COMPARISON OF THE LEVELS OF SELECTED SPECIFIC ANTIBODIES IN THE IgG OF COLOSTRUM, MILK AND SERUM IN DAIRY COWS (BOS TAURUS)

Abstract

In cattle (Bos taurus), the immunologically naïve calf receives immune factors, growth factors and nutrients from the dam via the colostrum. Colostral antibodies are primarily serum-derived and provide the calf with the broad-spectrum systemic immunity of the mother. There are a variety of commercially available products used to supplement or replace maternal colostrum. In addition to utilizing colostrum as the IgG source, there is an interest in using IgG from milk and serum as ingredients in colostrum replacement products. Immunoglobulins in milk are primarily derived from udder-localized plasma cells, which migrate from the intestinal mucosa at parturition and during lactation. We hypothesized that milk IgG would have lower levels of antibodies to systemic pathogens compared to colostrum and/or serum derived IgG however might contain higher levels of antibodies to mucosal and udder associated agents. We sampled serum (1-2hr post partum), colostrum (1-2hr post partum) and milk (day 5 post partum) from 24 post parturient dairy cows and heifers, measured total IgG (H+L) using a radial immunodiffusion assay (RID), and determined specific antibody units per gram of IgG for a variety of respiratory, gut and udder-associated pathogens via indirect Enzyme-Linked Immunosorbant Assay (ELISA) (ie., BRSV, BHV-1, PI3, Streptococcus uberis, Staphylococcus aureus., E. coli F5 (K99), rotavirus and bovine coronavirus). We performed additional ELISAs to determine antigen specific values for IgG1 and IgG2 antibody subclasses for BRSV, rotavirus and S. uberis. Wilcoxon signed-rank tests with conservative Bonferroni correction, showed that antigen specific antibodies to BRSV (IgG H+L), PI3 (IgG H+L), E. coli F5 (K99) (IgG H+L), S. aureus (IgG H+L), rotavirus (IgG H+L and IgG1) and BCV (IgG H+L) are higher (P<.017) in the IgG in colostrum than the IgG in milk. In comparison to the serum, colostrum IgG is higher (P<.017), in BRSV (IgG H+L and IgG1), BHV1 (IgG H+L), PI3 (IgG H+L), E. coli F5 (K99) (IgG H+L), S. uberis (IgG H+L), and rotavirus (IgG1) antibodies. Colostrum IgG also contains more specific antibody to S. uberis (IgG1) and BCV (H+L) than serum IgG. However, milk IgG contains more specific antibody to BRSV (IgG H+L and IgG1), BHV1 (IgG H+L), PI3 (IgG H+L), and rotavirus (IgG1) when compared to serum IgG (P<.017). Overall, colostrum derived IgG delivers more specific antibodies to most endemic pathogens compared to the IgG found in milk or serum. However, milk IgG, like that of colostrum, has higher amounts of specific IgG1 and delivers a similar spectrum of specific antibodies and thus may be a superior Ig source for the newborn calf when compared to serum IgG.