Hair Cortisol and DHEA-S in Foals and Mares as a Retrospective Picture of Feto-Maternal Relationship under Physiological and Pathological Conditions.
Authors: Lanci Aliai, Mariella Jole, Ellero Nicola, Faoro Alice, Peric Tanja, Prandi Alberto, Freccero Francesca, Castagnetti Carolina
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Hair cortisol and DHEA-S offer a unique window into feto-maternal stress dynamics during late pregnancy, as foal hair growth begins around day 270 of gestation and thus reflects hormonal exposure during the final trimester. Researchers measured these steroid hormones in hair samples from 107 mare-foal pairs using radioimmunoassay, stratifying animals by neonatal health status and delivery environment (hospital versus farm) to explore whether prenatal stress biomarkers correlated with clinical outcomes. Whilst foal hair cortisol alone did not distinguish healthy from sick neonates, a significant positive correlation emerged between maternal and foal cortisol concentrations (r = 0.312–0.349), and notably, elevated foal DHEA-S combined with a reduced cortisol/DHEA-S ratio appeared to characterise chronic prenatal stress and potentially indicate resilience mechanisms in sick foals. Hospitalization for attended parturition produced no measurable changes in maternal hair steroid profiles compared to farm deliveries, likely because the hospital stay was too brief to influence hair hormone deposition. These findings suggest that the cortisol/DHEA-S ratio warrants further investigation as a potential marker of hypothalamic-pituitary-adrenal axis activity and allostatic load in utero, offering practitioners a non-invasive tool to retrospectively assess prenatal stress exposure and neonatal adaptation capacity.
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Practical Takeaways
- •Hair steroid analysis, particularly the CORT/DHEA-S ratio, may offer retrospective insight into fetal stress during late pregnancy and neonatal resilience, but requires further validation before clinical application
- •The strong correlation between foal and mare hair cortisol suggests maternal prenatal stress directly influences fetal HPA axis activity—manage mare stress in the final trimester as a potential welfare intervention
- •Single cortisol measurements in foal hair have limited diagnostic value for identifying sick neonates; multi-hormone panels may be more informative than isolated cortisol analysis
Key Findings
- •Hair cortisol concentrations in foals did not differ between healthy and sick groups, suggesting cortisol alone is not a discriminative biomarker for neonatal health status
- •Significant correlations existed between foal and mare hair cortisol (r=0.312-0.349, p<0.02), indicating feto-maternal endocrine synchronization
- •Increased hair DHEA-S and decreased CORT/DHEA-S ratio were identified as potential biomarkers of chronic prenatal stress and resilience in foals (p=0.033 and p<0.001 respectively)
- •Hospitalization for attended parturition did not significantly alter mare hair steroid concentrations compared to breeding farm births, likely due to insufficient exposure duration