Chapter on the Zakāt of Cattle
No zakāt is due on fewer than 30 head of cattle. When the herd reaches 30, is left to pasture, and a full lunar year has elapsed, the obligation is one tabīʿ or tabīʿah—that is, a year-old calf, whether male or female. At 40 the due becomes one musinnah (a two-year-old cow) or musann.
If the number exceeds 40, Abu Ḥanīfah rules that zakāt is levied on the surplus in proportion to the following scale, until the herd reaches 60: for one additional animal the owner pays the value of one quarter of a tenth of a musinnah; for two, one half of a tenth; for three, three quarters of a tenth; and for four, a full tenth.
Abu Yūsuf and Muḥammad hold that nothing is owed on the excess until the herd reaches 60, at which point the due is two tabīʿs (male or female yearlings). At 70 it is one musinnah and one tabīʿ; at 80, two musinnahs; at 90, three tabīʿs; and at 100, two tabīʿs and one musinnah. Water-buffalo and ordinary cattle are subject to the same rulings.