CD79A and infection: As bovine colostrum has much lower concentrations of IgM and IgA (91.77 g/L IgG and approximately 5 g/L IgA and IgM), a combination of IgG, IgM, and IgA antibody levels can be used to determine whether antibodies in calves are likely maternally derived [74,75], or the result of an active infection.