FYI, if the milk hasn't been reheated, then it can be reused the next day.
Do you know how their storage is there?
If they have a freezer you could do what the PP suggested.
If they have a fridge then you could try sending more bottles with fewer ounces in them and tell them to heat and feed as needed. Then whatever is left can be used the next day. Breastmilk is good in the fridge for a few days.
Also by sending small quantities in more bottles would allow you to figure out exactly how much she is eating and after a week or so you will know how much she needs and you can send exactly the average she eats a day plus 1 extra bottle.
My mom ran a daycare most of my life and we had a full fridge and freezer system and would leave the bottles of breastmilk that weren't used in the fridge for the next day. We would use the leftover first the next day and then move on to what was sent fresh from home. If there was leftover again, we would continue to cycle until friday when they were picked up... then we would send home everything we had left.
I'd send six on Mondays and four other days. The two extra will be the first two for the following day. That way you always have enough and you can Gaige by the end of the week exactly how much you need.
Mélodie: Sept. 27, 2008
Maya: October 26, 2011
DS - Stephen 7/5/06 (born 6 weeks early)
DD - Sophia 9/16/11 (born at 37 weeks, 6 days)
Professional birth photos: