Question (Mishnah - R. Shimon ben Gamliel): Even until 10 generations are exempt. (We are thinking that he refers to the Reisha, without designation.)

This is not difficult for Rav Yehudah. Because the first Tana exempts Vladei Vlados, even though they were not born to the mothers, R. Shimon had to specify 10 generations. (Had he said only "Vladei Vladei Vlados," we would have thought that these are exempt, but the next generation is liable);

However, according to Rav Huna, the first Tana forbids only Vlados. R. Shimon could have said just "Vladei Vlados," and we would understand that just like these are exempt because the Nochri might sieze them (even though they were not born to his animals), and the same applies to all generations!

Answer: R. Shimon refers to the Seifa, in which there was designation. (The first Tana exempts Vladei Vlados. Rav Huna explains like Rav Yehudah did above.)

Version #1 - Question (against Rav Yehudah - Reisha of Mishnah): If Shimon received Tzon Barzel from a Nochri, Hen Vlados (the very offspring of the mothers) are exempt from Bechorah, and Vladei Vladoseihen are liable. (This is like Rashi's text, according to Bach. Rosh (cited in Shitah Mekubetzes 2) says that it is a Beraisa. We did not ask from the Reisha of our Mishnah (which lacks the word "Hen") because it exempts "Vlados" without specifying how many generations are exempt.)

Answer: It means, Hen u'Vlados (are exempt. It is no Chidush to exempt the mothers. Surely "Hen" refers to the Vlados, and "u'Vlados" refers to Vladei Vlados.)

Version #2 - Question (against Rav Huna - Reisha (or Beraisa)): If Shimon received Tzon Barzel from a Nochri, Hen u'Vladoseihen are exempt, and Vladei Vladoseihen are liable. ("Hen" refers to the Vlados. "U'Vlados" refers to Vladei Vlados.)

Answer: It means that Hen Vlados (the very offspring) are exempt, and Vladei Vlados are liable.

(Mishnah): If a sheep gave birth to a goat... (Whenever we say that an animal was born to a certain species, we refer to the mother's species, unless we specify the father.)

(R. Oshaya of Neharda'a - Beraisa - R. Meir): A (female) sheep born to a goat, or a goat born to a sheep is liable. (This will be explained);

Chachamim exempt.

Question (R. Hoshaya): What does R. Meir obligate?

Suggestion: He obligates Kedushas Bechor.

Rejection: Surely, R. Meir agrees with the following!

"Ach Bechor Shor" teaches that a calf has Kedushas Bechor only if it and its mother are cattle (and similarly for sheep and goats).

Suggestion: He obligates Reishis ha'Gez.

Rejection: Surely, R. Meir agrees with the following!

(Beraisa - Tana d'Vei R. Yishmael): Reishis ha'Gez does not apply to sheep whose wool is too hard to make garments (that give warmth) - "umi'Gez Kevasai Yischamam." (All the more so it does not apply to goats!)

Answer #1 (Rav Huna): The case is, a sheep gave birth to a goat. The father was a goat. They argue about whether we are concerned for the seed of the father, regarding Oso v'Es Beno;

R. Meir is concerned, and Chachamim are not.

Rejection: If so, they should argue in general about this (not only in this case), like Chananyah and Chachamim!

Answer #2: Really, they argue about Bechorah;

Answer #2A: The case is, a lamb was born to a sheep born to a goat. R. Meir holds that since it resembles its mother, it is not a Nidmeh, Bechorah applies to it;

Chachamim hold that since the grandchild is unlike the mother's mother, it is considered Nidmeh. It is exempt from Bechorah.

Answer #2B: The case is, a sheep was born to a goat born to a sheep. R. Meir holds that since it resembles its grandmother, it returns to its original status. It is not considered Nidmeh, and Bechorah applies to it;

Chachamim hold that it does not return to its original status. It is Nidmeh, so it is exempt.

Answer #2C (Rav Ashi): The case is, it resembles its mother in some ways; Chachamim hold like R. Shimon, who exempts from Bechorah unless its head and majority resemble its mother.

(R. Yochanan): R. Meir agrees that Se'ir Rosh Chodesh (the Chatas of Musaf) must be born to a goat.

Question: What is the reason?

Answer: It says "Echad" - it must be unique, i.e. pure lineage (all goats) from the six days of creation. (Note: The Gemara did not give signs to recognize this, nor does it mention a tradition for goats of pure lineage (e.g. that Avraham received from Shem...) It seems that we may assume that a goat's lineage is pure, unless we have reason to suspect otherwise.)

Question: We learn this from a different verse!

(Beraisa): "Shor Oh Kesev" excludes Kil'ayim; "Oh Ez" excludes Nidmeh.

