The Prophet ﷺ had a special share called the safi. He could choose a male slave, a female slave, or a horse, selecting it before the fifth was set aside.
حدثنا محمد بن كثير أخبرنا سفيان عن مطرف
كان للنبي ﷺ سهم يدعى الصفي إن شاء عبدا وإن شاء أمة وإن شاء فرسا يختاره قبل الخمس
No references are available.
[Its chain of transmission is daif] Reported by Nasai, section on al-fay, chapter 1, no. 4150, from the hadith of Mutarrif in this manner. The chain is mursal.