A man who gives a gift

It is narrated from al-Zuhri that Sayyiduna Umar (may Allah be pleased with him) gave a judgment concerning a man who had given another man an animal as a gift, and the animal then gave birth. He said: "He may take back its value, according to the day on which he gave the gift."

Umar bin Abd al-Aziz wrote: "He may go back on the gift at its value on the day he gave it." And he further wrote that if the gifted item increases (for example, it gives birth and so on), that increase belongs to the one who received the gift.