I have heard Johnes is a risk feeding raw cow's milk, but someone with more experience than I would know more. I would say if it is your cow milked individually and you know she is Johnes free go for it, if you are getting it out of a bulk tank from large dairy I would think the risk is there.
edited to add: I have also used pasturized homogenized whole cow's milk successfully (store bought!)
We had great luck with whole pasteurized cow's milk. When they were young we added probiotics. When they were a month old or so we just gave it to them warm. I don't know about raw milk so I'll let others comment on that.
JD
From what I have heard, unpasteurized non homogenized can cause gut disruption and scours in kids. The proteins in raw cow milk are too big for them to process properly, I think. But I am so not the go to source for new information.
That is just what I think I remember from previous discussions on the subject. Ha! We use whole cows milk from the grocery store with a nip of molasses or karo syrup on several kids and haven't had problems!
I wouldn't get milk replacer. There have been several threads on here lately of kids getting diarrhea and it was found to be milk replacer. Just whole milk from the store works great.