"The Messenger of Allah ﷺ prohibited that an animal with a A'dab (stump) horn or ear should be slaughtered as a sacrifice." Qatadah (one of the narrators) said: "So I mentioned this to Sa'eed bin Al-Musayyab and he said: 'The A'dab is that which equals or more than that.'"
نَهَى رَسُولُ اللَّهِ ﷺ أَنْ يُضَحَّى بِأَعْضَبِ الْقَرْنِ وَالأُذُنِ قَالَ قَتَادَةُ فَذَكَرْتُ ذَلِكَ لِسَعِيدِ بْنِ الْمُسَيَّبِ فَقَالَ الْعَضْبُ مَا بَلَغَ النِّصْفَ فَمَا فَوْقَ ذَلِكَ