The Healthy Newborn Foal: Why is Passive Transfer Important?

Infection can cause serious illness in neonates. Make sure your newborn receives enough disease-fighting antibodies from his dam’s first milk.

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Failure of Passive Transfer
Newborn foals rely on antibodies in colostrum for protection against common pathogens. | Photo: iStock

Foaling season is here! Healthy newborn foals are fun to watch and rewarding to care for. It is critical to be vigilant in the first few days to weeks of life, however, to be certain they have the best start possible.

Infection can cause serious illness in neonates. Though they are immunocompetent at birth, meaning they can mount a normal immune response, they need additional protective immunity against common environmental pathogens (disease-causing organisms). Maternal immunity does not transfer through the placenta to the fetus, so newborn foals rely on the disease-fighting antibodies present in colostrum (the mare’s first milk) for passive antibody ­protection—in other words, naturally acquired ­immunity.

Adequate passive antibody transfer, known as passive transfer, should be the cornerstone of all neonatal preventive health programs. During the first one to two months of life, foals depend on it for protection from infectious diseases. Failure of passive transfer is not a disease; however, it predisposes neonates to infection and sepsis (a systemic inflammatory response to infection) if not identified and corrected immediately

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Written by:

Amanda Martabano House, DVM, Dipl. ACVIM, is an assistant professor in the department of large animal clinical sciences at the University of Florida’s College of Veterinary Medicine.

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