Hematological and biochemical blood parameters in dairy cows depending on the management system.

Monitoring the health of dairy herds is central to the assessment of animal health and welfare. The aim of this study was to analyse hematological and biochemical parameters in Holstein-Friesian dairy cows depending on the management system. Thirty cows from the foundation stock with an average annual yield of 6500-7000 l of milk were selected for the experiment. The cows were characterized by similar yields and were in a similar lactation period (second and third lactation). The cows were divided into three groups of 10 cows each: confined to a barn (control group C), housed in a barn with free access to an outdoor run (O) and maintained on a pasture (P). Blood samples to determine hematological and biochemical parameters were collected from animals on an empty stomach before the onset of the experiment and towards the end of the pasture period. The present study showed a positive effect of pasturing dairy cows on their hematological parameters. In the group of pasture-fed cows, there were also significant (P≤0.05) differences between the results before and at the end of the trial. There was a significant (P≤0.05) increase in total white blood cell count and in basophil and neutrophil percentages. There were also significant (P≤0.05) increases in the concentration of hemoglobin (by 8%) and hematocrit (by 7%). Biochemical analysis showed slightly higher urea concentrations in the group of pastured cows when compared to the other groups. The high content of nitrogen compounds in the pasture forage could have a certain effect on hepatic nitrogen metabolism, which could increase serum concentrations of AST and ALT enzymes in cows from group P.