It is narrated from Abu Huraira (may Allah be pleased with him) that he stated: The Messenger of Allah (peace and blessings be upon him) said: "Do not withhold the milk of camels and goats, and whoever buys an animal whose milk has been withheld, he has the option, after milking it, 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 / 1382
Hadith Takhrijصحيح اخرجه النسائي، البيوع، باب النهي عن المصراة وهو ان يربط اخلاف الناقة او الشاة...... الخ (4492) - واحمد: (2/ 242)۔