Post-partum concentrations of serum progesterone, oestradiol and prolactin in Arabian mares demonstrating normal maternal behaviour and Arabian mares demonstrating foal rejection behaviour.
Authors: Berlin D, Steinman A, Raz T
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Foal Rejection and Post-Partum Endocrine Profiles in Arabian Mares Foal rejection remains a challenging and poorly understood maternal behaviour problem in post-partum mares, prompting Berlin and colleagues to investigate whether hormonal imbalances might underpin this condition. Their prospective study measured serum progesterone, oestradiol and prolactin concentrations in eight normal Arabian mares and fifteen rejecting mares on days 1 and 3 post-partum, examining whether specific endocrine signatures could differentiate maternal acceptance from rejection behaviour. Whilst absolute hormone concentrations showed no statistically significant differences between groups, the temporal patterns and hormonal ratios proved revealing: rejecting mares exhibited significantly steeper declines in both progesterone (3.14 to 0.49 ng/dL) and prolactin (216.2 to 145.2 ng/mL) over the three-day window, and critically, the oestradiol-to-progesterone ratio was significantly lower in rejecting mares on day 1 (47.3 versus 114.8) before rising sharply by day 3. These findings suggest that inadequate oestradiol dominance relative to residual progesterone in the immediate post-partum period may contribute to rejection behaviour, offering potential diagnostic markers and directing future research towards hormonal interventions during the critical early post-partum window when maternal-foal bonding is established.
Read the full abstract on PubMed
Practical Takeaways
- •Single hormone measurements cannot reliably predict foal rejection behaviour in Arabian mares; the hormone ratio dynamics appear more informative than absolute concentrations
- •Foal rejection mares show a sharper drop in both progesterone and prolactin by day 3 post-partum, suggesting possible dysregulation in the normal post-partum endocrine transition
- •Close monitoring of maternal behaviour and early intervention protocols may be warranted in the first 72 hours post-partum, as hormonal markers suggest changes occur rapidly during this window
Key Findings
- •No statistically significant differences in oestradiol, progesterone, or prolactin concentrations between rejecting and non-rejecting mares when groups were compared directly
- •Rejecting mares showed significant decreases in progesterone (3.14±6.2 to 0.49±0.18 ng/dL) and prolactin (216.2±325.4 to 145.2±311.4 ng/mL) from day 1 to day 3 post-partum
- •Non-rejecting mares had significantly higher oestradiol-to-progesterone ratios on day 1 (114.8±140.2 vs 47.3±21.1), and this ratio increased significantly in rejecting mares between days 1 and 3