INFLUENCE OF NIACIN SUPPLEMENTATION ON THE METABOLIC PARAMETERS AND LIPOLYSIS IN DAIRY COWS DURING EARLY LACTATION.

The objective of this study was to evaluate the effect of niacin on the metabolic parameters and lipolysis inhibition in dairy cows during early lactation. A total of 30 clinically healthy, multiparous Holstein-Friesian cows in late gestation were enrolled in the study (15 supplemented with niacin (120 g/d/cow) and 15 in the negative control group). Blood samples were taken weekly for 3 weeks after calving. The research results show that cows that received niacin indicated lower NEFA concentrations in all three weeks of the experiment. The NEFA concentrations did not change from weeks 0 to 2 after calving in the niacin group, whereas the NEFA concentrations in the control group were significantly increased (P<0.05). The administration of niacin exerted significant effects on the metabolic adaptations in cows during early lactation. Niacin significantly decreased BHB, MDA, total bilirubin, urea and phosphorus concentrations and liver enzyme activity (AST, ALP and GGT) and increased albumin, cholesterol, triglyceride and glucose concentrations. The administration of niacin significantly affected the correlation and regression between NEFA concentrations and other metabolic parameters, rendering the glucose, cholesterol, triglycerides, total bilirubin, AST, albumin, urea and phosphorus values less regressed against the NEFA values. In conclusion, niacin administration decreases lipolysis and metabolic adaptations proved to be less dependent on NEFA concentrations in niacin group compared to the control group.