Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) said (Zuhayr said: I think he narrates it from the Prophet (peace and blessings be upon him)), and he narrated the hadith, mentioning the zakah of silver, sheep and camels, and said: "If they exceed ninety by even one, there are two hiqqahs in them, ready to be mounted by the stud, up to one hundred and twenty. If the camels are more than that, then in every fifty there is a hiqqah, and in every forty such-and-such. And those grazing together are not to be separated, and those grazing separately are not to be combined, for fear of zakah."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7331