3 month old EBF not accepting formula
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I've been breastfeeding exclusively for 3 months with an occasional pumped milk in bottle when I'm out or want a break. She has no issues with taking my pumped milk from the bottle and will suckle it down happily. But I want my husband to start giving her one formula bottle a day so I get a break and don't want her to be so reliant on breastfeeding so it becomes harder to wean when I get back to work.
We've tried for two days now and she scream and cries and spits it up till I give up and give her my boob. First time we did just formula, she cried but drank about 50ml in between the screaming. Second day I mixed 60ml breastmilk with 30ml formula and she screamed and cried for half an hour and drank maybe 10ml only. (Im so annoyed at the wasted liquid gold!!!!). I know the bottle and teat isn't an issue because she has pumped milk in it! Ive been trying Kendamil because I heard its best accepted by breastfed babies.
Any ideas on how to get her to accept just one bottle a day, which doesnt include wasting pumped milk? ChatGPT said to just keep trying for 5 - 10 mins everyday and if she cries then stop and try again next day. Is gentle exposure the way to get to accept formula?
Also: she did have 2 or 3 formula bottles when she was a newborn with no issues on the days I had supply issues. I used Cow and Gate then. But I think she didn't protest as much because she was just a sleepy newborn and now she's an opinionated 3 month old with very strong lungs!