Rules for Firstborn Animals

Leviticus 27:26-27

Only the firstling among beasts, which is made a firstling to Jehovah, no man shall sanctify it; whether it be ox or sheep, it is Jehovah’s.

And if it be of an unclean beast, then he shall ransom it according to thine estimation, and shall add unto it the fifth part thereof: or if it be not redeemed, then it shall be sold according to thy estimation.