בֶהֱמַת הַשֻּׁתָּפִין חַיֶּבֶת בִּבְכוֹרָה. לֹא נֶאֱמַר (דברים יב יז) (דברים יד כג) "בְּקָרְךָ וְצֹאנֶךָ" אֶלָּא לְמַעֵט שֻׁתָּפוּת הַנָּכְרִי שֶׁאִם הָיָה שֻׁתָּף בַּפָּרָה אוֹ בָּעֻבָּר אֲפִלּוּ הָיָה לַנָּכְרִי אֶחָד מֵאֶלֶף בָּאֵם אוֹ בַּוָּלָד הֲרֵי זֶה פָּטוּר מִן הַבְּכוֹרָה. הָיָה לוֹ בְּאֶחָד מִשְּׁנֵיהֶם אֵיבָר אֶחָד כְּגוֹן יָד אוֹ רֶגֶל. רוֹאִין כָּל שֶׁאִלּוּ יֵחָתֵךְ וְהָיָה בַּעַל מוּם הֲרֵי זֶה פָּטוּר. וְאִם אֶפְשָׁר שֶׁיֵּחָתֵךְ אֵיבַר הַנָּכְרִי וְלֹא יִפָּסֵל. הֲרֵי זֶה חַיָּב בִּבְכוֹרָה:
There is an obligation to apply the laws of a firstborn to an animal owned by partners. The terms "your cattle and your sheep" was used only to exclude an animal owned in partnership with a gentile. For if a gentile was a partner in the ownership of a cow or of the fetus it is carrying - even if the gentile owns only a thousandth share of the mother or the offspring, it is exempt from the requirements pertaining to the firstborn. If the gentile owned one specific limb of one of them, e.g., a forefoot or a hindfoot, any limb which if cut off that limb would render the animal as blemished, exempts it. If the limb owned by the gentile could be cut off without disqualifying the animal as a firstborn, it is obligated in the laws of the firstborn.
