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Endurance Horses (endurance + horse)
Selected AbstractsEffects of oral electrolyte supplementation on endurance horses competing in 80 km ridesEQUINE VETERINARY JOURNAL, Issue S36 2006F. SAMPIERI Summary Reasons for performing study: There is no evidence that use of oral electrolyte pastes enhances performance in competing endurance horses. Objective: To ascertain whether oral administration of a high dose (HD) of sodium chloride (NaCl) and potassium chloride (KCl) to endurance horses would differentially increase water intake, attenuate bodyweight (bwt) loss and improve performance when compared to a low dose (LD). Methods: A randomised, blinded, crossover study was conducted on 8 horses participating in two 80 km rides (same course, 28 days apart). Thirty minutes before and at 40 km of the first ride 4, horses received orally 0.2 g NaCl/kg bwt and 0.07 g KCl/kg bwt. The other 4 received 0.07 g NaCl/kg bwt and 0.02 g KCl/kg bwt. Horses received the alternate treatment in the second ride. Data were analysed with 2-way ANOVA for repeated measures (P<0.05). Results: Estimated water intake was significantly greater with HD both at the 40 km mark and as total water intake; however, differences in bwt loss and speed between HD and LD were not found. Treatment significantly affected serum Na+, Cl,, HCO3, pH and water intake, but not serum K+ or bwt. Serum Na+ and Cl, were significantly higher at 80 km when horses received HD, but no differences were found in early recovery. Venous HCO3 and pH were significantly lower throughout the ride and in early recovery when horses received HD. Conclusions and potential relevance: Other than enhancing water intake, supplementing endurance horses with high doses of NaCl and KCl did not provide any detectable competitive advantage in 80 km rides. Further, the elevated serum electrolyte concentrations induced with HD might not be appropriate for endurance horses. [source] Endurance exercise is associated with increased plasma cardiac troponin I in horsesEQUINE VETERINARY JOURNAL, Issue S36 2006T. C. HOLBROOK Summary Reason for performing study: Information is lacking regarding the influence of long distance exercise on the systemic concentration of cardiac troponin I (cTnl) in horses. Objectives: To determine if the concentration of cTnl in horses competing in 80 and 160 km endurance races increases with exercise duration and if cTnl concentrations can be correlated with performance data. Methods: Blood samples for the measurement of cTnl and 3 min electrocardiogram recordings were obtained from horses prior to, during and after completion of 80 and 160 km endurance races at 3 ride sites during the 2004 and 2005 American Endurance Ride Conference competition seasons. Results: Full data sets were obtained from 100 of the 118 horses. Endurance exercise was associated with a significant increase in cTnl over baseline in both distance groups. Failure to finish competition (poor performance) was also associated with an increased cTnl concentration over baseline at the time of elimination when data from both distances were combined. Other than one horse that developed paroxysmal atrial fibrillation, no arrhythmias were noted on the 3 minute ECG recordings that were obtained after endurance exercise in either distance group. Conclusions: Systemic concentrations of cTnl increase in endurance horses competing in both 80 and 160 km distances. Although final cTnl concentrations were significantly increased over their baseline values in horses that failed to finish competition, the degree of increase was not greater than the increase over baseline seen in the horses that successfully completed competition. The clinical significance of increased cTnl in exercising horses could not be ascertained from the results of this study. Potential relevance: These data indicate that cardiac stress may occur in horses associated with endurance exercise. Future studies utilising echocardiograpy to assess cardiac function in horses with increased cTnl are warranted. [source] Thyroid hormone responses to endurance exerciseEQUINE VETERINARY JOURNAL, Issue S36 2006E. A. GRAVES Summary Reasons for performing study: Limited information exists about changes in circulating thyroid hormone concentrations during prolonged endurance exercise in horses. Objective: To examine the effects of prolonged exercise on serum iodothyronine concentrations in horses performing endurance exercise of varying distances. Methods: Serum concentrations of iodothyronines were measured in horses before and after completion of 40, 56, 80 and 160 km endurance rides (Study 1); daily during a 5 day, 424 km endurance ride (Study 2); and before and for 72 h after completion of a treadmill exercise test simulating a 60 km endurance ride (Study 