response: I do not.  I do know that some of the things that vary can include the track surface, the horse's gait, the race distance, and also whether or not there are obstacles.
original_response: i do not but i do know there are often restrictions on certain breeds and running on different rack surfaces
history: I am thinking on betting in horse racing. Oh yes?  In 2008, horse betting generated about 115 billion US dollars worldwide! 115 billion dollars is a lot of money.I want to grab some of that. it also depends on what country you want to bet in, each country has developed their own horse racing traditions Do you know anything about the traditions here in the USA?
knowledge: Variations include restricting races to particular breeds, running over obstacles, running over different distances, running on different track surfaces and running in different gaits.