Riderintherain, for some reason I can’t quote your post, sorry!
I studied abroad in Siena twice, and was there for the entire week of the July 2015 Palio. Those horses are truly treated like kings. The race itself is dangerous- a jockey hurt he knee or lower leg pretty bad in the palio I saw- that is honestly the only difficulty in their life. I’m facebook friends with the owner of a recent palio winning horse and he has it so good. Lots of turnout in huge fields and they seem to get a lot of time off and live out until they’re brought back into work in the new year. Vets are involved in every single step of the race. There are multiple vettings several weeks out, to select which horses run in the trial races. Vets give the ok for the horses to run in the selection races. Once horses are assigned, each contrada has a vet that is responsible for the care of the horse until after the race.
I have several books about Siena and il Palio, but this is just what I can remember off the top of my head!