What is the ruling regarding milk drawn by a buyer from a non-withheld animal after purchase, if the buyer subsequently discovers a defect in the animal?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If a buyer purchases an animal that was not withheld (not for Tasriyat), milks it, and then discovers a defect, the buyer has the right to return the animal. If there was no milk present in the udder at the time of the contract, the buyer owes nothing for the milk drawn afterward, as the milk produced after the contract is considered property occurring under the buyer's ownership. If there was milk present at the time of the contract, but it was a small amount normally expected in an udder, no compensation is due because such a small quantity is insignificant by custom and follows the status of the subsequent milk.
Supporting text
If the milk present at the time of the contract was substantial, and the animal was otherwise sound regarding the milk quantity (i.e., not intentionally withheld), the ruling on whether the buyer must return the milk depends on the established ruling regarding the return of milk in cases of Tasriyat. If the ruling is that the milk cannot be returned, its remaining presence is treated as if it were destroyed. Returning the animal itself is subject to differing narrations concerning the return of a purchased item when a part of it is destroyed or becomes defective. The more common position within the Madhhab is that the return is permissible, requiring the buyer to return an equivalent amount of milk, as milk is considered a fungible item (mithli). The principle mandates compensation for fungibles by like kind, but the specific exception for Tasriyat milk is established by explicit text, meaning the general principle applies elsewhere.