It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) commanded us to examine the eye and the ear (of the sacrificial animal) carefully, and not to sacrifice an animal whose ear is cut at the front, or cut at the back, or split, or has a hole in it. Abu Ishaq explained that muqabalah is one whose ear has its tip cut off, mudabarah is one from the side of whose ear something has been cut, sharqa' is one with a split ear, and kharqa' is one with a pierced ear. All the chains of this hadith are sahih (authentic), but the two Shaykhs (Bukhari and Muslim) did not record it. My assumption is that this is due to an addition in the narration of Qays bin al-Rabi' from Abu Ishaq, although the two Shaykhs did not use Qays as evidence.