bluuebunny/crossref_metadata_2025_split huggingface dataset:
Harnessed vs. mounted Standardbreds on the track: changes in gait and physiological variables
Authors: MOTTINI V. , LELEU C. , COTREL C. 
Published: June 2010

SummaryReasons for performing study:It has become apparent through analysis of elite races over the past 20 years that mounted races are always slower than harnessed races when performed by the same horses over the same distances on the same tracks.Objectives:To investigate and compare physiological and gait variables in mounted and harnessed activities in trotters.Methods:Ten trotters were taken at random in 2 standardised field exercise tests one week apart: a harnessed and a mounted test with standardised weight jockeys and drivers. Speed, heart rate (HR), respiratory frequency (RF), blood lactate concentration (La), stride characteristics (length, frequency [SF], symmetry, regularity, dorsoventral displacement of the sternum and vertical, longitudinal and lateral activities measuring the amount of deceleration and acceleration along the 3 axis) were measured.Results:Pairedttests and an analysis of variance were calculated between the 2 conditions and revealed that V4(speed for a La of 4 mmol/1), V200(speed for a HR of 200 beats/min), stride length, trot symmetry, lateral activity were lower in the mounted condition. In contrast, RF, SF, dorsoventral displacement, vertical and longitudinal activities were significantly higher in mounted horses compared to harnessed horses.Conclusion:The significant physiological and biomechanical differences between pulling whilst harnessed and being ridden reflect an increase in the energy requirement of locomotion in the mounted condition compared to the harnessed condition. Trotting mounted at maximal speed is more demanding for the horse than harnessed as reflected by the lower V4and V200and some gait variables change in relation to this phenomenon.Potential relevance:This study demonstrates that trotting mounted at sub‐maximum and maximum speed is more demanding for the horse when ridden and that it modifies some gait variables, either as a result or even as a possible cause.
Correlation between routine radiographic findings and early racing career in French Trotters
Authors: ROBERT C. , VALETTE J.‐P. , DENOIX J.‐M. 
Published: June 2010

SummaryReasons for performing study:The relationship between the presence of radiological abnormalities and subsequent racing performance is controversial. However, as training is expensive and time consuming, it would save time and money to identify subjects with osteo‐articular lesions not compatible with a normal racing career on the basis of routine radiographic screenings at yearling age.Objectives:To evaluate the impact of osteo‐articular lesions on racing ability in French Trotters and identify radiographic changes associated with failure in ‘qualification’, in order to provide objective criteria for selection of horses based on their osteo‐articular status.Hypothesis:The influence of radiographic findings (RF) on racing ability depends on their nature, location, clinical relevance and number.Methods:The limbs of 202 French Trotters were radiographed just before they started training. All the RF were graded according to a standardised protocol depending on their severity. The success in ‘qualification’ (first race in career of French Trotters) was the criteria used to assess racing ability. Breeders and trainers were questioned about the causes for horses not racing.Results:Overall 113 (55.9%) horses qualified. Osteoarticular lesions were directly responsible for nonqualification in 31% of the horses. Subjects with more than one abnormal RF, with abnormal RF on the fore‐, hind‐fetlock or proximal tarsus were less likely to qualify. Dorsal modelling in the front fetlock and osteochondrosis of the lateral trochlear ridge of the femur also significantly reduced the qualification rate.Conclusions:Most RF are compatible with beginning a racing career, but severe RF or multiple abnormal RF significantly compromise future racing career.Potential relevance:This study supports the use of routine radiographic programmes for detection of osteoarticular lesions in yearlings. A synthetic radiographic score, based on both the severity and the number of lesions, could be useful for breeders and trainers as complementary information to select their horses.
Evaluation of race distance, track surface and season of the year on exercise‐induced pulmonary haemorrhage in flat racing Thoroughbreds in Brazil
Authors: COSTA M. F. M. , THOMASSIAN A. 
Published: June 2010

SummaryReasons for performing study: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.Objectives: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 respiratory endoscopies were recorded, in a total of 1003 individual horses. All horses in the study were certified bleeders (deemed positive by registered veterinarians following one or more endoscopies) and were administered FUR prior to each race. Data was analysed using both ordinary logistic regression and multiple logistic regression.Results:The results suggest that race distance, season of the year and racetrack surface affect the recurrence of EIPH. Also, despite the use of FUR, the majority (62%) of horses continued to display some degree of haemorrhage.Conclusions:There was a tendency for horses that remained positive despite the use of FUR to finish unplaced in a race. Horses which had a significant reduction in bleeding and became HPIE negative after the use of FUR, tended to finish in top positions. It was not possible to determine a pattern of severity of EIPH in horses with more than one endoscopy. Further studies are required to improve our understanding of this syndrome and its correlations to performance in the racing Thoroughbred, together with the role of FUR and its possible enhancing performance effects and efficacy in consistently diminishing EIPH.Potential relevance:This study enabled a better understanding of the use of FUR in Brazilian Thoroughbred racehorses and showed there was a tendency towards improvement in performance after administrion of FUR in bleeders. The fact that a large number of horses remained positive for EIPH despite the use of FUR should encourage the scientific community to search for better ways of reducing, or preventing, this syndrome.
The effect of inspired gas density on pulmonary artery transmural pressure and exercise induced pulmonary haemorrhage
Authors: DEATON C. M. , BROWN‐FELTNER H. , HENLEY W. E. , ROBERTS C. A. , LEKEUX P. , SCHROTER R. C. , MARLIN D. J. 
Published: June 2010

