Bechoros 2:9 - 3:1

יוצא דפן (a fetus extracted by means of the cesarean section) – its mother was operated upon by a section and they removed the fetus through its walls.

והבא אחריו – that which is born after it through the path of the womb.

ירעו עד שיסתאבו – for it is doubtful to Rabbi Tarfon if the firstling of the offspring is holy even though it is not a firstling to the womb, such as a fetus extracted by means of cesarean section which is the first that is born even though it did not open up the womb. If it is a firstling to the womb, it is holy even though it is not the firstling to the offspring, as for example, that which comes after one born by means of cesarean section which is the first that opened the womb bur is not the firstling of the offspring since the one born by means of cesarian section preceded it. But from doubt, both are sent to pasture until they develop blemishes and their owners will consume them with their blemishes for perhaps, we require both [that it is the first to open the womb and the first one born] of them to be firstlings of offspring and to [the opening of] their wombs, but neither one of them is holy. But he who wants to exact [compensation] from his fellow bears the burden of proof. But for Rabbi Akiva, it is obvious to him that we require both [of these prerequisites] require, and not a single one of them is holy. And the Halakha is according to Rabbi Akiva.

הלוקח. עז בת שנתה – [a goat] a year old that produced an offspring within its first year.

ודאי- that offspring belongs to the Kohen, for prior to this it had not produced offspring.

ספק - it would be sent to pasture until a blemish befalls it and the owners would consume it in its blemishes (see Tractate Bekhorot, Chapter 2, Mishnayot 6-7). But if it is a doubtful firstling donkey, he would separate a lamb and it would be his.

טנוף (discharge from the womb indicating abortion) – bubbles/pustules of blood that the animal discharges. And they show them to a wise shepherd and recognizes them if they are because of the pregnancy that it miscarried and perhaps it discharged within the first year which is a doubtful offspring and it is exempt from the laws of firstlings, therefore, even a goat that is one year old is doubtful.

שליא – a kind of covering over the fetus that the fetus is lying in it (i.e., placenta).

שפיר – above from the placenta is a membrane/skin that has in it congealed blood and it is called the sac of a fetus. And my teachers/Rabbis explained, it is a piece of flesh that has on it the form of a human. But there are those who say that is called a sac of a fetus, because it is made like a tube.

ששפעה חרדת דם (that discharged a clod of blood) – that discharged a portion of blood (see also Tractate Hullin, Chapter 4, Mishnah 7 regarding to the placenta).

הרי זו תקבר – to inform that it was exempted from the [law of] the firstling, for a person who sees that they bury it knows that what comes after it (i.e., born afterwards) is not holy for the [law of] the firstling. And the Halakha is according to Rabbi Akiva and [according to] Rabbi Eliezer ben Yaakov.