Administration of heat inactivated Escherichia coli antigens by intramuscular and intramammary routes induced elevated antibody levels in sow serum and colostrum, predominantly associated with IgG. Colostral IgG accounted for approximately 80 per cent of the total antibody activity, and there was a similar distribution in the sera of one-day-old piglets. The additional antibody activity was carried almost entirely by IgM following intramuscular injections and was evenly distributed between IgM and IgA following intramammary stimulation. The distribution of antibody activity and all three major immunoglobulin classes in colostrum and milk from individual mammary glands was remarkably uniform. A similar uniformity was inferred for the ingestion and absorption of colostrum by individual piglets as judged by the contents of their blood sera during the neonatal period.
Animals Animals, Newborn