Deuteronomy 15:19-23

19You must set apart for the Lord your God every firstborn male born to your herds and flocks. You must not work the firstborn of your bulls or shear the firstborn of your flocks.

20You and your household must eat them annually before the Lord your God in the place he chooses.

21If they have any kind of blemish – lameness, blindness, or anything else – you may not offer them as a sacrifice to the Lord your God.

22You may eat it in your villages, whether you are ritually impure or clean, just as you would eat a gazelle or an ibex.

23However, you must not eat its blood; you must pour it out on the ground like water.