Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 115
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 115, with English translation by Maimonides (Rambam).
להיות מעריך בהמה טמאה נותן דמיה, שנאמר: "וְהֶעֱמִיד אֶת הַבְּהֵמָה" (ויקרא כז, יא).
For a person who makes an endowment valuation concerning a non-kosher animal to give [the required amount of] money, as [Leviticus 27:11] states: "And he shall cause the animal to stand...."