My DS had a NF until he was 8 months, when we started experiencing the same issues. Has she started solids yet?
Essentially I did as pp suggested, I'd drop the NF bottle by an ounce and hold for 3-4 days, then drop by another ounce until he was weaned off his NF. But, like I said he was a bit older and well established on solids at 8 months.