bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arterial and mixed venous acid‐base status and strong ion difference during repeated sprints
Authors: TAYLOR LYNN E. , FERRANTE PAMELA L. , WILSON JUDITH A. , KRONFELD D. S. 
Published: June 2010

SummarySeven horses performed six, 1 min sprints separated by 4 min intervals at a walk, followed by a 30 min recovery period. To evaluate changes in blood gases and strong ions, blood samples were taken from the carotid artery (A) and the right heart (mixed venous, V) at rest, after a submaximal warm‐up, during the last 15 s of sprints 5 and 6 and at 5 and 30 min of recovery. At both arterial and venous sites, plasma [H+], PCO2, PO2, albumin ([Alb]), strong ion concentrations ([Na+], [K+], [Cl−]), blood lactate ([Lac]) and haemoglobin concentrations ([Hb]) were measured. Strong ion difference ([SID]), bicarbonate concentration ([HCO3−]) and total weak acid ([Atot]) were calculated. Between sites (A vs. V) there were differences in [H+], PCO2, PO2, [HCO3−], [Cl−], [SID], [Na+], [K+] and [Lac−]. Arterial PO2remained constant during exercise, was increased at 5 min recovery and returned to the resting level by 30 min recovery. The PvO2decreased during exercise before returning to resting levels at 5 min of recovery. During exercise, [Cl−] increased at A and decreased at V, which is consistent with the chloride shift. The [H+], PCO2and [HCO3−] decreased at A and increased at V. During exercise, [Na+], [K+] and [Lac] increased at both sites, with [Na+]V, [K+]Vand [Lac−]Aincreasing to a greater extent. Plasma [SID]Adecreased due to a greater increase in [Lac−]Acompared to other strong ions and [SID]Vincreased due to increased [Na+]Vand [K+]Vand decreased [Cl−]V. Plasma [Alb] and blood [Hb] increased with exercise, with no site differences. Plasma [H+] increased at V and decreased at A before returning to pre‐exercise values at 30 min recovery. These changes reflected the patterns of change in PCO2, but not [SID]. In turn, the decrease in PaCO2was probably associated with hyperventilation that maintained the PaO2at a constant level during repeated sprints. Results show that SID, [Atot] and PCO2have different effects on plasma [H+] and [HCO3−] at sites A and V and that the chloride shift is evident in the exercising horse.
Effect of a diet containing supplementary fat on the capacity for high intensity exercise
Authors: EATON M. D. , HODGSON D. R. , EVANS D. L. , BRYDEN W. L. , ROSE R. J. 
Published: June 2010

SummaryThis study investigated the effects of increased fat consumption on aerobic and anaerobic performance. Eight Thoroughbred horses that had undergone a 9 week, 6 days/week conditioning programme were randomly divided into 2 groups,Group F(5 horses) andGroup C(3 horses). For 2 weeks before the study all horses consumed a standard diet (2% fat) fed as 2 equal portions. Horses then undertook an incremental treadmill exercise test (+10% slope); 3 min at 4 m/s, 2 min at 6 m/s and 1 min at 8 m/s. Speed was then increased by 1 m/s every 60 s until fatigue. Maximal accumulated oxygen deficit (MAOD) was determined 72 h later. Horses inGroup Fwere then fed a diet containing 12% of the digestible energy in the form of fat (390 ml corn oil), a diet that was isocaloric with the control diet. Horses inGroup Ccontinued to receive the standard diet. All horses continued training (3600 m/day, at speeds up to 10 m/s, 6 days/week). After 4 weeks, the exercise tests were repeated. Prior to fat supplementation, V̄O2maxwas mean ± s.e. 145 ± 5.3 and 148.0 ± 6.0 ml/kg/min, time to fatigue during the MAOD test was mean ± s.e. 84.2 ± 18.4 and 85.0 ± 14.8 s, mean ± s.e. peak plasma [lactate] was 24.8 ± 3.1 and 23.5 ± 1.7 5 mmol/l and MAOD was 56.5 ± 5.3 and 68.1 ± 4.7 mlO2eq/kg forGroups FandCrespectively. The V̄O2maxand run time to fatigue in the incremental exercise test did not change in either group following fat supplementation. Run time (mean ± s.e. 97.2 ± 17.8 s), MAOD (65.5 ± 6.2 mlO2eq/kg) and peak plasma [lactate] (29.5 ± 2.6 mmol/l) increased during the MAOD test inGroup Fbut remained unchanged inGroup C.Resting muscle [glycogen] depletion during the MAOD test was not altered by the dietary manipulation. Provision of an increased proportion of the diet in the form of fat increased high intensity exercise capacity and the MAOD during intense treadmill exercise.
Effect of grain type and vitamin supplementation on performance of exercising horses
Authors: McMENIMAN N. P. , THORNTON J. R. , DOWSETT K. F. 
Published: June 2010

