1) PRIVATE PROPERTY VERSUS PUBLIC PROPERTY
QUESTION: If the owner of a Korban Asham died before he had a chance to offer his Korban, the animal is left to graze until it develops a blemish (Mum) that disqualifies it, and then it is sold and the money used to buy a Korban Olah. The Gemara asks why the animal is left to graze until it develops a Mum, and is then redeemed. When the owner of the Korban Asham died, we should slaughter the animal itself with intention to offer it as a Korban Olah. The Gemara answers that the Rabanan enacted that a Korban Asham not be slaughtered l'Shem Olah, lest one think that he is permitted to slaughter an Asham as an Olah even when the owner is still alive.
The Gemara proves from a Beraisa that the Rabanan made such an enactment. The Beraisa says explicitly that an Asham whose owner died must graze until it develops a Mum, and then it is sold and the money used for either a public Olah (a Nedavah) according to the Tana Kama, or for a private Olah according to Rebbi Yehoshua. Why must we wait until the animal has a Mum and then use its value as an Olah, and not simply slaughter the animal itself as an Olah? It must be that the Rabanan enacted that the Asham itself may not be offered as an Olah, lest a person think that he may slaughter an Asham for the sake of an Olah even when the owner is alive.
RASHI (DH b'Damav) explains that the Gemara's question and proof is according to Rebbi Yehoshua, who maintains that an Asham becomes a private Olah when its owner dies. The Gemara says that if the money from the sale of the animal is going to be used to buy a Korban Olah, why is the animal itself not offered as an Olah before it gets a Mum and has to be sold? It must be that the Rabanan enacted that an Asham not be offered as an Olah.
Why does Rashi explain the Gemara's proof only according to Rebbi Yehoshua? The same question and answer applies to the opinion of the Tana Kama as well. The Tana Kama should permit the animal itself to be offered as a public Olah without having to sell it. (Indeed, this is the way RABEINU CHANANEL explains the Gemara.)
ANSWER: The TOSFOS RID answers that Rashi maintains that an animal designated as a private Korban, such as an Asham, may never be offered as a public Korban. Only an animal that was designated as a public Korban may be used as a public Korban. An animal that was designated as a private Korban may be offered as a public Korban only by letting it graze and develop a Mum. The animal then may be sold and the money used to purchase a different animal that can be designated as a public Korban. Therefore, the Gemara does not question why the Tana Kama requires that the Asham (a private Korban) be sold and the money used to buy a new animal to be offered as a public Korban. (The RASHASH also suggests this justification for Rashi's explanation.)
2) A MISTAKEN "AKIRAH"
QUESTION: The Gemara explains that according to Rav, who says (73a) that a Korban Asham does not need Akirah in order to be changed to a Korban Olah, a Korban Pesach similarly should not need Akirah in order to become a Shelamim. If a Korban Pesach becomes disqualified, it should automatically become a Shelamim.
Rav Chisda challenges this opinion from a Beraisa that explains the Mishnah (71b). The Beraisa says that if one slaughtered a Korban Pesach on Shabbos and then found out that its owners had withdrawn their ownership from it, he is not liable to bring a Chatas even though the Korban that he slaughtered is disqualified, because he had no way to know that the owners withdrew. If the same case occurred on a weekday, the Korban must be burned right away, like any Korban that has a Pesul ha'Guf, an intrinsic invalidating element, for it was slaughtered "she'Lo li'Menuyav," for people who are not appointed to eat from it.
It is evident from the Beraisa that the Korban Pesach needs an Akirah, and since it did not have an Akirah, it is considered a disqualified Korban Pesach and is burned immediately. If the Korban Pesach would not need an Akirah, then it would not be a disqualified Korban Pesach, but rather a Shelamim that was slaughtered after the Korban Tamid was offered (which is not a Pesul ha'Guf). It would need Ibur Tzurah (to be left until it became Pasul with Linah) before it could be burned, because it has no intrinsic Pesul yet.
Rav Papa answers that this Korban is actually a Shelamim already, because a Pesach does not need an Akirah to become a Shelamim. It has a Pesul ha'Guf not because it is a Pesach that was slaughtered "she'Lo li'Menuyav," but because it is a Shelamim that was slaughtered l'Shem Pesach, which is Pasul according to Rebbi Eliezer and Yosef ben Choni. That is why the Beraisa states that it is burned right away.
This answer is problematic. We learned that an unintentional, mistaken Akirah ("Akirah b'Ta'us") is not an Akirah (72a). When a person thinks that the animal he is slaughtering is one type of Korban, but in reality it is another type of Korban, his thoughts are disregarded and the Korban is valid. In the case of the Beraisa, the person who slaughtered the Korban had no idea that the owners had withdrawn themselves from it. When he slaughtered it l'Shem Pesach, he was not thinking that it was a Shelamim being made into a Pesach. He thought that it was a Korban Pesach! If the Akirah was completely unintentional, why should his action be considered an Akirah and the Korban be Pasul? (TZELACH)
(a) The TZELACH points out that it is Rav Chisda's question on Rav that the Gemara is trying to answer. Rav Chisda in Menachos (49a) argues with the Gemara in Pesachim (72a) and asserts that a mistaken Akirah is an Akirah. Thus, the Gemara is answering Rav Chisda's question according to his own opinion. The Gemara answers that the Beraisa refers to a mistaken Akirah, and the Korban is Pasul because the Akirah is valid.
(b) The SEFAS EMES suggests that perhaps there is a difference between a case of two types of Korbanos that became mixed up, and one Korban which itself was once a Pesach and is now a Shelamim. When one slaughtered an animal when he was mistaken about the animal itself and thought that it was another animal, his Akirah is a mistaken Akirah and the Korban is not Pasul. In contrast, if he did not make a mistake about the animal itself and he knew that it was a Korban Pesach, but some Halachic change occurred that made it a Shelamim, even though he did not know about the Halachic change his act is not considered a mistaken Akirah. In such a case, he was not completely misled. Since it once was a Pesach and it was the same animal that he thought it was, his assumption that it was a Pesach was not completely incorrect.