If you need a reason to vaccinate against rabies consider the
following: it is my understanding that, in the event an animal exhibits any
rabies like symptoms, the only way to rule out rabies as a cause is to
destroy the animal in order to examine the brain.
I would also be concerned about personal liability in the event that
a horse (or other animal) prove to have been infected.
I judge ECTRA CTR's and would wear protective gloves when examining
mucous membranes if management has not required rabies vaccinations.