The research has been carried out with the project named as «Study of feeding of highly productive cows under different confinement systems with the account of their biochemical status and milk quality in the European North of the Russian Federation». Regular biochemical blood tests make it possible to respond, to classify and to take measures for eliminating the adverse impact in a timely way. The article describes the results of biochemical blood tests of highly productive cows in tie-up and freestall housing in different periods of their physiological cycle.