I don't think cows bother deer at all...the deer i've watched while cows where in the area seem to look up every so often and watch the cows for a couple seconds but otherwise pay no attention to them at all....possibly b/c they have seen them since they where fawns? i don't know. but we've had cows on our land for a very long time so i think the deer are just accustomed to seeing them. Since the area you are hunting hasn't had any cattle on it before(?) the deer may not trust the cows yet lol, but i don't think the cows are really going to throw your hunting off to much.
Tell me and I forget. Show me and I remember. Involve me and I understand.