The concentration of plasma IgG at 28 days of age was
also significantly higher in the CoF group than that in
the CoD group (Fig. 2). The half-life of colostral IgG in
the bloodstream of piglets is 12 to 14 days (Curtis &
Bourne 1971). In addition, Rooke et al. (2003) suggested
that a majority of plasma IgG around weaning was synthesized
by piglets themselves. These facts indicate that
differences in fecal IgA and plasma IgG concentrations
between the CoF and CoD groups resulted from underdevelopment
of the ability to synthesize IgA and IgG in
the CoD group due to deprivation of colostrum intake
during the first 24 h after birth.