وَقَالَ أَبُو يُوسُفَ وَمُحَمَّدٌ: لَا زَكَاةَ فِي الْخَيْلِ
Translation: Abu Yusuf and Muhammad said: There is no zakat on horses.
Their statement concerns the distinct livestock levy on horses, not the established zakat on horses purchased and owned as trade inventory.