The Boss Cow, Lead Cow, or Top Cow.
This could be because the cow feels threatened by the human, if it is a female cow she could be protecting her calf. Some cattle have an aggressive temperament and will charge at humans for no particular reason.
A cow thief..
There's not really an answer... You just call it a cow...
A newborn calf, a baby calf or just a calf.
dial a collect phone cal by dialing 0 it will charge the # you call
Momma cow.
Just a cow.
every cow moos
I believe you would call it a "heifer".
They call him/her a calf.
A cow shed. A cow shed is called a BYRE
A grazing cow or grazer.