Bekhorot 21a (כא.) — the Talmud in English

Shall we say that the first tanna holds

the first tanna

that an animal that discharges does not return and give birth within its year?

That is, even if it discharged in this year, it does not again return and give birth until a year has elapsed from the discharge; all the more so in the case of one that gave birth in this year, which does not return and give birth until a year has elapsed from the previous birth. Therefore, it is impossible to combine daughter after daughter for the animal tithe, because they were not born in the same year.

And we reject this:

even if you should say that an animal that discharges returns and gives birth within its year,

but

one that gives birth

to a fully formed offspring,

certainly does not return and give birth within its year,

and it is impossible for an animal to give birth to one daughter after another within a year.

The Gemara proceeds to explain the continuation of the beraita:

Rabbi Shimon said: I saw a kid goat

that was tithed within its year:

The Gemara asks:

What difference is there between the first tanna and Rabbi Shimon?

The Gemara explains that they disagree in a case where the daughters discharged on the final day of the sixth month after their birth. Their dispute is as follows: According to the first tanna, the daughters and granddaughters can be found to become subject to the animal tithe only if the daughters give birth on the day that their year from birth is completed. Rabbi Shimon, by contrast, holds that there are instances in which the daughters and granddaughters become subject to the tithe even “within its year,” meaning even within—and not only at the end of—the same year in which the mother gave birth to the first three daughters. The Gemara explains the basis of their dispute in several ways:

The first explanation:

The difference between them,

between the first tanna and Rabbi Shimon, is

the opinion of Ze’iri.

For Ze’iri said: There is no discharge that lasts less than thirty days,

meaning that the animal does not accept a male until thirty days have passed from the time it discharged:

The first tanna agrees with Ze’iri,

and one must count from the day on which they discharged, which was the day the sixth month after their birth ended, another full thirty days. Only on the following day, at the end of the seventh month from their birth, do they accept a male; one must then count another five full months of gestation, and they give birth on the following day—that is, on the day their year from birth is completed.

But

if

Rabbi Shimon does not agree with Ze’iri,

they need not wait thirty days from their discharge before accepting a male. Consequently, even if they discharged on the day six months from their birth were completed, they could give birth during the final month of their year, and not specifically on the day their year from birth was completed.

The second explanation:

And if you prefer,

to explain the basis of their dispute:

everyone agrees with Ze’iri,

that the animal does not accept a male until thirty days after its discharge,

and here they disagree with regard to an animal that gives birth after an incomplete period:

The first tanna holds: An animal does not give birth after an incomplete period,

and it does not give birth until the day after the completion of five months of gestation.

And Rabbi Shimon holds: An animal does give birth after an incomplete period,

and it can give birth during the fifth month of its gestation, and not specifically on the day its year from birth is completed.

The third explanation:

And if you prefer, everyone agrees that an animal does not give birth after an incomplete period; here they disagree with regard to the principle that part of a day is equivalent to the entire day:

whether part of the final day of the thirty days counted from the discharge, and part of the final day of the five months of gestation, are considered like a full day,

they disagree: According to the first tanna, we do not say “

part of a day is equivalent to the entire day,”

and the animal requires thirty full days from its discharge, and only on the following day does it accept a male. Likewise, it requires five full months, and gives birth on the following day. Consequently, it will not give birth until the final day of the year of its birth.

According to Rabbi Shimon, we do say “

part of a day is equivalent to the entire day,”

and consequently it gives birth one or two days before the end of the year of their birth.

The fourth explanation:

And if you prefer, everyone agrees that we say that part of a day is equivalent to the entire day.

And here they disagree with regard to an animal whose time has not yet arrived,

before the eighth day after its birth, when it is not fit to be offered, as it is written: “From the eighth day onward it will be acceptable as an offering made by fire to the Lord”: whether it

enters the pen to be tithed, they disagree:

The first tanna holds:

an animal whose time has not yet arrived

does not enter the pen to be tithed.

And Rabbi Shimon holds:

an animal whose time has not yet arrived

enters the pen to be tithed.

Therefore Rabbi Shimon said that they become subject to the tithe within their year, meaning that it is possible to tithe them within the year in which they were born, on the very day of their birth, if they were born before the end of the day. According to the first tanna, however, they are tithed for the following year.