I've raised a few bottle calves over the years. Used to be all holsteins, now there are alot of mixes with angus or black limi or black simme.... If they are fed right, they will come close to what
@Son of Butch said. I figured 300 at 4-5 months and then they should start to really grow from there. BUT.....
@MurraysMutts is right... MORE GRAIN LESS HAY.
Because of the way we have bred dairy cattle... they need concentrates... AND they need it to be WELL BALANCED. I fed a 14 % calf starter/grower ration... NON-MEDICATED and they were getting 2-4 lbs per day per calf until they hit the 5-6 month age.. what you are feeding is not balanced. They are not getting the little extras that their bodies need.
Bottle calves are not profitable in the normal scheme of things in today's market. The best ones are ones that are grafted on a cow that lost a calf and can have all the milk they want as well as learning to eat what the cow is eating and I have weaned 550+ lb holsteins off beef cows at 6-7 months because they get the balance nutrients they need out of a beef cows milk and not getting any creep feed except whet they get from a feeder when I call the cows into the catch pens to keep them friendly and give them a treat. Maybe a couple pounds feed a week if that.
Holstein steers get hay guts if they are not getting enough nutrients... they will eat and eat and eat because their bodies are craving the nutrients that they have been designed to eat over years of how we have bred and developed dairy cattle.
They also should be getting the very best hay fed in limited quantities... to get the roughage but not enough so that they just stand and eat 20 hrs a day.
Also, we do not band our holstein bull calves until they are 4-5 months old as a rule. They grow better as bull calves and they are not rank or have attitudes at 4-5 months so not a problem to deal with. Any time we get a bull calf to graft on a cow it is left a bull until weaning or we are moving/working them and have them where they can get handled through a chute.
I agree with getting them on some good textured feed and getting their rumens developed better and getting them a more balanced feed.
Sadly, as you are finding out... you cannot feed holsteins on the "cheap" like you can with some beef calves.... I like to get them at 300+/- lbs now and then get them going on feed and silage for a bit... with some hay... and then get them ready to turn out and they will get with the program. You are feeding more frame-body developement for the first 6-8 months before they even start to fill out.
Holstein steers here are in the 1.20 range if they are in good flesh. We took 6 straight jersey steer calves to market for a friend, and they were in the 350-500 range... they had raised them on bottles... and they got good feed and looked good and I figured I was going to wind up buying them to feed out at $.50.... they brought $.85 and .95 .... and I sure didn't buy them.