THE OPINION OF R. YISHMAEL
Defense (of Answer #2 - Ravina): He can hold like Chachamim;
Chachamim follow a majority that does not depend on an act occurring (such as judges' opinions or stores), they do not follow a majority that depends on an action (an animal must breed to become pregnant and bear a child).
(Beraisa - R. Yishmael): If a goat gave birth in its first year, the kid is Vadai (a definite Bechor). It is given to a Kohen. If it gave birth after this, it is a Safek;
If a sheep gave birth within two years, the lamb is Vadai, it is given to a Kohen; if it gave birth after this, it is a Safek;
If a cow gave birth within three years, the calf is Vadai, it is given to a Kohen; if it gave birth after this, it is a Safek;
A donkey is like a cow;
R. Yosi says the cutoff age for a donkey (for a Vadai Bechor) is four years.
R. Yehoshua: R. Yishmael erred!
If the Halachah were that only a proper child exempts from Bechorah, he would be right;
However, Chachamim taught that the following are Simanim of a child - Tinuf in a small animal, a Shilya in a large animal, and a Shapir or Shilya in a woman.
I disagree with them (this will be explained). Rather, if a six month goat had Tinuf, it can give birth in its first year. If a yearling sheep had Tinuf, it can give birth in its second year.
R. Akiva says I argue with this. Rather, if we know that an animal previously gave birth, the Kohen does not receive anything;
If we know that it did not give birth before, the Bechor belongs to the Kohen;
If we do not know whether it gave birth before, the owner eats it when it gets a Mum.
Question: What do R. Yishmael and (Chachamim according to) R. Yehoshua argue about?
Suggestion: They argue about whether Tinuf exempts from Bechorah. R. Yehoshua says that it does, and R. Yishmael says that it does not.
Answer #1: No, all agree that Tinuf exempts from Bechorah;
Rather, they argue about whether we are concerned for Tinuf if we did not see it. R. Yehoshua is concerned, R. Yishmael is not.
Question: Surely, R. Yishmael is concerned. Rava concluded that R. Yishmael holds like R. Meir, who is concerned for the minority!
Answer #1: He is concerned for the minority only to be stringent. (If one buys a goat from a Nochri after one year, he is concerned lest it is from the minority that do not gave birth within a year. Its first child is a Safek Bechor. One may not shear it, work with it, or eat it before it gets a Mum);
He is not concerned for the minority to be lenient. (If a Yisrael bought a goat from a Nochri and it gave birth to a kid in the first year, it is a Vadai Bechor. He gives it to a Kohen. We do not consider it a Safek (perhaps Tinuf preceded it) to let the Yisrael keep it).
Answer #2: He is concerned for the minority, whether it is a stringency or a leniency. The Beraisa discusses a goat that was Metanef and later gave birth in the first year:
R. Yishmael says that if it was true Tinuf, it could not give birth in the first year. (Therefore, surely it was not proper Tinuf);
R. Yehoshua says that it can Metanef and give birth within the first year.
(Beraisa - R. Yehoshua): I disagree with them. Rather, if a six month goat had Tinuf, it can gave birth in its first year. If a yearling sheep had Tinuf, it can gave birth in its second year.
Question: What is the difference between R. Yehoshua's own opinion and what he said in the name of Chachamim (that Tinuf is a sign of a child)?
Answer #1: The case is, a goat was Metanef after six (full) months. They argue about Ze'iri's law:
(Ze'iri): An animal will not become pregnant (Rashi - mate) less than 30 days after Tinuf (or a proper birth).
Chachamim hold like Ze'iri. (Therefore, such a goat will not become pregnant within seven months, so it cannot give birth within the year, for the gestation of goats is five months.) R. Yehoshua argues with Ze'iri. (It can become pregnant within seven months, and give birth within the year.)
Answer #2: All agree to Ze'iri's law. They argue about whether the (five) months of pregnancy must be complete;
Chachamim hold that the months must be complete (therefore, since it cannot become pregnant within seven months, it cannot give birth within the year), R. Yehoshua 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;
R. Yehoshua counts it like an entire day. Therefore, if it was Metanef on the first day of the seventh month, it could become pregnant 29 days later, and give birth within the year;
Chachamim do not count it like an entire day. (It cannot become pregnant until 30 days later, i.e. the eighth month, so it cannot give birth within the year.)
ARE WE CONCERNED FOR THE MINORITY?
(Beraisa - R. Akiva): I disagree. Rather, if we know...
Question: What is the difference between R. Yehoshua and R. Akiva?
Answer (R. Chanina of Sura): They argue about whether milk exempts from Bechorah;
R. Akiva alludes to another way of knowing that an animal is exempt from Bechorah, i.e. if it has milk. Most animals do not have milk before giving birth;
R. Yehoshua is concerned for the minority of animals that have milk before giving birth.
Question: (Elsewhere,) R. Yehoshua is not concerned for the minority!
(Mishnah): (Reuven and his wife Leah went overseas.) If Reuven died (without any known children or brothers), Leah need not be concerned (lest his mother gave birth to a boy before Reuven died, which would obligate Leah to wait to do Yibum or Chalitzah. Rather, she may remarry.)
If his mother was pregnant when they left, Leah must be concerned.
R. Yehoshua says, she need not be concerned.
Question: What is his reason?
Answer: Half of all babies born are females. A minority of pregnant women miscarry;
When we combine the half that are females with the minority of miscarriages, we find that a minority of pregnant women give birth to males. R. Yehoshua is not concerned for the minority. (Sometimes twins of both genders are born, so more than half of all live births include at least one male. We must say that miscarriages are more common than mixed twins. This is even if she is already in the ninth month, for R. Yehoshua permits in all cases. Perhaps we consider only the entire category of pregnant women (the majority do not give birth to males), and do not distinguish stages of pregnancy. If R. Yehoshua accepted the opinion of R. Akiva (Yevamos 79b), that Yibum and Chalitzah do not apply to a Seris Chamah (a male who will not develop like a normal male), it suffices to say that miscarriages and Serisim together are more common than mixed twins.)
Answer: The opinions in our Beraisa must be switched.
Support (Beraisa - R. Yehoshua): Having milk exempts from Bechorah;
R. Akiva says, it does not exempt.
BIRTHS WITHIN ONE YEAR
(Beraisa): If a goat gave birth to three females, and each of those gave birth to three females, all of them (except for the grandmother - Rashi's preferred explanation) enter the pen together for Ma'aser (i.e. if all were born in the same year. The Tana teaches that this is possible);
R. Shimon says, I witnessed such a case (with a goat). Ma'aser was taken within the year.
Question: Why does the (first) Tana say that all three daughters gave birth to three females? Even if only one of them gave birth to three, and the other two give birth to two each, this would comprise 10 (for Ma'aser)!
Answer: Since he must say that one of the daughters gave birth to three, (for brevity or parallel structure) he says that all of them gave birth to three.
Question: Why must he say that even one daughter gave birth to three? Each could give birth to two, and their mother could have another child at that same time!
Suggestion: The Tana holds that an animal that was Metanef (or gave birth) cannot give birth again within the year.
Answer: No. Even if an animal can give birth in the same year after Tinuf, it cannot give birth twice in one year.