Bekhorot 19A

דהך דלא ביכרה שביח טפי צריכא.

that this offspring born to the ewe that had not previously given birth is superior. The Talmud concludes: Consequently, it was necessary to teach each case.

מתני׳ יוצא דופן והבא אחריו, רבי טרפון אומר: שניהם ירעו עד שיסתאבו, ויאכלו במומן לבעלים. רבי עקיבא אומר: שניהן אינן בכור, הראשון ⁠— מפני שאינו ״פטר רחם״, והשני ⁠— מפני שקדמו אחר.

Mishnah: With regard to an animal born by caesarean section and the offspring that follows it, since there is uncertainty whether each is a firstborn, neither is given to the priest. R' Tarfon says: Both of them must graze until they become unfit, and they may be eaten in their blemished state by their owner. R' Akiva says: Neither of them is firstborn; the first because it is not the one that opens the womb (see Exodus 13:12), as this animal did not itself open the womb, and the second because the other one preceded it.

גמ׳ במאי קמיפלגי? רבי טרפון מספקא ליה: בכור לדבר אחד, אי הוי בכור אי לא הוי בכור, ורבי עקיבא פשיטא ליה: בכור לדבר אחד לא הוי בכור.

Talmud: The Talmud asks: With regard to what do R' Akiva and R' Tarfon disagree? R' Tarfon is uncertain with regard to an animal that is a firstborn in one aspect, e.g., first to be born or first to open the womb, whether it is considered a firstborn or whether it is not considered a firstborn. And conversely, it is obvious to R' Akiva that an animal which is a firstborn in only one aspect is not considered a firstborn.

תנו רבנן: מכלל הצריך לפרט ומפרט הצריך לכלל, כיצד? ״קדש לי כל בכור״, יכול אפילו נקבה במשמע? תלמוד לומר ״זכר״.

With regard to the definition of a firstborn, A baraita states: This halakha can be derived by means of the form of exegesis known as: From a generalization that requires a detail, and from a detail that requires a generalization. How so? The verse states: “Sanctify to Me all the firstborn, that which opens any womb among the children of Israel, both of man and of animal, it is Mine” (Exodus 13:2). Had the verse written only the generalization: “Sanctify to Me all the firstborn,” one might have thought that even a female animal is included in the category of a firstborn. Therefore, the verse states the detail: “Every firstborn male…you should sanctify to YHWH” (Deuteronomy 15:19).