How Long is a Horse Pregnant
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How Long is a Horse Pregnant? Conception to Birth. The Timeline of a Horse Gestation Unveiled

When springtime rolls around for broodmare horse owners, the excitement can be felt in the air because they know new baby horses will soon be arriving!

A horse’s pregnancy usually lasts about 340 days on average with most births seemingly taking place at night. Knowing how long your mare should be pregnant will help you plan for the due date of your newborn foal and help you take the best care of them. 

Keep reading to learn all about how long mares are pregnant, caring for a pregnant horse, and preparing for foaling season. 

horse foaling period

How Many Months Are Horses Pregnant?

A horse’s pregnancy usually lasts between 10 to 12 months. In days, horse pregnancies usually are around 325 to 375 days in duration.

There are several factors that make horse gestation vary.

Horse Pregnancy Terms You Need to Know

Before we get started talking about how long mares are pregnant and foaling, there are a few terms that may make this easier to understand. 

Horse Pregnancy Terminology

  • Mare – a female horse
  • Foal – a baby horse
  • Sire – the stallion who is the father of the newborn foal
  • Dam – the mare who is the mother of the foal
  • Heat or “in heat” – Ovulation cycle and breeding stage for a female horse (mare)
  • Foaling – the process of a mare giving birth to her unborn foal
  • The mare “took” or not – Whether or not your mare is confirmed pregnant

How to Tell If Your Horse is Pregnant

Many signs will help tell you if your mare is pregnant. He is a short list.

How to Tell If Your Horse is Pregnant
  1. Is your horse acting differently? Very often if your horse is pregnant they will start to behave in a manner that may seem odd to you.

    Often your horse may show signs of being protective and they may try to make a nest in their stall or where they spend most of their resting time.
  2. Are your horse’s eating habits noticeably changing? That could be a sign they are pregnant.
  3. Does your horse look like it is gaining weight? Their stomach may look bigger and more round.
  4. You may notice that their utters are getting bigger.
  5. With some mares, you may notice a vaginal discharge when they become pregnant. 

Remember, if you suspect your horse may be pregnant call your horse veterinarian immediately so they can give her an examination.

How Long is a Normal Horse Pregnancy?

A normal pregnancy for a female horse (mare) is anywhere from 335 days up to 360 days but this can vary.

Even if you keep extremely well-detailed breeding records, throughout the breeding season, your mare still may throw a curveball at you and go an extra few days past her due date. 

Mares almost always foal when no one is looking, so do not get too worried if a few days pass beyond her due date and you don’t have your foal here yet. 

A Horse’s Gestation Can Last 12 Months

Your mares pregnancy could easily go to 12 months of gestation without any issues. 

This may be more common among maiden mares or mares who have never been through the foaling process before.

If your mare is leaning towards 360 days of pregnancy the best chance at having a healthy foal and happy mare is to have your preferred vet keep track of her progress often. 

What to Expect During a Horse’s Pregnancy

It is exciting to have a mare that you are expecting a foal from, but there is a lot of time, planning, preparation, and care that goes into caring for your broodmare and preparing for your new foal. 

How Your Vet Can Check the Status of a Pregnancy

There are multiple things that your vet can do to check the status of your mare’s pregnancy and confirm that she is carrying a foal within the first month. Some mares do not show any signs of pregnancy until three months.  

In the later stages of your mare’s gestation, you will begin to notice a lot of changes within your mare’s body.

List of Ways to Confirm a Horse Pregnancy

  • Ultrasound scan to confirm the developing foal
  • The absence of any signs of estrus
  • Rectal palpation

First Trimester of a Horse’s Pregnancy

You may be wondering how to know whether your mare “took” or not.  There are several things to consider during a horse’s first trimester of pregnancy.

Because mares are considered polyestrous they can go into heat several times during a year. The breeding season will be limited to summer, with your mare coming into heat approximately every three weeks. 

Be sure to carefully plan when you are going to have your mare bred as you only get a few chances per year.

