Alterations in clinical, hematological and metabolic variables in bovine neonatal endotoxemia.

Endotoxemia is an important cause of morbidity and mortality in the neonate. Although many models are used to study the problem, none completely simulates the natural disease. To more clearly define a bovine neonatal endotoxemia model we studied the effects of dose of endotoxin on clinical, hematological and biochemical variables. Thirty-four neonatal calves were administered Escherichia coli endotoxin (LPS) at 0 (0.9% saline solution), 0.2, 2.0 or 20 micrograms/kg, by either IV bolus or infusion over 50 minutes. Variables monitored included mean arterial blood pressure (MAP), leukocyte (WBC) count, plasma glucose and lactate concentrations and clinical status. All LPS-treated calves displayed similar clinical signs within one hour. Dose-dependent differences in response to LPS among groups became evident over time. Substantial dose-dependent changes in attitude, appetite, mucous membrane character, capillary refill time, MAP, plasma glucose and lactate concentrations, and WBC count were noted in LPS-treated calves. Higher doses of LPS induced a more prolonged clinical response and significantly (p < 0.05) greater hypotension, lacticemia and hypoglycemia. While dose altered the response to endotoxin, the method of administration had no overall effect on the variables measured.