SummaryReasons for performing study:Pulmonary capillary stress failure, largely as a result of high pulmonary vascular pressures, has been implicated in the aetiology of EIPH. However, the role of the respiratory system in determining the magnitude of EIPH has received little attention.Hypothesis:Horses breathing a gas of greater density than air will exhibit greater transmural pulmonary arterial pressures (TPAP) and more severe EIPH, and horses breathing a gas of lower density than air will exhibit lower TPAP and less severe EIPH, both compared with horses breathing air.Methods:Following a warm‐up, 8 Thoroughbred horses were exercised for 1 min at 10, 11 and 12 m/sec (5° incline) breathing air or 21% oxygen/79% helium or 21% oxygen/79% argon in a randomised order. Heart rate, respiratory rate, pulmonary arterial pressure and oesophageal pressure were measured during exercise. Bronchoalveolar lavage fluid (BALF) was collected from the dorsocaudal regions of the left and right lungs 40 min post exercise and red blood cell (RBC) counts were performed.Results:The exercise tests induced mild EIPH. Maximum changes in oesophageal pressure were lower on helium‐oxygen compared to argon‐oxygen (P<0.001). TPAP and median RBC counts did not differ between gas mixtures. BALF RBC counts from the left lung correlated with counts from the right lung (P<0.0001). However BALF RBC counts from the left lung were higher than those from the right lung (P = 0.004).Conclusion:As alterations in pulmonary arterial and oesophageal pressure caused by changes in inspired gas density were of similar magnitude, TPAP remained unchanged and there was no significant effect on EIPH severity.Potential relevance:Manipulations that decrease swings in intrapleural pressure may only decrease the degree of EIPH in horses severely affected by the condition.
Correlations between exercising arterial blood gas values, tracheal wash findings and upper respiratory tract abnormalities in horses presented for poor performance
Authors: DURANDO M. M. , MARTIN B. B. , DAVIDSON E. J. , BIRKS E. K. 
Published: June 2010

SummaryReasons for performing study: There are limited data on the correlations between arterial blood gas (ABG) values, tracheal wash (TW) cytology and upper respiratory tract (URT) abnormalities.Objectives: 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 results, TW cytology and URT endoscopy were compared.Results: Two hundred and eleven horses met the study criteria of a complete treadmill examination and could have ABG evaluated. There were no significant differences in the age distribution of horses having normal and abnormal ABG or upper respiratory tract (URT) examinations. There was a significantly higher percentage of geldings with abnormal ABG analysis. In the horses with abnormal URT examinations, there were no differences in the proportion of horses having mucus vs. no mucus. However, in the horses with normal URT, there were a higher percentage of horses with visible mucus in the group with abnormal ABG analysis. The majority of horses had abnormal TW cytology and evidence of prior EIPH, with no differences in proportions between the groups.Conclusions: Because such a large percentage of horses had evidence of inflammation and/or evidence of prior EIPH on TW cytology, it was not possible to determine the effect of these findings on gas exchange. Mucus was present in a larger percentage of cases with abnormal ABG analysis and normal URT examinations, suggesting that the presence of mucus may affect gas exchange. Standardbreds may be more likely to have abnormal gas exchange than Thoroughbreds. A larger number of horses is needed to determine the significance of these findings.Potential relevance: Abnormal TW cytology and endoscopic visualised mucus may contribute to impairment of gas exchange, but they do not specifically predict abnormal ABG analysis.
Haematological and respiratory gas changes in horses and mules exercised at altitude (3800 m)
Authors: GREENE H. M. , HURSON M. J. , WICKLER S. J. 
Published: June 2010

