A total of 298 primi - and multiparous German Holstein cows of a high-production dairy herd ( average daily milk yield : 32 l ) were assigned randomly to a control or treatment group and were hand fed with 0 or 60 g/d of RPC as ReaShure , respectively , from 21 days before expected calving to 21 days post partum ( p. p. ) as a top dressing .