Gestation Length:
Light horses 325-355 days range (335-345 days average)
Premature <300 days
Immature 300-325 days
Prolonged >365
Mares as individuals, often repeat with similar lengths of gestation.
Signs of impending parturition:
(Some mares may show no premonitory signs)
| Mammary development - enlargement usually starts 3-4 weeks prior to foaling. |
| Ventral edema - associated with mammary development and fetal pressure on vessels. |
| Teats fill with colostrum approx. 48 hours prior to parturition |
| “Waxing of teats” - colostrum adhered like beads of honey at teat orifices 24-48 hours prior. Approximately 60-70% of mares “wax” |
| Relaxation of vulva and pelvic ligaments, 24-48 hours prior to foaling. |
| Milk flow approximately 4 hours prior to foaling. Some mares will leak milk 7-10 days prior, the foals of these mares should be supplemented with colostrum |
| Restlessness-mares tend to leave other horses, become unfriendly, mild signs of colic, stall walking and appear uncomfortable. Usually within 24 hours. |
Approximately 90% of mares will foal at night. They can control the final stage of labor.