(Beraisa - R. Shimon): I witnessed such a case with a goat...

Question: What do they argue about?

Answer #1: They argue about Ze'iri's law:

(Ze'iri): An animal will not become pregnant (Rashi: mate) less than 30 days after Tinuf.

The case is, the daughters were Metanfos on the last day of their sixth month. Chachamim hold like Ze'iri. Therefore, the earliest they could become pregnant is the last day of their seventh month, so they cannot give birth before the last day of their first year;

R. Shimon argues with Ze'iri. They can become pregnant during the seventh month, and give birth within (i.e. some days before the end of) the first year.

Answer #2: All agree to Ze'iri's law. They argue about whether the months of pregnancy must be complete;

Chachamim hold that they must be complete. (Therefore, they cannot give birth within the year.) R. Shimon holds that the months need not be complete.

Answer #3: All agree (with Ze'iri's law and) that the months of pregnancy must be complete. They argue about whether part of a day counts like an entire day;

Chachamim do not count it like an entire day. Therefore, they cannot give birth within the year;

R. Shimon counts it like an entire day. Therefore they can give birth within the year.

Answer #4: All count part of a day like an entire day. They argue about whether Mechusar Zeman (an animal too young to be offered, i.e. before its eighth day) enters the pen for Ma'aser. (Chachamim say that it does not. It is impossible for the animals to be within the same (normal, 12 month) year for the sake of Ma'aser. They can be within the same (13 month) leap year. R. Shimon says that Mechusar Zeman enters the pen. They can be within the same (normal) year.)

Support (Beraisa - R. Shimon ben Yehudah citing R. Shimon): Mechusar Zeman enters the pen for Ma'aser. This is like the law of Bechor;

Just like Bechor becomes Kadosh (when it is born) before it may be offered (on the eighth day), also Mechusar Zeman can get Kedushas Ma'aser, to be offered in the proper time.

Question: Why doesn't he learn from other Kodshim, which cannot become Kodesh Mechusar Zeman?

Answer #1: He learns from Bechor, for it is like Ma'aser in the following ways:

It cannot be redeemed (even with a Mum), even a Ba'al Mum becomes Kodesh, its Temurah is not offered, if it gets a Mum, it is eaten like Ma'aser (Rashi - without Pidyon; Tosfos - it may not be slaughtered or sold in the meat market, and it may not be sold by weight.)

Question: Perhaps we should learn from Kodshim. Also they resemble Ma'aser in four ways! (Some of these do not apply to all Kodshim. However, all apply to Shelamim, so he could learn from Shelamim.)

They need not be males, they do not become Kadosh automatically, they are not given to Kohanim, and they apply to Peshutim (non-firstborns).

Answer #2: R. Shimon learns from a Gezeirah Shavah "Ha'avarah-Ha'avarah" from Bechor.

Question: What is Tinuf?

Answer #1 (Rava): It is like shepherds of Tzalta (a certain place) say. It comes from a fetus that was detained in the womb and dissolved.

Answer #2 (Shmuel): It is bubbles (globules) of blood.

One must show it to a Chacham (to verify that it is truly Tinuf).

Question: How will a Chacham know whether or not it is Tinuf?

Clarification (Rav Papa): It must be shown to a shepherd Chacham.

Question (Rav Chisda): A human fetus is formed after 40 days (from conception. If it was miscarried after this, there is Tum'as Yoledes);

When is a (small) animal fetus formed (to be considered Tinuf if it is miscarried)?

Answer (Rav Papa): This is Ze'iri's law!

(Ze'iri): Tinuf is never (after) less than 30 days.

Rejection (Abaye): No, Ze'iri means that an animal will not mate less than 30 days after Tinuf.

Question: Our Mishnah teaches about one who buys an animal from a Nochri;

What is the law of one who buys from a Yisrael?

Answer #1 (Rav): The first child born (if it is male) is a definite Bechor;

Had the mother given birth already, the seller surely would have told the buyer, for such an animal is worth more. (The proper text of Rashi - a female is prone to die in its first birth. If it already gave birth, the danger passed; Tosfos - the buyer keeps all offspring.)

Answer #2 (Shmuel): The first child is a Safek Bechor;

Perhaps the mother already gave birth. The seller did not tell the buyer, for he assumed that the buyer intends to slaughter it. (It will not bear offspring.)

Answer #3 (R. Yochanan): The child is definitely Chulin;

Had the mother not given birth already; surely the seller would have told the buyer (so he will know that the first child will be a Bechor).

Support (for R. Yochanan - Beraisa): If the seller didn't say anything, the buyer may slaughter on the day he buys (without concern for Oso v'Es Beno, i.e. lest its mother or child was sold to someone else to be slaughtered that day).

Suggestion: This refutes Rav and Shmuel!

Rejection: No. It is incumbent on the seller to alert the buyer that its mother (or child) will be slaughtered today. (Rashi -- "b'Yom Echad" teaches that there are special days, when most animals bought are for Shechitah, and on those days a seller must tell the buyer if he sold its mother or child; Tosfos - the buyer need not suspect that the mother was sold today);

Regarding Bechor, it is the buyer's responsibility (to determine whether the child is a Bechor).

(Mishnah - R. Eliezer ben Yakov): If a clump of blood came out of a large animal's womb, it must be buried (perhaps a male was inside, and was dissolved). The animal is exempt from Bechorah.

(Gemara - Beraisa - R. Chiya): The clump does not have Tum'as Maga or Masa (to be Metamei one who touches or moves it).