The foster cow system is an alternative way of calf rearing, where two to four calves are simultaneously nursed by one cow, which is not additionally milked. Therefore, it represents a compromise between the increasing demands for more animal welfare and the immediate separation of cow and calf after calving. Based on the literature, essential aspects of this type of husbandry were summarized. The calves seem to benefit primarily from natural sucking behavior and living in a social group. Negative effects on calf health have not yet been proven. Problems arise mainly when the foster cow does not accept her foster calves or prefers certain calves. Suckling might also help to improve the udder health of the foster cow. Nevertheless, there is a lack of current and methodically precise studies, which also consider a possible transfer of pathogens between cow and calves during suckling. The same applies for the impact of suckling on diseases of the periparturient cow as well as the optimal duration of the suckling period.