Commentary for Kiddushin 110:14

R. Yohanan is surprised by R. Oshaya’s explanation of the mishnah about the lost animal (see section one). Do we say to a person “Sin” by intentionally redeeming an animal intended to be offered as a sacrifice. An animal designated to be sacrificed cannot be redeemed unless it has become flawed and cannot be sacrificed. Even though he will have the merit of donating two sacrifices in its place, and thereby remedy the situation, we do not generally tell people to sin even if the sin will eventually result in merit.
Therefore, R. Yohanan has another suggestion. We wait until the animal is blemished. Then it is redeemed and we make a stipulation. If the animal was a burnt offering, then the first offering will be a burnt offering in its place and the second a voluntary peace offering. If the animal was a peace offering, the second animal is a peace offering in its place and the first offering is a voluntary burnt offering. After doing this, the animal he found is successfully desacralized. He may now eat it. Bon Appetit!

The Talmud adds another possibility—the animal might be a thanksgiving offering, so he has to bring one of those too. And the loaves that go with it. The altar is really making out here!

It can’t be a guilt offering because a one year old animal was found, not a two year old (no idea how they know this). It is not assumed to be a guilt-offering of a leper or a nazir which are yearlings because these are not common sacrifices.

We are not concerned with the animal being a Pesach because people don’t lose those sacrifices so close to Pesah. And when it is not close to Pesah, the animal has the status of a peace offering.

If it is a firstling or tithe, then this is not a problem. We wait for a blemish and then eat it when blemished, which is always the rule for firstlings and tithes.

The Talmud adds another possibility—the animal might be a thanksgiving offering, so he has to bring one of those too. And the loaves that go with it. The altar is really making out here!

If a two year old is found it is not a sin offering and we do not assume it is a sin offering whose time passed.

If a female yearling is found then we have to treat it as if it is a sin-offering. There is nothing that can be done to redeem this sin-offering. It can’t be sacrificed because it might not have been a sin-offering. And one cannot redeem it and use the money to bring another sin-offering because one cannot bring a voluntary sin-offering. The only thing that can be done is simply put it in a pen and starve it until it dies. I know, this is not a nice halakhah.

Second tithe money should not be used to buy food outside of Jerusalem. According to the first opinion, if one uses second tithe money to buy an animal outside of Jerusalem, if unwittingly, the sale is void. The money returns to its “place” meaning it stays second tithe. But if he does so deliberately, the sale is valid and the animal must be brought to Jerusalem and eaten there.
R. Yehudah explains the first opinion—the person was buying an animal to be used as a peace-offering, which seems to have been a normal thing to be done with second tithe money. If he does so intentionally, then the acquisition is valid. But if he was trying to buy a non-sacred animal, meaning his intent was to turn the second tithe into non-sacred money, then the exchange is invalid whether done unwittingly or deliberately.