Mishnayos Bechoros Perek 9 Mishnah 5

שלש גרנות למעשר בהמה (three harvesting seasons/threshing floors for tithing of cattle) – in three periods during the year, the cattle are tithed. And the language of גרנות/harvesting seasons/threshing floors, like the grain of the threshing floor which is subject to sacred gifts/forbidden as eatables forbidden pending the separation of sacred gifts and we don’t consume from them until they are tithed, so in these three periods of the year we don’t eat from the cattle nor do we sell them until we tithe them.

פרוס הפסח – fifteen days prior to Passover, that is the last day of [the month of] Adar. And the language [usage of] פרוס, is one-half, one-half of the time that we ask [questions] about the laws of Passover, as it is taught in a Baraita (Talmud Megillah 32a): We ask questions about the laws of Passover thirty days prior to Passover. And similarly, [the phrase] פרוס עצרת/half-a-month before Atzeret/Shavuot, 15 days prior. And similarly [the phrase] פרוס החג/fifteen days prior to the Festival/Sukkot, that is the last day of Elul. And they (i.e., the Rabbis) established these three times that they would establish for the tithing of cattle, in order that the cattle would be available/found for those making Pilgrimage [to the Temple in Jerusalem], and even though it is taught [towards the conclusion] in our Mishnah that until the time of the threshing floor/harvesting seasons, it is permitted to sell and to slaughter, that the harvesting season/threshing floor is what establishes the tithing [of cattle], nevertheless, people did not slaughter until they tithed, for it was satisfactory for people to fulfill the Mitzvah with his money for a matter in which he is not lacking anything, as for example the tithing of cattle in which he himself offers up the tithe and eats it as a peace offering, but if they didn’t tithe at these three periods [of the year] there would be many prevented from selling because they didn’t tithe, and there would not be cattle readily found for those making Pilgrimage [to the Temple].

בן עזאי אומר בתשעה ועשרים באדר – that is fifteen days prior to Passover. But that Rabbi Akiva holds that the Adar that is closest to Nisan (i.e., the month in which Purim falls – the Second Adar in a leap year) is sometimes defective/short – i.e., 29 days and sometimes full – i.e., 30 days) and fifteen days prior to Passover, sometimes we begin on the twenty-ninth of Adar and sometimes on the thirtieth [day] of Adar, therefore, they did not establish for it [an exact] time. But Ben-Azzai holds that the Adar nearest Nisan (i.e., Second Adar in a leap year) is always defective/short, and the beginning of the fifteen-day period prior to Passover is always on the twenty-ninth [day of] Adar.

באחד בסיון – because of the paucity of cattle that give birth from Nisan until Atzeret/Shavuot (see Talmud Bekhorot 58a), if one advances it fifteen days prior to Atzeret, all of them will be consumed prior to Atzeret, and there won’t be cattle found for those making Pilgrimage [to the Temple in Jerusalem].

בעשרים ותשעה באב – Ben Azzai, according to his reasoning, who stated further on [in our Mishnah], [The cattle born] in Elul are tithed by themselves and they are not combined with those that were born prior to Elul, for perhaps, on the first of Elul is the New Year for the Tithing of Cattle (see Tractate Rosh Hashanah, Chapter 1, Mishnah 1) and there would be new and old, and it is doubtful to him when is Rosh Hashanah – either Elul or Tishrei, therefore he did not set a time for their “threshing floor” of the summer on the twenty-ninth of Elul so that they don’t come to combine those born in Elul with them.

באחד בניסן – they (i.e., Rabbi Eleazar and Rabbi Shimon) hold like Rabban Shimon ben Gamaliel who stated that we ask questions about the laws of Passover two weeks prior to Passover, that is, also regarding the laws of Passover that we tithe for cattle in order that they are not appropriate on the Festival/Yom Tov.

באחד בסיון – as we stated the reason of Ben Azzai, because of the small number of cattle that are born from Nisan until Atzeret.

מפני שהוא יום טוב – he said one thing and more. First – because we need recognition of that which is new and old, that the first of Tishrei is Rosh Hashanah for the tithing of cattle, for even though he did not come to combine them with those of Tishrei, for not a single lamb had been born today, and if it had been born, it was not old enough. Even so, we don’t tithe that of today, because we need to establish recognition between new and old, so that people would know to not combine the new with the old. Nd furthermore, because it is Yom Tov, because of the required marking with red paint (see Talmud Bekhorot 58a) that one paints on each tenth in order that it would be recognized, but it is forbidden to pain on Yom Tov/the holy day.

האלוליין מתעשרין בפני עצמן – as we explained above, that it is doubtful to him whether the New Year for the tithing of cattle is on the first [day] of Elul or on the first [day] of Tishrei, therefore, we don’t tithe those of Elul with those [animals] born from Tishrei and onwards, because one doesn’t combine old with the new.