The two sons of Jabir narrate from Sayyiduna Jabir (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), that he (peace and blessings be upon him) said: "There is no zakah on less than five wasq, there is no zakah on less than five uqiyah, and there is no zakah on less than five camels."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7423