A qualified veterinarian can use ultrasound to verify a heartbeat and viability around 25 days into the gestation period. 

Second Trimester

For your mare, her second trimester will begin on day 114 of pregnancy and continue until day 225. 

It is possible to work and ride your mare during this time period under the direct guidance of a professional vet. Most experts agree that riding and light work for a mare can be beneficial until around the eighth month of pregnancy. 

During the second trimester, your mare will also need to have vet checks and vaccinations. 

Third Trimester

During the last trimester, you will want to move your mare to where you plan on having her foal. 

This is a beneficial part of normal foaling that will help expose your mare to any bacteria, viruses, or potential hazards that could affect the foal. 

Her body’s natural response will be to create antibodies, and she will pass them to her foal during the birth process as the foal travels through the birth canal. 

During the second and third trimesters, you will also begin to notice your mare’s belly begin to grow rapidly. 

Did You Know? A baby horse is called a foal until it reaches the age of 12 months. During pregnancy, the term fetus will be used after about 40 days when the new horse starts forming facial features.

Final Weeks of Pregnancy

The final month:

  • In the last two to three weeks, your mare’s stomach muscles will begin relaxing and you will begin to see the foal “drop”. This is especially obvious in older mares.
  • In the last three to four weeks, your mare’s muscles will begin to relax and become Jell-O-like near her tail.
     
  • During the final stage before labor, usually around two weeks prior, your mare’s udder will enlarge, and milk production will begin. You may see some of your mares’ first milk creating a waxy appearance on her teats. 

Causes for a Mare’s Pregnancy to Abort

Please note that not all horse pregnancies go normally. There are many reasons that can cause a disappointing result which include the following.

  • Stress
  • Fever
  • Bacterial infections
  • Uterine infections 
  • Equine herpesvirus (EHV)
  • Hormone abnormalities
  • Having twins 
signs of horse miscarriage

Is Caring For a Pregnant Mare Different Than For a Normal Horse?

The first thing I want to mention in this section regards the actual care that a broodmare receives. I have seen many trainers and horse breeders simply breed their mares and then toss them out into a pasture until a few days prior to when the mare foals. 

Do not care for your mare like this. It is not smart to do so. Pregnant mares need the same, if not much more care than regular horses. 

Steps  to Have a Healthy Mare During Pregnancy 

  • Ensure that your mare gets all of the standard veterinarian care and checkups that she needs along with vaccinations, boosters, and any other veterinary recommendations you receive. 
  • Keeping up with the recommended vaccinations will help create antibodies within the mare’s colostrum that will be passed to the foal.
  • Hoof care should continue as usual.
  • Once you reach the last trimester (the 9th to 11th months of pregnancy.) This is one of the most vital times for the developing foal. 
  • You will need to discuss with your vet or equine nutritionist a good quality feed program that is designed specifically for the stages of pregnancy your mare goes through.
  • Supplements are a great way to meet your mare’s nutritional needs, but she will also need roughly 2% or more of her body weight in forage per day. 

Your horse’s nutritional needs will increase during pregnancy. Make sure you feed them properly and include the necessary vitamins and minerals per your vet’s suggestions.

The Foaling Process

Prior to when your mare foals, it is a good idea to understand the birthing process inside and out. Especially if this is the first foal for you or your mare. 

A Mare’s Four Stages of Giving Birth

Stage #1

One thing to expect is that more than likely your horse will foal during the night. This is common among wild horses due to the cover of darkness and allowing the foal to gain control of their legs.

Even though we have domestic horses, this is still common for almost all foaling mares.

During the first stage of foaling, your mare will seem restless and almost as if she is suffering from colic. She may lie down and get back up repeatedly, or show other signs of discomfort. 

Stage #2

In the next stage of delivery, your mare’s water will break and your mare’s uterus will begin its uterine contractions that push the foal out through the birth canal. 

Most mares are standing up during this stage. Within 20 minutes you should see the front legs of the foal emerging. If more than 20 to 30 minutes pass without any sign of the feet of the foal, please call your vet and keep your mare walking until your vet arrives.

