Daf Yomi: Chullin 79 (cycle 13) | Rabbi Shmuel Silber

Rabbi Silber's Daf Yomi shiur on Chullin 79 continues the sugya of oso v'es b'no, the prohibition against slaughtering a mother animal and its young on the same day, and turns to a sharper technical question: for the laws of kilayim (forbidden crossbreeding), does an animal's halachic identity follow its mother, its father, or both? The Gemara works this out through the case of mules and the koy — the mysterious offspring of a goat and a deer — probing how far a hidden, uncertain lineage can shape what the law considers an animal to be.

• Halacha generally traces an animal's identity through its mother rather than its father, with real consequences for the laws of kilayim.
• Two mules can look identical yet differ halachically depending on which parent was the horse and which was the donkey.
• Visible physical signs — ears, tail, voice — can be enough to establish an animal's legal identity even without certainty about its lineage.
• The koy, born of a goat and a deer, is treated with halachic caution across several areas of law precisely because its category was never fully resolved.