You speak of communal offerings? Communal offerings are different, in accordance with what Rabbi Tavi said in the name of Rabbi Yoshiya. As Rabbi Tavi said that Rabbi Yoshiya said that the verse states: “This is the burnt-offering for every New Moon upon its renewal throughout the months of the year” (Numbers 28:14). The Torah said: Renew and bring Me an offering from the new contribution. This indicates that communal offerings must be brought from the donations of the current year and not from the donations of the previous year.

The Gemara challenges this solution: This works out well with regard to the Yom Kippur goat, which is a communal offering and is purchased with money from the Temple treasury. However, with regard to the High Priest’s bull which he pays for himself and which is considered an individual offering, what is there to say? The Gemara answers: There is a rabbinic decree with regard to the bull due to the goat.

The Gemara expresses surprise: Is it right that due to a rabbinic decree the offerings should be left to die instead of being left to graze? And furthermore, this statement that Rabbi Tavi said in the name of Rabbi Yoshiya is itself a mitzva ab initio, but is not indispensable. As Rav Yehuda said that Shmuel said: With regard to communal offerings that are brought on the first of Nisan, it is a mitzva to bring them from the new year’s shekel contributions. However, if he brought them from the old shekels that were donated during the previous year he has fulfilled his obligation, but he lacked the mitzva, i.e., he did not perform the procedure in the proper manner. It is difficult to argue that due to this inessential detail the Sages would issue a decree that the High Priest’s bull should be left to die.

Rather, Rabbi Zeira said that the reason the bull and goat of Yom Kippur are left to die is because the lottery does not establish designations from one year to another. Therefore, a goat designated by the lottery one year is not eligible for use the next year. The Gemara challenges this explanation: But let us bring this goat and another one and draw lots again. The Gemara responds: It is a rabbinic decree that was enacted lest people say that the lottery establishes designations from one year to another.

The Gemara challenges: This works out well with regard to the goat, but with respect to the bull of the High Priest, which is not chosen by lottery, what is there to say? The Gemara answers: There is a rabbinic decree with regard to the bull due to the goat. The Gemara challenges further: Is it right that due to a rabbinic decree the offerings should be left to die instead of being left to graze? Therefore, this answer should be rejected.

The Rabbis stated another solution before Abaye: It is a rabbinic decree, due to a concern that the bull will become a sin-offering whose owners have died, since the High Priest might die during the year. The Gemara responds: This works out well with regard to the bull, but as for the goat, which is a communal offering, what is there to say? The Gemara answers: There is a rabbinic decree with regard to the goat due to the bull.

The Gemara asks: Is it right that due to a rabbinic decree the offerings should be left to die instead of being left to graze? Rather, it is a rabbinic decree due to a concern that the goat will become a sin-offering whose year has passed. A goat may not be brought as a sin-offering once it is more than a year old, and there is a concern that the goat will be too old by the Yom Kippur of the following year. The Gemara expresses surprise: Is this a rabbinic decree? It is certainly a sin-offering whose year has passed, as the goat will certainly be more than a year old by the following Yom Kippur.

The Gemara responds: This is not difficult, as it is possible that the goat will not be disqualified, in accordance with the opinion of Rabbi Yehuda HaNasi. As it was taught in a baraita: With regard to redeeming houses in a walled city the Torah states: “And if it not be redeemed within the space of a full year” (Leviticus 25:30), which indicates that he counts 365 days, in accordance with the number of days in a solar year; this is the statement of Rabbi Yehuda HaNasi. And the Rabbis say: He counts twelve months from day to day. Therefore, according to the opinion of Rabbi Yehuda HaNasi, if the goat was less than eleven days old on the first Yom Kippur, it will not be disqualified on the following Yom Kippur because it will still be less than 365 days old, as long as the first year was not a leap year. Nevertheless, it is disqualified by rabbinic decree due to a concern that other goats would be used in similar circumstances even if they were more than a year old.