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Whether or not they need milk depends on what age they are when you get them. If they are drop calves, obviously they will need milk. If they are older they do not. I would suggest you start off with calves in the 300 pound range. All the baby problems will be past. I usually kept...
I used to buy a steer calf and raise it up. I had limited pasture so they got fed hay and grain. I fed a lot of grain to my steers. It wasn't cheap but I liked the end result. To me it was worth every penny.
Just a comment. To me the ideal beef steer is a Jersey Angus cross. It makes a nice meaty carcass, not too big, and the flavor from the Jersey is outstanding.