Stage #3

This is the stage of the birth when the mare will lie down and labor proceeds. In a normal birth, the amnionic sac along with the feet will appear, and following will be the nose of the foal. 

After this, the foal usually delivers quickly. The mare may remain lying down for a minute or so. If there is anything different than this scenario, please call the vet immediately.

Stage #4

This is the final stage of the birthing process and involves passing the placenta or afterbirth. Your mare may act colic-like again and usually will pass the placenta within a couple of minutes to an hour after birth.

You want to carefully examine your mare’s afterbirth to ensure that it is intact and nothing is left within your mare’s uterus. Leaving the placenta inside the mare’s uterus can cause infection and death.

Related Horse Pregnancy Questions

At what ages can a mare bear foals?

A filly would technically be capable of carrying a foal as young as just 18 months old, but your best chance of having a healthy foal and mare is to wait until she is at least four years old.

What should I do after the birth of the foal?

The best thing to do is prepare by talking with your vet before the birth. They will provide you with guidelines or even a checklist to follow.

What are some health checks I can do with my newborn foal?

There are certain things to check your newborn for which include the following.

Newborn Foal Checklist

  1. Their heart rate should be in the 80 to 100 beats per minute range. Note that a normal foal’s heart rate will increase during the first 24 hours to about 80 to 100 beats per minute. The foal’s heart rate will lower over time as it grows.
  2. Respiration should be in the range of 40 to 60 breaths per minute. If you notice shallow, slow, or irregular breathing call your vet immediately. Note that after an hour from birth the rate should be about 30 breaths per minute. Your vet will provide guidance for you.
  3. The foal’s temperature should be between 99.5 and 102 degrees. This is an important metric as a new horse can suffer from low body temperature. Call your vet if you are unsure.
  4. Their gums should be pinkish in color and moist-looking. If you see dark red or even a purplish color call your vet immediately.
  5. The “suckle reflex” should be noticeable within 30 minutes after birth.
  6. Your new foal should be standing on its own within 60 minutes of birth. If they are taking longer than two hours to stand that is not normal.
  7. You should notice their first urination within six hours for a colt (male) and within up to 11 hours for a filly (female).

What is the 1-2-3 rule for newborn foals I heard about?

The 1-2-3 rule is just a simple measure to check how your foal is doing.

  1. The newborn foal should be standing up on its own within an hour or two of birth. This is an important indication of their health.
  2. Your new foal should be nursing from its mother within two hours of being born.
  3. The foal should pass ‘meconium’ within the first two to three hours of life. This is an important indication that their intestines are not blocked in addition to other health concerns. Meconium is a baby horse’s first fecal material or manure and consists of matter from the birthing process.

A Short Story About a New Foal

When I was about 18 years old my parents obtained a broodmare. A broodmare is a female horse that is used for breeding. 

They got this horse as part of a debt payment. You see, my father loved horses (so did I) and he wanted to be involved in the horse racing business. So he invested in a horse.

Well, the horse didn’t win any money and the horse was sold. For some reason they didn’t pay my father his share and when he asked about it the money had already been disbursed.

So they offered my father, Ellie, the broodmare as payment and my father accepted. Ellie quickly became part of the family. 

My father decided to try and breed Ellie with a somewhat famous stud horse. I didn’t pay much attention to what was going on at the time and just went about my business with my horse.

One morning when I walked outside I could not believe my eyes! Standing there in the bright green pasture next to Ellie was a new baby horse! Wow! 

We really didn’t expect the arrival to come when it did and everyone was surprised with this new gift. Ellie had the baby foal, during the night and did everything all on her own! Amazing!

A New Horse is a Great Gift

I hope this article has answered some questions regarding how long mares are pregnant for and how to care and prepare for your new bundle of joy! Birth is a wonderful thing to behold, but preparation and understanding the birth process are key to keeping both your mares and your foals safe! 

Good luck this breeding and foaling season.

how long is a horse pregnant in months

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