It is narrated from Abu Huraira (may Allah be pleased with him) that the Prophet (peace be upon him) said: "Do not withhold the milk of camels and goats, and if someone buys an animal whose milk has been withheld, then after milking it, he has the option: if he likes it, he may keep it, and if he dislikes it, he may return it along with one sa’ of dates."
Hadith Referenceمسند الإمام الشافعي / كتاب البيوع / 1381
Hadith Takhrijاخرجه البخارى البيوع، باب النهى للباع أن لا يحفل الابل والبقر والغنم وكل محفلة (2150) ومسلم ، البيوع، باب تحريم بيع الرجل على بيع اخيه، وسومه ...... الخ (1515)۔