Leviticus 27:9-13

9“Now if it is an animal that may be brought as an offering to Adonai, anything that one gives to Adonai will be holy.

10He is not to replace it or exchange it, either good for bad, or bad for good. But if he does exchange one animal for another, then both it and the one for which it is exchanged will become holy.

11If it is any sort of unclean animal that may not be brought as an offering to Adonai, then he is to set that animal before the kohen.

12The kohen is to evaluate it, whether it is good or bad. As the kohen values it, so it will be.

13But if he would redeem it, then he is to add a fifth to its valuation.