The functional state of liver cells in dairy cows during transition and lactation

Abstract

The objective of this study was to determine characteristic blood parameters, i.e. indicators of the functional state of liver in the following groups of cows: in cows (n=15) from day 15 to day 1 prior to parturition, in cows (n=15) from day 1 to day 15 after parturition and in those (n=15) from day 90 to day 100 of lactation. Blood glucose levels were statistically significantly lower in the early lactation cows than in the preparturient cows and those examined during the maximum lactation period, which suggested an increased glucose uptake by the mammary gland at the beginning of lactation and decreased gluconeogenesis in the liver as induced by fatty infiltration and liver cell degeneration. The significantly lower blood triglyceride levels as well as the low total blood cholesterol levels in the postparturient cows reflected their accumulation in liver cells, as opposed to the cows before parturition and those during maximum lactation. Significantly lower blood levels of total protein, albumin and urea were recorded in the postparturient cows, which suggested the reduced synthetic capacity of liver cells in the early lactation cows. Blood bilirubin levels in the early lactation cows were significantly higher as compared to the preparturient and maximum lactation cows, which clearly indicated the reduced excretory capacity of the liver. Significantly increased AST, GGT and LDH activities in the blood in the postparturient cows clearly evidenced the disturbed morphological and functional integrity of liver cells and the release of these intracellular enzymes into the blood due to the fat accumulation in the hepatocytes. The obtained results suggested that fatty infiltration and different degrees of liver cell degeneration were recorded in the early lactation cows, as opposed to the preparturient cows and those during maximum lactation showing preserved morphological and functional capacities of hepatocytes.