>>1441266cows ("cow" specifically refers to a female) are generally harmless. bulls can sometimes be aggressive if they feel you're getting too close or are otherwise made anxious (I've had some charge & ram the gate at stockyards). some bulls are total pushovers. I don't know what makes the difference.
some cows can be surprisingly aggressive if they have a babby and think you're a danger to it. they won't try to gore you but will run into you and headbutt you, and it feels similar to getting hit by a car at low speeds.
the ones that followed you were most likely curious if you had food. they're moderately curious animals and will wander around to investigate strange noises or smells.
t. farmeranon