Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) said: In every five cattle there is one sheep, in ten cattle two sheep, in fifteen three, and in twenty cattle four sheep.
Imam al-Zuhri (may Allah have mercy on him) said: When they reach twenty-five, there is one cow up to seventy-five; when they exceed seventy-five, there are two cows up to one hundred and twenty; and when they exceed one hundred and twenty, there is one cow in every forty. Ma'mar said: Al-Zuhri said: It has reached us that their saying that the Prophet (peace and blessings be upon him) said: "In every thirty cattle there is a yearling calf, and in every forty cattle one cow," was a relief for the people of Yemen, and then this came after that.
So this hadith is mawquf (stopping short of the Prophet) and munqati' (with a broken chain); it has also been narrated from al-Zuhri through another chain as munqati', and a munqati' report does not establish proof. The reports before it are better known.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7298