there was a follow up to that video on one of the news channels, they said the dog was a stray.
There are still plenty of dogs in the Australian north that earn their keep just like that, except that the cattle are proper wild animals. Known as bullcatching dogs, they don't necassarily need to be a bull x to be any good at it.They come in all shapes and sizes, to suit the country they work in and type of catching they do, whether from a vehicle or quad, or from behind a horse.
Regards