Thoroughbreds bolt from the starting gate during Del Mar Racetrack’s 2010 season. Track officials say more than 660,000 visitors placed more than $430 million in bets in 2011.

Thoroughbreds bolt from the starting gate during Del Mar Racetrack’s 2010 season. Track officials say more than 660,000 visitors placed more than $430 million in bets in 2011.

The Del Mar Racetrack turned 75 this year, but has a decidedly youth-oriented approach to promoting and planning the annual horse races that have become a high-profile industry event and regional economic generator...