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13 Ways to Tell If a Horse Is Pregnant

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Watching your horses grow and carry a foal is an experience like no other. Unfortunately, sometimes what we think is a baby horse growing in a horse’s belly turns out to just be fat, or vice versa! Most of the time, simply looking at a female horse, also referred to as a mare, cannot confirm a pregnancy. Here are 13 ways to help tell if a horse is pregnant or just fat.

Pregnant horse in green field eating grass

1. Has Your Mare Been with a Stallion Recently?

In order to be pregnant, the mare in question must have been with a stallion, an intact male horse, sometime within the past 13 months.

Most mares carry their foals anywhere from 320 to around 370 days, sometimes longer. This means that in some cases, a horse can go a little over 12 months before giving birth.

If you are sure that the mare has not been with in stallion within this time frame, then there is a better chance that she is just overweight. (source)

It is important to know that a true gelding, a castrated male horse, cannot breed with a mare.

Brown and black couple horses in the forest

2. Is the Horse Skipping Her Regular Heats?

Mares should experience a heat, a cycle, multiple times a year. This happens many during the warm months about every 18 to 23 days.

A pregnant mare will not show the normal signs of a heat including squealing, pacing, or raising her tail.

Starting in April until about September, unpregnant mares should cycle in and out of their heat every few weeks or so.

Pay close attention to the mare in question. If she is still experiencing regular heat cycles, she is probably just overweight. If not, this could be a sign of possible pregnancy. (source)

3. Does the Mare Refuse to Stand for a Stallion?

Mares that are not pregnant and are in heat will naturally hold their tails up to entice stallions to mate with them.

While they can be irritable shortly before their heats, a mare that is not pregnant will welcome a stallion that attempts to mount them.

Pregnant mares will often refuse to be mounted by a stallion. If the mare in question is constantly refusing the advances of a stallion, this is another possible indicator of pregnancy.

a pregnant brown horse

It is important to know that sometimes a pregnant mare will still act interested in a stallion, but the percentage is low, but only about 5-10%. (source)

4. She Has Gained Weight for No Other Reason.

Most horses gain weight naturally whenever their caloric intake is increased or when they become less active than normal.

Has anything changed activity-wise or food-wise in the last few months? Active horses that are suddenly stalled but fed the same amount will often gain weight.

A pregnant horse will gain weight when nothing has changed. If the mare’s activity level has not decreased and you have not changed her diet recently, then pregnancy may be the cause of the weight gain.

5. Her Belly is the Only Thing Growing.

Horses that are simply fat, or overweight, will gain weight all over their body. Fat will form over areas that previously well-defined. Their neck, chest and bellies along with their hind quarters will all increase in size with little definition.

Pregnant Grey Horse walking on the farm

A pregnant mare will mainly gain weight in her stomach. The rest of her body, apart from her udders, will stay relatively the same size as they were before she got pregnant.

Think of it this way, if you could not see her belly, would she still look overweight? If the answer is no, she could be pregnant.

6. There is Movement in Her Abdomen.

If you notice movement in your horse’s abdomen, it may indicate that there is a baby rolling around in there.

As a horse reaches the tail-end of a pregnancy, you will be able to see sudden movement in your mare’s belly as the foal runs out of room.

You may even notice that your horse’s abnormally large belly suddenly looks flat on the sides while it almost points downwards. It will almost look like the foal has moved towards the birth canal.

These are all positive indications that your horse may indeed be pregnant and not just fat.

7. Her Udders Are Getting Bigger.

Approximately two weeks to a month before she gives birth, a mare’s udder will start to expand as it fills up with milk. Days before she foals, the udders may even leak some of the milk out.

White horse mare and foal in a grass

If you have an unpregnant mare, you can compare their udders to see if they look different.

If your mare’s udders have not expanded, it does not necessarily mean she is not pregnant. A full and distended udder, however, is a clear indication of a pregnancy as well as an indicator of impending delivery. (source)

Never milk a horse you suspect is pregnant because the foal should get the first milk, also known as the colostrum.

