The Gemara cites two conflicting statements of Rav regarding a hanging limb of an animal. In one statement, Rav rules that eating this limb incurs lashes, while in the other, he rules it does not. Rav Yosef resolves this contradiction: if the animal dies naturally, death causes legal detachment (oseh nipul), retroactively defining the hanging limb as ever min hachai (a limb from a living animal) which incurs lashes for one who eats it. Conversely, if the animal is slaughtered, slaughter does not cause legal detachment (eino oseh nipul), meaning the limb is not treated as a separate forbidden entity and the eater does not receive lashes. Rava brings a biblical source for this differentiation between death and slaughter, and the Gemara raises two difficulties against his proof but resolves them both.

Rav Chisda and Rabba dispute whether the debate between Rabbi Meir and the Rabbis - regarding whether slaughter causes legal detachment for an emerged fetal limb - applies only when the fetus is alive, or even when the fetus is dead. Rav Chisda holds that when the fetus is dead, the emerged limb is definitely considered detached and carries impurity.

In the course of a back-and-forth argument between the Rabbis and Rabbi Meir in the Mishna, it was mentioned that slaughtering would not remove impurity from an eight-month fetus, as it is not viable, and there is no type of eight-month fetus that can be validly slaughtered. However, a braita states that there are eight-month fetuses that can be permitted by slaughter. Rav Kahana reconciles this by differentiating between slaughtering the fetus itself and permitting the animal via its mother's slaughter (ben pekua).

Rav Hoshaya inquires whether a live nine-month-old fetus can be validly slaughtered while still in utero. This question is evaluated under the views of both Rabbi Meir and the Rabbis. Rav Chananya attempts to resolve this inquiry from a braita, but his answer is ultimately rejected by Rava.

The Mishna introduces a dispute regarding the laws of ben pekua and whether they apply to a fully formed, nine-month-old fetus found inside its slaughtered mother. Rabbi Meir rules that the laws of ben pekua do not apply here, and the fetus requires its own independent slaughter. Conversely, the Rabbis and Rabbi Shimon Shezuri hold that as long as the fetus is still inside the womb, it is covered by the laws of ben pekua and is permitted by the slaughter of the mother.

Operating under the Rabbis' position, Rabbi Eleazar states in the name of Rabbi Oshaya that the mother's slaughter only covers the animal born from this womb regarding the laws of eating. In other halakhot, this animal is considered a distinct entity and standard animal laws apply to it. The Gemara presents two versions of what Rabbi Oshaya's statement was coming to exclude: the first version suggests it excludes the animal's fat, sciatic nerve, and blood from the mother's exemption, while the second version suggests it excludes using the animal for work or illicit cross-breeding. The first version is ultimately rejected based on other sources, leaving the second version as the preferred explanation.

Rabbi Yochanan and Reish Lakish disagree about whether the blood of a ben pekua (a nine-month fetus) is permitted as well. Rabbi Yochanan raises one difficulty against Reish Lakish's position, which the Gemara subsequently resolves.

According to the position of the Rabbis, a question is asked whether one can redeem a firstborn donkey with a ben pekua. Mar Zutra and Rav Ashi disagree.

A second question is asked whether a ben pekua that is still in utero can be considered a separate unit for the laws of ritual impurity. This is a dispute between Rabbi Yochanan and Reish Lakish, and each one raises a difficulty against the other's position.