My son is afraid of cows. I don't know why, but he's made it very clear that cows scare him. Real cows don't seem to bother him. His toy cows make him uneasy, but he still plays with them. The cows in his mind scare the crap out him. He has cow related nightmares about twice a week.
We were talking the other day about cows and he said that they scare him. I asked why and he said that they were coming to get him. Apparently he's old enough to be convinced that cows are out to get him, but not old enough to understand that the idea is absurd.
With the amount of beef and cow related products our family consumes, I'd think that the cows should be afraid of us.