حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ قَالَ بَلَغَنِي أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ، كَانَ يَقُولُ لِلْفَرَسِ سَهْمَانِ وَلِلرَّجُلِ سَهْمٌ ‏.‏ قَالَ مَالِكٌ وَلَمْ أَزَلْ أَسْمَعُ ذَلِكَ ‏.‏ وَسُئِلَ مَالِكٌ عَنْ رَجُلٍ يَحْضُرُ بِأَفْرَاسٍ كَثِيرَةٍ فَهَلْ يُقْسَمُ لَهَا كُلِّهَا فَقَالَ لَمْ أَسْمَعْ بِذَلِكَ وَلاَ أَرَى أَنْ يُقْسَمَ إِلاَّ لِفَرَسٍ وَاحِدٍ الَّذِي يُقَاتِلُ عَلَيْهِ ‏.‏ قَالَ مَالِكٌ لاَ أَرَى الْبَرَاذِينَ وَالْهُجُنَ إِلاَّ مِنَ الْخَيْلِ لأَنَّ اللَّهَ تَبَارَكَ وَتَعَالَى قَالَ فِي كِتَابِهِ ‏{‏وَالْخَيْلَ وَالْبِغَالَ وَالْحَمِيرَ لِتَرْكَبُوهَا وَزِينَةً‏}‏ وَقَالَ عَزَّ وَجَلَّ ‏{‏وَأَعِدُّوا لَهُمْ مَا اسْتَطَعْتُمْ مِنْ قُوَّةٍ وَمِنْ رِبَاطِ الْخَيْلِ تُرْهِبُونَ بِهِ عَدُوَّ اللَّهِ وَعَدُوَّكُمْ‏}‏ فَأَنَا أَرَى الْبَرَاذِينَ وَالْهُجُنَ مِنَ الْخَيْلِ إِذَا أَجَازَهَا الْوَالِي وَقَدْ قَالَ سَعِيدُ بْنُ الْمُسَيَّبِ وَسُئِلَ عَنِ الْبَرَاذِينَ هَلْ فِيهَا مِنْ صَدَقَةٍ فَقَالَ وَهَلْ فِي الْخَيْلِ مِنْ صَدَقَةٍ

Yahya related to me that Malik said that he had heard that Umaribn Abd al-Aziz used to say, "The man on horse-back has two shares,and the man on foot has one." Malik added, "I continue tohear the same." Malik, when asked whether a man who waspresent with several horses took a share for all of them, said, "Ihave never heard that. I think that there is only a share for thehorse on which he fought." Malik said, "I think that foreignhorses and half-breeds are considered as horses because Allah, theBlessed, the Exalted, said in His Book, 'All horses, and mules, andasses, for you to ride, and as an adornment.' (Sura16 ayat 8). Hesaid, the Mighty, the Majestic, 'Make ready for them whatever forceand strings of horses you can, to terrify thereby the enemy of Allahand your enemy.' (Sura 8 ayat 60). I think that foreign breeds andhalf-breeds are considered as horses if the governor accepts them." Said ibn al-Musayyab was asked about working horses, andwhether there was zakat on them. He said, "Is there any zakat onhorses.?" Translation Not Available

Book Ref: Muwatta Imam Malik Book 21 Hadith 982
Web Ref:  Muwatta Imam Malik Book 21 Hadith 21