Musannaf Ibn Abi Shayba 35:136

Waki' narrated to us, Hammad bin Salamah narrated to us, from Muhammad bin Ziyad, from Abu Hurairah, who said: The Prophet (peace be upon him) said: "Whoever buys a *musarrah* (an animal whose milk has been withheld in the udder to deceive the buyer), he has the choice regarding it; if he wishes, he may return it and return with it a *sa'* of dates."