Hematology of the neonatal calf. II. Response associated with acute enteric infections, gram-negative septicemia, and experimental endotoxemia.

The hematological responses of neonatal calves with acute enteric infections were compared to the responses of calves with septicemia and experimentally induced endotoxemia. The mean hematocrit of septicemic calves (45.0% +/- 7.8) was similar to that of calves with primary enteric infections (45.3% +/- 7.0) but the total plasma protein concentration of septicemic calves (5.8g/100 ml +/- 0.69) was significantly lower than that of calves with primary enteric infections (8.6 g/100 ml +/- 1.5). The difference in total plasma protein concentration was due primarily to the hypogammaglobulinemia observed in septicemic calves. The leukocytic response to septicemic calves was similar to that of nonsepticemic calves with enteric infections. In most calves of both groups, moderate but significant leukocytosis and neutrophilia were observed. Marked leukopenia was observed terminally in 2 of 9 septicemic calves but in only 1 of 26 calves with primary enteric infections. Leukopenia was a characteristic finding in calves with experimental endotoxemia. Leukopenia developed within 5 minutes following intravenous administration of endotoxin and persisted until death in most calves. In calves which lived 12 hours or longer, there was a biphasic leukocytic response with leukocytosis being observed 24 hours following endotoxin administration.