Reference for Bekhorot 2:3
כֹּל שֶׁקָּדַם הֶקְדֵּשָׁן אֶת מוּמָן, אוֹ מוּם עוֹבֵר לְהֶקְדֵּשָׁן, וּלְאַחַר מִכָּאן נוֹלָד לָהֶם מוּם קָבוּעַ (וְנִפְדּוּ), פְּטוּרִין מִן הַבְּכוֹרָה וּמִן הַמַּתָּנוֹת, וְאֵינָן יוֹצְאִין לְחֻלִּין לִגָּזֵז וּלְהֵעָבֵד, וּוְלָדָן וַחֲלָבָן אָסוּר לְאַחַר פִּדְיוֹנָן, וְהַשּׁוֹחֲטָן בַּחוּץ חַיָּב, וְעוֹשִׂין תְּמוּרָה, וְאִם מֵתוּ יִקָּבֵרוּ:
If their consecrations precede their blemishes, or passing blemishes precede their consecrations, but afterward they develop permanent blemishes (and they are redeemed), they are exempt from the [the obligations of] the firstborn and the [priestly] gifts. They do not leave [their consecrated status] to become unconsecrated to be shorn and worked. Their offspring and milk [from] after they are been redeemed are forbidden. One who slaughters them outside [the Temple courtyard] is liable. They make [their] replacement [sacred]. If they die, they are buried.