SummaryEffects of multivitamin supplementation and type of grain on exercise capability and behaviour was determined in 2 groups of 4 Australian stockhorses. Initially the horses were fed diets containing chopped oaten and lucerne hay and either rolled oats grain or cracked maize. The grains were fed on an isoenergetic basis and contributed 60% of the digestible energy content of the diets. After an 8 week training programme the horses were subjected to 2 standard exercise tests (SET) 2 weeks apart. Each SET was followed, 3 days later, by a run to exhaustion (RTE) at a speed equivalent to 110% of the VO2maxrecorded during the previous SET. Both diets were then fortified with a complete vitamin mix (except for ascorbic acid and choline) that: supplied vitamins at a level that equalled or exceeded NRC (1989) recommendations. After 2 weeks of supplementation the SETs and RTEs were repeated. Neither grain type nor vitamin supplementation had any significant effect on liveweight, VO2max, VLA4or total run time to exhaustion. Vitamin supplementation reduced maximum heart rate (mean ± s.e. 227.8 vs. 233.2 ± 1.86 beats/min) and maximum plasma lactate concentrations (11.1 vs. 14.2 ± 0.67 mmol/l) during the SETS. Grain type had no effect on any of the horses' behavioural characteristics. Under the conditions of our experiment neither grain type nor vitamin supplementation affected the performance capability of the horses.
Blood gas, plasma lactate and bronchoalveolar lavage cytology analyses in racehorses with respiratory disease
Authors: COUËTIL L. L. , DENICOLA D. B. 
Published: June 2010

SummaryThe purpose of this study was to evaluate the relationship between bronchoalveolar lavage (BAL) cytology, arterial blood gases and plasma lactate concentration during a standardised treadmill test (STT) in racehorses with small‐airway inflammation (SAI), or exercise‐induced pulmonary haemorrhage (EIPH).Sixteen Thoroughbred and 20 Standardbred actively racing racehorses, were divided into a control group (n=10), EIPH group (n=13) and SAI group (n = 13). Each STT consisted of a 2 min trot at 4 m/s followed by 5 × 1 min, incremental speed steps (6, 8, 10, 11 and 12 m/s) at 10% incline for Thoroughbred and 5% for Standardbred horses, followed by a 15 min recovery period. Blood was collected via a transverse facial artery catheter at the end of each step.Total nucleated cell count of bronchoalveolar lavage fluid (BALF) collected from horses with EIPH was significantly higher than controls. Neutrophil count and percentage in BALF collected pre‐STT from horses with SAI were significantly higher than controls. Horses with EIPH or SAI exhibited a more severe exercise‐induced arterial hypoxaemia than control horses during the first 4 steps of the STT (P<.001). Poorly performing horses were more severely hypercapnic than control horses during the STT recovery period (P<.05). Five and 15 min post exercise, horses with SAI and EIPH had higher blood lactate and lower blood bicarbonate concentrations than control horses (P<.05).The results of this study suggest that lung ventilation‐perfusion mismatch may be more severe in horses with respiratory disease. BALF of horses with SAI and EIPH was characterised by neutrophilic and lymphocytic inflammation, respectively. Very few parameters were significantly different between groups of good and poor performers.
Effects of frusemide on pulmonary capillary pressure in horses exercising on a treadmill
Authors: GLEED R. D. , DUCHARME N. G. , HACKETT R. P. , HAKIM T. S. , ERB H. N. , MITCHELL L M. , SODERHOLM L V. 
Published: June 2010

