Haematological and biochemical changes in horses competing in a 3 Star horse trial and 3-day-event.

This study analyzes the hematological and biochemical changes in horses competing in advanced endurance tests during a Horse Trial and a 3-day event. The researchers found that horses in the 3-day event showed greater fluid and electrolyte losses, reduced kidney activity, increased glucose breakdown, and higher leakage of enzymes from muscles during competition as compared to horses in the horse trial.

Study Design and Methodology

• The research involved two groups of horses undergoing different endurance activities: An advanced Horse Trial (HT, n = 22) and an advanced (CCI) 3-day-event (TD, n = 11).
• The endurance activities for both groups took place on the same day, over a similar course and under cool environmental conditions.
• Blood samples were collected from the horses in each group at three instances: the evening prior to the Endurance Test, within 60 seconds after completion of Phase D (cross-country jumping), and 10 minutes after the completion of Phase D.
• A range of hematological and biochemical parameters in the blood samples were analyzed and compared between the two groups of horses.

Observations and Results

• Two parameters, packed cell volume (PCV) and serum creatinine [Cr], were notably higher in the TD group, albeit the difference was not statistically significant (P = 0.063 and P = 0.057, respectively).
• Other parameters like serum total protein [TP], serum albumin [ALB], plasma sodium [Na], glucose concentration and aspartate aminotransferase (AST) and creatine kinase (CK) activities were found to be significantly higher in the TD group after exercise.
• Conversely, serum chloride [Cl] and serum inorganic phosphate [PO4] were significantly lower in the TD group after exercise.

Conclusions

• The significantly higher levels of certain blood metabolites in the TD group are indicative of greater fluid and electrolyte losses during competition.
• Higher serum creatinine [Cr] and lower serum chloride [Cl] indicate reduced glomerular filtration — a measure of kidney function in the TD group.
• The noted elevation in glucose concentration and creatine kinase (CK) and aspartate aminotransferase (AST) activities suggest increased glycogenolysis (breakdown of glycogen to glucose) and higher enzymatic leakage from working muscles.
• The differences in the blood profiles between the two groups of horses accentuate the physical strain induced by the 3-day competitive event as compared to the Horse Trial.

This study provides valuable insights into the physiological demands and impacts of competitive endurance events on horses and can guide better horse care and management during such events.