Plasma vasopressin concentrations in healthy foals from birth to 3 months of age.
Authors: Wong D M, Vo D T, Alcott C J, Peterson A D, Brockus C W, Hsu W H
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Plasma Vasopressin in Healthy Foals Arginine vasopressin (AVP) has emerged as a potentially useful biomarker in equine critical care, yet baseline reference values for foals remain poorly characterised—a significant gap given that interpreting AVP concentrations in sick foals requires knowledge of age-appropriate norms. Wong and colleagues conducted a prospective observational study measuring plasma AVP in 13 healthy university-owned foals at ten time-points spanning birth to 84 days of age, using radioimmunoassay to quantify plasma concentrations. Remarkably, no statistically significant age-related variation was detected across this period, with mean AVP concentrations remaining stable at 6.2 ± 2.5 pg/mL regardless of foal age. These findings suggest that clinicians can use a single reference range for AVP interpretation in foals from birth through three months, simplifying the diagnostic utility of this marker in neonatal and young foal populations without needing to account for developmental stage. However, the modest sample size warrants cautious application, and further research establishing reference ranges for older foals and investigation of AVP behaviour in disease states would strengthen the clinical value of this biomarker in equine medicine.
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Practical Takeaways
- •When using AVP measurements to assess sick foals, clinicians can use a single reference range (6.2±2.5 pg/mL) regardless of foal age from birth to 3 months without age-adjustment
- •Deviations from this AVP baseline suggest pathological involvement rather than age-related variation, helping differentiate healthy from critically ill foals
- •This reference data supports the clinical utility of AVP measurement in equine critical care by providing age-independent comparison values for foals under 3 months old
Key Findings
- •Plasma AVP concentrations remained stable from birth to 84 days of age with a mean of 6.2±2.5 pg/mL
- •No statistically significant age-related differences in plasma AVP concentrations were detected across the 3-month study period
- •AVP concentrations are consistent across healthy foals from birth to 3 months of age, establishing baseline reference values