1,166. When the Animal Develops a Blemish

177:4 Nowadays, the first-born animal must be kept until it develops a blemish. Once this happens, it is shown to three Torah scholars, one of whom must be expert in identifying whether a blemish is permanent. If it is, they permit it. After this, the animal may be slaughtered and, if it proves kosher, eaten. The first-born animal may also be eaten by Israelites (i.e., non-kohanim), but it may not be sold in a butcher shop or weighed on a scale, nor may it be fed to dogs, or sold or given to a non-Jew.

177:5 If a first-born animal was born with a blemish, if there are local men who are qualified to permit it, it may be shown to them immediately. Once an animal has been permitted, it should not be retained for too long; if it was permitted within its first year, it may be retained until it reaches one year old. If it was permitted close to the end of its first year or after, it may not be retained longer than thirty days. If the owner violated this rule and kept the animal longer, it does not become disqualified.