Question about giving formula to EBF baby?

JulySpark05

The reason I ask is because I finally got DD2 to take a bottle the other night (I gave her breast milk in the bottle) and DH and I are going away with her this weekend but I need to give her a bottle so MIL can feed her while we are out that evening.

I do have some frozen breastmilk and would prefer to give her breastmilk but we will be on the road and stopping at a few spots before we get to our final destination and I'm scared the milk would go bad.. We will probably leave around 10am, get there by supper time and MIL would probably be feeding her around 8pm. I also think travelling with ready made formula would be so much easier.

So my question is, if you give the occasional bottle of formula to your previously EBF baby, did it affect them in being really gassy or give them an upset stomach? Also, how many oz do you give if you give formula or breastmilk? TIA!