What Happens When a Horse Foals?

The foaling process, by which a mare gives birth to a young horse, consists of many physiological changes that indicate the stages of labor and delivery. Owners and caretakers of a mare should familiarize themselves with the foaling process to make the mare more comfortable and recognize signs of complications.

  1. Gestation Period

    • The average gestation period -- the time between fertilization and foaling -- is 340 days, but can vary by about 10 days. The length of this period depends in part on the climate and the time of year, as horses tend to carry their foals for slightly longer in cold weather. Early signs that the mare is nearing the end of gestation include a softening of the muscles in the rump, a filling of the udder and a relaxing of the genitalia. These changes generally occur two the four weeks before the mare foals.

    The Approach of Labor

    • As the mare nears labor, several physical and behavioral signs are often noticeable. A swelling of the vulva and a leaking of fluid from the teats indicate that the mare's body is preparing for foaling. The mare's affect is also a reliable indicator, as most will become slightly nervous, withdrawing from other horses and refusing food. The uterine contractions may also lead the horse to pace in the stall, sweat and urinate frequently. During this initial phase, which can last from two to 24 hours, the foal turns into position and moves toward the birth canal.

    Delivery Process

    • When the contractions of the mare's uterus become more powerful, the horse's outer water bag will rupture. From this point, the delivery process should take only 10 to 15 minutes. (If the delivery exceeds 30 minutes, the foal may be improperly positioned, and a veterinarian should be contacted.) The mare will either stand upright or position herself on her side with her legs extended, and may take a period of rest after the foal's shoulders have emerged and again after the passage of the foal's hips. When the foal has fully emerged, the mare's inner sac will rupture, but the umbilical cord will continue to pulsate as the foal receives the rest of the blood in the placenta. After about 15 minutes, the cord can be cut and its end disinfected.

    Post-Delivery Period

    • In the hours after labor, continued uterine contractions expel the placenta. In some cases, the placenta is retained, and should be tied near the horse's vulva to prevent her from stepping on it. The mare devotes attention to her foal in the hours after delivery, cleaning it and waiting as it struggles to stand and finds its way to her teat. The foal must receive milk in the first six hours to clear its intestines and prevent infection. The mares whose udders are sore or inflamed may become anxious and reject their foal initially. The mare's owner or caretaker can gently milk the mare and hold her down to prevent injury to the foal.