 This sport is also very dangerous, with 700 to 800 horse deaths per year- an estimated amount of two breakdowns out of 1000.Horse races vary widely in format and many countries have developed their own particular traditions around the sport.Variations include restricting races to particular breeds, running over obstacles (cross-country), running over different distances (typically a mile, mile and a quarter, mile and an 8th, mile and a 16th), running on different track surfaces and running in different gaits.