A Field Study of Serum, Colostrum, Milk Iodine, and Thyroid Hormone Concentrations in Postpartum Draft Mares and Foals.

The study investigates iodine levels in the colostrum, milk, and blood of mares and their newborn foals, exploring their relationship with thyroid hormone concentrations. It finds that colostrum and milk are significant sources of iodine, and that high iodine levels in foals are correlated with thyroid hormone levels, critical for their early development.

Study Context

• This study focuses on Iodine, thyroxine (T4) and triiodothyronine (T3) – essential elements for normal fetal growth, maturation, and the survival of newborn animals.
• Previous understanding of iodine levels in the colostrum, milk, and bloodstream of mares and foals after a healthy pregnancy was inadequate. Therefore, the researchers aimed to characterize these factors effectively.

Research Methodology

• The research examined ten healthy postpartum mares and their foals. Their average iodine intake during pregnancy was estimated at 39mg per day.
• At different instances – the day of foaling and ten days later, the research collected colostrum, milk, and jugular blood samples from the draft breed mares and foals.
• The main parameters in focus were serum, colostrum, and milk iodine levels and thyroid hormone concentrations in both mares and foals.

Key Findings

• The study found that the iodine levels in colostrum were significantly higher than in milk (165 μg/L vs. 48 μg/L).
• Furthermore, iodine, TT4, and TT3 levels in the foal’s serum were higher at birth than ten days later.

implications of the Findings

• The research concludes that the mammary tissue in mares concentrates iodine beyond plasma levels. This makes colostrum and milk significant sources of iodine, more so than previously understood.
• Furthermore, high iodine levels in foals during the early neonatal period are positively correlated with TT4 levels, which play a vital role in the adjustment of neonates to their new environment.

Conclusion

• This study has offered valuable insights into iodine levels in mares and foals postpartum, revealing critical findings about their sources and significance.
• The research can contribute to enhancing prenatal and postnatal care for mares and their foals, ensuring successful pregnancies and healthy foal development.