But if another animal was inadvertently slaughtered together with the red heifer in the same action, according to Rabbi Natan, who holds that the slaughter of non-sacred animals without intent is valid, the red heifer is disqualified, because an additional labor was performed with its slaughter, and the other animal is fit for consumption, as its slaughter was valid. According to the Rabbis, who hold that slaughter of non-sacred animals without intent is not considered slaughter, the red heifer is fit for use in the purification rite because no other labor was performed with its slaughter, and the other animal is unfit for consumption.

The Gemara asks: That is obvious; why did Rava have to teach that? The Gemara answers: It was necessary for Rava to teach the halakha according to the opinion of Rabbi Natan in the case where another animal was inadvertently slaughtered in the same action with the red heifer. It may enter your mind to say: The Merciful One states with regard to the slaughter of the red heifer: “And you shall give it to Elazar the priest…and he shall slaughter it before him” (Numbers 19:3), from which it is inferred: One may slaughter it, but not it and another animal simultaneously. And what are the circumstances of that prohibition? It is a case where one slaughtered two red heifers at the same time. But in a case where one slaughtered a red heifer together with a non-sacred animal, say no, that it does not disqualify the red heifer. Therefore, Rava teaches us that even slaughter with a non-sacred animal disqualifies the red heifer.

Rava adds: If one slaughtered a red heifer and in the same action cut a gourd together with it, everyone agrees that the red heifer is disqualified. If one slaughtered a red heifer and a gourd was inadvertently cut together with it in the same action, everyone agrees that the red heifer is fit for use in the purification rite, as that is not labor that disqualifies a red heifer and it is also not excluded by the derivation from the verse “And he shall slaughter it.”

MISHNA: If, when one was in the middle of slaughtering an animal, the knife fell and he lifted it and then completed the slaughter, or if his garments fell and he lifted them and then completed the slaughter, or if he had honed the knife and grew weary before completing the slaughter and another came and slaughtered the animal, if he interrupted the slaughter in one of these ways or in a different way for an interval equivalent to the duration of an act of slaughter, the slaughter is not valid. Rabbi Shimon says: The slaughter is not valid if he interrupted the slaughter for an interval equivalent to the duration of an examination.

GEMARA: The Gemara asks: What is the meaning of an interval equivalent to the duration of an act of slaughter? Rav said: It means an interval equivalent to the duration of an act of slaughter of another animal, not the duration required to complete the act of slaughter that was interrupted.

Rav Kahana and Rav Asi said to Rav: Is the interruption that invalidates the slaughter an interval equivalent to the duration of an act of slaughter of another animal for an animal, i.e., in a case where an animal was being slaughtered, and an interval equivalent to the duration of an act of slaughter of another bird for a bird? Or perhaps it is an interval equivalent to the duration of an act of slaughter of an animal even for a bird, and if the interruption is any shorter it does not invalidate the slaughter?

Rav said to them: When we studied this topic I did not feel sufficiently intimate with my beloved uncle, Rabbi Ḥiyya, such that I could ask him that question. Rav was able only to transmit that which he heard from Rabbi Ḥiyya, but was unable to resolve their dilemma.

It was stated that there is an amoraic dispute with regard to this matter. Rav said: An interval equivalent to the duration of an act of slaughter of another animal for an animal, and an interval equivalent to the duration of an act of slaughter of another bird for a bird. And Shmuel said: An interval equivalent to the duration of an act of slaughter of an animal even for a bird. And likewise, when Ravin came from Eretz Yisrael to Babylonia he said that Rabbi Yoḥanan said: An interval equivalent to the duration of an act of slaughter of an animal even for a bird.

Rabbi Ḥananya said: An interval equivalent to the period in which one can bring another animal and slaughter it. The Gemara asks: Does that mean the time in which one can bring an animal even from anywhere else, regardless of the distance? Occasionally, there is no animal available in close proximity. If so, you have rendered your statement subject to circumstances; it does not apply uniformly to all cases.

