Circulating concentrations of vitamins C, D and E vary with age but not with pneumonia status in foals during the first 5 months of life.
Authors: Helbig, Berghaus, Venner, Berghaus, Hart
Journal: Equine veterinary journal
Summary
# Editorial Summary Researchers tracked circulating vitamin C, D and E concentrations in 100 Warmblood foals from birth through five months of age, serially collecting blood samples and monitoring weekly for subclinical and clinical bronchopneumonia; post-weaning, 15 foals each from healthy, subclinically pneumonic and clinically pneumonic groups were selected for vitamin quantification via ELISA and HPLC analysis. The study found striking age-dependent patterns in vitamin availability: vitamins C and E spiked within the first week of life before declining progressively to weaning, whilst vitamin D remained depressed at day 7 then gradually increased throughout the period. Notably, circulating vitamin concentrations did not differ between healthy foals and those developing either subclinical or clinical bronchopneumonia, challenging the assumption that low antioxidant or fat-soluble vitamin status predisposes foals to respiratory disease. One unexpected finding warrants attention—vitamin C concentrations were paradoxically higher at pneumonia diagnosis in foals affected at or before eight weeks compared to healthy counterparts, though the mechanism remains unclear. For practitioners, these results suggest that routine vitamin supplementation targeting pneumonia prevention may lack biological rationale, though the relatively homogenous study population (single breed, farm management system) limits broader applicability and highlights the need for larger, multi-centre investigations across diverse management conditions.
Read the full abstract on PubMed
Practical Takeaways
- •Foal vitamin status changes naturally with age regardless of pneumonia development, so vitamin concentrations alone cannot be used diagnostically for bronchopneumonia
- •Consider age-specific reference ranges for vitamins C, D, and E when interpreting foal blood work, as concentrations change substantially from birth through weaning
- •Vitamin supplementation decisions in foals should not be based on pneumonia risk, as vitamin deficiency was not associated with pneumonia development in this study population
Key Findings
- •Circulating vitamins C, D, and E concentrations vary significantly with foal age (p<0.001) in vitamin-specific patterns from birth to weaning
- •Vitamins C and E increased during the first week of life then decreased until weaning, while vitamin D was lowest at Day 7 and increased steadily thereafter
- •No significant differences in vitamin C, D, or E concentrations were found between healthy foals and those with subclinical or clinical bronchopneumonia
- •Vitamin C concentrations were higher at pneumonia diagnosis in foals diagnosed at or before 8 weeks of age compared to healthy foals