[Effects of a single dose of dexamethasone-21-isonicotinate on the phagocytosis performance of neutrophilic granulocytes and monocytes in periparturient dairy cows].

The objective of the study was to describe the effects of a short acting glucocorticoid which was administered immediately after parturition in dairy cows on haematological, immunologic and metabolic parameters. The study was performed on 104 cows, 52 cows received an intramuscular injection of 2 mg/100 kg BW dexamethasone within 12 hours after parturition. The numbers and the phagocytic activity of granulocytes and monocytes were measured on day 1 and day 3 post partum in 17 randomly chosen cows from each group. From day 1 to day 3 the percentage of phagocytic granulocytes increased in the dexamethasone group from 73.2 +/- 6.1% to 79.6 +/- 6.6% (P < 0.05); in the control group the percentage remained unchanged (74.7 +/- 6.3% and 76.2 +/- 5.8%). The cellular phagocytic activity of granulocytes did not change significantly between day 1 and 3. In both groups the phagocytic activity of monocytes also remained unchanged. The concentrations of endotoxin, haptoglobin and the anti-lipid-A-IgG-antibody-titer did not show significant differences between the groups. Between both groups differences were not observed in the clinical parameters, milk yield or in the incidence of diseases in the peripartal period. The effects of the glucocorticoid on the metabolic parameters were especially seen in bilirubin and free fatty acid concentration. The present study shows that a single injection of glucocorticoids within 12 hours after parturition did not influence the phagocytic activity of neutrophils and monocytes negatively and did not have an effect on the measured parameters of acute-phase-response. Therefore, it seems possible to benefit from the positive effects of glucocorticoids on metabolism in this critical early postpartal period in high yielding cows.