Adrenal Gland Ultrasonographic Measurements and Plasma Hormone Concentrations in Clinically Healthy Newborn Thoroughbred and Standardbred Foals.
Authors: Lauteri Eleonora, Mariella Jole, Beccati Francesca, Roelfsema Ellen, Castagnetti Carolina, Pepe Marco, Peric Tanja, Barbato Olimpia, Montillo Marta, Rouge Stefanie, Freccero Francesca
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Establishing reference ranges for neonatal adrenal function across different foal breeds is essential for identifying pathological HPA axis dysfunction, yet previous work has not examined how breed, age, weight and sex influence adrenal ultrasonographic measurements or baseline hormone profiles in healthy newborns. This multicentre study collected ultrasound images and blood samples from 20 clinically healthy neonatal foals (10 Thoroughbreds, 10 Standardbreds) within the first weeks of life, measuring adrenal gland dimensions and quantifying plasma ACTH, cortisol, DHEA, progesterone and aldosterone concentrations, then calculating hormone ratios to assess HPA axis balance. Breed emerged as a significant variable: Standardbred foals displayed wider adrenal glands (both right and left) compared with Thoroughbreds, whilst Thoroughbreds showed elevated cortisol and depressed ACTH concentrations alongside a markedly higher cortisol/DHEA ratio, suggesting breed-dependent differences in either baseline stress responsiveness or metabolic handling of adrenal steroids. Foal bodyweight correlated positively with right adrenal gland height, indicating that simple biometric variables should be factored into interpretation of adrenal ultrasound dimensions. These breed-specific reference values now allow clinicians to better contextualise adrenal measurements and hormone profiles when investigating failure of passive transfer, sepsis, hypoglycaemia or other neonatal emergencies, and the observed cortisol/DHEA ratio differences hint at genuine physiological variation between breeds that warrants further investigation in disease states.
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Practical Takeaways
- •Breed-specific reference ranges for adrenal ultrasound measurements and hormone concentrations are needed for accurate clinical interpretation in neonatal foals
- •Thoroughbreds and Standardbreds show different baseline HPA axis hormone profiles and adrenal morphometry, which may reflect different breed predispositions to stress response
- •Adrenal ultrasonography combined with hormone panels can provide complementary diagnostic information for neonatal foal health assessment, but interpretation must account for breed differences
Key Findings
- •Right adrenal gland height showed significant positive correlation with foal weight
- •Standardbred foals had significantly wider adrenal glands and medulla compared to Thoroughbreds
- •Thoroughbred foals had significantly higher cortisol and lower ACTH plasma concentrations than Standardbreds
- •Cortisol/DHEA ratio was significantly higher in Thoroughbreds, suggesting breed-related differences in environmental stress response