Impaired post partum neutrophil function in cows which retain fetal membranes

The post partum neutrophil function in cows which had retained fetal membranes (RFM) for at least 24 hours post partum were compared with matched herdmates which had not retained their fetal membranes. Cows from a single dairy herd which had spontaneously occurring RFM (n = 8) were matched with herdmates (n = 8) which had calved within 48 hours before or after them and had not experienced RFM. Blood samples were collected from the cows three times post partum: two to five days, three weeks and six weeks. Neutrophils were isolated by differential centrifugation followed by hypotonic lysis of erythrocytes. In vitro neutrophil function was assessed by superoxide anion (O2-) generation and by stimulus-induced shape change. Neutrophils from cows with RFM produced significantly less superoxide anion during the first week post partum and six weeks post partum. Cows with RFM had impaired neutrophil shape change immediately post partum. Shape change responsiveness increased in both groups from the first post partum week to three weeks post partum.