“I knew it was going to be racehorses for me.”

At 5:35 a.m., Keri Wolfsont responds to a direct message within seconds. Every morning’s busy, but this one is particularly so, the eve of the Colonial Cup card in Camden, where she and a half dozen equine charges await tomorrow’s races. The assistant to Hall of Fame trainer Jonathan Sheppard, Wolfsont is based at his…