SummaryWe hypothesised that frusemide would decrease pulmonary capillary pressure in horses during strenuous exercise. Seven horses were tested after receiving saline or frusemide (2 mg/kg bwt) in random order with an interval of at least one week. Measurements were made with the horses standing, exercising at 75, 90 and 100% HRmax(maximal heart rate), and then walking 2 min after cessation of 100% HRmax. The exercise tests lasted for ˜3 min with an interval of walking between them. Pulmonary artery and oesophageal pressures were recorded continuously and subsequent analysis of the pulmonary artery pressure signal was carried out after subtraction of the oesophageal pressure signal. Pulmonary arterial pressure, pulmonary capillary pressure, pulmonary artery wedge pressure, breathing rate, heart rate and arterial blood gas tensions were recorded at each level of exercise. Pulmonary arterial wedge and pulmonary capillary pressures were determined from the pulmonary arterial waveform after dynamic occlusion of a branch of the pulmonary artery. The resulting decay in pressure was submitted to exponential curve fitting and the amplitude on this curve at the moment of occlusion was recorded as pulmonary capillary pressure. When adjusted for horse and exercise intensity, horses receiving frusemide had lower pulmonary capillary and wedge pressures (adjusted least‐squares means=36 mmHg and 28 mmHg, respectively) when compared with control values (adjusted least‐squares means=41 mmHg (P=0.042) and 35 mmHg (P = 0.002), respectively). Pulmonary arterial pressure, breathing rate, heart rate and arterial blood gas tensions did not differ between treatments at any exercise intensity.We conclude that frusemide reduces pulmonary capillary and wedge pressures. This is compatible with reduced transcapillary filtration and, therefore, reduced accumulation of lung water at exercise. It may also account for the putative protective effect of frusemide against exercise‐induced pulmonary haemorrhage.
Sequential changes in bronchoalveolar cytology after autologous blood inoculation
Authors: McKANE S. A. , SLOCOMBE R. F. 
Published: June 2010

SummarySix horses, free of recent exercise‐induced pulmonary haemorrhage (EIPH), each had 8 bronchial segments inoculated with 40 ml of autologous blood lavaged on Days 3, 5, 7, 10, 14 and 21 after inoculation. The bronchoalveolar lavage (BAL) fluid samples were analysed, and total leucocyte counts and differential cell percentages determined. Statistical analysis of the differences between the 8 post inoculation and 1 pre‐inoculation (control) lavage sites demonstrated an early neutrophilic response, rising from <5% of alveolar leucocytes to 10% by 24–48 h post inoculation. As this response waned, macrophage numbers increased and persisted at mildly elevated levels for the remainder of the experiment. Small numbers of erythrophagocytes were observed prior to 3 days post inoculation, but their numbers increased 10‐fold by Day 10. In the first 3 days, blood was observed endoscopically streaming from inoculated lung regions, suggesting that mucociliary clearance is a major mechanism of early erythrocyte clearance. However, both free and phagocytosed whole erythrocytes were recovered in lavages 14 days after inoculation with small numbers of erythrocytes still present at 21 days. We conclude that intrapulmonary blood provokes a mild, but prolonged inflammatory reaction and that the removal of alveolar haemorrhage is dependent on a combination of mucociliary clearance and phagocytic mechanisms. Erythrophagocytosis is slow to commence and the removal of blood prolonged, suggesting that horses in fast work, sufficient to induce EIPH, are unlikely to recover fully if intervals between strenuous work are less than 14 days.
Relationship between running speed, isoenzymes of serum creatine kinase and lactate dehydrogenase and left ventricular function in stallions
Authors: RUECA F. , CONTI M. B. , PORCIELLO F. , SPATERNA A. , ANTOGNONI M. T. , MANGILI V. , FRUGANTI G. , AVELLINI G. 
Published: June 2010

SummaryThe purpose of this study was to assess the possible relationship between maximal running speed, serum isoenzyme patterns of creatine kinase (CK) and lactate dehydrogenase (LDH) and echocardiographic indices of left ventricular function. A group of 15 healthy, 3‐year‐old Maremmano stallions were given a 100 day training programme. At the end of this the animals carried out a maximum speed test and were divided into 2 groups (A and B) according to whether or not they had attained a speed of 15 m/s. Venous blood samples were taken from each horse before exercise (T0), 2 min (T1) and 24 h (T2) after exercise. Total serum activity of CK and LDH was measured and their isoenzyme distribution pattern determined. The day before the speed test echocardiographic examination was carried out at rest to assess the left ventricular function by calculating telediastolic, telesystolic and stroke volume, ejection fraction and stroke index. Statistically significant differences were found for the CK isoenzyme pattern at T2, where Group A showed an increase in the MM fraction (P=0.003) and a decrease in the MB fraction (P = 0.014). These changes were thought to be linked to an increased membrane leakage due to exercise and not to muscle fibre disruption because the CK and LDH total activities remained within the normal range. In Group A there was also greater left ventricular telediastolic volume (P=0.044) and length (P=0.033) at rest as well as a greater stroke index (P = 0.032). We concluded that the evaluation of CK pattern after exercise and of echocardiographic left ventricular function indices at rest made it possible to select for the fastest horses (Group A).
Cardiac responses to training in 2‐year‐old Thoroughbreds: an echocardiographic study
Authors: YOUNG LESLEY E. 
Published: June 2010

