Bekhorot 61A

והא דתני יקריבו ⁠— רבי שמעון היא, דאמר: מביאין קדשים לבית הפסול.

And the ruling of this tanna, who teaches: Both animals must be sacrificed, is in accordance with the opinion of R' Shimon, who says that one may bring sacrificial animals to a situation where the likelihood of disqualification is increased.

והא דתני ימותו ⁠— רבי יהודה היא, דאמר: טעות מעשר, תמורה הויא, קסבר רבי יהודה: תמורת מעשר מתה.

And the ruling of this tanna, who teaches: Both animals must die, is in accordance with the opinion of R' Yehuda, who says: When the owner makes a mistake in designating animal tithe, e.g., if one designates the 9th animal as the tenth, the designated animal has the status of a substitute animal. And R' Yehuda holds that a substitute for an animal tithe must be left to die. Since it is uncertain which animal is the 11th, both are left to die.

וקסבר רבי יהודה תמורת מעשר מתה? והתנן, אמרו משום רבי מאיר: אילו היה תמורה לא היה קרב, מכלל דרבי יהודה סבר קרב!

The Talmud asks: And does R' Yehuda hold that a substitute for an animal tithe must die? But didn’t we learn in the Mishnah: The rabbis said in the name of R' Meir, in response to the statement of R' Yehuda: The 11th animal is not considered a substitute for the animal tithe, since if it were a substitute it would not be sacrificed, as the substitute for an animal tithe is not sacrificed?By inference, R' Yehuda holds that the 11th animal is sacrificed, and not put to death, despite the fact that it has the status of a substitute animal.

וכי תימא: רבי מאיר למאי דסבירא ליה קאמר, והתניא: אין בין אחד עשר לשלמים, אלא שזה עושה קדושה ליקרב, וזה אין עושה קדושה ליקרב, דברי רבי יהודה. קדוש ליקרב הוא דלא הוא עביד, הא איהו גופיה קריב!

The Talmud continues: And if you would say that R' Meir is saying his statement according to what he himself holds, and therefore nothing can be inferred from his comment with regard to the opinion of R' Yehuda, that cannot be so; but isn’t it taught in a baraita: The difference between the 11th animal mistakenly designated as animal tithe and a peace offering is only that this, the peace offering, renders a substitute sanctified to the extent that it can be sacrificed, but that, the 11th animal mistakenly designated as animal tithe, does not render its substitute sanctified to be sacrificed; this is the statement of R' Yehuda? The Talmud infers: It is stated only that the 11th animal mistakenly designated as tithe does not render its substitute sanctified with enough sanctity to be sacrificed, which indicates the 11th animal itself is sacrificed and not put to death.