Zakat (Kitab Al-Zakat)
Dawud :: Book 9 : Hadith 1656
Narrated AbuHurayrah:
I heard the Apostle of Allah (peace_be_upon_him) as saying something similar to this tradition. He (the narrator) said to AbuHurayrah: What is due on camels? He replied: That you should give the best of your camels (in the path of Allah), that you lend a milch she-camel, you lend your mount for riding, that you lend the stallion for covering, and that you give the milk (to the people) for drinking.