Faunaphilia is the proper term for it.
Latin. Fauna being animal, philia being love of. Just like pedophilia is love of the young. And yeah, it's sick.
Yes, I know the language sources. But the move is on, I think, to relabel the act from "bestiality" (a well-known term that invokes revulsion almost universally) to "faunaphilia" (a term that is not well know and thus can be "marketed" differently).