A Randomized Clinical Trial Evaluating Metabolism of Colostral and Plasma Derived Immunoglobulin G in J ersey 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 ( I g G ) undergoes increased catabolism as reflected by a rapid decrease in serum I g G concentration with an increase in fecal I g G concentrations within 48 h. Animals Thirty newborn J ersey 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 I g G concentrations were determined by radial immunodiffusion. Results Calves in the CL group maintained serum I g G concentrations consistent with adequate transfer of immunity (≥1,000 mg/dL) throughout the study period. Calves in the PL group achieved median I g G 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 I g G concentrations were not different between the 2 groups during the first 48 h ( P  >   .05). Conclusions and Clinical Importance Catabolism of plasma derived I g G occurs rapidly during the first 12 h after transfusion. Fecal excretion did not explain the fate of the plasma derived I g G .