Pregnancy-associated glycoprotein and decreased polymorphonuclear leukocyte function in early post-partum dairy cows

Phagocytosis and oxidative burst activity of polymorphonuclear neutrophil l eukocytes (PMN) isolated from blood and pregnancy-associated glycoprotein ( bPAG) concentrations in plasma were evaluated in two longitudinal studies i n dairy cows from 3 weeks before until 5 weeks after calving, carried out i n the United States and in Europe. Ingestion of Staphylococcus aureus by bl ood PMN increased during the first week after calving and normalised 3 week s post-partum. Phagocytosis of Escherichia coli did not change in the early post-partum period. In both studies, a significant decrease in oxidative b urst activity of PMN was observed between 1 and 3 weeks after calving. In a ll cows, a very significant increase in plasma bPAG concentration was found between 1 week before and 2 weeks after calving. The peak of bPAG concentr ation in plasma immediately preceded the alterations of blood PMN functions . These results suggest that bPAG may be associated with inhibition of PMN function of dairy cows during the early post-partum period. (C) 1999 Elsevi er Science B.V. All rights reserved.