Concentration of beta-carotene and vitamin A in blood serum of cows in peripartal period

In a herd of high-productive dairy cows of the Holstein breed, 40 cows were selected for an experiment. The animals were chosen at the period of advanced gravidity. Data on mean values of beta-carotene concentrations in blood serum of the cows show that significantly higher values (p<0.01) were established in advanced gravidity (x=9.53± 3.49 μmol/l) in comparison with the values on calving day (x=5.69±3.14 μmol/l) and in early puerperium (x=2.25±1.00 μmol/l). The average concentration of vitamin A in blood serum of cows varied approximately the same as the concentration of beta-carotene. The highest average concentration of vitamin A in blood serum of cows was determined in advanced gravidity (x=1.856±0.52 μmol/l), and the lowest in early puerperium (x=0.988±0.31 μmol/l) (p