What is suckler bred?
Was she being bottle fed (which I doubt if she's wild) or fresh off a cow?
At a month old if she's off a cow your going to have quite the battle on your hands. I've seen it go both ways.
We've had luck several ways before. Got a halter on them, safely tie them up so they get used to being restrained, wait until they are extremely hungry then pin them into a corner and stick a bottle in their mouth. Must wait until they are very hungry or your waisting your time. Sometimes once the milk runs in (usually after a tantrum and them ending up on the ground) they realize they want it due to extreme hunger. Others are so worked up they would rather starve.
In which case either find a nurse cow who will take it and graft it or provide smaller stem hay and a calf starter grain (and fresh water) and hope nature kicks in and it gets the idea. They usually end up quite a bit behind but they do survive.
Be careful. You can get the snot knocked out of you by a 1 month old. Instinct tells them to fight for their life and they do. Have her in a very sturdy pen or panels.