Is it allowed to own a pet that was previous castrated by a non-jew without consent? Practical exemple: a well-behaved female dog adopted by a Jewish family after the castration (and adopted regardless the castration)
אָסוּר לוֹמַר לְעַכּוּ''ם לְסָרֵס בְּהֵמָה שֶׁלָּנוּ. וְאִם לְקָחָהּ הוּא מֵעַצְמוֹ וְסֵרְסָהּ מֻתָּר. וְאִם הֶעֱרִים יִשְׂרָאֵל בְּדָבָר זֶה קוֹנְסִין אוֹתוֹ וּמוֹכְרָהּ לְיִשְׂרָאֵל אַחֵר
It is forbidden to ask a non-Jew to castrate an animal of ours. But if he [the non-Jew] took it himself and castrated it, it [i.e keeping the animal] is permitted. But if the Jew connived in the matter, we fine him [by ruling that] he sell it to another Jew.
(Translation/elucidation is mine.)