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

BACKGROUND Intravenous plasma administration has been recommended in healthy or sick calves with failure of passive immunity. HYPOTHESIS IV administered plasma-derived immunoglobulin G (IgG) undergoes increased catabolism as reflected by a rapid decrease in serum IgG concentration with an increase in fecal IgG concentrations within 48 h. ANIMALS Thirty newborn Jersey calves. Fifteen were fed colostrum (CL group) and 15 were given bovine plasma IV (PL group). MATERIALS AND METHODS Randomized clinical trial. Calves in the CL group were fed 3 L of colostrum once, by oroesophageal tubing. Calves in the PL group were given plasma IV at a dosage of 34 mL/kg. Serum and fecal samples were collected at 0 h, 6 h, 12 h, 48 h, 5 d, and 7 d. Serum and fecal IgG concentrations were determined by radial immunodiffusion. RESULTS Calves in the CL group maintained serum IgG concentrations consistent with adequate transfer of immunity (≥1,000 mg/dL) throughout the study period. Calves in the PL group achieved median IgG concentrations of ≥1,000 mg/dL at 6 h but the concentrations were <1,000 mg/dL by 12 h. Calves in the PL group were 5 times more likely to experience mortality compared to the CL group (hazard ratio = 5.01). Fecal IgG concentrations were not different between the 2 groups during the first 48 h (P > .05). CONCLUSIONS AND CLINICAL IMPORTANCE Catabolism of plasma derived IgG occurs rapidly during the first 12 h after transfusion. Fecal excretion did not explain the fate of the plasma derived IgG.