English: "Year by year" — this teaches that the firstborn is eaten year by year, whether unblemished or blemished.
On the daf / in context: Both a perfect firstborn (offered and eaten in Yerushalayim) and a blemished firstborn (eaten anywhere) are subject to a one-year time limit.
Type of Learning
Derash on the verse (Bekhoros) — the one-year limit applies to both perfect and blemished firstborns.
What Is Learned
A firstborn animal, whether perfect or blemished, must be eaten within its first year.