FYI.
Interested in Veterinary medicine today ambrose? ;~\
Rectal exams (by veterinarians, not by any Joe Billy Bob) are pretty common as a way to explore the cause of a colic, and also for prenatal examination of pregnant mares. This article is informative for those who haven't had to deal with a colic, or for those who didn't know what the vet was doing up there, and were too polite to ask.