Salim narrates from his father (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) wrote out the zakah dues, but he had not yet sent it to his officials when he (peace and blessings be upon him) passed away, so it was tied to his (peace and blessings be upon him) sword. Then Abu Bakr (may Allah be pleased with him) implemented it until he too passed away, then Umar (may Allah be pleased with him) acted upon it until he too passed away. It was as follows: "On five camels one goat, on ten camels two goats, on fifteen camels three, and on twenty four goats. On twenty-five camels a bint makhad (one-year-old), up to thirty-five. When they exceed that, up to forty-five a bint labun. Then if they exceed that, up to sixty a hiqqah. Then if more than that, up to seventy-five a jadha'ah. If more than that, up to ninety two bint labun. If they exceed that, up to one hundred and twenty two hiqqahs (three-year-olds). Then if the camels are more than even that, on every fifty a hiqqah and on every forty a bint labun. On forty sheep there is one sheep, up to one hundred and twenty. When they exceed that, up to two hundred there are two sheep. When they exceed two hundred, up to three hundred there are three sheep. When the sheep are more than that, on every hundred there is one sheep; until the number reaches a hundred there is no sheep due on it. Flocks grazing together are not to be separated, nor flocks grazing separately combined, for fear of zakah. Those who are partners will settle equally between themselves. In zakah, neither an old sheep nor a defective one is to be taken."
Al-Zuhri (may Allah have mercy on him) said: They are to be divided into three parts, the best, the middling and the inferior, and the zakah is to be collected from the middling.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7252