The sooner they eat a few pounds of grain a day, the sooner ya can get em off that dadgum expensive milk replacer. Grain is much cheaper.
Often times, grass and hay does not have sufficient nutrition for the baby calf to thrive.
They will eat tons and tons of grass and end up potbellied. I've even seen em die. Granted that was only once, and it wasnt my calf.
O! And just a tip..
@jruppe89
Keep FRESH starter out. Even if it's just a cupful or 2. Fresh every day. They seem to get started on it better.
I've also penned em up without milk for as long as a full day. The light bulb usually comes on and they decide they'd kinda like to eat something.