Answer: We need both verses:

Had it said only "Oh Ez," we would disqualify only a Nidmeh that does not resemble its mother, we would not require pure lineage from creation;

Had it said only "Echad," we would have thought that Nidmeh is Pasul only for obligatory Korbanos, but not for Nedavos.

(Rav Acha bar Yakov): All agree that one is not lashed for wearing Kil'ayim if the wool was from a sheep born to a goat:

It says "Lo Silbash Sha'atnez (Tzemer u'Pishtim)" - just like flax is unchanged, the wool must be unchanged.

(Rav Papa): All agree that such wool (from a sheep born to a goat) is Pasul for Techeles. (Rambam - it is Pasul for Tzitzis, for a garment made of a different material);

It says "Lo Silbash Sha'atnez (Tzemer u'Pishtim)... Gedilim Ta'aseh Lecha" - just like flax is unchanged, also the wool.

(Rav Nachman bar Yitzchak): All agree that Tzara'as does not apply to a garment of such wool:

It says "b'Veged Tzemer Oh b'Veged Pishtim" - just like flax is unchanged, also the wool.

(Rav Ashi): If one draped a vine over a fig tree, wine from its grapes is Pasul for Nesachim:

It says "Zevach u'Nesachim" - just like the Zevach must be unchanged, also the Nesachim.

Question (Ravina): If so, you should also say that if one draped flax over a bush, the flax is considered to be changed;

This opposes the three previous teachings. They all assume that flax never changes!

Answer (Rav Ashi): Draping a vine over a fig tree changes the smell of the wine (R. Gershom - and this disqualifies Nesachim). Draping flax over a bush does not change its smell. (R. Gershom - there is no significance to the changed smell.)

(Mishnah - R. Yosi ha'Gelili): If Reuven's sheep (a Mevakeres) gave birth to twins, and their heads left the womb at the same time, both are (Kadosh and are) given to Kohanim - "ha'Zecharim la'Shem."

Chachamim say, Iy Efshar Letzamtzem (two things cannot occur simultaneously; Tosfos - we will never know that they are exactly the same);

Therefore, he keeps one of them. He gives the other to a Kohen.

R. Tarfon says, the Kohen takes the nicer one;

R. Akiva says, Meshamnim Beineihem (this will be explained).

Reuven's animal grazes until it gets a Mum (and he eats it). (Rashash - R. Tarfon says that the nicer one is a definite Bechor, and the inferior is definitely Chulin, so this clause is unlike R. Tarfon. Others say that both are Safek Bechoros, and R. Tarfon agrees with this clause.)

Matanos (Zero'a, Lechayayim and Kevah) must be given (to a Kohen);

R. Yosi exempts.

R. Tarfon says, if one of the twins dies, they share the other one (R. Tarfon retracted from what he said above);

R. Akiva says, ha'Motzi mi'Chavero Alav ha'Re'ayah. (To take money from a Muchzak, one must bring proof. The Kohen must prove that the live animal is the Bechor in order to receive.)

If a male and female were born at the same time, the Kohen does not receive anything.

(Gemara - d'Vei R. Yanai): R. Yosi ha'Gelili holds (in our Mishnah) that Efshar Letzamtzem b'Yedei Shamayim (events can naturally occur simultaneously, distances can be exactly equal, even though Hash-m has no need for this), and all the more so b'Yedei Adam. (People sometimes want and intend to make two things be equal.)

Question: Chachamim say (in our Mishnah) Iy Efshar Letzamtzem b'Yedei Shamayim. What is their opinion about b'Yedei Adam?

Answer #1 (Mishnah): The Chut ha'Sikra (a red strip) girds the Mizbe'ach in the middle, to distinguish between (the place for) upper and lower blood.

If Iy Efshar Letzamtzem, perhaps the Chut is slightly above (or below) the middle, and blood thrown just below (or above) is really on the top (or bottom) half of the Mizbe'ach, the Zerikah is Pasul!

Rejection: Perhaps the Chut was so thick that the middle was surely contained within it.

Answer #2: The Torah gave precise measures for the Mizbe'ach and Kelim (Aron, Menorah and Shulchan). This shows that people can be exact!

Rejection: The Torah commanded to make the Kelim. It accepts whatever people are able to make. (Rashi; Shitah Mekubetzes - normally, one cannot be exact. Ru'ach ha'Kodesh helped people to make the Kelim exactly right - "ha'Kol bi'Chsav mi'Yad Hash-m Alai Hiskil.")

Answer #3 (Rav Katina - Mishnah): (If an oven broke and one of the fragments comprises the majority, it is Tamei.) If an oven was cut into two equal parts, they are Tamei, for it is impossible to make them exactly equal (we cannot discern which is the majority, so we are stringent).

Rejection (Rav Kahana): Earthenware Kelim are different. They do not cleave evenly when cut, rather, there are craters, so one cannot cut them precisely in half.