Foaling Basics: What to expect when your mare is expecting

Learn about foaling basics, preparing for your mare's delivery, and key milestones to ensure a healthy outcome. Read our comprehensive guide for broodmare owners.

Spring means foaling season for many farms. Welcoming a new little horse to your herd can be a very exciting time! Luckily, the majority of foalings occur without incident and result in a healthy and happy mare and foal. However, when foaling issues occur, they are often very serious and can quickly threaten the life of the foal and mare. For this reason, we recommend all foalings be observed, so intervention can be given immediately when needed. Knowing when your mare is going to foal, and what to expect when that occurs, is critical information for any broodmare owner. 

In this blog we will cover the following topics: 

  • Determining a Due Date
  • Premature Foals
  • Overdue Foals
  • Predicting Foaling
  • How to Prepare for Foaling
  • The Foaling Process
  • Important Foaling Benchmarks
  • Other Things to Monitor 


Determining a Due Date

The average gestation length for mares is 340 days (or “11 months, 11 days”). This is counted from the day of ovulation. If you bred your mare with reproductive ultrasound tracking, you should have an exact date of ovulation. You can then use this helpful calculator to predict the due date:

If you have a mare that was pasture bred, or if you acquired a mare that was already pregnant with an unknown due date, we have some ability to estimate the age of the fetus. Using an ultrasound, we can sometimes measure the size of the eye of the fetus, which has been shown to be directly related to age. 

Even though 340 days is an average length, there are plenty of mares that will foal before or after that day. For this reason, it is still important to monitor them closely and be very familiar with all of the signs immediately leading up to foaling. 


Premature Foals

Foaling before 320 days of gestation is considered premature and comes with many health issues. If your mare foals unexpectedly early, it is important to have a foal exam performed within the first 12 hours to ensure they are healthy. There are many things which can appear normal externally but actually be underdeveloped and will need medical management. 

The most common cause of premature birth is fetal stress from uterine infection (placentitis) or illness of the mare such as colic or pneumonia. If you notice any vaginal discharge with your mare, or any milk development/dripping before day 320, you should contact us immediately for an evaluation. 


Overdue Foals

There are very few medical concerns with a mare going beyond her expected due date. We do not induce labor in overdue mares as there is no benefit to forcing the process. 

One known cause of late delivered foals is fescue toxicosis. This occurs when mares in late pregnancy ingest fescue grass that is infected with a particular fungus. This fungus will cause abnormalities with the reproductive tract that can lead to infertility, extended gestation time and problems during delivery (dystocia). If you have a pregnant mare grazing on fescue pastures, it is recommended you have the grass tested for the presence of endophytes.


Predicting Foaling  

Many mares will foal before the 340 day mark, so we recommend keeping an eye for these physical changes starting at day 320. Some of the changes can be very subtle so it is important to be familiar with your mares and knowing their regular routine and physical traits. 

Mammary Development: Mare’s will generally start to develop some fill to their udder two to three week before foaling

Relaxation of Muscles and LIgaments: Close to foaling the mare’s vulva may see to become longer and softer, her abdomen may seem to drop and the ligaments around her tailhead and pelvis will soften

Waxing of Teats: Dried secretions usually develop on the teats, called “waxing”. 90% of mares will foal within 24-48 hours of waxing

Behavioral Changes: When a mare enters the first stage of labor, they may show some behavioral signs such as pacing, laying down, pawing, sweating or acting restless. These signs can mimic mild colic, so it is important to monitor her closely and make sure she is still passing manure and the discomfort doesn't worsen beyond mild agitation. Stage one labor can last anywhere from one to twenty-four hours before foaling. 

Mammary Secretion Tests: One reliable way to predict the time of foaling is to measure the amount of calcium in the mare’s early milk. When a mare’s milk calcium levels rise above 200 parts per million, there is a 50% chance she will foal within 24 hours, an 85% chance she will foal within 48 hours and a 95% she will foal within 72 hours. There are several commercially available milk calcium tests available such as FoalWatch and Predict-A-Foal. 

You can also measure the pH of the milk, as there is a high probability that the mare will foal within 24 hours once the pH drops to 6.5 or lower.

These tests can be influenced by high risk pregnancies or abnormal milk secretions, but in healthy mares with normal pregnancies they can be very reliable. 

*It is important to note that Maiden mares often do not show the classic pre-foaling signs and require extra close monitoring. 


How to Prepare For Foaling 

If you have been watching your mare closely and believe there is a chance that she will foal within the next few days, there are some steps that you can take to ensure everything goes as smoothly as possible. 

