That the Messenger of Allah ﷺ said: "Whomever you see having relations with an animal then kill him and kill animal." So it was said to Ibn 'Abbas: "What is the case of the animal?" He said: "I did not hear anything from the Messenger of Allah ﷺ about this, but I see that the Messenger of Allah ﷺ disliked eating its meat or using it, due to the fact that such a (heinous) thing has been done with that animal."  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ وَجَدْتُمُوهُ وَقَعَ عَلَى بَهِيمَةٍ فَاقْتُلُوهُ وَاقْتُلُوا الْبَهِيمَةَ فَقِيلَ لاِبْنِ عَبَّاسٍ مَا شَأْنُ الْبَهِيمَةِ قَالَ مَا سَمِعْتُ مِنْ رَسُولِ اللَّهِ ﷺ فِي ذَلِكَ شَيْئًا وَلَكِنْ أُرَى رَسُولَ اللَّهِ كَرِهَ أَنْ يُؤْكَلَ مِنْ لَحْمِهَا أَوْ يُنْتَفَعَ بِهَا وَقَدْ عُمِلَ بِهَا ذَلِكَ الْعَمَلُ  

"Whoever has relations with beast, then there is no legal punishment for him."  

أَنَّهُ قَالَ مَنْ أَتَى بَهِيمَةً فَلاَ حَدَّ عَلَيْهِ حَدَّثَنَا بِذَلِكَ مُحَمَّدُ بْنُ بَشَّارٍ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ حَدَّثَنَا سُفْيَانُ الثَّوْرِيُّ وَهَذَا أَصَحُّ مِنَ الْحَدِيثِ الأَوَّلِ وَالْعَمَلُ عَلَى هَذَا عِنْدَ أَهْلِ الْعِلْمِ وَهُوَ قَوْلُ أَحْمَدَ وَإِسْحَاقَ