The administration of convalescent plasma or hyperimmune immunoglobulin is often used for treatment of emerging infectious diseases. However, production of large quantities of anti-pathogen human plasma and/or immunoglobulin with high affinity and avidity antibodies currently requires donations by convalescent humans, a process that can limit availability for a number of reasons. One novel alternative source is transchromosomic (Tc) cattle that produce fully human polyclonal IgG (hIgG) de novo and mount a robust antibody immune response after vaccination.