Hadith 5:128
Hafs narrated to us, from Ash'ath, from al-Sha'bi, who said: Regarding thirty cows, [the zakat is] a *tabi'* (a one-year-old male calf) or a *tabi'ah* (a one-year-old female calf) that has reached the age of *jadha'* (or *jadha'ah*). And regarding forty [cows], [the zakat is] a *musinnah* (a two-year-old cow).
حدثنا حفص عن أشعث عن الشعبي قال في ثلاثين بقرة تبيع أو تبيعة جذع أو جذعة وفي أربعين مسنة