M. Veličković, D. Vuković
Journal name not available for this finding
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<0.05). It can be concluded on the grounds of the results obtained in this work that the average concentration of beta-carotene and vitamin A in blood serum of cows in advanced gravidity and on the day of calving is within the limits of physiological values and in keeping with the values cited in literature, and that concentrations of beta-carotene and vitamin A in blood serum of cows two weeks after calving are significantly lower than the values obtained in advanced gravidity and on the day of calving and are lower than the physiological values most often reported in literature for this animal specie.