My Nubians do not grow as fast as some report. I have ended up waiting to breed everyone one I've bought, except my buck. He's a big boy. The girls though - I guess I could feed them calf manna or something and try to push them, but they are nice size given more time. Maybe if I dam raise one, I'll see a difference - with the bottle fed there is a limit to how long I will keep going with that and like Kathie I stick with two liters. If there is a correlation, I would think it due to the same people pushing for faster growth pushing for maximum production. But I think some bloodlines are just bigger than others. Some Nubians are giants, but they aren't all. Some look huge in photos and you go see them, and they aren't so big. I think I tend to like a very dairy type free from muscling.