Mishnayos Bechoros Perek 2 Mishnah 1

With regard to one who purchases the fetus of a cow that belongs to a gentile; one who sells the fetus of his cow to a gentile, even though one is not permitted to sell a large animal to a gentile; one who enters into a partnership with a gentile with regard to a cow or its fetus; one who receives a cow from a gentile to tend to it in exchange for partnership in its offspring; and one who gives his cow to a gentile in receivership, so that the gentile owns a share of the cow’s offspring; in all of these cases, one is exempt from the obligation of redeeming the firstborn offspring, as it is stated: “I sanctified to Me all the firstborn in Israel, both man and animal” (Numbers 3:13), indicating that the mitzva is incumbent upon the Jewish people, but not upon others. If the firstborn belongs even partially to a gentile, the sanctity of firstborn does not apply to it. The mishna continues: The priests and the Levites are obligated in the mitzva, i.e., their animals have firstborn sanctity, as they were not exempted from the mitzva of the male firstborn of a kosher animal; rather, they were exempted only from redemption of the firstborn son and from the redemption of the firstborn donkey.

הַלּוֹקֵחַ עֻבַּר פָּרָתוֹ שֶׁל נָכְרִי, וְהַמּוֹכֵר לוֹ אַף עַל פִּי שֶׁאֵינוֹ רַשַּׁאי, הַמִּשְׁתַּתֵּף לוֹ, וְהַמְקַבֵּל מִמֶּנּוּ, וְהַנּוֹתֵן לוֹ בְקַבָּלָה, פָּטוּר מִן הַבְּכוֹרָה, שֶׁנֶּאֱמַר (במדבר ג), בְּיִשְׂרָאֵל, אֲבָל לֹא בַאֲחֵרִים. כֹּהֲנִים וּלְוִיִּם חַיָּבִין. לֹא נִפְטְרוּ מִבְּכוֹר בְּהֵמָה טְהוֹרָה, (וְלֹא נִפְטְרוּ) אֶלָּא מִפִּדְיוֹן הַבֵּן וּמִפֶּטֶר חֲמוֹר: