IgG antibody subtype is the most abundant serum immunoglobulins of the immune system. It is secreted by B cells and is found in blood and extracellular fluids and provides protection from infections caused by bacteria, fungi and viruses. Maternal IgG is transferred to fetus through the placenta that is vital for immune defence of the neonate against infections. Bovine IgG is purified from pooled normal bovine serum by fractionation and ion-exchange chromatography.