Heat stroke in horses is a severe heat-related illness caused by prolonged exposure to high temperatures and humidity, overwhelming the body’s ability to regulate its temperature. Factors contributing to heat stroke include intense physical exertion, inadequate hydration, poor ventilation, and high ambient temperatures, especially in hot and humid climates. It can lead to rapid elevation of body temperature, dehydration, electrolyte imbalances, and potentially fatal complications if not promptly treated with cooling measures and veterinary care.