Wild cattle (if such things still exist) would be severely hampered by not feeling pain. The thing is, we're not releasing the cattle we manipulate. When we are farming cattle, we don't need the cattle to know they've been injured as it can only make them less cooperative with their handlers and other cattle. In fact, what we plan on doing to cattle (slaughtering them for food) isn't good for their overall safety either.
Much of the excitement we get out of our work is that we don't really know what we are doing. -- E. Dijkstra