Decay of passive antibodies in calves fed maternal colostrum or a colostrum replacer
Keywords:passive antibodies, passive transfer, colostrum, colostrum replacements, antibodies
The passive transfer of immunoglobulins to neonatal calves via maternal colostrum is a major determinant of the calf’s health early in life. It is important that each calf receive 150-200g immunoglobulin G (IgG) within two hours of birth. However, maternal colostrum (MC) can be highly variable in its IgG content and specific antibody levels. Colostrum replacers (CR) can substitute for MC and may provide a more consistent dose of both IgG mass and specific antibodies. Since high levels of colostral antibodies can interfere with the humoral immune response to vaccination, knowing the time that calves become seronegative could allow for strategic timing of vaccination to produce a more consistent protective humoral immune response. The first objective of this study was to compare the level and persistence (antibody decay curves) for specific antibodies in calves fed either MC or CR. A second objective was to investigate whether feeding a CR (vs MC) would result in a more consistent time to seronegativity, with less calf-to-calf variability. We hypothesized that both forms of colostrum would transfer similar mean levels of antibodies, but that CR would deliver a more consistent time to seronegativity for diseases of interest.