Failure of Passive Transfer in Calves

Acquisition and absorption of adequate amounts of colostral immunoglobulins are essential to the health of the newborn calf. Calves are born lacking any significant amount of circulating immunoglobulins and relyon antibodies acquired from colostrum for protection against common environmental pathogens. The major immunoglobulin in colostrum is IgG 1, but there are also significant amounts of IgG2, IgM and IgA. Considerable amounts of these immunoglobulins in ingested colostrum are transferred across the epithelium of the small intestine during the first few hours of life and transported via the lymphatic system to the blood. Immunoglobulins in the blood then enter extravascular fluids and external body secretions, depending upon the immunoglobulin class. The absorbed immunoglobulins protect against systemic invasion by microorganisms (and therefore against bacterial septicemias) during the neonatal period. In addition, both unabsorbed immunoglobulins and immunoglobulins re-secreted back into the gut play important roles in protection against intestinal infections for several weeks following birth. Good passive immunity also reduces the occurrence of respiratory disease during the first months of life and may be a determinant of improved lifetime productivity. Partial or complete failure of passive transfer of colostral immunoglobulins is a major determinant of susceptibility to neonatal disease and mortality in calves. Consequently, it is important that calves acquire adequate circulating concentrations of immunoglobulin from the colostral transfer process.