(The Mishnah taught that Vetch of Ma'aser Sheni may be eaten as shoots and may be brought in and out of Yerushalayim. The permission to take it out of Yerushalayim) only allows him to take an amount to make a small dough and eat it in Yerushalayim and then do the same again.

Question: Does the Mishnah follow Rabban Shimon ben Gamliel, who said that all produce can be taken out of Yerushalayim to make into dough and then returned?

Answer: No; the Mishnah follows all opinions - it's a leniency said specifically about Vetch.

(The Mishnah taught that if it became Tamei, R. Tarfon says that it must be divided into small Tahor doughs (of Ma'aser Sheni and added to less than an eggs-amount of Vetch). This applies specifically when they are added to Vetch of Ma'aser Sheni.

(R. Gurion citing R. Yosi ben Chanina): R. Tarfon's reason (that he does not allow the Tamei Vetch to be redeemed) is that one may not redeem Kodshim in order for them to be fed to the dogs.

(R. Yona): It appears that the Chachamim reason that that which is suitable for human consumption may not be redeemed for animals; but that which is not suitable for human consumption may be redeemed for animals.

Question (R. Yitzchak bar Eliashiv): If it became Tamei outside Yerushalayim (where it cannot be divided into doughs and eaten); how can it be redeemed, since one may not redeem Kodshim in order for them to be fed to the dogs?

(R. Yona): That's a very strong question! (Note: This entry follows the explanation of Rav Eliyahu Fulda. There are several other explanations in the commentators, including the Vilna Gaon who changes the Gemara's text.)