Hello fu_fanny,
You can start giving 12 months old BBs fresh milk. In US & Canada, it is recommended to give fresh whole milk / homogenized milk (with 3.25% fat) to babies from 1 to 2 years old because they need the fat for healthy brain growth. After 2, you can start giving regular milk with 2% fat. They need 16oz of milk a day for the calcium, maximum 20-24oz., or they will start loosing iron in the poo poo.
Does the fresh milk sold in HK has labels to tell you the fat content?
As told by my son's pediatrician, if you continue to give straightly baby formula to BBs 12 months or older, they will be filled up with milk and eating a lot less solid food, thus not able to obtain enough nutrients for healthy growth. There are of course formula designed for babies older than 12 months to supplement normal solid food diet. I think your baby's doctor can suggest something for you.