What is the white stuff on a race horse's butt and does it mean anything?

Answer 1

I presume you mean the white that seems to spread from the butt cheeks and down the inside part of the back legs. If so, that's actually sweat, more commonly called lather in horse racing circles. The sweat "lathers" up (much like shampoo does in hair) where hide meets hide (butt cheeks) and also where leather meets hide. Sometimes you'll notice that there are also streaks of white where the reins rub against the horse's neck. Does it mean anything? Not always, but if a horse gets too hot and anxious before a race, he/she usually doesn't run very well. I'd say that if the lather is running all the way down the horse's back legs, it's not a good sign. It means the horse is too anxious and worked up and usually runs very quickly right out of the gate, only to tire and not finish well. There you have it.