Halfway through this Omud the Gemoro brings R. Poppa's Shittoh that even on the night before its OK because "Lyloh Ein Mechusarv Zman" and then this is the part I cant quite follow because to back up his Klal he brings a Tonna Debei Reb Yishmoel about Maaser Beheimoh at night AND THEN seems to bring this Din of R.Aptorki about a similar Limmud with Korbonos Bichlal Lav Davka Maaser Beheimoh where we can see that "Lyloh Loy Chozi ..."
So in essence my Shyloh is that why Lefi the Shakloh Vetaria of the Sugya do we need both Meimros "Taipuk Lay" that R.Aptorki is enough not sure how the Tanna DeBei R.Yishmoel is noygea to the Sugya it does not seem to add to what R.Poppa wants to prove could you explain how you understand how the 2 Meimros follow on.
Boruch Kahan, London England
1) This question is also asked by the Brisker Rosh Yeshiva, Rav Dovid Soloveitchik shlit'a, in Shi'urei Rav Meshulam Dovid, on Zevachim 12a, pages 197-8.
2) He first points out that there is a difference between Rashi and the Shitah Mekubetzes, because Rashi (DH l'Kedushah) writes that it is from the Din of Rebbi Aptoriki that we learn that Lailah Lav Mechusar Zman, while the Shitah Mekubetzes (#20) writes that this is learned from Tana d'Vei Rebbi Yishmael.
(It seems to me that in the conclusion, when Rav Dovid explains how a different thing is learned from each Meimra, as we will see b'Ezer Hash-m, there is no Machlokes between Rashi and the Shitah Mekubetzes, because there is something we learn from each Meimra.)
3) Rav Dovid explains that without Tana d'Vei Rebbi Yishmael we would have thought that even if one was Makdish the animal on the eighth night, the Kedushah does not apply even b'Di'eved. This is because before the time of Ma'aser Behemah has arrived, it is totally "Mufka" -- removed -- from any Dinim of Ma'aser Behemah.
Rav Dovid proves this, in the name of his father, the Brisker Rav zt'l, from the Rambam in Hilchos Bechoros 6:15. There is a Din (see Rambam there, 6:10) that one is liable for Ma'aser Behemah only if the animal was born in one's possession, but not if one bought the animal. However, the Rambam (6:15) writes that this exemption on what was bought applies only if they were bought after they were fit for tithing. Therefore, if one bought the babies before they are seven days old, one must tithe them when they become seven days old. The Rambam writes that since they are Mechusar Zman, they are equivalent to embryos. Just as it is not possible to do Ma'aser on embryos, so it is impossible to do Ma'aser on babies under 7 days old. We learn from the Rambam that Mechusar Zman of under 7 days old is totally Mufka from Ma'aser Behemah, in the same way that embryos are Mufka from Ma'aser Behemah.
4) The Chidush of Tana d'Vei Rebbi Yishmael is that on the 8th night the baby is no longer Mufka from Ma'aser Behemah, and if one put the young animal in the "Dir" it does become Kadosh.
5) However we would not know from Tana d'Vei Rebbi Yishmael that one is allowed to be Makdish the animal l''Chatchilah. The reason why the Gemara records Rebbi Aptoriki is to teach us that on the 8th night there is also no longer a prohibition against being Makdish an animal too early.
[I highly recommend seeing inside what Rav Dovid says, because I put it in a very shortened form.]
Kol Tuv,
Dovid Bloom