What to expect when your horse is expecting

Horse Health: The majority of mares foals between dusk and dawn

Foaling is a remarkable process that few owners witness. They usually arrive to discover a healthy foal having already nursed and easily following alongside its dam.

An uneventful foaling and a vigorous newborn foal are the natural outcome of a healthy mare with an excellent nutritional program and opportunity for plenty of movement.

The duration of pregnancy in mares is generally 330 to 345 days, or about 11 months, however, this period can span from 310 to 387 days and not be unusual. Even though a mare can be checked any time to determine if she is pregnant, evaluations done earlier on in the gestation period tend to be more reliable when predicting delivery dates. Many mares will have very similar gestation lengths from year to year.

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In order for the mare to become acclimatized to the environment in which she will foal in, it is best to introduce her into the foaling location at least one month prior to the anticipated delivery date. This time frame not only allows the mare to settle into her new surroundings, it also provides her immune system the opportunity to produce antibody-specific colostrum. These colostral antibodies will protect her newborn foal in the environment into which it is born. Clean grassy pastures provide an ideal environment for a mare to foal.

During the last two weeks of gestation mares commonly have a pronounced abdomen, develop a distended udder, and show relaxing and/or softening of the buttocks, tailhead, and vulvar region. Teats generally “wax” or weep a clear, syrupy secretion 24 to 48 hours before foaling. Milk kits are available to test the calcium concentration in the milk prior to foaling. Typically calcium concentrations in the milk begin to rise significantly 48 hours prior to impending parturition.

The majority of mares foals between dusk and dawn. This is likely an innate behaviour from the wild ensuring the foal has ample time to nurse and easily follow its dam by morning light.

When it is time to foal, the mare experiences three stages of labour. During the first stage the mare generally seeks isolation, stops eating, and often appears restless and uncomfortable, perhaps pacing or sweating. This is normal and is a part of the pro-cess that prepares proper positioning of the foal for delivery. At some time within the next 24 hours the mare progresses to the second stage of delivery. Initial uterine contractions cause signs of mild discomfort, tail switching, sweating, and frequent urination.

As the uterine contraction become stronger and more frequent, they force the white glistening fetal membranes and foal’s feet forward through a dilating cervix. Once the water bag breaks and fetal fluids are expelled, most mares lay down and begin strong abdominal labour. Both of the foal’s feet will then appear with one foot leading the other by a hand’s breadth. This unlocks the shoulders and allows easy passage of the foal through the pelvic canal. The nose of the foal follows close behind.

From this point, the foaling process is almost explosive with each abdominal effort moving the foal through the birth canal within a short period of 15 to 20 minutes. Variations in this normal presentation are an indication for veterinary assistance.

After delivery, the mare may remain laying down for up to 30 minutes before standing and bonding with the foal. This period allows the mare to rest and the foal to become familiar with its new environment. The umbilical cord often remains attached as long as the mare remains down and allows a reserve of blood to flow from the placental unit to the foal. As the foal begins to move around the umbilical cord separates about six to eight inches from the umbilicus. During the final stage of delivery the placenta is passed.

Ideally the newborn foal will stand within one hour of delivery, nurse within two hours of birth and the mare will expel her placenta within three hours. Healthy foals will pass their first manure and/or meconium shortly after ingesting colostrum. The 1-2-3-hour rule following foaling is directly linked to the health and well-being of both mare and foal.

If there are any delays, a call to your veterinarian is crucial, as this is a critical time.

About the author


Carol Shwetz is a veterinarian focusing on equine practice in Millarville, Alberta.

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