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.

The half-life of 17.1 d for colostral IgG reported in this study is consistent with a previous study 17 that reported a half-life of 17.9 d. However, the colostral derived IgG half-life also is shorter in comparison to other studies. 4 Additionally, the half-life for plasma derived IgG reported in this study was substantially shorter than the 27.3 d reported in previous studies. 4 Two possible reasons might account for the differences in the results. First, serum IgG determination was only performed 48 h after colostrum or plasma administration in the other studies. 4 Considering that a significant decrease in serum IgG concentration occurred during the first 12 h after plasma transfusion and a significant increase in serum IgG concentrations occurred before 48 h in the CL group (Table 2) in this study, the estimation of IgG half-life potentially was affected by the study design. The second potential explanation for the differences in the half-life of colostral or plasma derived IgG between the studies was the duration of the followup period. The study period reported here was 7 d compared to 35 d in a previous study. 4 We chose to collect samples only up to 7 d because antibodies to different bacterial, protozoal, and viral antigens do not appear in blood before 14-30 d of age. 18, 19 Thus, we chose a time period before the expected appearance of endogenously synthesized immunoglobulins to minimize effects on serum IgG half-life determination. Mortality rates in the PL group were significantly high compared to the CL group consistent with previous studies 4 indicating that plasma is unlikely to provide protective immunity comparable to maternal colostrum. Based on survival analysis, calves in the PL group were 5 times (hazard ratio, 5.01) more likely to experience mortality compared to those in the CL group. Based on logistic regression analysis, PL group calves that received treatments were 1.4 times more likely to experience mortality (relative risk, 1.4) compared to the PL group calves that received treatment.