I started feeding Holsteins in a hoop building end of January.  They started at an average of 440# an now 10 months later are averaging between 1350 and 1400 lbs.  I feed 6# dry ddg's, .7# Land of lakes R-700 co-product balancer and enough corn so they clean the bunk every day (now about 23#corn/day).  They are also bedded with corn stalk bales every week and they eat some of them.  I did notice that with the hot weather this summer they backed off on the feed consumption and have taken a long time getting back up on feed.  Since this is my first year not sure if it was the weather or like you said get so big and then back off.  Will pay attention next year to see if it happens again.

Had planned to add another building this fall so I could switch to wet ddg's, but with the price of corn I think I will sell the corn this year and build the building next year.  The extra $2.00/bushel for corn will go a long way in paying for a new building.