Does Shavuot have makeup days? TB Haggigah 17

At least when my children were young and watched Sesame Street, one of the segments was called "one of these things is not like the other." The viewers had to point out the one that was different and see if they were correct. We can play that game concerning the three pilgrimage holidays, Passover, Shavuot, and Sukkot. Shavuot is the holiday that is different. Both Passover and Sukkot are celebrated for seven days while Shavuot is only a one day holiday. If a person failed to bring his special holiday sacrifices on the first day of Passover and Sukkot for any valid reason, he could bring those holiday sacrifices on any of the day of the rest of the holiday. These 6 days are called in Hebrew tashlumin (תַּשְׁלוּמִין ), makeup days where one can redress the lack of bringing the holiday sacrifices. Does Shavuot have tashlumin or not since it does not have any intermediary days like Passover and Sukkot? Daf TB Haggigah 17 proves conclusively even though Shavuot is a one day holiday it too has six days of redress just like the other two pilgrimage holidays.

“GEMARA: Rabbi Elazar said that Rabbi Oshaya said: From where is it derived that the Shavuot offerings can be redressed, i.e., that the obligatory Festival offerings can be sacrificed all seven days following the Festival? As it is stated: “Three times a year all your males shall appear…on the festival of Passover, and on the festival of Shavuot, and on the festival of Sukkot” (Deuteronomy 16:16). The verse compares the festival of Shavuot to the festival of Passover by analogy: Just as one can redress the failure to bring the offering on the festival of Passover on all seven days of the Festival, so too, on the festival of Shavuot, one can redress the failure to bring the offering for all seven, i.e., Shavuot and the six days following it.” (Sefaria.org translation) Even though the Gemara then throws three challenges to Rabbi Oshaya's drash, explanation of the verse, each one is deflected.

Even though we do not offer any sacrifices anymore, in the course of the analysis we learned one practical halakha concerning counting the omer. “Rava said: And how can you understand it that way? Is that to say that for Shavuot we count days but we do not count weeks? Didn’t Abaye say: It is a mitzva to count days, in the counting of the omer, as it is written: “Until the morrow of the seventh week, you shall count fifty days” (Leviticus 23:16); and it is also a mitzva to count weeks, as it is written: “Seven weeks you shall count for yourself, from when the sickle is first put to the standing corn” (Deuteronomy 16:9); and further, it is written: “The festival of weeks [shavuot]” (Deuteronomy 16:10), which indicates that it is a Festival that is established through a count of weeks? Consequently, the days of redress for Shavuot should last a week, in accordance with its components. ” (Sefaria.org translation)

When we count the omer we mentioned both the day and the week as Abaye teaches. For example, Ashkenazim say, "Today is the eighth day which is one week and one day in the omer" . The Sephardim have a variation of the formula. They say, "Today is the eighth day of the omer which is one week and one day." There's some who say that if a person counts only the days are only two weeks, he is fulfill his obligation after the fact. There are those who say one must repeat the formula correctly without a blessing. (See Shulkhan Arukh, Orekh Hayim, 489:1)

These days of tashlumin still impact practical halakha in two other areas. One does not recite the penitential prayers takhanun for six days after Shavuot just like one does not recite them during the intermediary days of Passover and Sukkot. Secondly, the one day of Shavuot counts as seven days towards the first 30 days of the mourning period called sheloshim.