Failure of passive transfer in neonatal foals - A review

Failure of passive transfer (FPT) is a major contributor to morbidity and mortality in neonatal foals worldwide. Adequate ingestion and intestinal absorption of colostral immunoglobulin G (IgG) during the first hours of life are essential to ensure protection against early-life infections, such as diarrhoea and pneumonia, frequently with fatal outcome. This review summarizes current knowledge on the physiology of passive immunization, risk factors for inadequate IgG absorption, diagnostic methods, therapeutic strategies, and evidence-based preventive measures. Recent research highlights the importance of early and accurate assessment of immune status using reliable field and laboratory techniques. A comprehensive understanding of FPT pathogenesis, combined with consistent management practices, is critical for reducing neonatal disease, improving survival, and enhancing long-term performance outcomes in horses.