Ketubot 79B

ולד בהמת מלוג ⁠— משלם תשלומי כפל לאשה.

the offspring of an animal of a woman’s usufruct property must pay payment of double the principal to the woman. Apparently this ruling is based on the assumption that the offspring is not treated as the produce of her property but as the principal, which belongs to the woman.

כמאן? לא כרבנן ולא כחנניה! דתניא: ולד בהמת מלוג לבעל, ולד שפחת מלוג לאשה, וחנניה בן אחי יאשיה אמר: עשו ולד שפחת מלוג כולד בהמת מלוג.

The Talmud asks: In accordance with whose opinion was this halakha stated? It is not in accordance with the opinion of the Rabbis, and not in accordance with that of Ḥananya. The Talmud explains the dispute alluded to here: As it is taught in a baraita: The offspring of a usufruct animal belongs to the husband, whereas the child of a usufruct female slave belongs to the wife. And Ḥananya, son of Yoshiya’s brother, said: They made the status of the child of a usufruct female slave like that of the offspring of a usufruct animal, which belongs to the husband. Both opinions in the baraita agree that the offspring of a usufruct animal belongs to the husband. Why, then, must the thief pay the double payment to the woman?

אפילו תימא דברי הכל: פירא תקינו ליה רבנן, פירא דפירא לא תקינו ליה רבנן.

The Talmud answers: You can even say that all agree with R' Yannai’s ruling, as there is a difference between the general use of property and the double payment. This is because the rabbis instituted for the husband to consume the produce, but the rabbis did not institute for him to consume the produce of the produce. The double payment does not have the status of the offspring itself but of produce resulting from its theft, which is considered the produce of the produce and therefore is given to the woman.