And in addition, he holds that these distinguishing characteristics apply by Torah law, such that they may be relied upon to allay concerns of violating even a prohibition that is mandated by Torah law.

§ The Sages taught in a baraita (see Tosefta 5:1): The prohibition against slaughtering an animal itself and its offspring applies to the offspring of diverse kinds of animals, such as a goat and a ewe, and to the koy, even though the prohibition does not apply to undomesticated animals. Rabbi Eliezer says: With regard to a hybrid that results from the mating of a goat and a ewe, the prohibition of a mother and its offspring applies; with regard to a koy, the prohibition of a mother and its offspring does not apply. Rav Ḥisda says: What is the koy about which Rabbi Eliezer and the Rabbis disagree? It is that which results from the mating of a goat and a doe.

The Gemara asks: What are the circumstances surrounding the birth of this koy? If we say that it is the result of a goat that mates with a doe, and she gives birth, and one slaughters her and her offspring on the same day, that is difficult: But doesn’t Rav Ḥisda say: All concede in the case where she is a doe and her offspring is a goat, because she mated with a goat, that one who slaughters them both on the same day is exempt from lashes for violating the prohibition of a mother and its offspring? He is exempt because the Merciful One states: ''And whether it be a bull or a sheep, you shall not slaughter it and its offspring both in one day'' (Leviticus 22:28), indicating that the prohibition applies to a domesticated animal and its offspring, but not to an undomesticated animal and its offspring, such as a doe and its offspring.

Rather, perhaps this koy is the product of a deer that mates with a female goat, and she gives birth, and one slaughters her and her offspring on the same day. But doesn’t Rav Ḥisda say: All concede that in the case where she is a goat and her offspring is a deer because she mated with a deer, that one who slaughters them both on the same day is liable? He is liable because the Merciful One states in the Torah: ''A sheep…and its offspring'' (Leviticus 22:28), indicating that the prohibition applies to a domesticated animal such as a sheep and its offspring of any species, even if it is an undomesticated animal.

The Gemara responds: Actually, the dispute between Rabbi Eliezer and the Rabbis is in the case of a goat that mates with a doe, and she gives birth to a female offspring, a koy, and this female offspring gives birth to a male offspring, and one slaughters her and her male offspring on the same day.

The Rabbis hold: One needs to be concerned with its paternity, and therefore the koy is partially a goat due to its father, and the word ''sheep'' in the verse means that even if it is partially a sheep, i.e., a domesticated animal, it may not be slaughtered with its offspring in a single day. And Rabbi Eliezer holds: One need not be concerned with its paternity, and the status of the koy is unaffected by the fact that its father is a goat, and therefore, in this case we do not say that the word ''sheep'' mentioned in the verse means that even if it is partially a sheep it may not be slaughtered with its offspring in a single day, as the father’s component is ignored.

The Gemara challenges: And let them disagree with regard to any animal of mixed breed about whether one needs to be concerned with its paternity, i.e., with regard to the issue that is the subject of the dispute between Ḥananya and the Rabbis, whether the prohibition against slaughtering an animal and its offspring on the same day also applies to a father and its offspring because one needs to be concerned with an animal’s paternity.

The Gemara responds: If they would disagree only about that issue, I would say: With regard to this issue of a doe mother and a goat father, even the Rabbis concede that we do not say that the word ''sheep'' mentioned in the verse means that even if an animal is partially a sheep, i.e., a domesticated animal, it may not be slaughtered with its offspring in a single day. Therefore, the baraita teaches us that according to the Rabbis, not only does one need to be concerned with paternity, but the word ''sheep'' indicates that even if it is partially a sheep, i.e., a domesticated animal, it may not be slaughtered with its offspring.

The Gemara challenges: But that which we learned in a mishna (83b) appears to contradict this: One may not slaughter a koy on a Festival, because covering its blood entails the performance of prohibited labor that is permitted only if there is a definite obligation to do so. And if one slaughtered a koy on a Festival after the fact, one does not cover its blood, as the Sages prohibited transporting soil on a Festival where it is uncertain that a mitzva by Torah law exists.

