A Randomized Clinical Trial Evaluating Metabolism of Colostral and Plasma Derived Immunoglobulin G in Jersey Bull Calves

Pipkin, K.M.; Hagey, J.V.; Rayburn, M.C.; Chigerwe, M.

F ailure of passive immunity (FPI) resulting from inadequate colostral immunoglobulin intake in calves is a cause of immunodeficiency. Failure of passive immunity is a significant risk factor for morbidity and mortality from diseases of calves including diarrhea and pneumonia. 1, 2 In clinical settings, IV administration has been recommended as part of medical management of healthy or sick calves with FPI, that >24 h because colostral immunoglobulin G (IgG) absorption has ceased. [3] [4] [5] A recent study 4 evaluating serum IgG concentrations after IV plasma administration at the recommended dosage of 30 mL/kg 5 indicated that the majority of calves did not achieve serum IgG concentrations consistent with adequate transfer of immunity (ie, serum IgG ≥1,000 mg/dL) 6 at 48 h of age. A limitation of this study 4 was that serum IgG concentrations were not evaluated until 48 h after plasma transfusion. Thus, metabolism of IgG before 48 h was not determined. In studies of humans, suggested reasons for increased catabolism of IV administered IgG include formation of IgG aggregates during processing of plasma. The IgG aggregates result in activation of complement leading to increased catabolism followed by fecal and urinary excretion of plasma-derived immunoglobulins. 7 In calves, excretion of IV administered plasma derived IgG is predominantly through feces. 6 Currently, studies evaluating metabolism of plasma derived IgG in cattle are lacking. In clinical practice, it is assumed, that healthy or sick neonatal calves with FPI that are given plasma IV, at the recommended dosage of 20-40 mL/ kg 4 will achieve and maintain serum IgG concentrations consistent with adequate transfer of immunity (ie, serum IgG concentrations ≥1,000 mg/dL). 6 We hypothesized that IV administered plasma derived IgG would undergo increased catabolism as reflected by a rapid decrease in serum IgG concentration and an increase in fecal IgG concentrations within 48 h. Increased IgG catabolism will result in serum IgG concentrations consistent with FPI (<1,000 mg/dL) 6 at 48 h after transfusion. The objective of this study was to determine the rate of catabolism of colostral derived IgG administered by oroesophageal tubing compared to IV administered plasma IgG. Additionally, the half-life of plasma and colostral derived IgG was determined. standard deviation of 207 mg/dL for serum IgG concentrations in calves given plasma IV in previous studies 4 (alpha = 0.05, power = 0.8, minimal detectable IgG concentration = 196 mg/dL). The required sample size was at least 7 calves in each group. To account for an anticipated dropout of up to 50% because of mortality, 30 calves (15 in each group) were enrolled. Thirty Jersey bull calves from a single farm in Hilmar, California were enrolled. Adult cows on the farm of study were vaccinated annually with a modified live respiratory disease vaccine containing infectious bovine rhinotracheitis, bovine viral diarrhea, parainfluenza-3, and bovine respiratory syncytial viruses. Additionally, the cows were vaccinated with a multivalent vaccine containing Escherichia coli, rotavirus, and coronavirus during the dry cow period. Jersey bull calves delivered from eutocia and observed births were immediately separated from their dams before nursing colostrum. The calves were randomly assigned using a coin toss to 2 groups. Fifteen calves were assigned to the control group to receive colostrum (CL group) by oroesopheagal tubing, and 15 to the trea