pumped milk question

rxbeth

This weekend I plan on introducing a bottle since LO will be 5 weeks old.  I have been pumping (just once a day when I can) and have maybe 50 ounces in the freezer. 

My question is concerning how breastmilk changes to meet the caloric needs of the baby.  How often/quickly does this happen?  When I give her a bottle this weekend, since it will be expressed milk from when she was only 5-6 days old, should I make sure that I thaw extra since she might need more to meet her caloric goals?  Or will she drink the same amount and just be hungry sooner?  I only plan on giving a bottle once a week right now to make sure she is used to it and then possibly more often if I build up my stash and DH and I can get away for a night every so often.

Also, if anyone wants to reassure me that giving a bottle didn't mess up their latch with their LO, I could use the reassurance.