In an attempt to determine the passive immunity failure in Holstein and Nelore calves, 413 blood samples were drawn from animals from both breeds. Calves born from pluriparous cows, from both breeds, and Holstein calves had greater serum concentrations of total protein, gamma globulin and IgG than Nelore newborns. However, the passive immune failure index was higher in Holstein calves than those found in Nelore calves at 24 and 48 hours. Some values of serum components were established to predict the passive immunity failure in dependency of environmental antigenic challenge.
Calf; IgG; passive immunity
