ACTIVITIES OF ALT, AST, ALP AND LDH ENZYMES IN CATTLE BLOOD PLASMA DEPENDING ON REPRODUCTIVE CYCLE AND SEASONAL CHANGES

Abstract

The study was aimed at determining levels of alanin aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in the plasma of 229 dairy Holstein-Friesian breed cows in different stages of the re¬production cycle and regarding the seasonal changes (diet conditions). Cows were divided into the groups: lactation (Group A), postpartal period within 15 days from calving (Group B) and dry period (Group C). Seasonal variations affected AST activity within Groups A and B, while Group C showed no seasonal influence. Differences between Groups A and B were determined during winter, as well as among Groups A and C during the same season. The highest activity of ALT was measured in cows from Group A during the winter season. ALP activity showed no statistical difference among groups, though statistical significance was noted within seasonal changes. The activity of LDH showed no statistical significance within Group C with regard to the seasonal changes. Statistically significant difference was found between cows of Group A and C during the winter season. Differences were considered statistically significant when p<0,05.Research results showed a significant influence of milk production and dry period on the activities of measured enzymes in the blood plasma so we can conclude that there is a need for constant monitoring of the described parameters during the production period.Key words: dairy cows, ALT, AST, ALT, LDH