SummaryReason for performing study:Despite the common use of equids as visitors to high altitude mountainous environments, there are a paucity of carefully orchestrated scientific approaches. Further, again as a function of a common perceived advantage of mules over horses in these similar environments there are needs for controlled comparisons between these 2 equids.Objective:To measure haematological and respiratory function in horses and mules at low altitude (225 m), at rest and post exercise. In addition the rate and magnitude of these changes were followed over a 13 day period at high altitude (3800 m) to contrast acclimatisation.Methods:Resting and exercise venous blood samples (1 min post exercise) were obtained from 6 horses and 5 mules housed at 225 m (LA) and then transported to 3800 m (HA) for 13 days. The standardised exercise tests at both LA and HA consisted of trotting (3.0 m/sec) up an incline (6%) for 2 km. Data were analysed with repeated measures ANOVA (comparison of altitude acclimatisation and species) for changes in haematological and respiratory gases.Results:At low altitude, no group differences were found with both resting (P=0.69) and exercising (P=0.74) heart rates. Resting PCV was 8% lower in the mules (P=0.02) and 20% lower during exercise (P=0.02). Horses had significantly higher 2,3‐diphosphoglycerate (2,3‐DPG)/g Hb at both rest (P=0.003) and exercise (P=0.03). Exercise at HA increased PCV (P=0.03) in both groups, but the increase was attenuated in the mules compared to horses. The increase with 2,3‐DPG/g Hb was expressed at HA in both groups (P=0.001) and was also attenuated in mules (P=0.03). Both groups were alkalotic compared to LA (P=0.001), and there were no group differences (P = 0.95).Conclusion:Of the variables measured, the most notable distinction between species was identified for only PCV and 2,3‐DPG with both higher in horses, at both LA and HA. While the attenuated response of PCV in mules for the same exercise might argue for an improved adaptation to altitude, the lower 2,3‐DPG might not. Other variables during the exercise bout were not different between species.
Observations on respiratory flow strategies during and after intense treadmill exercise to fatigue in Thoroughbred racehorses
Authors: CURTIS R. A. , KUSANO K. , EVANS D. L. 
Published: June 2010

SummaryReasons for performing study: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.Objectives: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 and clinically normal Thoroughbred horses were exercise tested on a treadmill (slope 10%). Breath‐by‐breath pulmonary ventilation was measured continuously during exercise and recovery using a Quadflow mask.Results:Five different breath types were identified, and classified as normal monophasic, normal biphasic, deglutition, effort pause, or large breaths. Exercising at 10 m/sec, the number of large breaths was significantly related to Rf (r=‐0.86, P = 0.03). During 120 sec after exercise there were 2 distinct populations of breaths, large and normal monophasic.Conclusions:BRC type breaths are a normal feature of ventilation during and after intense exercise. In recovery there are two distinct breath populations. During exercise BRC frequency is inversely associated with respiratory frequency and highly dependant on the individual horse. From intense exercise to recovery, high flow rates and LRC limited tidal volumes are replaced by high tidal volumes and progressively decreasing flow rates. There is a temporal association between BRC occurrence and PECO2.Potential relevance:Breath types and the physiological mechanism for driving each type is important in the clinical interpretation of respiratory disease or dysfunction. The demonstration of BRC association with PECO2may help understand the driving mechanism for the BRC. In pulmonary function testing, breath type is important in quantitative results. The demonstration that high tidal flows with limited tidal volumes during intense exercise being replaced by high tidal volumes and progressively decreasing flows in recovery has potential clinical relevance.
Effects of dietary glycaemic response after exercise on blood concentrations of substrates used indirectly for muscle glycogenesis
Authors: LACOMBE V. A. , HINCHCLIFF K. W. , KOHN C. W. , REED S. M. , TAYLOR L. E. 
Published: June 2010

SummaryReasons for performing study:Exercise depletes muscle glycogen stores, which could subsequently impair performance. Muscle glycogen replenishment is determined by substrate availability.Objectives:To study the effects of feeding meals of varying glycaemic responses on blood concentrations of substrates used for glycogenesis in horses with exercise‐induced glycogen depletion.Methods:In a 3‐way crossover study, 7 horses received each of 3 isocaloric diets for 72 h after undergoing glycogen‐depleting exercise: 1) a high soluble‐carbohydrate diet, which induced a high‐glycaemic (HGI) response; 2 and 3) a low soluble‐carbohydrate or a mixed soluble‐carbohydrate diet (control group), which both induced a similar low‐to‐moderate glycaemic (LGI) response. Muscle biopsies and venous samples were collected before and up to 72 h after exercise.Results:Feeding HGI diet resulted in a higher (P<0.001) rate of muscle glycogenesis over 72 h compared to LGI diets. Plasma glycerol, triglyceride, lactate, serum NEFA and total protein concentrations, and haematocrit were significantly (P<0.001) higher after compared to before exercise. Whereas no significant overall dietary effect was observed on these metabolites over 72 h, there was a tendency for glycerol, NEFA and triglyceride concentrations to be lower for LGI compared to HGI diets over 6 h after exercise (P<0.05; 1, 6 and 4–6 h after exercise, respectively).Conclusions:These data suggest that horses fed LGI meals after exercise had limited lipid utilisation without any significant shift of substrate utilisation toward gluconeogenesis, which could have contributed to the slower rate of muscle glycogenesis compared to horses fed HGI diets.
Route of carbohydrate administration affects early post exercise muscle glycogen storage in horses
Authors: GEOR R. J. , LARSEN L. , WATERFALL H. L. , STEWART‐HUNT L. , McCUTCHEON L. J. 
Published: June 2010

