There is a dispute between Rav Yehuda in the name of Rav and Rav Chanania bar Shlemia in the name of Rav regarding which practical skills a Torah scholar must master through repetition. The first opinion lists writing, slaughtering, and circumcision, while the second adds the knot of the tefillin, the sheva berakhot, and the tying of tzitzit.

Rav Yehuda quotes two further statements in the name of Shmuel. The first is that a slaughterer must be expert in the laws of shechita; otherwise, the meat may not be eaten. Since meat can be disqualified for five specific reasons, an unlearned slaughterer might perform an invalid slaughter without realizing it.

The second statement of Rav Yehuda in the name of Shmuel is that a slaughterer must inspect the two simanim (the windpipe and gullet) to ensure they were properly severed. While Rav Yosef attempts to provide a proof for this requirement, Abaye rejects it. The Gemara discusses the status of meat that was not inspected, debating whether it is classified as a treifa or a neveila. Both positions are rooted in their interpretation of Rav Huna's principle: a living animal is presumed forbidden until it is proven that a valid shechita was performed, but once slaughtered properly, it is presumed kosher until proven to be a treifa.

The Gemara then analyzes the second half of Rav Huna's statement, inferring that an animal remains kosher even if there is an unproven concern that it might be a treifa. This is illustrated by a case where a wolf takes an internal organ and returns it with a hole; we do not assume the hole existed prior to the wolf's intervention. Rabbi Abba challenges this from a ruling regarding food nibbled by creatures, where we fear teh hole where they are nibbling was a pre-existing hole from a snake who may have injected venom into it. To resolve this, Rav Huna distinguishes between matters of danger and matters of ritual prohibition (issur). While Rava rejects this distinction, arguing that stringency regarding danger should imply stringency regarding prohibitions, Abaye accepts the differentiation, citing proofs from the laws of impurity. After Rava rejects Abaye's proof and Rav Shimi raises a difficulty with Rava's position that the Gemara resolves, Rav Ashi concludes by bringing support for Rav Huna's position.