“…From that first description, a wealth of research has been accomplished with different approaches. They have been reviewed on the aspects of protection against infectious agents (BRENNER, 1991), as well as on the factors interfering with passive transfer of Ig to calves (REBELATTO & WEIBLEN, 1992). Examples of these factors are environmental factors such as temperature (STOTT et al, 1976), season (DONOVAN et al, 1986;HANCOCK, 1985), management (ROY, 1990), and sanitary conditions (BUSH & STALEY, 1980 The influence of so many factors predisposes calves to FPT (HANCOCK, 1985).…”