Is the stipulation valid if a female slave is required to produce a specific, measured amount of milk daily?

Chapter on Selling the Musarrah (Animal with milk retained in udder)

Al-Mughni

Book of Sales

Book 12 · Issue 4 · Bab 5

Open in Qurani

Primary text

The stipulation that a slave must yield a specific, known measure of milk daily is invalid because it cannot be fulfilled reliably, as milk production naturally varies and cannot be precisely controlled.