EN
The aim of the study was to establish the influence of dried yeast and a preparation isolated from the walls of beer yeast cells (MOS) on the yield and composition of milk of Polish Hf breed cows (red-white strain), fed in the PMR system, during the first 100 days of lactation, and taking physiological-biological as well as morphotic blood factors into consideration. Dried yeasts produced by InterYeast® Krosniewice and Biolex® MB 40 preparation isolated from the walls of beer yeast cells (MOS) produced by Leiber GmbH were used. The experiment was conducted on 75 cows of Hf (red-white) breed, kept on tethers. The cows were calving from June till August, joining randomly (in turn) the 1st, 2nd or 3rd experimental group. Starting from 7th day before planned calving, cows of the 1st group were given an additional preparation at the amount of 200 g/ head/day (including 80 g of yeast); cows of 2nd group MOS preparation an amount of 50 g/head//day (including 20 g of mannoligosaccharides), cows of 3rd group were the control and were not given any additives. Eight cows from each group (24 in total) were randomly chosen for the analysis of biochemical factors and blood morphology. The use of preparations: dried beer yeasts and MOS in high milk cows feeding in first 100 days of lactation caused a statistically significant rise of milk yield, 3 and 2.2 kg of milk/day respectively, in comparison to cows that were not given such additives. A statistically significant increase of erythrocytes and leucocytes number in the blood of experimental cows was observed, and a significant decrease of somatic cells count (SCC) in milk, which proves that the use of yeast preparations had favorably stimulated the immune system.