3). Results: In Study 1, 40 and 56 km of endurance exercise had little effect on serum iodothyronine concentrations with the exception of a 10% decrease (P<0.05) in free thyroxine (FT4) concentration after the 56 km ride. In contrast, total thyroxine (T4), total triiodothyronine (T3), FT4 and free triiodothyronine (FT3) concentrations all decreased (P<0.05) after successful completion of 80 and 160 km rides, with decreases ranging from 13,31% and 47,54% for distances of 80 and 160 km, respectively. Further, pre-ride T4 concentration was lower (P<0.05) and FT3 concentration was higher (P<0.05) in horses competing 160 km as compared to horses competing over shorter distances. In Study 2, serum concentrations of T4, T3 and reverse triiodothyronine (rT3) progressively decreased (P<0.05) over the course of the multi-day ride. In Study 3, the greatest decrease (P<0.05) in all iodothyronines was observed at 12 h of recovery, ranging from 25% for FT4 to 53% for FT3, but all thyroid hormone concentrations had returned to the pre-exercise values by 24 h of recovery. Conclusion: Endurance exercise results in transient decreases in serum iodothyronine concentrations. Potential relevance: These data are important to consider when thyroid gland function is assessed by measurement of serum iodothyronine concentrations in endurance horses. [source] Effects of glucose polymer with and without potassium and different diets on glycogen repletion after a treadmill exercise test in endurance horsesJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2005T. M. Hess Glycogen repletion involves absorption of glucose and its uptake into the muscle cells through GLUT-4 transporters. In the muscle and adipose tissue GLUT,4 transporters facilitates the glucose transport in the presence of insulin and K+. Potassium supply has been shown to stimulate insulin secretion. This study tested the effects of a glucose polymer added with electrolytes containing potassium (GP+K) compared to a glucose polymer with electrolytes without potassium (GP-K) on glycogen repletion. Also it compared the effect of different diet adaptations on glycogen repletion. Six horses were fed a diet rich in sugar and starch (SS), and six horses a diet rich in fat and fibre (FF) for 6 months before the test. In a crossover designed study, 12 trained Arabian or Arabian cross horses were submitted to a glycogen depleting exercise test on the treadmill. After exercise stopped six horses were supplied with GP-K and six other horses supplied with GP+K, at a dose of 5 g/kg BW, and a rate of 1 g/kg BW/hour through naso-gastric gavage. Muscle biopsies were taken before, just after they stopped exercise, and 16 h after they had been supplied with glycogen replacing formulas, and analysed for muscle glycogen. Blood was taken before, after 3 h of exercise, after the stepwise exercise test, at 0, 1 and 4 h after exercise stopped and analysed for plasma glucose, insulin and [K+]. Muscle glycogen decreased from 516.41 ± 12.92 glucosyl units/kg dry weight muscle to 408.74 ± 12.92 glucosyl units/kg dry weight muscle (79%). Sixteen hours after the repletion protocol horses recovered their muscle glycogen to 458.53 ± 12.91 glucosyl units/kg dry weight muscle (89%). Plasma glucose had a glucose polymer by sampling effect (p = 0.013) and a feed by sampling effect (p = 0.022). Plasma glucose was higher in SS fed horses at 1 and 4 h after exercise. Plasma glucose was lower in GP+K supplied horses 4 h after exercise. Plasma insulin had a trend (p = 0.070) for a glucose polymer effect. No differences were found in muscle glycogen between the two GP treatments. Although the present results demonstrate that intensive nasogastric supplementation with glucose polymer can result in glycogen repletion approaching that following i.v. administration, the addition of potassium conferred no advantage. [source] Amino acid concentrations in blood serum of horses performing long lasting low-intensity exerciseJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-6 2005D. Bergero Summary The aim of this work was to evaluate the changes in the concentrations, after two rides different for distance covered, of different amino acids in endurance horses. Blood samples have been collected from horses just before the start, at the top of a steep slope (819 m difference in height) and just at the end of a 32-km endurance ride. A second group, competing in a 72 km endurance ride, has also been sampled immediately before and after the race. In serum samples, the concentrations of alanine, arginine, asparagine, glycine, isoleucine, histidine, leucine, lysine, methionine, ornithine, phenylalanine, tryptophan, tyrosine and valine have been measured by high-performance liquid chromatography (HPLC). anova and t -test have been used to study the differences in the concentrations