Musannaf Ibn Abi Shaybah 10160 — Zakah on camels: what is due on them

Yahya bin Sa'id said: When Umar bin Abd al-Aziz sent them to collect zakah, he wrote them a letter. He wrote that on twenty-five camels, one bint makhad is due as zakah, and when they exceed that, one male ibn labun is due as zakah.