Is 'Umra valid for non-immovable property such as animals or plants?

Primary text

The 'Umra is valid for non-immovable property, such as animals and plants, because it is a type of gift, and gifts are valid for such property. Regarding the ruling on the 'Umra of a female slave (Jariyah), Ahmad expressed reservations about conjugal relations (Wat'), not due to lack of ownership, but out of piety, given the scholarly dispute over whether the 'Umra transfers ownership or merely usufruct.