SummaryGuided M‐mode echocardiography was performed in seven 2‐year‐old Thoroughbreds before commencement of commercial flat‐race training, and 18 weeks later, when all horses were either racing regularly (5 horses), or at racing fitness (2 horses). M‐mode echocardiography was performed using a 2.5 MHz annular phased array ultrasound transducer and a Vingmed 800 Supervision echocardiograph. Images were obtained from the right hemithorax; a short axis view of the left ventricle (LV) at the level of the chordae tendinae was used to position the M‐mode cursor. The following variables were measured: left ventricular (LV) internal diameter in diastole (LVIDd) and systole (LVIDs) and interventricular septal (IVS) and left ventricular free wall thickness (LVFW) in systole and diastole. The following variables were also calculated: LV fractional shortening (%FS), LV ejection fraction (EF), LV relative and mean wall thickness and muscle mass. Values before and after training were compared using a paired Student's t test.Training resulted in significant reductions in %FS and EF. Left ventricular internal diameter increased from 11.38 (s.d=0.58) cm before training to 12.16 (s.d. = 0.7) cm after training (P<.001). Calculated left ventricular mass also increased significantly (mean increase of 33% P<.001). Bodyweight was unchanged in the present study. Relative wall thickness was significantly increased in all horses, suggesting that eccentric cardiac hypertrophy occurs in response to commercial flat‐race training. The mean post training value for relative wall thickness of 0.45 (s.d.=0.05) for the horses in the present study is similar to that of human athletes in power/endurance disciplines.
Sedation and antisedation as tools in equine lameness examination
Authors: BUCHNER H. H. F. , KüBBER P. , ZOHMANN E. , PEHAM CH. 
Published: June 2010

SummaryA kinematic study was performed to establish the locomotion pattern of horses under detomidine sedation and the effects of antagonisation for possible use during lameness examinations in uncooperative horses. The kinematics of 17 Warmblood horses (9 sound, 8 lame with chronic forelimb lameness) were recorded on 2 days using a high‐speed video system while trotting (3.9 m/s) on a treadmill. On each day a control measurement was carried out prior to sedation with detomidine (10 μg/kg bwt) and repeated recordings at 15, 25, 35, 45 and 60 min after sedation. On the second day, sedation was antagonised using atipamezole (100 μg/kg bwt) after the 15 min recording.Head height and pulse rate documented the level of sedation. The head dropped from mean 1.23 m (s.d. 0.13) to 0.50 m (0.26) following sedation to reach again 1.06 m (0.19) after 60 min. Antagonisation reversed the height significantly at the 25 min recording to 1.06 m (0.11). Walking and trotting were possible in all sedated horses in response to voice commands only. Forelimb lameness symmetry parameter (Head Acceleration Asymmetry: HAAS) in 8 lame horses did not change significantly due to sedation. Stride length increased significantly from mean 2.53 m (0.18) to 2.66 m (0.20) 15 min after sedation and reversed to 2.56 (0.17) m after antagonisation. Stride and stance durations changed accordingly. In conclusion, sedation did not change the degree of lameness, but did alter the general locomotion pattern. Antagonisation diminished most of these effects, but small differences to the unsedated pattern remained.
The kinematics of loading and fatigue in the Standardbred trotter
Authors: JOHNSTON C. , GOTTLIEB‐VEDI MARIANNE , DREVEMO S. , ROEPSTORFF L. 
Published: June 2010

SummaryThe Standardbred trotter must pull a considerable load when racing and, consequently, draught loading is a common method of training in the Standardbred and the effects of loading and fatigue due to loading on the locomotor pattern was the purpose of this investigation. Four mature healthy Standardbred horses trotted with and without a horizontal‐pulling loading of 34 kg until the horses were no longer willing to keep pace with the treadmill despite encouragement. Heart rate was monitored every min using a bipolar electrocardiogram. The kinematics for 5 consecutive strides were filmed. Horses exercised on the treadmill for 7–10 mins. The mean heart rate was 206 beats/min at the end of the exercise. Due to draught loading, the horses reduced significantly the time of the stance phase in both the fore‐ and hindlimb. Three of the 4 horses reduced their stride lengths as the result of increased loading. The general movement pattern of the horses remained similar. More dramatic changes in the movement pattern were observed because of fatigue. The limbs of the horse were significantly more compressed as the result of greater joint excursion during the stance phase. Furthermore, the length of stride was significantly increased as the result of fatigue. The results show that both loading and fatigue change the locomotor pattern of the Standardbred trotter. Although the horizontal loading was. considerable, the horse maintained similar joint movement with increases in stride frequency. During fatigue the horse seems to be unable to maintain stride frequency, probably due to a compromised power capacity of the muscles. The increase in joint excursion due to fatigue may have an important influence on certain types of injury to the locomotor system of the racehorse.
Muscular and metabolic responses to moderate‐intensity short‐term training
Authors: GEOF R. J. , McCUTCHEON L JILL , SHEN HUA 
Published: June 2010

