Body weight, hematologic findings, and serum and plasma biochemical findings of horses competing in a 48-, 83-, or 159-km endurance ride under similar terrain and weather conditions.

This study investigates the physiological, hematological, and biochemical characteristics in horses competing in endurance rides of different distances. It assesses whether factors like total distance covered, speed, and conditioning affect these characteristics and how travel before the competition can affect blood results and the competition outcome.

Study Method

• The study utilized 83 horses competing in endurance rides of either 48-, 83-, or 159-kilometers conducted on the same day.
• Each horse was monitored before, during, and after the ride. Measurements taken comprised weight, rectal temperature, and blood samples.
• The blood samples were used to determine variables including plasma protein, lactate, white blood cell count, serum electrolyte, and calcium concentrations, packed cell volume (PCV), and creatine kinase (CK) activity.
• The study aimed to discover whether differences among the groups with respect to the total traveled distance could be explained by factors such as lap speed or conditioning. It also investigated the effects of transit time or time on-site before the competition on the results of blood analyses or competition outcome.

Study Results

• Preride serum concentrations of sodium, chloride, bicarbonate, and calcium were found to be lowest in horses that were in the 159-kilometer group.
• As the number of hours in transit increased, variables such as preride plasma protein concentration, serum sodium, chloride, and bicarbonate concentrations were significantly affected. There was also a significant increase in CK activity at 159 kilometers.
• Horses with high transit times were more likely to be eliminated from the competition.
• Horses that completed the ride tended to have significantly higher preride serum sodium concentration in comparison to those that were eliminated.

Study Conclusion

• The study concluded that factors such as the distance covered, speed, level of fitness, and experience of the horses had little effect on the measured variables.
• However, significant effects were observed in horses who were transported for long distances before the competition. Thus, the study suggests that electrolyte and water supplementation and arriving earlier at the event might be beneficial for such horses.