361. Moo: The prohibition against redeeming the animal tithe
…it may not be redeemed. (Leviticus 27:33)
Animals of maaser beheima had to be taken to Jerusalem and eaten; they could not be redeemed or sold. The reason we may not do so is because it would circumvent the entire reason of having maaser beheima in the first place, which is to cause us to spend more time in Jerusalem, where the Temple and Sanhedrin could be found.
One was not permitted to sell the flesh of a slaughtered animal of maaser beheima, but he could sell other parts, like the hide.
This mitzvah applies to everyone, in all times and places. Even though we do not currently observe the mitzvah of maaser beheima, if someone did designate an animal as such, it would be subject to this mitzvah.
This mitzvah is discussed in the Mishnah in the first chapter of tractate Maaser Sheini. It is codified in the Mishneh Torah in the sixth chapter of Hilchos Bechoros. This prohibition is #109 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos. This mitzvah is not listed in the Sefer HaMitzvos HaKatzar of the Chofetz Chaim.
This is the last mitzvah in Sefer Vayikra, the Book of Leviticus.