Numbers 18:15-18

1512Every first issue of the womb of all flesh, whether man or animal, which they offer to the Lord, shall be yours; nevertheless the firstborn of man you shall surely redeem, and the firstborn of unclean animals you shall redeem.

16As to their redemption price, from a month old you shall redeem them, by your valuation, five 3shekels in silver, according to the 4shekel of the sanctuary, which is twenty gerahs.

17But 5the firstborn of an ox or the firstborn of a sheep or the firstborn of a goat, you shall not redeem; they are holy. 6You shall sprinkle their blood on the altar and shall offer up their fat in smoke as an offering by fire, for a soothing aroma to the Lord.

18Their 7meat shall be yours; it shall be yours like the 8breast of a wave offering and like the right thigh.