If, as I'm presuming, you're new to cattle, It makes things so much easier if the animals are quiet and well handled.
My first Dexters were bought off a local breeder and they were very tame and halter trained. Dexters can have small animal syndrome and can be very awkward. It is therefore so much better to have one you can go up to in the field, and maybe put a halter on to lead where you want, or that at least will follow you for food.
I once went to look at some and the chap selling them kept a stick near the gateway which he picked up before entering the field. He assured us that you should never enter a field of cattle without carrying a stick. Well all our cattle are happy for us to go up to them and talk to them and I certainly wouldn't expect to have to beat them off with a stick! Needless to say, we didn't buy any off him.