Passive transfer of colostral leukocytes: A benefit/risk analysis.

Passive immunity is a requirement for survival of conventionally reared domestic animals. Maternal antibody is recognized as the primary effector mechanism of protection of the neonate. There is interest, especially in bovine medicine, in the maternal leukocytes that are also transferred in colostrum. These leukocytes are thought to somehow aid in the development of the neonatal immune system and participate in cellular immune reactions in the neonate, although the means by which this is accomplished is unknown. The purpose of this article is to review the immunology of this maternal/neonatal interaction, and on that basis, evaluate the practical benefits and risks of assuring passive transfer of colostral leukocytes. Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.