 min fast trot recovery (n = 8, 420 m/min). Before, during and 1 h after exercise, speed, heart rate, blood lactate concentration were measured as well as respiratory frequency and rectal temperature. Creatine kinase (CK) was measured 1, 3 and 5 h after exercise.Results:Walk, slow trot and fast trot recovery corresponded respectively to 45–50%, 55–60% and 65–70% of max HR. Heart rate and blood lactate concentration were significantly lower after the 10 sec recovery with increasing intensity of recovery.Conclusion:The most efficient intensity of recovery was the 10 min fast trot recovery (65–70% max HR) as this type of recovery allows the optimal blood lactate disappearance.Potential relevance:Considering the usual habits of trainers or drivers, recovery intensity after trot races should be increased in intensity to optimise its efficiency.