Split Heat & Foal Heat – Species

Split heat & foal heat is common in:

Correct Answer: Mare

Both split heat and foal heat are characteristic reproductive phenomena of the mare.

Split Heat (Double Ovulation)

• Split heat in mares refers to an interrupted estrus — the mare shows signs of heat, then appears to go out of heat briefly, then comes back into heat, with ovulation occurring during the second part. This is due to FSH surges stimulating two follicular waves.
• Mares have a higher incidence of double ovulation (~25%) compared to other species.

Foal Heat

• The first postpartum estrus in the mare occurs very early — approximately 7–12 days after foaling — this is called the foal heat.
• Mating during foal heat is possible but conception rates are lower due to incomplete uterine involution.
• The second postpartum heat (30–35 days) has better conception rates.