Many dairy farms rely on a feeding regimen that can be described as ad libitum or at least intensified and expect this to result in significant gains in growth and calf health at the herd level. Yet any feeding concept can only work as well as the calf's passive immunity allows. What matters is not only the amount of colostrum offered but primarily the immunoglobulin absorbed, and therefore the quality, feeding time and hygiene of first colostrum. This presentation places findings from a feeding trial under farm conditions into context and shows which points in the daily farm routine determine calves' immune status. The focus is on colostrum management, hygiene and rearing strategies.