Hair steroid hormones concentrations in Martina Franca jennies and their donkey foals from parturition to 6 months postpartum

The period after parturition/birth represents a delicate time for the dam and the offspring, during which several physiologic changes occur under finely tuned hormonal control, with the hypothalamic-pituitary- adrenal (HPA) axis playing a key role. This period, well studied in horses, received little attention in donkeys, despite the importance of species-specific knowledge for population preservation programs in many endangered donkey breeds. The present study aimed to investigate cortisol (C), DHEA(S), 17-β-estradiol (E2), progesterone (P4), testosterone (T), and allopregnanolone (AlloP) hair concentrations in jennies and donkey foals from parturition to 6 months postpartum. The results, obtained in 10 Martina Franca jennies and 10 donkey foals, showed higher C and AlloP hair concentrations at birth in donkey foals compared to jennies, as well as a higher C:DHEA(S) ratio. Distinct hormonal profiles were found between donkey foals and jennies for all hormones, except DHEA(S), T, and AlloP. In fact, in both jennies and donkey foals, a significant decrease was seen between T0 and T1-T6 (AlloP), and between T0 and T2-T6 (DHEA(S) and T). Male donkey foals showed higher C hair concentrations and C:DHEA(S) at 90 days after birth in comparison to females, but the results were obtained from a small number of subjects and must be considered with care. In conclusion, the results obtained from a small number of Martina Franca donkeys, and therefore cautiously considered, revealed both similarities and differences in the mean hormone profiles between jennies and donkey foals, suggesting slightly different physiologic activation of the HPA axis during the 6 months following parturition/birth in dams and offspring.