The paper summarizes the losses of calves in the milk nutrition period and their causes and clarifies stress factors affecting calves during rearing. In the introduction, attention was paid to the definition of calves (legislative view of this age category). Further attention was paid to the calving pens, or more precisely the matter of an effective determination of the number of birthplaces (the aspect of the seasonal calving and its’ fluctuations included.) The paper also deals with the problematics of paired housing as a perspective system of calf housing in the milk nutrition period. The comments to the field of milk nutrition were summarized in the conclusion – non-market milk feeding, elimination of diarrheal diseases of calves, the milk and milk fodder mixture quality control using refractometer and so on.