The Mishna rules that if one slaughters an animal on Shabbat or Yom Kippur, the slaughter is valid. However, Rav asserts that the meat may not be eaten on that Shabbat, even raw. The Sages in the Yeshiva explained that Rav's position accords with the opinion of Rabbi Yehuda regarding the laws of Shabbat, and the Gemara attempts to identify which specific ruling of Rabbi Yehuda serves as the basis for this.

Rabbi Abba suggests it refers to Rabbi Yehuda's view on hachana -the requirement that an item be designated for use before Shabbat - citing the example of Rabbi Yehuda's prohibition against cutting up an animal that died on Shabbat to feed to one's dogs. Abaye rejects this, arguing that animals intended for food are considered inherently designated for slaughter for human consumption (but not for animal consumption) even while alive, citing laws of Yom Tov as proof. Although Rabbi Abba attempts to resolve the difficulty by employing the principle of breira (retroactive designation) to understand the Yom Tov law, this is rejected as Rabbi Yehuda does not accept the concept of breira.

The Gemara attempts to find the source for the fact that Rabbi Yehuda does not hold by breira. Initially, it attempts to prove this from a case involving the separation of teruma from wine, but after rejecting that proof, the Gemara derives it from Rabbi Yehuda's position regarding eruv techumim.

Rav Yosef suggests the source is Rabbi Yehuda's position regarding broken vessels that were not broken before Shabbat; these are forbidden by Rabbi Yehuda if they cannot be used for their original function. However, this comparison is rejected because an animal can be considered "food" even before it is slaughtered. This discussion aligns with Rabbi Yehuda's opinion regarding liquids that seep out of fruits.

The Gemara offers a third suggestion based on Shmuel's understanding of Rabbi Yehuda's view on liquids leaking from olives and grapes. Shmuel posits that Rabbi Yehuda agrees with the Sages that such liquids are forbidden to prevent one from intentionally squeezing the fruit; likewise, permitting meat from a Shabbat slaughter might lead one to intentionally slaughter an animal on Shabbat. This is rejected because Rav disagrees with Shmuel's interpretation of Rabbi Yehuda's position on grapes and olives; since the goal is to clarify Rav's own ruling, it cannot be based on a premise that Rav himself does not accept.

Rabbi Sheshet suggests a fourth possibility based on Rabbi Yehuda's ruling on lamps. Rabbi Yehuda deems used lamps muktze because they are repulsive (mi'us); similarly, a living animal would be muktze because it cannot be eaten in its current state. This is also rejected, as the Gemara distinguishes between muktze due to repulsion and muktze resulting from a prohibition.