Yesterday, the fifth chapter of Tractate Chullin began with a mishnah exploring the prohibition on slaughtering an animal and its offspring on the same day. While this directive seems fairly straightforward, this is the Talmud, so the Gemara immediately raises several challenges, most centered on definitively identifying the mother and father of the offspring. This information is critical not only regarding the initial question raised by the mishnah, but because the Torah prohibits cross-breeding in the first place (Leviticus 19:19).
Therefore, it’s important to know the provenance of the animal in order to avoid violating the halakhah when mating it in the future.
In the midst of this discussion, the Talmud shares a related episode:
Rabbi Abba said to his servant: If you bring me mules attached to a wagon, look for those that are similar to each other and bring those for me.
In addition to prohibiting cross-breeding of animals, Deuteronomy 22:10 states: “You shall not plow with an ox and a donkey together.” This is generally understood to mean that the Torah forbids yoking two different species at the same time. Mules are the offspring of a horse and a donkey. Yoking two together is acceptable, but Rabbi Abba is particularly fastidious, and wants to make sure that the mules attached to his wagon have mothers that are both horses or both donkeys, but not one of each.
Prohibited mixing of species comes under the broader category of kilayim. In the adjacent verses (Deuteronomy 22:9 and 22:11), the Torah prohibits two additional types of mixing: planting a field with different types of seeds and weaving together linen and wool in the same garment (shatnez). Mishnah Kilayim deals extensively with these matters, but because the Babylonian Talmud doesn’t have a Gemara for it, we won’t study it in depth as part of the Daf Yomi cycle.
In Mishnah Kilayim 8:2, we encounter a passage that further details the prohibition on plowing with two different animals:
A (domesticated) beast (behemah) with a domesticated beast (of another species); a wild animal (hayyah) with a wild animal (of another species); a behemah with a hayyah; a hayyah with a behemah; an unclean beast with an unclean beast (of another species); a clean beast with a clean beast (of another species); or an unclean beast with a clean beast; or a clean beast with an unclean beast — they are all forbidden for plowing, and it is forbidden to pull them or lead them (while tied together).
In addition to the Torah’s avoidance of mixing species in general, there’s a practical reason for this prohibition: Plowing with beasts of different sizes and strengths is unfair to both animals. It can be overly taxing for the smaller or weaker animal, and it can be similarly difficult for the larger or stronger animal to set its pace at a slower rate. Other problems would arise from yoking a wild animal with a domesticated one, since they presumably have very different temperaments.
Underscoring the severity of such a violation, the mishnah rules on the punishment:
The person driving (the two different animals yoked together) receives the 40 lashes. And the person sitting in the wagon receives the 40 lashes.
Today, it’s unlikely that we will be faced with this scenario, but it did happen in a story related by Rabbi Moshe Sofer, a leading 19th-century rabbi, that is quoted by DafDigest.org in an essay on today’s daf.
One very snowy day, the Chatam Sofer (Rabbi Moshe Sofer) and his rebbe, Rabbi Nosson Adler, were riding in a carriage when the horses’ hooves became stuck in the frozen mud. Upon seeing that the wagon driver had procured a team of oxen as reinforcements to help the horses, Rabbi Adler jumped out of the carriage and began dancing in the snow in his stocking feet! When the Chatam Sofer asked what he was doing, Rabbi Adler replied: “If we would have sat in the wagon we would have violated the prohibition of kilayim. Now that I have finally merited to fulfill this rare mitzvah I feel filled with joy and cannot stop myself from dancing!”
Read all of Chullin 79 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on July 18, 2026. If you are interested in receiving the newsletter, sign up here.
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