Immunologic responses in colostrum-fed and colostrum-deprived calves.

The influence of colostrum on several aspects of the neonatal immune response, including lymphocyte reactivity in vitro, was examined in the calf from birth through 96 hours after delivery. Using a whole blood microculture assay, the blastogenic response of peripheral blood lymphocytes (PBL) incubated with phytohemagglutinin (PHA), pokeweed mitogen (PWM), or Escherichia coli lipopolysaccharide (LPS) were examined for colostrum-fed (CF) and colostrum-deprived (CD) calves. The PHA and PWM stimulated significant levels of [3H]thymidine incorporation in both calf groups, although LPS was only marginally mitogenic. However, PBL from CD calves during the first 24 hours after delivery had significantly greater amounts of total label incorporation in response to the three mitogens as compared with the label in PBL from CF calves. Differential and total WBC counts differed markedly between CF and CD calves during the first 48 hours after delivery; CF animals had significantly increased leukocyte counts at 6, 12, and 24 hours, due primarily to transient neutrophilia. Blood sera collected from calves before ingesting colostrum contained trace amounts of immunoglobulin (Ig) M and IgG; all three classes of Ig (M, G, and A) were present in significant amounts in sera of calves after colostrum feeding. The observed effects of colostrum on various components of the immune system are discussed.