I'm trying to introduce bottle to my 7 week old LO. She seems to be taking it well but i still want to BF her. How often should i give her the bottle to ensure that she does not reject BF?

Thanks mummy, LO refuses MAM but is taking to NUK well.. she finishes 120ml in 10 mins when bottle feeding which is worrying to me too. and i'm afraid she won't want to nurse anymore since during nursing, we will typically take 30 mins..