SummaryReasons for performing study:No studies in horses have examined the effect of route of carbohydrate (glucose) administration on the rate of muscle glycogen storage following glycogen‐depleting exercise.Hypothesis:Glucose delivery from the gastrointestinal tract limits the rate of muscle glycogen storage following glycogen‐depleting exercise.Methods:In a crossover design, 7 fit horses completed treadmill exercise (EX) on 3 occasions to deplete muscle glycogen by approximately 50%. After EX horses received: 1) i.v. glucose infusion (IV; 0.5 g/kg bwt/h for 6 h), 2) oral glucose boluses (OR; 1 g/kg bwt at 0, 2 and 4 h post EX) or 3) no glucose supplementation (CON). Blood samples for measurement of glucose and insulin concentrations were collected before EX and during the 6 h treatment period. Muscle biopsies for measurement of muscle glycogen content (GLY) and glycogen synthase (GS) activity were taken before and after exercise and at 3 and 6 h.Results:Mean plasma glucose concentrations were significantly higher in IV and OR than in CON throughout treatment. The average serum insulin responses in IV and OR treatments were also significantly greater than in CON. After EX, GLY was not different among the 3 treatments. However, glycogen storage rates were significantly higher in IV than in CON and OR during the first 3 h and second 3 h of recovery, and GLY was significantly higher in IV than in OR and CON at 6 h of recovery. GS activity was significantly higher in IV than in OR and CON at 3 h of recovery.Conclusions:Muscle glycogen storage in horses during a 6 h period after exercise was enhanced by i.v. glucose administration (3 g/kg) but not by an equivalent glucose dose administeredper os. While oral administration of glucose achieved a level of hyperglycaemia and hyperinsulinaemia that markedly accelerates glycogen storage in other species, the rate of glycogen storage following oral supplementation was not different to control conditions.Potential relevance:Glucose supplementation via the i.v. route should be considered when rapid replenishment of muscle glycogen stores is desired.
Effect of amino acid and glucose administration following exercise on the turnover of muscle protein in the hindlimb femoral region of Thoroughbreds
Authors: MATSUI A. , OHMURA H. , ASAI Y. , TAKAHASHI T. , HIRAGA A. , OKAMURA K. , TOKIMURA H. , SUGINO T. , OBITSU T. , TANIGUCHI K. 
Published: June 2010

SummaryReasons for performing study: In man, muscle protein synthesis is accelerated by administering amino acids (AA) and glucose (Glu), because increased availability of amino acids and increased insulin secretion, is known to have a protein anabolic effect. However, in the horse, the effect on muscle hypertrophy of such nutrition management following exercise is unknown.Objectives: To determine the effect of AA and Glu administration following exercise on muscle protein turnover in horses. We hypothesise that administration of AA and Glu after exercise effects muscle hypertrophy in horses, as already shown in man and other animals.Methods: Measurements of the rate of synthesis (Rs) and rate of degradation (Rd) of muscle protein in the hindlimb femoral region of thoroughbred horses were conducted using the isotope dilution method to assess the differences between the artery and iliac vein. Six adult Thoroughbreds received a continuous infusion of L‐[ring‐2H5]‐phenylalanine during the study, the stable period for plasma isotope concentrations (60 min), resting periods (60 min), treadmill exercise (15 min) and recovery period (240 min). All horses were given 4 solutions (saline [Cont], 10% AA [10‐AA], 10% Glu [10‐Glu] and a mixture with 10% AA and 10% Glu [10‐Mix]) over 120 min after exercise, and the Rs and Rd of muscle protein in the hindlimb measured.Results: The average Rs during the 75–120 min following administration of 10‐Mix was significantly greater than for the other solutions (P<0.05). The second most effective solution was 10‐AA, and there was no change in Rs after 10‐Glu.Conclusions: Administration of AA following exercise accelerated Rs in the hindlimb femoral region, and this effect was enhanced when combined with glucose, because of increasing insulin secretion or a decreased requirement for AA for energy.Potential relevance: Further studies are required regarding the effect on muscle hypertrophy of supplementing amino acids and glucose in the feed of exercising horses.