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Text Excerpt
הכי אמר רבי יוחנן: אפילו מום קל. והדתנן: רחל שילדה מין עז ועז שילדה מין רחל — פטורה מן הבכורה, ואם יש בו מקצת סימנין — חייב. מום קבוע הוי לשחוט עליו.
This is what R' Yoḥanan said: Even if only a slight blemish would result from the removal of the portion of the animal owned by the non-Jew, the animal still does not have firstborn status. And in addition, R' Yoḥanan also commented on that which we learned in a Mishnah (16b): A ewe that gave birth to a goat of sorts and a goat that gave birth to a ewe of sorts are exempt from the mitzva of the firstborn. And if the offspring has some of the characteristics of its mother, it is obligated, i.e., subject to the obligations of firstborn status. R' Yoḥanan commented: Nevertheless, it may not be sacrificed on the altar because this is a permanent blemish. Therefore, a priest is permitted to slaughter it outside of the Temple.
The Talmud asks: Granted that R' Yoḥanan’s first statement that the animal does not have firstborn status even if it has a slight blemish is necessary, as he teaches us that he holds in accordance with the opinion of Rav Huna, who said previously (2b) that even if the non-Jew owns only the ear of the firstborn it does not have firstborn status, and his statement is to the exclusion of the opinions of Rav Ḥisda and Rava, who said the non-Jew must own a portion of the fetus that would render it a carcass or a tereifa if it were removed.
אלא מום קבוע — מאי קא משמע לן? דכיון דאישתני הוה ליה מומא? תנינא: ופיו דומה כשל חזיר — הרי זה מום!
But with regard to R' Yoḥanan’s second statement that a goat of sorts that was born to a ewe but has some characteristics of the mother is considered to have a permanent blemish, what is it teaching us? Is it teaching that since it looks different from the normal appearance of a sheep this appearance is considered a blemish? We already learned this in the Mishnah (40a): Or with regard to a lamb whose mouth is similar to that of a pig, that is a blemish that enables slaughter of the firstborn.