The article is focused on the analysis of main factors affecting economic parameters of a dairy herd and a milk production. The analysis showing that daily milk yield, as a main revenue source, is depended on a length of calving interval. This one simultaneously affected number of born calves a year. Cow fertility disorders are the often cause of precocious culling of cows increasing replacement costs and decreasing an average milk production. Improvement of fertility and health parameters are key factors for improvement of dairy cows‘ profitability.