The objective of this study was to evaluate serum bilirubin concentration and AST activity in
Simmental cows in two different geographic regions (Lijevce polje lowlands and high altitude
Nevesinje). A total of 42 healthy cows, 21 per farm, were tested. Cows were allocated to three
groups viz. late pregnant or dry cows (7 animals), cows in the first days
post-calving (7 animals), and cows in the second to third month of lactation (7
animals). The study was conducted during the autumn-winter period (2008) and
repeated during spring (2009) involving the same cows. Blood samples were collected
for analysis by puncture of the coccygeal vein (vena coccigea) using sterile needles
into sterile single-use vacuette blood collection tubes without an anticoagulant. After 24
hour storage at room temperature, serum was separated, deep-frozen, and transported within
48 days to the laboratory for further biochemical assays. Blood (serum) bilirubin
concentration was within the physiological range in all experimental cows in both locations. The
results related to AST activity showed a slight increase above the physiological limit in
all groups of cows, with late pregnant cows (Nevesinje location, winter period) exhibiting
significantly higher values.
Key words: Concentration, Serum, Geographic area, Bilirubin, AST