Bovine neonatal immunology

Early fetal immune development occurs independent of antigen exposure, whereas later development depends on exposure to specific antigens. Although neonates are immunocompetent at birth, they are clearly immunonaive and dependent on passively acquired maternal immunoglobulins, immune cells, and other substances from colostrum for protection. Neonates that suffer failure of passive transfer of maternal immunoglobulins may be at increased risk for disease; however, many other factors interact in conjunction with the level of passively acquired immunoglobulin to determine the occurrence of disease.