Hadith 5:123
Ibn Numayr narrated to us, from Ubayd Allah ibn Umar, from Nafi, who said: It reached me that Mu’adh said: "In thirty [cows] is a tabi’ (a one-year-old calf), and in forty [cows] is a musinna (a two-year-old cow)."
حدثنا بن نمير عن عبيد الله بن عمر عن نافع قال بلغني أن معاذا قال في ثلاثين تبيع وفي أربعين بقرة