of the amino acids. The pre-ride concentrations of the free amino acids were different between the two races, except for methionine and leucine. Differences between start and end race have been found for both groups for all the considered parameters except asparagine, isoleucine, leucine and lysine for the 72 km ride. Increases have been recorded for the shorter and decreases for the longer ride in the blood serum concentrations. Significant increases have also been found between the starting sampling and the second, at the top of the slope, only for alanine, arginine, asparagines, phenylalanine and lysine. The ride length has a significant impact on blood serum amino acids mobilization and uptake; in the shorter race the increases stand only for mobilization, whereas in the longer the decrease can be considered the effect of the onset of the amino acids catabolism. [source] Blood serum branched chain amino acids and tryptophan modifications in horses competing in long-distance rides of different lengthJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-4 2004A. Assenza Summary During long-distance exercise, branched-chain amino acid (BCAA) catabolism could lead to an increase in the blood tryptophan/BCAA ratio and an early onset of ,central fatigue'. Based on these considerations, we studied the modifications of blood serum BCAA and tryptophan (Try) levels in 30 endurance horses competing in rides varying in distance from 20 to 72 km. From all horses, blood samples were drawn just before and just after the end of the ride. Samples were analysed for their leucine (Leu), valine (Val), isoleucine (Iso) and Try levels. Data were processed by anova, using sampling moment and ride as factors, and by LSD post hoc test. Significant differences were recorded among the different distance rides for Leu, Val, Iso, Try, Try/BCAA ratio; the same trend was recorded between samples taken at the start and the end of the race for Val and Leu. The main effect observed was an increase of BCAA levels for all rides, except the 72-km ride; for Try, a significant increase was present in all races, except the 50-km ride. The Try/BCAA ratio decreased in 20- and 50-km races and increased in the others. These data confirm that long-distance exercise involves a mobilization of BCAA. The utilization of BCAA seems to be important in prolonged exercise: in the 72-km ride, we observed a decrease in BCAA blood serum levels, while a major role of Try was indicated by its increase, resulting in a rise of the Try/BCAA ratio. [source] Clinical and biochemical abnormalities in endurance horses eliminated from competition for medical complications and requiring emergency medical treatment: 30 cases (2005,2006)JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 5 2009C. Langdon Fielding DVM, DACVECC Abstract Objective , To describe the clinical and clinicopathologic abnormalities in endurance horses eliminated from competition and requiring emergency medical treatment. Design , Retrospective study over a 2-year period (2005,2006). Ten horses that successfully completed the ride in 2006 were included for comparison. Setting , Temporary equine emergency field hospital. Animals , All horses (n=30) that were removed from endurance competition and treated for a metabolic abnormality were studied. Interventions , Horses were treated with IV fluids and analgesics. Monitoring included lab work (PCV, total protein, and electrolytes) and serial physical examinations. Statistical analysis included descriptive statistics and parametric and nonparametric comparisons (ANOVA, Friedman's test, and Kruskal-Wallis) where appropriate. Measurements and Main Results , The clinical diagnoses identified included colic, esophageal obstruction, poor cardiovascular recovery, myopathy, and synchronous diaphragmatic flutter. As a group, these sick horses had lower plasma chloride and potassium and higher total plasma protein concentrations as compared with 10 healthy horses that successfully completed the ride (P<0.05, <0.01, and <0.05 for chloride, potassium, and total protein, respectively). Horses with colic had a lower PCV as compared with horses with poor recovery and those with synchronous diaphragmatic flutter (P<0.05). All horses, including colics, were treated medically and discharged to owners. Conclusions , Based on the results of this study, the prognosis for horses requiring emergency veterinary treatment after being removed from endurance competition (for metabolic reasons) appears to be good if horses are withdrawn from competition under the same criteria outlined in this study. Biochemical abnormalities tend to be mild and do not necessarily aid in delineating sick horses from successfully completing horses. None of the horses with gastrointestinal disease required abdominal surgery. [source] | ||||||||||