  1. Move her to an easily observable location where you can check on her frequently without disturbing her. If the barn has access to wifi, there are lots of high quality, inexpensive security cameras that can be set up for constant stall surveillance. 
  2. Prep the area to be spacious and clean. An ideal foaling stall is a minimum of 14’x14’ and kept meticulously clean. I prefer mares to foal out on straw versus shavings as it does not stick to wet newborns and is less likely to contaminate their umbilicus after breaking. 
  3. Set up a schedule for 24/7 observation. As mentioned before, it is very important for foalings to be observed as problems can occur quickly and can sometimes be life threatening without immediate intervention. Setting up a rotation of friends and family can help reduce the amount of sleep lost by one individual person. If you live near a college or university with an agricultural program there may be some equine studies students that are willing to participate in a foal watch rotation in order to gain some hands-on experience. Be sure everyone involved is well trained on what to watch for and knows who to call if there are any problems. 
  4. Alert your veterinarian that you are starting foal watch. It is always nice for us to know when clients are expecting foals as we can make sure the truck is fully stocked and ready for any foaling emergency. 
  5. Keep the mare clean and sanitary. It is always a good idea to wash the mare’s vulva and udder with a gentle soap before foaling as it will reduce the bacterial exposure of the foal within the first few hours of life. You may also keep the mare’s tail wrapped to keep it clean and out of the way of the coming birthing fluids.  
  6. Assemble a foaling kit. I recommend you have the following items in your kit: 
  • Chlorhexidine solution and a small disposable cup for umbilical dipping
  • A thermometer and stethoscope 
  • Vetwrap 
  • Fleet enema
  • Disposable exam gloves 
  • Clean towels
  • A clean pair of scissors 
  • A flashlight or headlamp 
  • Notepad for keeping notes of observed activity  


The Foaling Process

As mentioned before, the behavioral signs before foaling (stage one labor) can last up to several hours. Once the water breaks, stage two begins. It is easy to confuse water breaking with urination, but one way to tell the difference is mares will not posture when their water breaks. As soon as stage two starts, things become very time sensitive. If the foal is not fully delivered within 20 minutes of the water breaking, it is considered an emergency! In a prolonged delivery the oxygen supply is compromised and the foal’s life is at risk. The first thing that should be seen from the mare’s vulva is a translucent white bag and two front hooves. Here is a good example of a normal foaling presentation:

If the delivery process is not progressing quickly, or if you suspect an abnormal presentation, please call us immediately! The sooner that help can arrive the better chance of survival for the foal and mare. 


Red Bag Delivery

One potential emergency that every broodmare owner should be aware of is called a “red bag delivery”. In this situation the placenta separates prematurely from the uterus and the foal appears to come out in a red bag instead of the thin amniotic membrane. This is a serious emergency as the foal is being completely oxygen deprived because the placenta is no longer providing oxygenated blood and the nostrils are covered with the thick placenta. The foal can die quickly if the red bag is not cup open immediately (this is the reason for keeping scissors in your foaling kit!) It is important that anyone observing the foaling process knows what a red bag looks like and how to react if they see one. Here is a helpful image provided by the AAEP of a red bag versus normal delivery: 


Important Post Foaling Benchmarks

Once the foal is delivered, there are some important milestones that should be reached within the first few hours. We call it the “1-2-3” rule and it goes as follows:

  • The foal should be standing within one hour
    • If the foal can not stand unassisted in this time, it may have abnormalities with its limbs or mental delay due to oxygen deprivation during abnormal delivery.  
  • The foal should be nursing within two hours
    • The first milk of the mare is known as colostrum and contains essential proteins to help the foal develop proper immunity. Without colostrum the foal will be at risk of developing an infection which can be life threatening 
  • The placental should be passed within three hours
    • If the afterbirth is not passed within this time, it is considered a “retained placenta.” This can cause serious health complications for the mare and requires veterinary attention. Be sure to save the placenta, even if if passed appropriately with a normal birth. We will need to examine it and ensure no pieces were left behind


Other Things to Monitor:

  • The umbilical cord should break naturally when the foal is attempting to stand. If the cord does not break on its own, it can be gently torn to remove. You should not cut it as that will cause bleeding from the stump
  • The umbilical stump should be dipped in a disinfectant such as chlorhexidine solution after it breaks to prevent it from getting infected. It can be dipped daily for the first few days after birth. 
  • The foal should pass its first manure, known as “meconium” within a few hours of birth. If the meconium does not pass a Fleet enema can be administered. Meconium impaction can cause discomfort and colic in newborn foals. Do not administer multiple fleet enemas as they can be irritating to the tissue.
  • All foals should have a healthy foal exam within the first 24 hours of birth to make sure there is no illness or abnormality. Sick foals can start with very subtle signs which can be difficult to identify. The key to successful treatment is early detection. The healthy foal exam will also involve a blood test to make sure the foal was able to absorb enough antibodies from the mare’s colostrum to have proper immune function. 



Being prepared for your mare to foal is the most important step to ensure a healthy delivery. 

Not all problems can be prevented, but by understanding what to look for you have the best chance to identify issues quickly. 

Please contact us if you have any questions or concerns about your broodmare!

(Note: We do not offer foaling services at the clinic at this time as we do not have overnight staff required for monitoring)



About The Author

Dr. Alyson Waring-Scott

MVB, cVMA, VSMT  |  Equine Veterinarian

I am an Equine Veterinarian at Carrollton Equine and enjoy all aspects of equine medicine. I am especially passionate about dentistry and ophthalmology, and have received advanced training in both of these areas. I am also certified in medical acupuncture and VSMT (chiropractic). 

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