[If] one buys an animal from a non-Jew, and it is not known whether it had borne its first [offspring] or not —- R’ Yishmael says: [The offspring of] a goat in its first year certainly belongs to a Kohen, from here on it is questionable; [the offspring of] a ewe in its second year certainly belongs to a Kohen, from here on it is questionable; [the offspring of] a cow or donkey in its third year certainly belongs to a Kohen, from here on it is questionable. R’ Akiva said to him: If offspring alone would exempt the animal, it would be as you say; but they said: The sign of offspring in small livestock [is] a womb-discharge; and in large livestock, an amniotic sac; and in a woman, an embryo or an amnioti sac. This is the rule: [With] any [animal] known to have previously borne its first, the Kohen receives nothing; and [with] any one that had not borne its first, this [first male offspring] belongs to the Kohen; if it is questionable, it may be eaten in its blemished [state] by the owner.  R’ Eliezer ben Yaakov says: [If] a large livestock animal discharges a mass of congealed blood, it must be buried, and it is exempt from the laws of bechor.

Rabban Shimon ben Gamliel says: [If] one buys a nursing animal from a non-Jew, he need not suspect that it was the offspring of another animal. [If] he entered among his flock and saw that those that had just borne for the first time were nursing, and that those that had previously given birth were nursing [as well], he need not suspect that the offspring of this one came to that one, or that the offspring of that one came to this one.

R’ Yose ben Meshullam says: [If] one slaughters a bechor he may make a space for a butcher’s hatchet on either side, and pluck the hair, provided that he does not dislodge it from its place. The same [is true for] one who plucks the hair to observe the place of a blemish.

[If] the hair of a blemished bechor fell out and he placed it in a recess in the wall, and afterward [he] slaughtered it —- Akavya ben Mahalalel permits [it], and the Sages prohibit [it]; [these are] the words of R’ Yehudah. R’ Yose [however] said: Not in this [case] did Akavya [alone] permit [it]. Rather [they argued about] the hair of a blemished bechor that fell out and was placed in a recess, and afterward [the animal] died —- in this [case], Akavya ben Mahalalel permits [it] and the Sages prohibit [it].  [If] wool is hanging from a bechor —- that which appears to be from the shearing is permissible; and that which does not appear to be from the shearing is prohibited.