Leviticus 27:26-27

“No one is allowed to dedicate the firstborn of an animal; the firstborn, as firstborn, already belongs to GOD. No matter if it’s cattle or sheep, it already belongs to GOD. If it’s one of the ritually unclean animals, he can buy it back at its assessed value by adding twenty percent to it. If he doesn’t redeem it, it is to be sold at its assessed value.