Are antibodies passed on to baby for the entire time they breastfeed (example for 1 year), or is it just for the first few months?

The entire time: At anytime, breast milk has some low level of iga, some igg and other proteins that are thought to help infant protected against infection. The first year of life, your child relies on antibodies from mom including the ones from breast milk. At about 6 months, infant makes some immunoglobulins ; starts to make more over time until about 2 years old when he / she has an almost mature immune system.