Are you waiting with anticipation, wondering when your mare is going to drop that precious foal you've been dreaming about for the last 11 months (or more?) The estimation of a mare's foaling date is always calculated from the last breeding date and the average gestation length in the horse is 340 days. However, there is never an exact science to figuring out when – exactly – your mare will drop her foal. The range can be 320 to 360 days, and this fact can keep breeders on their toes.
The following are 7 of the best external signs a mare will display prior to foaling, plus the length of time they typically display these signs before the birth happens. Just remember, these signs are extremely variable and of course they all change from mare to mare.
1. Rubbing her tail – Mares who become uncomfortable in pregnancy may begin to rub their tails. You might interpret this as needing to be dewormed, but if you have your broodmare's deworming up to date – not to worry. Some mares like to deal with the weight of the foal and the physical discomfort of gestation by pressing their butts against the wall or rubbing their tail heads. This can occur 2-3 months prior to foaling, right up to the day of.
2. Distention of the abdomen – the mare's abdomen will often conform to a \”pear shape\” within 2 to 6 weeks of foaling. You will also see her belly \”drop\” and seem to have a \”shelf-like\” appearance.
3.Relaxation of croup muscles – in the mare's hind end, on either side of the tail, you will begin to notice a \”spongy-like\” feel to the muscles in this area. This typically occurs 7 to 10 days before foaling.
4. Udder development -4 to 6 weeks prior to foaling, the mare's udder will begin to fill up with milk. Many people refer to this as \”bagging up.\” Her teats will also begin to fill up and become shiny and black – this happens within 4 to 6 days of foaling.
5. Waxing of teats – Colostrum begins to ooze out of both of the mare's teats at 4 to 6 days prior to foaling. Of course, some mares will begin to wax out of one teat and throw you for a loop or there are also some mares who wax for days and days, or will quit waxing altogether for a spell in between. That's why it's best to document some notes about your broodmares every year so you can know what is typical behavior for their pregnancy.
6. Dripping of Milk – This is probably the most reliable sign that your mare will foal soon as it usually occurs within 24 to 48 hours of foaling.
7. Elongation of the Vulva – As the mare gets closer to parturition, her vulva begins to stretch and relax downwards in preparation for the foal to come out of the pelvic canal. Again, this happens usually within 24 to 48 hours.
Happy Foaling Season!!