The Messenger of Allah ﷺ said, "When one of you buys a milk camel or a sheep whose udder has been bound up to look full, he has the better of two choices after he milks it. Either he is satisfied with it, or else he returns it along with a measure of dates."
وقال رسول الله ﷺ إذا ما أحدكم اشترى لقحة مصراة أو شاة مصراة فهو بخير النظرين بعد أن يحلبها إما يرضى وإلا فليردها وصاعا من تمر
This is a sahih hadith, narrated by Muslim in volume 4, page 14, Shaab edition, and narrated by Abu Dawud, Ibn Majah, Shafii, Darimi, and Ibn Jarud, and Bukhari mentioned it without a full chain.The word musarrah comes from sarr, and also from sirr, meaning the tying up of the animal's teats. Its meaning is the accumulation of milk in the udder when one intends to sell it, so that the udder appears large and the buyer thinks that the abundance of milk is its usual, continuous state.Shafii said, tasriyah means tying up the teats of a she-camel or a ewe and leaving it unmilked for two or three days until the milk collects, so that the buyer raises the price because of this, thinking it is her normal habit.Abu Ubayda said, it comes from sarra al-laban fi dirihā, meaning he confined it there, and tasriyah is forbidden whether it is done to a she-camel, a cow, a ewe, a slave girl, a mare, a female donkey, or anything else, because it is fraud and deception. The sale of such an animal is valid despite being forbidden, and the buyer has the choice of keeping it or returning it.The word laqhah, with the lam vowelled either as kasrah or fathah (the kasrah being more correct linguistically), refers to a she-camel that has recently given birth, about two or three months earlier.Khattabi said, the statement of Abu Ubayd is hasan, and the statement of Shafii is sahih. He said, the Arabs used to tie up the udders of milking animals. He argued for the correctness of Shafii's statement by citing the Arab saying, "One does not excel at the charge," meaning the assault in battle, "unless he excels at milking and tying up the udder," and by the words of Malik bin Nuwayrah, "I said to my people, these are your charity animals, their teats tied up, not left to swell painfully."He said, it is possible that the origin of musarrah is musrurah, with one of the two ras changed into an alif, similar to His saying, "and he has failed who has concealed it" [Shams 91:10], meaning he hid it through ignorance, that is, he concealed it, they disliked the combination of three letters of the same kind.