The research comprised 15 cows in the winter feeding period and 15 in the summer feeding period, which aimed tracking down the changes in the blood parameters during the drying-out and lactation period. Blood from these animals was taken in three stages: I – the drying-out period (about 3 weeks before calving), II – the 2^nd day after calving, III- the lactation peak (50 the day after calving). In the samples taken the following were marked: glucose, insulin, ((only in the winter period), cholesterol, triglycerides (TAG), free fatty acid (FFA), alanine (ALT) and asparagine (AST) aminotransferaze. The FFA:Cholesterol and FFA:TAG quotients were also calculated. Substantially higher concentration of cholesterol, glucose and insulin was found in the dried cows than in those during lactation in the winter season. In all the research stages the concentration of triglycerides and free fatty acids was approximately at the same level as well as the FFA:TAG quotient and ALT activity. However the FFA:Cholestrol ratio was considerably lower in animals during lactation and AST activity the lowest in the drying-out period. In the summer season namely, there was a dramatic fall in the TAG, cholesterol and glucose concentration on the 2nd day after calving. In this period the FFA concentration went up but these were not statistically substantial changes. On the 2^nd day after calving the lowest values in comparison to the other periods were obtained both after calculating the FFA:TAG and FFA:Cholestrol quotient .ALT activity was higher in the dried cows than in those in the lactation period, but AST remained unchanged.

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