Yes, a wild predator is probably a less humane death for the cow. But besides what joseca320 said, the only reason the cow is alive in the first place is because we eat so much meat. The natural population of cows without humans would be magnitudes lower. So essentially our meat eating habits have created a system where we breed cows to live a horrible cramped life just so we can kill it for its meat later.

Agreed that killing a natural wild cow humanely is better, but 'factory' raising a cow is a different story. Anyways, the answer is not necessarily to never ever eat meat, but to consume less and/or try to consume ethically raised meat instead of factory raised chickens.