Suwayd ibn Ghaflah said:
I went myself or someone who accompanied the collector of the Prophet (ﷺ) told me: It was recorded in the document written by the Messenger of Allah (ﷺ) not to accept a milking goat or she-camel or a (suckling) baby (as zakat on animals); and those which are in separate flocks are not to be brought together, and those which are in one flock are not to be separated.

The collector used to visit the water-hole when the sheep went there and say: Pay the sadaqah (zakat) on your property. The narrator said: A man wanted to give him his high-humped camel (kawma'). The narrator (Hilal) asked: What is kawma', AbuSalih? He said: A camel a high hump.

The narrator continued: He (the collector) refused to accept it. He said: I wish you could take the best of my camels. He refused to accept it. He then brought another camel lower in quality than the previous one. He refused to accept it too. He then brought another camel lower in quality than the previous one. He accepted it, saying: I shall take it, but I am afraid the Messenger of Allah (ﷺ) might be angry with me, saying to me: You have purposely taken from a man a camel of your choice.

Abu Dawud said: This tradition has also been narrated by Hushaim from Hilal bin Khabbab to the same effect. But he said: Those which are in one flock are not to be separated.