Just the STAT test, your ATAR and a Vet Science Commitment Statement (for Sydney Uni anyway - I suggest you get started really really early on this). No interview here but CSU does an interview (they really drill you for how much you love Agriculture and cows etc) and James Cook from knowledge does a similar thing to the commitment form, just a short-answer style application about why you want to be a vet etc. It's different again if you're coming from another degree already.