Zuhayr said: I think that Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrates from the Messenger of Allah (peace and blessings be upon him) that he (peace and blessings be upon him) said: "Bring me a quarter of a tenth." Then he narrated the long hadith, in which he said: "In thirty cattle there is one yearling calf, and in forty cattle one musinnah, and there is no zakah on working animals."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7294