SummaryThe objectives of this study were to determine the effects of 10 consecutive days of moderate‐intensity training on 1) the muscular metabolic response to exercise at 100% of the pre‐training maximum rate of oxygen consumption (V̇o2max); and 2) mitochondrial enzyme markers (citrate synthase, CS; succinate dehydrogenase, SDH; 3‐hydroxy‐acyl‐CoA dehydrogenase, HAD) of oxidative capacity in middle gluteal muscle. Six mature, unfit Thoroughbred horses completed both incremental (for determination of V̇o2max) and high‐intensity exercise protocols before (HI1) and after (HI2) training. Training consisted of 10 consecutive days of running at 55% V̇o2maxfor 60 min per day (13–14 km/day). For the HI, horses completed a 10 min warm‐up, followed by exercise at 100% of pre‐training V̇o2max(mean speed 9.8 m/s) until fatigue. Training resulted in an 8.9% increase in V̇o2max(Pre: 142 ± 4 ml/kg bwt/min; Post: 155 ± 4 ml/kg bwt/min) and a 24% increase in run time to fatigue during HI. Whereas V̇o2during HI was not altered by training, peak values for V̇co2and R were significantly lower following training. Compared to HI1, there was a 45% reduction in the net rate of muscle glycogenosis during HI2. Peak (end exercise) values for plasma and muscle lactate concentrations decreased by 22 and 23%, respectively, after training. Training also attenuated the exercise‐associated increase in plasma norepinephrine, but there was no effect on plasma epinephrine concentrations. Maximal activities of CS, SDH, and HAD were unaltered by training. We conclude that 10 days of moderate‐intensity exercise results in decreases in muscle glycogenosis and anaerobic metabolism during high‐intensity exercise at the same absolute workload. Furthermore, development of measurable increases in mitochondrial oxidative potential may not be required for expression of these metabolic adaptations in early training.
Partition of plasma hydrogen ion concentration changes during repeated sprints
Authors: KRONFELD D. S. , FERRANTE P. L. , TAYLOR LYN E. , TIEGS W. 
Published: June 2010

SummaryIncreases in blood [H+] and lactic acid [La−] attend fatigue. We applied Stewart's physiological model of acid‐base status and simple regressions to assess the importance of independent variables and [La−] on [H+] during repeated sprints. Eight well‐conditioned Arabians performed 9 sprints. Plasma from jugular vein samples was analysed for pH, Pco2, Na+, K+and Cl−. Plasma [La−] was calculated from blood [La−], plasma [H+] from pH, SID from Na+, K+, Cl−and La−, Atotfrom pH, Pco2and SID.Peaks for SID, Pco2and [H+] were reached at sprint 1, ‐2 and ‐3, respectively. At sprint 3, the 5.7 nmol/l peak in [H+] was partitioned into 2.3, 2.7 and 0.7 nmol/l for Atot, Pco2and SID, respectively. From sprint 3 to sprint 9, increases in Atotand decreases in SID tended to increase [H+] but were counteracted by a steady decrease in Pco2that determined the progressive decrease in [H+]. Therefore Pco2was the dominant determinant of [H+] during 9 repeated sprints, and the expected major effect of [La−] was moderated in the SID by opposing increases in [Na+] and [K+]. In the work‐adapted phase (sprints 3–9), decreasing [H+] was correlated positively with Pco2(r = 0.997, P<.001) but negatively with La−(r = ‐0.986, P<.001). Respiration was therefore completely compensating for the effects of metabolism on [H+]. During the transition from rest to sprint 3 (peak plasma [H+]), increasing [H+] was highly correlated (r=0.99, P = 0.011) with [La−] but no other variable. The empirical and physiological analyses were consistent with one another during the work‐adapted phase, but emphasis was placed on [La−] by the regression analysis, in contrast to Pco2by the Stewart analysis, during the rest‐work transition.