i don't think they'd do that well. it would take a long time for them to revert back to a wild state and i don't think they'd survive long enough to get to that point. there are too many predators that can take them down easily

Those that survived the initial rigors of it- would probably revert BACK to something similar to Their Original Forms... :)

I think after many generations, they would evolve back into their aurochs state. Horns on both sex, large size, dorsal stripe. I think they would do well in the wild, as their wild ancestors and extinct subspecies did for thousands of years. Some would die because of diseases and being too dependent on humans for their needs, but I think cattle as a whole would do well in the wild without humans.