Most old farm kids yelled HERE BOSY HERE BOSY.
Cows are not that hard to train.
Just start making the sound that you want them to come to when you start feeding them.
I have seen many hundreds of cows come to the honking of a vehicle horn. From miles around.
Of course people who were not raised around them wouldn’t know.
My Uncle used to call ‘Here, Bossy!’ to his cows.
(And he kissed every pig he sent to slaughter....:-)