Determination of the activity of specific enzymes of blood in the peripartum period and during the full lactations

This study examined the activities of aspartate-aminotransferase (AST), gamma-glutamyl-transferase (GGT) and lactate-dehydrogenase (LDH) in the blood serum of 45 dairy Simmental cows divided into three groups according to production period. The first group (n=15) consisted of late pregnant dairy cows, the second group (n=15) cows in the early lactation, and the third group (n=15) cow in mid lactation. The significant higher activity (P<0.05) of AST, GGT and LDH were determined in the early lactation period than in dry period and during full lactation. Research results showed possibility of mild degree of hepatic lesions, probably due to fat infiltration in early lactation cows. Serum AST enzyme activities were significant correlated (P<0.05) with GGT and LDH activities and may be most sensitive indicator. Keys words: dairy cows, serum enzymes activities