Mishkat al-Masabih 6 Zakat كتاب الزكاة 29

وَعَنْ مُعَاذٍ: أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَمَّا وَجَّهَهُ إِلَى الْيَمَنِ أَمْرَهُ أَنْ يَأْخُذَ مِنْ الْبَقَرَة: مِنْ كُلِّ ثَلَاثِينَ تَبِيعًا أَوْ تَبِيعَةً وَمِنْ كل أَرْبَعِينَ مُسِنَّةً. رَوَاهُ أَبُو دَاوُدَ وَالتِّرْمِذِيُّ وَالنَّسَائِيُّ والدارمي

Mu’adh said that when the Prophet sent him to the Yemen he ordered him to take a male or female calf of a year old for every thirty cattle and a cow in its third year for every forty. Abu Dawud, Tirmidhi, Nasa’i and Darimi transmitted it.