If they bother them I have never noticed. But I havent had the chance to hunt land that was not at least semi surrounded by cows. Yesterday evening i was watching some land across the road going up to another ridge. There was a deer moving up to the ridge. About 5 cows where 150 yards farther down from him. This land has cows all on it with patches of woods breaking it up. I have been in my stand and seen plenty of deer in these fields. Granted ive never seen the cows and deer close to each other, but have seen deer one field over or at the edge of the woods (in same field) from the cows.
Dont get me wrong. Im not gonna hunt over a cow field, but deer will use the surrounding area. Old school hunters around here use to tell me to step in a pile of cow crap before i walked to my stand to cover my scent. Thats how common cows are around here.