The Messenger of Allah ﷺ wrote regarding the zakat on cattle that when the number of cattle reaches thirty, a yearling male or female calf is due. This continues until the count reaches forty. When it reaches forty, a mature cow is due. When the cattle become numerous, for every forty head of cattle, one mature cow is due.
حدثنا عفان حدثنا مسعود بن سعد حدثنا خصيف
كتب رسول الله ﷺ في صدقة البقر إذا بلغ البقر ثلاثين ففيها تبيع من البقر جذع أو جذعة حتى تبلغ أربعين فإذا بلغت أربعين ففيها بقرة مسنة فإذا كثرت البقر ففي كل أربعين من البقر بقرة مسنة
Its chain is daif because of a break in it. Masud bin Saad Jufi is trustworthy, having been deemed reliable by Ibn Main, Nasai, and others. Bukhari mentioned him in Tarikh al-Kabir 4/1/423, and it is related from Yahya bin Adam that he said, "Masud was among the finest of Allah's servants."His name was confused in [kh], where it was written as both Ibn Masud and Ibn Saad, and we have corrected it based on [k]. The hadith was narrated by Tirmidhi 2:4 and Ibn Majah 1:284 in abridged form, through the route of Abdul-Salam bin Harb from Khaseef. Tirmidhi said, "Abu Ubayda bin Abdullah did not hear from his father."The tabi' is a calf in its first year. The jadha' among cattle is one that has entered its second year.Musinnah, Ibn Athir said, Azhari said, the cow and the sheep are given the designation "musinn" when they grow their second teeth, which happens in their third year. The meaning of their being musinn is not that they have grown old as an old man grows old, but rather that their tooth emerges in the third year.