8. How is Her Mood?

Think about your mare and if her mood has changed recently. A pregnant horse that is nearing the tail-end of her pregnancy may become more irritable that she normally acts.

She may be less friendly with other horses and you may notice her separating herself from the herd. A pregnant horse will often pace and seem restless as well.

Horses that are simply fat and not pregnant should show little to no change in their regular mood or demeanor. She may seem more tired and winded, but that can be attributed to the weight gain.

Mood changes are never a definite indication of pregnancy as a female’s attitude can also change during her heat cycles.

9. Check Her Vulva  

When a mare is getting closer to giving birth, her vulva, or lady parts, will begin to relax and loosen up. It is preparing for the stretching that will happen during birth.

It is possible to begin seeing changes in the vulva around day 315 of your horse’s possibly pregnancy. (source)

If you suspect that your horse is pregnant, you may want to compare her vulva to that of an unpregnant horse.

A quick google search can give you some pictures to compare. A fat horse that is not pregnant should have a tight, normal vulva.

10. Test Her Urine with an At-home Equine Pregnancy Test

Purchase your own at-home horse-specific pregnancy test and conduct your own testing! If you are not sure if your horse is pregnant, at-home test may be the quickest and cheapest option before you call in a professional.

Over-the-counter equine pregnancy tests detest the level of estrone sulphate, a hormone is indicative of pregnancy in horses. Be aware some tests may have a false-negative and the test should not be performed before 110 days from when you think she could have been impregnated.

11. Get a Vet to Test Her Blood.

Your vet can take a blood sample from your horse to confirm if there are pregnancy hormones present or not. The blood test can be used to detect pregnancy hormones in a horse that you think may be pregnant.

Using stethoscope. Female vet examining horse outdoor

A blood test is more less costly than more invasive exams and tests that your vet can perform. This test is most effective by day 70 when the hormones are high enough to detect in most horses.  (source

12. A Vet Can Perform a Rectal Palpitation.

Your veterinarian can perform a rectal exam to see if they feel a growing foal or swelling uterus.

Rectal palpation is most accurate from day 30 of the pregnancy, but it depends mainly on the experience and skill of the practitioner. (source)

While rectal palpation is considered low-risk on average, there are room for complications. It is one of the most common pregnancy exams performed by vets during farm visits.

A rectal tear can occur by an inexperienced examiner, that is why is it important to only allow an experienced professional to perform the palpation. (source)

13. Confirmation Via Ultrasound.

The best and most cost-effective option for an ultrasound is to have a veterinarian confirm the possible pregnancy via ultrasound. If you want to know for sure if your horse is pregnant or just fat, an ultrasound is hands down the best option.

Another option is to purchase a portable ultrasound scanner that you can use at home. It is the higher upfront cost option, but it can be used multiple times for multiple horses for years to come. You also might be able to borrow one for free from a fellow equestrian.

Keep in mind that, as we mentioned above, horses can tear during a rectal ultrasound. This type of injury is 100% fatal in all cases. Ultrasounds are best left to the professionals.

Horse Pregnancy Test Options

Many of the methods above are not concrete and could have other explainations that do not include pregnancy. Hormones and ovarian cysts, for example, could cause a mare to illicit pregnancy symptoms.

There are a wide variety of pregnancy test options for horses. Here are some of the most common, as well as their estimated costs.

Remember that evaluation by a licensed veterinarian is the best way to determine if your mare is pregnant or not.

MethodVet Required (Y/N)Estimated CostAccuracy
At-Home Urine TestNo$37 to $60Fair
Blood TestYes$25*Fair
Portable Rectal UltrasoundNo$0-$850**Good
Portable UltrasoundNo$0-$980**Good
Rectal PalpitationYes$50Very
Vet UltrasoundYes$55Very

*This does not include the farm call or visit fee your vet may charge.

**The cost depends on if you borrow or purchase the portable machine.