Halakhah su Levitico 27:11

The commandment of the appraisal of a beast, such that one give according to what the priest appraises: To rule in the case of appraisals of beasts according to that which the Torah commanded us about it - as it is stated (Leviticus 27:11-12), "and he shall place the beast in front of the priest. And the priest shall appraise it" - and to give according to the appraisal that the priest appraises, and not less. As a man should not decrease and lie about that which he opens his mouth for the Heavens; and it is even forbidden to lie with common things, as I explained above (Sefer HaChinukh 350).

From the laws of the commandment is that which they, may their memory be blessed, said (Temurah 32b) that one who consecrates an unblemished beast for the altar and a blemish develops on it and it becomes disqualified, behold it is appraised and redeemed and he brings another beast instead of it. And about this is it stated (Leviticus 27:11), "And if it is any impure animal from which shall not be sacrificed to the Lord, he shall appraise the beast, etc." - as so did it come in the received traditional understanding, that Scripture expressed [this] with the expression of "impure." And whether a man consecrated a pure animal for the altar and a blemish developed upon it, as we said - or an impure [one] for the [Temple] upkeep - it requires being placed in front of the priest, as it is stated, "and he shall place the beast in front of the priest," and he appraises it. And if it died before it is appraised and redeemed, we do not appraise it and we do not redeem it after it died. But if he slaughtered two (the esophagus and the trachea) or the majority of two - even though it is like dead regarding slaughter, as it is established for us (Chullin 28a), as so was Moshe commanded about the majority of one with fowl and the majority of two with a beast - behold, it is living regrading appraisals. And [so] he brings it in front of the priest, and he appraises it. And the rest of its details are in [various] places in Temurah and Meilah (see Mishneh Torah, Laws of Substitution 4).