Narrated Abdullah ibn Abbas: The Prophet (ﷺ) said: If anyone has sexual intercourse with an animal, kill him and kill it along with him. I (Ikrimah) said: I asked him (Ibn Abbas): What offence can be attributed to the animal/ He replied: I think he (the Prophet) disapproved of its flesh being eaten when such a thing had been done to it. Abu Dawud said: This is not a strong tradition.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ النُّفَيْلِيُّ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ مُحَمَّدٍ، حَدَّثَنِي عَمْرُو بْنُ أَبِي عَمْرٍو، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ أَتَى بَهِيمَةً فَاقْتُلُوهُ وَاقْتُلُوهَا مَعَهُ " . قَالَ قُلْتُ لَهُ مَا شَأْنُ الْبَهِيمَةِ قَالَ مَا أُرَاهُ إِلاَّ قَالَ ذَلِكَ أَنَّهُ كَرِهَ أَنْ يُؤْكَلَ لَحْمُهَا وَقَدْ عُمِلَ بِهَا ذَلِكَ الْعَمَلُ . قَالَ أَبُو دَاوُدَ لَيْسَ هَذَا بِالْقَوِيِّ .
sunnah.com