Welfare, the level of animal comfort is that, what can make a great difference of economical results between herds with similar system of breeding. The goal of our effort in the field of animal welfare is to create the virtual system of evaluation the animal welfare from the point of physical condition maintained in the stables, the system and condition of feeding, maintenance care and the veterinary care. In the presented experiment was investigated the effect of supplementation of the daily feed ratiowith the various doses of the grained feed on the body mass growth of heifers, their entering into the gestation period, the course of gestation and the body mass of the calves born. A special objective of this experiment was the interpretation of the results by means of the new methodology based on the evaluation of the growth curve by the classical Gompertz function with the simultaneous evaluation of the energy balance with respect to the influence of the ambient environment.