And this Mishnah will talk about the firstborn of a kosher (ritually fit) animal that looks like a different animal. It doesn’t look like its mother. How do we treat it in terms of whether it is a Bechor (firstborn) or not?
The Mishnah says: If you have a female sheep that gave birth to a firstborn that looks like a goat, the baby sheep is deformed and looks like a goat, not like a sheep. The opposite case is if you have a goat that gave birth to a firstborn that looks like a sheep. It does not look like a goat. It’s deformed as well. They’re exempt from the laws of Bechor.
The laws of Bechor, which we learn from Pesukim (verses), require that the animal look like its mother. The firstborn resembles its mother. That’s when the laws of Bechor kick in. But if the firstborn doesn’t look exactly like its mother, yet you can identify that it belongs to its mother’s species, it’s chayav, it’s subject to the laws of Bechor. You can tell it resembles its mother in some way. It doesn’t look exactly like her. There’s definitely some sort of deformity, but you can still tie it back to the species of its mother. We would consider it to be blemished. Therefore, other laws would apply to it. It would be subject to the laws of a blemished Bechor. We wouldn’t offer it on the Mizbeach (altar), but the Kohen (priest) would slaughter it, and he would eat it outside of the Beit HaMikdash (Temple), if it resembles its mother in some capacity.