Thinning Hair Vitamins

I just gave a birth to my beautiful daughter. Her pediatrician gave me a bottle of liquid Vitamin D since I breastfeed exclusively. I tried to give it to my daughter, but she didn’t take it at all. I heard that I should mix the vitamin with my milk, but there is a good amount of vitamin that I have to give, and I can pump so much every time. I’m also afraid that she will get used to the bottle and won’t eat from my breast any more. I’m hoping to get good answers from breastfeeding moms. Thanks.