Yahya related to me from Malik from Yahya ibn Said that Muhammadibn Yahya ibn Habban said, "Two men from the Ashja tribe told me thatMuhammad ibn Maslama al-Ansari used tocome to them to collect theirzakat, and he would say to anyone who owned livestock, 'Select (theanimal for) the zakat on your livestock and bring it to me,' and hewould accept any sheep that was brought to him provided it met therequirements of what the man owed."Malik said, "The sunnawith us, and what I have seen the people of knowledge doing in ourcity, is that things are not made difficult for the muslims in theirpaying zakat, and whatever they offer of their livestock is acceptedfrom them."
USC-MSA web (English) reference: Book 17, Hadith 29
Arabic reference: Book 17, Hadith 606