I was just forced to wean 6 one month herefords. I have them on grain and I mix power replacer in with it. They are eating real good right now. We'll see what happens. I have weaned 4 month old simmyXherf calves with no problems.
3 months and they did fine. Started out smaller but by the time they calved there was no difference in size for the ones weaned a 6 months. We are starting to wean everything at about 5 months. Seem like the mature a little quicker.
When we bottle fed lots of calves we weaned at around 4 weeks. Most dairys wean at 4 weeks and you could never tell that those 1200 lb springers had been hurt any in their growth.