PSIV-5 Investigating passive transfer and the effects of stress on the newborn calf receiving immunoglobulins from colostrum.

Abstract The objective of the current study was to examine passive transfer of immunoglobulins A (IgA) and G (IgG) to the calf in relation to dam’s fecal cortisol and lactoferrin. Specifically, correlations of dam serum and colostrum IgG and IgA with calf serum IgG and IgA concentrations were assessed. In 2024, late-gestation, Angus crossbred heifers pregnant by artificial insemination (n = 30) were transported to the University of Arkansas Stocker Unit where they were housed on 0.42-ha grass paddocks beginning in mid-August. After calving, the cow-calf pair was left alone until the calf stood and suckled once, then they were moved to a chute for sample collection from the dam. Blood and fecal samples were collected, and colostrum was collected from the 4 quarters and composited and the calf was weighed. Blood and fecal samples were collected from each calf at 48 h and 14, 28, and 90 d of age. Blood and colostrum samples were used to determine IgA, IgG, and lactoferrin concentrations. Fecal samples were collected to determine lactoferrin and cortisol concentrations. All data were analyzed using MIXED and CORR procedures of SAS 9.4 (Cary, NC) with calf as the subject, with statistical significance determined at P ≤ 0.05 and tendencies were declared at 0.05 < P ≤ 0.1. Serum immunoglobulin concentrations were log transformed for data normalization. There was a moderate correlation between dam colostrum IgG and calf serum IgG at 48 h (r = 0.5819; P = 0.0007) and d 28 (r = 0.4302; P = 0.0177), but not d 14 (r = 0.1118; P = 0.56) or d 90 (r = 0.0844; P = 0.68). Additionally, there were moderate correlations between dam colostrum IgA and calf serum IgA at 48 h (r = 0.4006; P = 0.0283) and d 14 (r = 0.4456; P = 0.0136), but there were no relationships reported on d 28 (r = 0.2280; P = 0.23) or d 90 (r = -0.1752; P = 0.38). Finally, there was no correlation identified for dam serum IgG (P ≥ 0.1978) or IgA (P ≥ 0.1002) concentrations at the time of calving and calf serum concentrations during the 90-d period. Lactoferrin and cortisol concentrations will be included in future investigations which may aid in mechanistic explanation. To conclude, immunoglobulin concentrations in colostrum and calf serum were moderately correlated with each other demonstrating passive transfer within the first month following parturition. However, there were no correlations detected between immunoglobulin concentrations of dam serum and calf serum during this study.