I ver much doubt "water buffalo" have been able to make their way across to north Qld (unless someone has trucked a heap of them over that way). I strongly believe what you are referring to are the feral cattle ("scrub bulls").

I have shot quite a few of each and in MHO, the buffalo are a lot tougher animal, although equally enjoyable to hunt through scrub on foot when encountering at close range...

cheers
dok