Now are you saying creep feeding as in they have access to grain 24/7 and can eat as much whenever they want? Or are you simply just giving them 1.5 pounds a head a day?
This is what I do. At weaning they are cut off of being actually being creep fed and they get a measured amount of grain. They will get this for roughly a month. Quite honestly all I really want to do is feed the rest of the pallet of grain because it won’t keep till next year. After it’s gone they are done with grain. For me I see no point in pushing the feed to them when they will be more then large enough to breed at 18 months old without the extras. I don’t want them to get overly fat. Now this year I do have a exception, and that is 2 bucks that I am planning on using next month, they will only be 7 months old and I want them big enough to cover my does so they have been getting grain.
Other people never stop supplementing grain. I say no matter what way you decide to go keep a eye on body condition. If you cut them off and they start looking thin, or their growing has slowed a great deal start them back up. If you continue giving grain don’t let them get to fat. To a degree growing animals will pack on a few pounds and then shoot up and look thinner so just do the best you can on adjusting it