1) THE UNKNOWN "DERASHOS" OF REBBI YITZCHAK AND REBBI OSHIYA
QUESTION: The Gemara explains that the source for Rebbi Akiva's view that a Kohen may give meat of a blemished Bechor even to a Nochri is the verse, "ka'Tzvi v'cha'Ayal" -- "[In your gates you shall eat it...] like the deer and the gazelle" (Devarim 15:22). The Tana Kama, who maintains that a Kohen may not give meat of a blemished Bechor to a Nochri, argues that the three occasions of the words "ka'Tzvi v'cha'Ayal" are used already for three different Derashos, and thus we cannot learn from it that the meat of a Bechor may be given to a Nochri. The three Derashos are the teachings of Rebbi Yitzchak, Rebbi Oshiya, and Rebbi Elazar ha'Kafar.
The Derashah of Rebbi Elazar ha'Kafar refers to his statement in Chulin (28a) that the Tzvi and Ayal require Shechitah just like Pesulei ha'Mukdashin (to which the verse compares them), while birds do not require Shechitah.
What, though, are the teachings of Rebbi Yitzchak and Rebbi Oshiya? RASHI (DH v'Idach) says that he does not know where these Derashos are recorded.
ANSWER: TOSFOS suggests that these Derashos are the teachings of these Tana'im recorded in Makos (22a). The Gemara there quotes Rebbi Hoshiya (who may be the same as Rebbi Oshiya; see SEDER HA'DOROS, Tana'im v'Amora'im "Alef") who rules that one who breeds an animal of Pesulei ha'Mukdashin is punished with Malkus. The RIVAN there explains that the Torah prohibits breeding two animals of different species together, and a single animal of Pesulei ha'Mukdashin is considered two species in one, since it is part Kodshim and part Chulin. The Gemara there continues and quotes Rebbi Yitzchak, who rules that one who uses an ox of Pesulei ha'Mukdashin to pull his plow is punished with Malkus for transgressing the Isur of plowing with two different types of animals together: "Lo Sacharosh b'Shor uva'Chamor Yachdav" (Devarim 22:10). The Rivan explains that Rebbi Yitzchak also understands that the Torah views the ox as two animals, since it is part Kodshim and part Chulin. The Rivan (DH ha'Marbi'a) adds, however, that even if an animal of Pesulei ha'Mukdashin is considered a combination of Kodshim and Chulin, he knows of no source in the Torah that forbids breeding or binding an animal that is Kadosh with an animal that is Chulin.
TOSFOS here (DH Chad) and in Makos (22a, DH ha'Manhig) explains that the source for the teachings of Rebbi Yitzchak and Rebbi Hoshiya in Makos is the words "ka'Tzvi v'cha'Ayal." From the fact that the Torah compares Pesulei ha'Mukdashin to two distinct species of animals (Tzvi, Ayal), we derive that the prohibition against breeding two dissimilar animals together and the prohibition against working two dissimilar animals together apply to a single animal that is Pesulei ha'Mukdashin. Accordingly, these are the teachings to which the Gemara here refers.
The reasoning behind this prohibition may be understood better based on the premise of the SEFER HA'CHINUCH (Mitzvah #444), who writes that the prohibition against breeding Kil'ayim is intended to prevent people from changing the way the world develops naturally. Perhaps animals of Pesulei ha'Mukdashin are to be viewed as "unnatural phenomena," because, according to the way the world was created, animals were meant to be either Chulin or Kodshim. Animals of Pesulei ha'Mukdashin are entirely unusable. In order to prevent people from breeding Pesulei ha'Mukdashin and creating more animals that have no use in the world, the Torah equates Pesulei ha'Mukdashin with other unnatural combinations and prohibits their breeding.
Similarly, the RAMBAN (Devarim 22:10) explains that the prohibition against plowing with two species of animal is intended to prevent people from breeding the animals together. Accordingly, plowing with an animal of Pesulei ha'Mukdashin is prohibited for the same reason. (M. KORNFELD)
2) "EIN MARGILIN B'BECHOR"
QUESTION: The Beraisa teaches that one is forbidden to skin a blemished Bechor in the manner in which one skins an animal in order to make a leather sack -- by cutting the hide near the feet and then peeling back the hide towards the head (which is done in order to remove the entire hide as one piece), instead of peeling back the hide from the head to the feet through its legs. Skinning a sanctified animal in this manner is forbidden, and a blemished Bechor retains some of its Kedushah and still is considered to be sanctified.
Rav Chisda explains that the Beraisa follows the views of Beis Shamai, who maintains that a blemished Bechor retains its Kedushah and therefore may not be eaten by a Nidah (RASHI DH Beis Shamai). Beis Hillel, however, who permits a Nidah to eat a blemished Bechor, permits skinning it in this manner.
Why does Rav Chisda say that Beis Hillel argues and permits skinning in this manner? Even according to Beis Hillel, the blemished Bechor retains some of its Kedushah, as is evident from the fact that Beis Hillel agrees that one is forbidden to sell its meat in a public marketplace, as the Mishnah says.
ANSWER: The SEFAS EMES answers that the Gemara understands that the disgrace (Bizayon) of skinning a Bechor in this manner is not as severe as the disgrace of selling a sanctified animal in a public butchery. Skinning in this manner is prohibited only if the animal has the full Kedushah of a Korban.
