An Overview of Horse Pregnancy and Foaling
Female horses, more commonly referred to as mares, are usually capable of producing one newborn horse, or foal, every year. Mares are generally ready to produce a foal at 18 months of age, though it is safer to wait until the horse has reached her full size at about four years old. Mares can continue to produce foals until almost 30 years old, however, because of concerns for the mare’s health it is advised to retire her from breeding when she reaches the age of 20 years.
Under normal conditions, horses breed in the summer and give birth in the spring. Owners would be wise to maintain this schedule, as foals born in the spring receive the advantages of abundant food and mild weather in which to grow and gain strength. Mares go into heat several times in a regular pattern during the spring and summer, a pattern that breeders and medical specialists can manipulate to avoid a birth later in the year. This process involves using artificial lighting to make mares think the longer, warmer spring days have arrived early.
Breeders should begin testing for pregnancy when a mare ceases her estrus cycle. Pregnancy can be confirmed via ultrasound at two weeks or by a blood or urine test two to three months after conception. In some cases, a veterinarian may be able to feel the embryo via rectal palpation. A mare usually shows physical signs of pregnancy between three and six months.
Horses carry pregnancies for roughly 340 days, or roughly 11 months, though in some cases, the pregnancy may last more than 12 months. Early veterinarian support is critical, especially in rare but potentially hazardous cases of twins. It is not uncommon for vets to remove one of the twin embryos. Otherwise, there is a risk of losing both foals.
A horse’s udder will begin to expand in the later stages of gestation. This indicates that birth is most likely between three and six weeks away. Once the teats produce fluid, breeders can hope that the birth will occur within a few days. Other signs of the impending delivery include relaxed muscles in the tail head and a belly that drops as the foal maneuvers into the birth position. The final signs resemble colic symptoms, ranging from restlessness to frequently looking at her flanks.
While horses are usually capable of safely giving birth without human intervention, an equine veterinarian can help avoid a wide range of potential complications. Responsible horse owners should have stallions and mares evaluated before mating to ensure both animals are in sound physical condition. Pregnant mares should receive regular medical checkups and vaccines for the duration of the pregnancy.
Veterinary checkups leading up to the birth can help avoid or better manage situations such as a foal in a “breech” position. Another critical birthing scenario is sometimes called a “red bag” delivery, which involves the placenta separating from the uterus before the foal is ready to emerge. Without immediate medical intervention, a red bag delivery can result in suffocation.
To help promote a calm, easy birth, mares should be provided a spacious, clean stall bedded with straw. Horses typically give birth lying down, but it is not uncommon for a mare to stand up repeatedly and lay down during the process. Breeders should expect to see the foal’s front hooves and nose first, at which point the birthing process should be within a few minutes of completion.
