Stages in a Mare's Pregnancy

Horses, like humans, go through several stages of pregnancy and delivery. From conception to delivery, the horse will go through four distinct stages of pregnancy, with the actual delivery constituting three of the four stages. Many times, a mare will move in and out of the stages of labor and delivery without the knowledge of the handler, making it difficult to determine what stage a mare is in at any given point in the process.

  1. Conception

    • These days, horse breeding is highly scientific and rarely are horses left to let "nature take its course." Most mares are artificially inseminated as injury can occur during the mating process.

    Gestation

    • The average length of time a mare spends pregnant is anywhere from 335 to 340 days, just shy of one year. During this time, the fetus develops from the union of two cells into a fully formed and functional horse.

    Foaling

    • This term is used to describe the labor and delivery of the newborn horse. Foaling begins anywhere from two to six weeks before the onset of labor and involves the formation of the udder, or where the milk will be produced. Milk will move into the teats several days before the impending birth. Foaling also refers to the three stages of delivery, or parturition, that a horse experiences.

    Stage One Parturition

    • In this stage, the mare begins to experience contractions. It usually occurs anywhere from one to four hours before the mare begins pushing. The contractions are designed to put the foal into the correct position for delivery.

    Stage Two Parturition

    • In this stage, the mare delivers the foal. The mare will usually lie down, though some mares have been known to give birth standing up. The amniotic sac will appear first, followed closely by the two forelegs sandwiching the foal's head in between. This stage ends when the mare gets up and severs the umbilical cord.

    Stage Three Parturition

    • In this stage, the foal has already been delivered. The mare will still experience contractions and the placenta is expelled. This occurs within four hours after the delivery of the foal. It is important to inspect the placenta for any missing pieces as a retained placenta will cause infection.