(This answer suffices, however, only if the prohibition against skinning is due to the Bizayon involved. RASHI in Temurah (24a) explains that skinning is prohibited because it involves "Uvdin d'Chulin," an act normally done only to a non-sanctified animal, which is the same reason for the prohibition against selling a Bechor in a butchery. Since everyone agrees that a blemished Bechor may not be sold in such a manner, everyone also should agree that a blemished Bechor may not be skinned from its legs. Why, then, does Rav Chisda say that this law applies only according to the view of Beis Shamai?)
3) A BLEMISH THAT CAN BE HEALED
QUESTION: Rebbi Yehudah in the Mishnah maintains that one may not perform a procedure of bloodletting for an ill Bechor even if it will die if its blood is not let. RASHI (DH Ein) writes that bloodletting is prohibited even on a part of the animal where the bloodletting would create no permanent Mum, since the wound would heal. Rashi cites the Gemara in Pesachim (11a) that explains Rebbi Yehudah's reasoning: since a person is anxious not to lose his animal, if he would be permitted to let blood from a place where the wound does not create a Mum, he might come to let blood even from a place where the wound does create a Mum.
Rashi's words imply that one would have been permitted to make a Mum in a place where the Mum would heal if not for the Gezeirah that one might come to let blood on a part of the animal where the wound creates a permanent Mum. This is difficult to understand, however. Why would it have been permitted, l'Chatchilah, to make a temporary blemish (Mum Over) on a Bechor? As long as the Mum Over is present, mid'Oraisa the animal may not be offered as a Korban on the Mizbe'ach (as the RAMBAM in Hilchos Isurei ha'Mizbe'ach 1:5 states). Accordingly, making a temporary blemish should be included in the Isur d'Oraisa of "Kol Mum Lo Yiheyeh Bo" -- "no blemish shall be in it" (Vayikra 22:21).
Why, then, should one be permitted, according to Rashi, to let blood from a part of the animal where the wound can heal (if not for the Gezeirah that one may come to make a Mum Kavu'a)? (See RASHASH and TESHUVOS ACHIEZER 2:35:1.)
ANSWER: The ACHIEZER answers that Rashi agrees that one is not permitted to inflict even a temporary blemish on a Bechor. However, when blood is let from the animal, the wound that is created is not considered to be even a temporary blemish. Rather, it is merely a type of illness that, if not healed, will cause the skin and meat to deteriorate and then will develop into a Mum in an exposed area. Therefore, Rashi explains that the wound of bloodletting will heal and will never become a Mum at all, and it would have been permitted if not for the Gezeirah.
The Achiezer adds that this answer clarifies another statement of Rashi. Rashi in Zevachim (74b, DH Nekuvas) writes that when a thorn pierced the body of an animal but did not reach the internal cavity ("Chalal"), the animal remains Kosher. Rashi adds that this also is not considered a Mum with regard to Kodshim, because the wound will heal. Why, though, is it not considered at least a Mum Over, a temporary blemish, which disqualifies the animal of Kodshim from being offered as long as the Mum is present?
The Achiezer explains that although the puncture in the skin is a Mum, it has the status of a disqualifying Mum only when the hole is noticeable. A small hole in the flesh and skin which can heal is not even considered to be a Mum Over. Only if the wound would become larger and spread would it be considered a Mum at all.
The CHAZON ISH (Bechoros 25:9, DH u'Tenan) points out that Rava (41a) states that the Mum of "Charutz" ("gashed" (Vayikra 22:22); this includes a perforated or split eyelid, nose, or lip, or a gash at any place where there is a bone) does not apply to the flesh of the animal. Why, then, does Rashi in Zevachim say that a thorn in the flesh is not a Mum because it will heal, implying that if it will not heal then it is a Mum? The Chazon Ish explains that the Rabanan knew that there are certain blemishes even in the flesh that will become full-fledged blemishes if they do not heal. Whether or not a temporary wound will heal can sometimes determine whether or not it is considered an actual Mum. (D. BLOOM)
4) THE BLEMISH OF AN ILL "BECHOR"
QUESTION: The Chachamim in the Mishnah maintain that one may perform a procedure of bloodletting for an ill Bechor in order to save its life, even though he thereby will make a blemish in the Bechor. RASHI (DH ha'Kol) explains that the animal is already considered a Ba'al Mum (blemished) because of its illness, and therefore there is no prohibition against making another Mum.
However, if the animal is already considered a Ba'al Mum due to its illness, then why can it not be slaughtered now? Why is another blemish required in order to permit the Bechor to be slaughtered?
(a) TOSFOS (34a, DH Ileima) suggests two answers. Tosfos writes that mid'Oraisa the sick Bechor may be slaughtered, but the Rabanan required another Mum in order that it not be confused with a Tam (an unblemished Bechor).
(b) In his second answer, Tosfos writes that since bloodletting will save the sick animal's life, its sickness is considered only a "Mum Over," a temporary blemish. A Mum Over does not permit a Bechor to be slaughtered.
The ROSH adds that even though the illness is only a Mum Over, the Chachamim still permit making another Mum in the animal through bloodletting. Since the animal cannot be offered upon the Mizbe'ach as long as it has a Mum Over, the verse, "Tamim Yiheyeh l'Ratzon" (Vayikra 22:21), which teaches the prohibition against causing a blemish in a sanctified animal, does not apply. The Rosh concludes that when an animal is not sick but has some other temporary blemish, one is prohibited mid'Rabanan to make a Mum Kavu'a (a permanent blemish) in the animal.