In my experience some stand and stare. Other times my passing triggered a near stampede. And one time the bunch of 30 or so were so curious they aggressively surrounded and followed me so closely I couldn't wait to get out there!
Tell me about it! When I went at night one started to follow me and I bugged out of there. Then a big group of them later started slowly following me along.
I don't know what their intentions were but a group of cows heading your way in the dark does not look friendly! Made me nervous!