Bechoros Daf 24 בכורות דַף 24

A Mishnah on the previous Daf presented a ruling of Rabban Shimon ben Gamliel, which a Baraisa on this Daf presents as a machlokes: if one purchases בהמה מניקה – a nursing animal from an idolator, the Tanna Kamma says its next offspring is a safek bechor, מפני שמרחמת אף על פי שאינה יולדת – because [an animal] is sometimes compassionate and nurses a child even though it never gave birth. Rabban Shimon ben Gamliel says: דבר בחזקתו – the issue remains in its assumed status, i.e., that it definitely has given birth. The Gemara asks what he meant that it is "בחזקתו": did he mean only that an animal does not nurse any young unless it has once given birth, but once it has, חיישינן לרחומי – we are concerned for its compassion to nurse another animal’s young? Or, did he mean דידה מרחמא – it is compassionate and nurses its own young only, דלא דידה לא מרחמא ליה – but to young which is not its own, it is not compassionate? Meaning, does nursing prove that this is her child, or only that she once gave birth? The נפקא מינה is whether one would receive malkus for shechting them both on one day.

Among the proofs brought to resolve the above question, the end of the Mishnah is quoted. Rabban Shimon ben Gamliel said: if one entered among his flock and saw that the animals which had given birth for the first time were nursing, and those which had previously given birth were also nursing, אינו חושש שמא בנה של זו בא לו אצל זו – we are not concerned that perhaps the offspring of this one came to that one, or vice versa. Rather, we assume each animal is nursing its own child. But, if Rabban Shimon ben Gamliel agrees that a mother which has given birth would nurse another animal’s child, we should be concerned that they are nursing each other’s children, leaving us uncertain which ones are bechoros!? The Gemara replies that even if an animal would nurse the child of another, במקום דידה לא שבקא דידה ומרחמא דלא דידה – where her own offspring is present, [a mother] would not abandon her own and be compassionate to one which is not her own.

In the next Mishnah, Rebbe Yose ben HaMeshullam says that someone shechting a [blemished] bechor may make space by parting hair to either side of the shechitah area, ותולש את השער – and may pluck out the hair (although shearing a bechor is prohibited), but he cannot move the plucked hair from its place, so people do not think he sheared kodashim. Rav Huna was asked if this is also permitted on Yom Tov (for shechting ordinary animals). This depends on Rebbe Yose ben HaMeshullam’s reasoning: does he hold תולש לאו היינו גוזז – “plucking” is not the same as shearing, and is thus permitted for a bechor? If so, it would be forbidden on Yom Tov as עוקר דבר מגידולו – uprooting something from its place of growth. Or, does he hold תולש is considered shearing, and the plucking is permitted here as דבר שאין מתכוין – something which is not intended (i.e., he only meant to move the hair, and it was incidentally detached)? This would also be permitted on Yom Tov. Rav Huna said Rav permitted it on Yom Tov (i.e., the latter explanation is correct). The next Daf explains this ruling differently.