[Machine] The Messenger of Allah ﷺ forbade the castration of male horses.  

نَهَى رَسُولُ اللهِ ﷺ عَنْ عَسْبِ الْفَحْلِ  

Jabir b. 'Abdullah (Allah be pleased with him) reported that Messenger of Allah ﷺ forbade the hiring of a Camel to cover a she-Camel and from selling water and land to be tilled. So from all this the Messenger of Allah ﷺ forbade. (Using translation from Muslim 1565b)   

سَمِعْتُ جَابِرَ بْنَ عَبْدِ اللهِ يَقُولُ نَهَى رَسُولُ اللهِ ﷺ عَنْ بَيْعِ ضِرَابِ الْجَمَلِ وَعَنْ بَيْعِ الْمَاءِ وَالْأَرْضِ لِتُحْرَثَ فَعَنْ ذَلِكَ نَهَى رَسُولُ اللهِ ﷺ  

[Machine] "A man from the Banu Kilab asked the Messenger of Allah ﷺ about the lineage of a male horse, and he prohibited him from doing so. So, he said, 'O Messenger of Allah, we breed and honor, thus we inquire about lineage.'"  

أَنَّ رَجُلًا مِنْ بَنِي كِلَابٍ سَأَلَ رَسُولَ اللهِ ﷺ عَنْ عَسْبِ الْفَحْلِ فَنَهَاهُ عَنْ ذَلِكَ فَقَالَ يَا رَسُولَ اللهِ إِنَّا نُطْرِقُ وَنُكْرَمُ فَرَخَّصَ فِي الْكَرَامَةِ  

[Machine] The Messenger of Allah ﷺ prohibited it, so he mentioned it.  

نَهَى رَسُولُ اللهِ ﷺ فَذَكَرَهُ