Rav Pappa said: The practical difference between the opinion of Rabbi Ḥananya and that of the other Sages is in a case where there is an animal standing before the slaughterer and it is necessary to cast it to the ground in order to slaughter it. Even Rabbi Ḥananya disregards the time required to bring the animal from elsewhere. But Rabbi Ḥananya holds that the slaughter is invalidated only if the interruption lasts an interval equivalent to the duration of the act of casting the animal to the ground and slaughtering it. The Rabbis invalidate the slaughter even if an interval has elapsed that is equivalent to the duration of the act of slaughtering the animal, without casting it to the ground.

The Gemara cites an additional opinion with regard to the duration of the interruption that invalidates slaughter. They said in the West, Eretz Yisrael, in the name of Rabbi Yosei, son of Rabbi Ḥanina: The duration of the interruption that invalidates slaughter is equivalent to the period in which he can lift the animal from the ground and then lay it back on the ground and slaughter it. The interval is calculated based on the size of the animal in question. The duration of the interruption that invalidates slaughter of a small animal is equivalent to the period necessary to lift, lay down, and slaughter a small animal. And the duration of the interruption that invalidates slaughter of a large animal is equivalent to the period necessary to lift, lay down, and slaughter a large animal.

§ Rava said: In the case of one who slaughters with a blunt knife, even if the completion of the slaughter lasts the entire day, the slaughter is valid provided there is no interruption in the midst of the slaughter.

Rava raises a dilemma: If there were several short interruptions during a single act of slaughter, what is the halakha in terms of whether they join together to invalidate the slaughter if the sum of the durations of all the interruptions is greater than the maximum permitted interruption?

The Gemara challenges: And let Rava resolve the dilemma from his own statement, as he permitted an act of slaughter that lasts the entire day, during which there were presumably brief interruptions throughout. Apparently, the interruptions do not join together. The Gemara responds: There, Rava was referring to a case where there was no interruption, as the slaughterer drew the knife back and forth throughout.

Rav Huna, son of Rav Natan, raises a dilemma: If one cut the majority of the simanim and then interrupted the slaughter before proceeding to cut the minority of the simanim, what is the halakha? The Gemara answers: The dilemma shall stand unresolved.

§ The mishna teaches that Rabbi Shimon says: The slaughter is not valid if he interrupted the slaughter for an interval equivalent to the duration of an examination. The Gemara asks: What is an interval equivalent to the duration of an examination? Rabbi Yoḥanan said: It is an interval equivalent to the duration of an examination of the knife by a Sage prior to the slaughter of the animal. The Gemara objects: If so, you have rendered your statement subject to circumstances, as sometimes the Sage is near and sometimes the Sage is far, and the time required for examination varies accordingly. The Gemara responds: Rather, the reference is to an interval equivalent to the duration of an examination performed by a slaughterer who is a Sage. In that case, travel time is not factored in; only the time of the examination itself is considered, and this does not vary.

MISHNA: If one cut the gullet in the standard manner of slaughter with a back-and-forth movement, and he severed the windpipe not in the standard manner, or if one severed the windpipe and thereafter cut the gullet, or if one cut one of the simanim and waited until the animal died, or if one cut one siman and concealed the knife beneath the second siman and severed it from below, Rabbi Yeshevav says: The animal is an unslaughtered carcass and imparts ritual impurity through contact with it and carrying it. Rabbi Akiva says: The animal is a tereifa, and although eating it is prohibited, it does not transmit ritual impurity.

Rabbi Yeshevav stated a principle in the name of Rabbi Yehoshua: Any animal that was rendered unfit during its slaughter because the slaughter was not performed properly is an unslaughtered carcass; any animal whose slaughter was performed properly and another matter caused it to become unfit is a tereifa. And Rabbi Akiva conceded to his opinion.

GEMARA: The mishna teaches: If one cut the gullet…and Rabbi Akiva conceded to his opinion. And the Gemara raises a contradiction from a mishna at the beginning of the next chapter (42a): These wounds constitute tereifot in an animal: