Blood samples were collected from thirteen horses competing in the resistance phase of an advanced 3-day-event. Blood lactate was determined in the morning before competition, before and immediately after phases B and D, and 10 minutes after phase D. Significant increase in blood lactate was observed only after phase D, showing that animals were submitted to a great physical effort with development of metabolic acidosis due to lactate accumulation. There was significant decrease in blood lactate levels 10 minutes after cross country except horse 12, the only animal to finish phase D inside the given time, but showed clinical signs of exhaustion.
equine; lactate; cross-country; steeplechase
