>And that correlates with the report that he didn't have an open wound from this mess -- more good news.<
Fortunately, his hind legs were wrapped for the race.
The wrapping of racehorse legs for racing and standing around in a stall borders on witchcraft, if you look into the arcana of what goes onto the legs beneath the bandages and the [supposed] reasoning behind it. Other than protect from superficial cuts and rundown injuries, and keep a catastrophic wound clean, I'm not convinced running bandages offer any additional advantages.
I do wrap my mare very carefully to haul her (her legs are absolutely clean, she's 23, and I'm not taking any chances.) When I ride cross country I always use the big (long coverage) neoprene wraps. I guess it's mostly for protection from overstrikes or hitting something on an obstacle, but having worn neoprene wraps myself, it's also true that they offer some support and keep the leg nice and warm.
I don't put that nasty white grease all over the front of my mare, though!