Evaluation of liver transaminases activities in lactating cows in different diet conditions

The aim of the study was to determine the correlation of liver transaminases’ activities levels in dairy cows in farm breeding with the parameters of milk gained after milking, in feeding conditions with and without the addition of sunflower oil. The study included 30 cows from the 2nd to 7th lactation divided into three groups with 10 heads in each. The first group (group A) consisted of cows at lower production level (13-15 kg of milk), the second group (group B) of cows at medium (19-21 kg of milk), and the third group (group C) of cows at higher production level (25-27 kg of milk). The cows were kept on a controlled feeding regime, common for lactating cows’ meals with the addition of sunflower oil. Milk control as well as milk and blood sampling were performed at the beginning, middle and at the end of the experiment, i.e. Day 1 (sampling 0), Day 21 (sampling 1) and Day 42 (sampling 2). Blood samples were taken by puncture of the V. jugularis with the aim of obtaining plasma and measuring liver transaminases: AST, ALT and ALP. Serum enzyme activity levels ranged within physiological limits. Statistically significant differences between groups of experimental cows were found after the addition of sunflower oil. Elevated level of AST activity was found in the context of a positive correlation with the amount of milk gained after milking in both feeding methods, i.e. with and without the addition of sunflower oil. Obtained results could indicate the necessary compensatory intensification of metabolic processes as a liver response to additional stress due to higher flow of fatty components.