The Gemara explains the question: What are we dealing with? If we say that we are dealing with a goat who mates with a doe, and she gives birth, then whether according to the opinion of the Rabbis or according to the opinion of Rabbi Eliezer, let him slaughter the koy on the Festival ab initio and cover the blood, as the mother of the koy is a deer, and the koy therefore may be termed an undomesticated animal, whose blood requires covering. This should be so even if it is partially a deer, i.e., it has an undomesticated animal component from only one parent, since all agree that the offspring’s species derives from its mother.

Rather, we must be dealing with a case of a deer that mates with a female goat, and she gives birth. This, too, is difficult: If the mishna is in accordance with the opinion of the Rabbis that one needs to be concerned with paternity, let him slaughter this koy on the Festival ab initio and cover the blood, as it is partially an undomesticated animal due to its father. If the mishna holds in accordance with the opinion of Rabbi Eliezer that one need not be concerned with paternity, let him slaughter the koy on the Festival ab initio and not cover the blood, as it should be considered a domesticated animal, whose blood does not require covering due to its mother who is a goat.

The Gemara concludes that actually this mishna is in accordance with the opinion of the Rabbis, and it is referring to a case of a deer who mates with a female goat, and the Rabbis do not say with certainty that in determining the species of an animal one must be concerned with paternity, but rather the Rabbis are simply uncertain whether one needs to be concerned with its paternity or one need not be concerned. Therefore, they rule that one should not slaughter it on a Festival, ab initio, in order to avoid a possible prohibition, and if one did slaughter it, he should not cover the blood, to avoid violating a prohibition in order to perform an uncertain mitzva.

The Gemara infers: And from the fact that the Rabbis are uncertain, and therefore they rule that the prohibition of: Itself and its offspring, applies to a koy, it can be inferred that according to the opinion of Rabbi Eliezer, who rules that the prohibition of: Itself and its offspring, does not apply to a koy, it is obvious that, with regard to a koy resulting from a deer mating with a female goat, one need not be concerned with its paternity at all.

The Gemara asks: But according to this, that which is taught in a baraita (see Tosefta 9:1) presents a difficulty: The mitzva to give the foreleg, the jaw, and the maw of non-sacred animals to a priest applies both to a koy and to the offspring of diverse kinds of animals. Rabbi Eliezer says: A hybrid that results from the mating of a goat and a ewe is obligated to have gifts of the priesthood given from it; a hybrid that results from a koy is exempt from having gifts of the priesthood given from it.

The Gemara analyzes the baraita: What type of koy are we dealing with? If we say that we are dealing with a goat who mates with a doe, and she gives birth, granted, this is consistent according to the opinion of Rabbi Eliezer, who deems it exempt from having gifts of the priesthood given from it. As he holds that we do not say that the word ''sheep'' (see Deuteronomy 18:3) means that even if it is partially a sheep one must give gifts of the priesthood from it, as paternity is ignored and this koy is considered solely the offspring of a doe, exempting it from having gifts given from it.

But according to the opinion of the Rabbis, even if it is granted that they hold that the word ''sheep'' means that even if it is partially a sheep, or any other type of domesticated animal, one is obligated to give gifts of the priesthood from it, why should the owner of this koy be required to give the gifts to a priest? Granted, he does not give the priest half of the gifts, since half of the koy, i.e., the mother’s component, is an undomesticated animal; but with regard to the other half, as well, let him say to the priest: Bring proof that one needs to be concerned with its paternity and take that half; otherwise receive nothing.

Rather, we are dealing with the case of a deer who mates with a female goat and she gives birth. Granted, this is consistent according to the opinion of the Rabbis, who say that one is obligated to give gifts of the priesthood from it, as what is meant by: Obligated? It means: It is obligated in half of the gifts, since on its mother’s side the goat component is subject to the obligation to give the gifts, but with regard to the other half of the gifts he can tell the priest: Bring proof that one need not be concerned with paternity, and take it. But according to the opinion of Rabbi Eliezer, who says that one need not be concerned with paternity at all, such that this koy would be considered a domesticated animal like its mother, let the owner be obligated in all of the gifts. Why, then, does Rabbi Eliezer deem him exempt?

The Gemara answers: Actually, it is referring to a deer who mates with a female goat, and she gives birth, and Rabbi Eliezer is also uncertain whether, in determining the species of an animal, one needs to be concerned with its paternity or not. The Gemara asks: But since the conclusion is that the Rabbis are uncertain and Rabbi Eliezer is uncertain, in what case do they disagree where Rabbi Eliezer deems the owner exempt from giving the gifts entirely?