Bechoros 2:7-8

Bechoros 2:7

If two ewes that never gave birth before gave birth to two males, both are given to the kohein. If a male and a female, the male goes to the kohein. If two males and a female, one male belongs to the owner and the other goes to the kohein; Rabbi Tarfon says that the kohein can select the better one, while Rabbi Akiva says that the two parties decide between them. The other animal is left to graze until it develops a blemish and when it’s slaughtered, it is obligated in the portions given to a kohein, though Rabbi Yosi exempts it. If one of the animals died before the kohein receives one, Rabbi Tarfon says that the two parties divide the surviving animal, though Rabbi Akiva says that the burden of proof lies is on the kohein to prove that the surviving animal is the firstborn. If the mothers gave birth to two females and a male, or to two males and two females, then the kohein receives nothing (because there might not be a male firstborn).

Bechoros 2:8

If one ewe had given birth before and the other had not and they gave birth to two males, one belongs to the owner and the other goes to the kohein. Rabbi Tarfon says that the kohein can select the better one, while Rabbi Akiva says that the two parties decide between them. The other animal is left to graze until it develops a blemish and when it’s slaughtered, it is obligated in the portions given to a kohein, though Rabbi Yosi exempts it. Rabbi Yosi maintained that whenever a kohein has one of a pair of doubtful firstborns, it is exempt from the portions given to a kohein, though Rabbi Meir declares it obligated in these portions. If one of the animals died before the kohein receives one, Rabbi Tarfon says that the two parties divide the surviving animal, though Rabbi Akiva says that the burden of proof is on the kohein to prove that the surviving animal is the firstborn. If the mother gave birth to a male and a female, the kohein receives nothing.