For the research Latvian Brown breed (LB) cows were selected and assigned by the analogy principle to two treatments groups (n=2x12). During the trial, the dairy cows received the total feed mix (TMR) which consisted, calculating per cow per day of: 20 kg maize silage (45.15% by mass), 16 kg cereal grass - clover silage (36.12% by mass), 2 kg hay (cereal grass - clover) (4.51% by mass), 4 kg concentrated feed mixture (rape oil - cake-barley meal) (9.03% by mass), 2 kg protein concentrate (4.53% by mass), 0.1 kg mineralpremix ViloMin 9/6 (0.22% by mass), 0.1 kg sodium chloride (0.22% by mass) and 0.1 kg sodium carbonate (0.22% by mass). The analysis of the productivity indicators suggests that the milk yield in the experimental group of cows was approximately 0.17 to 1.02 kg ECM per day higher than that in the control group of cows. Feeding cows with the mineral and vitamin blocks has contributed to the improvement of indicators of the reproductive abilities: shortening of the service period by 9 days, the insemination index by 0.1 and the number of pregnant cows from the first insemination by 16%, as compared with the control group. Feeding of the supplementary blocks left a positive effect on the process of parturition of cows.