Sahih Muslim Book 10, Hadith Number 3634.
Chapter : Command pertaining to the selling of animal whose udder is tied up.
Abu Huraira (Allah be pleased with him) reported Allah’s Messenger (may peace be upon him) as saying: He who bought a goat having its udder tied up should go back with it, milk it, and, if he is satisfied with its milk, he should repair it, otherwise he should return it along with a sa’ of dates.