Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever buys a goat whose milk has been held back in its udders has the option for three days. If he wishes he may keep it, and if he wishes he may return it, and give a sa' of dates along with it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10730
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever buys an animal whose milk has been held back in its udders has the option for three days. If he returns it, he should give a sa' of grain, other than wheat."
Imam al-Bukhari (may Allah have mercy on him) said: Some narrated from Ibn Sirin: "a sa' of grain, and he has the option for three days."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10731