The Mysterious Cow
The korban Pesach (paschal offering) can be offered only with a male lamb or kid goat. It is therefore surprising to find the Torah declaring (Devarim 16:2) "You shall slaughter a korban Pesach for Hashem, your G-d, from sheep and cows."
Different approaches are offered by our Sages in explaining this apparent paradox. In his commentary on Chumash, Rashi mentions one of them. Since one is supposed to eat the flesh of the korban Pesach when he has approached satiety through eating sacrificial flesh, this is impossible to achieve when there are many subscribers to one animal and each will receive only a small portion. It is then a mitzvah for that company to offer that same day another sacrifice called "the chagiga of the 14th (Nissan)" and to eat its flesh before eating the korban Pesach. This sacrifice can be brought from the cow family, and it is to this which the passage refers. The shankbone and egg that we place on our Seder plate on Pesach are reminders of these two sacrifices.
In our gemara, however, we encounter a different approach suggested by Rabbi Nachman. If someone designated an animal to serve as a korban Pesach and it wandered away, another animal is offered in its place. Should the lost animal subsequently turn up it is considered as motar hapesach a Pesach leftover and is offered as a shelamim sacrifice. This is derived from the above-mentioned passage in the following manner: The sheep and cows mentioned hint at the Pesach leftover whose status now is that of the only korban category which is not limited to any particular animal or to a specific gender the category known as korban shelamim.
The Special Sacrifice
"They slaughtered the Pesach Sacrifice and the kohanim took the blood from their hands to sprinkle (on the altar) and the Levites flayed (the carcasses)" (Divrei Hayamim II 35:11)
This is the description of the service performed in regard to the Pesach Sacrifice offered one year during the reign of the righteous King Yoshiyahu. It is difficult, however, to discern from this passage exactly who was doing what. There are four stages in the offering of a sacrifice: slaughtering; receiving the blood in a sacred vessel; carrying it to the altar; and sprinkling the blood on the altar. The receiving of the blood and the sprinkling can be performed only by a kohen, while the slaughtering can be done by any Jew. Whether a kohen is required for carrying the blood after it has been received in a vessel depends on how we interpret the above passage.
Rabbi Chisda assumed that the same non-kohen who did the slaughtering was the one from whose hands was taken the blood for the sprinkling. The conclusion he therefore reaches is that a non-kohen is qualified for carrying the blood. This interpretation is refuted by Rabbi Sheishet who rules that a non-kohen is not qualified for carrying the blood and that all he did in this case was hold onto the blood until a kohen took it from him to carry and sprinkle.
There was something very special about this particular Pesach Sacrifice. In another passage (ibid. 35:18) we are told that there was no Pesach Sacrifice such as this even in the days of the Prophet Shmuel and all the kings of Israel. There are several explanations of what made it so special.
Rashi explains that this was the one time that the animals needed by all the Jews for their sacrifices were supplied by the king from his own funds. Radak writes that it was the first time since before the days of Shmuel that the entire nation wholeheartedly offered the Pesach Sacrifice. Metzudat Davids approach is that this sacrifice was offered by the kohanim and Levites with extraordinary care and purity. This is consistent with his commentary that slaughtering and holding were not done by an ordinary non- kohen but by a Levite who had a higher level of holiness.