The Messenger of Allah(ﷺ) as saying No sadaqah is due from a Muslim on his slave or his horse.
Sunan Abi Dawud Book 9, Hadith 40
← Previous Hadith The Prophet (ﷺ) said: No sadaqah is due on a horse or a slave except that given at the breaking of the fast (at the end of Ramadan).

Sunan Abi Dawud Book 9, Hadith 39 Next Hadith → The Messenger of Allah(ﷺ) as saying A tenth is payable on what is watered by rain or rivers or brooks or from underground moisture and a twentieth on what is watered by draught camels.

Sunan Abi Dawud Book 9, Hadith 41