Is it permissible to stipulate that what is in the cow's womb not be included in the sale?

The fetus is included in the sale of a pregnant animal by consensus (ijma'). The fetus and the fruit are included in every voluntary contract, such as sale and lease. If the seller stipulates that the fetus belongs to him, the contract and the exception are invalid because the fetus in the womb is unknown, and the ignorance of the subject matter of the contract prevents its permissibility. The Prophet, peace and blessings be upon him, forbade the sale of al-madameen (fetuses in wombs), al-malaqeeh (male camels whose sperm is used for breeding), and habal al-habala (the offspring of the offspring of a pregnant camel). Some scholars have held the view that it is permissible to exclude the fetus, based on the argument that the seller's exclusion of the fetus does not involve ignorance, as it is like selling a barren animal. The way to resolve this difference of opinion is by not excluding the fetus, unless there is a need to do so.