An old cow which is set free during the funeral rites and which is believed to help the deceased to cross the Vaitaraṇī (a fetid river between the earth and naraka or the nether world) is technically called anustaraṇī.
Since the root ‘stṛ’ has the sense of ‘spreading,’ anustaraṇī may also refer to an old cow which is immolated during the funeral rites, dissected and its various limbs spread on the dead body. This practice, however, ceased to exist long back.
The anustaraṇī is sometimes called rājagavī also.
See also ANTYEṢṬI.