Signs a Horse Might Be Pregnant

Jessica McDaniel
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When Do Horses Breed?

The average gestation period of a horse is approximately 11 months, or about 340 days, and the exact length of time between breeding and birth is impossible to predict. Most mares will foal (give birth) in the spring and summer, with heavier breeds tending to give birth in early spring, when temperatures are warmer. Quarter horse mares are typically due in the month of March or April.

Since breeding season is also considered the birthing season, breeding season for horses often overlaps with springtime, when there are more hours of daylight, and the weather is nicer.

How Long Is A Horse Pregnant?

It usually takes a horse twelve months to gestate or carry a baby. However, there are a number of factors which influence the gestation period like age, size, breed, weight, etc.

A horse's gestation is not the same as a human pregnancy. This means that the horse has to carry a baby all through a winter and deliver it in the spring. For a horse that is carrying a baby, you may notice some signs like frequent urination, swelling in the mammary glands, the appearance of the mare's teats, or signs of abdominal distention.

While it is not possible to 100% determine 'if your mare is pregnant' since there are no sure signs to indicate whether a horse is pregnant or not, there are some signs to look out for if you want to confirm your suspicions.

Also, you should remember that the female organs which are used for breeding are also used for urination. So, sometimes a very small change in female organ appearance or behavior is the only indication of pregnancy.

When Can You Tell if a Horse is Pregnant?

A mare is fertile for about 20 hours a day and can conceive several times a year. Signs of pregnancy may be harder to detect in a mare than in a human female, because a mare may continue to cycle and ovulate, even when she's pregnant.

Therefore, it is best that you keep track of your horse's cycles and pregnancy signs. Once pregnancy signs have been detected, you should begin to familiarize yourself with the physical and behavioral changes that take place during gestation.


Your mare may change her behavior after she mates. Some male horses are gentle and let their female lead the way. Your mare may change her behavior after she mates. Some male horses are gentle and let their female lead the way. Other horses are more dominant and may push against her or nudge her, to try to get his way.

With a dominant stallion, your mare may walk or run more slowly or may lie down when she or her male companion wants to rest. As the pregnancy progresses and the mare's body changes with the fetus inside, she may move more slowly.

Her belly may feel "full" if there is a large fetus inside, and it may be more difficult for her to lie down. The mare may kick, lie down, or roll to one side. If the mare lies down, she may rest on her abdomen.

How To Tell If A Horse Is Pregnant?

Horses give birth to a single foal. Foals are usually born with a full coat of hair and are able to stand within an hour of being born. It is important to note that you may only be able to tell if a mare is pregnant up to 7 weeks gestation.

During gestation a mare can lose weight and look thin as the weight is lost from the foal. They may also eat less, due to the lack of energy required for producing milk. This is quite common in thoroughbreds.

Prior to the birth of the foal, you can notice swelling of the mare’s udder. They may become more sensitive to their surroundings and may refuse food if they are in pain. They may also become reluctant to move or even act as if they are lame.

Some mares will stop eating immediately after they give birth, and will not eat until the foal is several hours old. This is quite common in horses that have not previously experienced the birthing process.

Transrectal Ultrasonography

Taken at an abattoir, with the horse lying down to offer the optimum vaginal space, the transrectal ultrasonography scan is probably the most accurate way of diagnosing pregnancy in mares and cows.

In layman's terms, the veterinarian inserts an instrument into the rectum of the horse and uses ultrasound to locate the ovaries. A pregnancy can be determined by the size and position of the fetal pole.

Once a pregnancy is confirmed, the veterinarian may use an intravenous catheter to onset labor and also to determine if the placenta is viable. If the placenta is removed and examined, an accurate estimation of the gestational age of the fetus, as well as an estimation of its sex can be made.

Blood Tests

Horses can be difficult to detect pregnancy and even more difficult to have them tested. The best test to determine pregnancy is a blood test.

Blood tests are performed by a veterinarian. Only 5 percent of veterinarians in the United States do equine blood testing.

Many diagnostic laboratories participate in blood testing horses. The procedure is performed at a veterinary clinic. The veterinarian takes a blood sample from your horse and sends it to the specific diagnostic lab for testing. The lab then sends you the results.

Blood tests can detect pregnancy as early as 15 days after breeding and possibly as late as 90 days after.

Whether or not this option makes sense for you depends on how many mares you have and if they are pregnant or not.

Behavioral Signs

If you own your horse and have seen it during each estrus cycle, then you can use your observation skills to help add to the accuracy of the pregnancy test. After 48 hours of confinement, if you notice behavioral symptoms not seen during estrus, then you can consider those as pregnancy signs. For example, if your horse is a stallion and never used to lick his penis but then starts doing it, you can consider it as a pregnancy sign.

What Should You Do if a Mare is Pregnant?

To be able to answer this question, you first need to know how to identify and confirm if a mare is pregnant. Usually, a mare is pregnant for 280 to 300 days. In this time, the mare will experience a wide range of different physical, behavioral and emotional changes during gestation.

This chapter provides signs and symptoms of a pregnant mare, at each stage of the gestation, which you can use as a checklist for a vigil pregnancy surveillance.


When she's your friend, your furry best buddy, your chill-out buddy, your family's protector, everywhere buddy, the center of attention, and the one taking all the blame whenever you miss the target, you know your dog is your best friend (I am not being biased, at least!).

Now you know the best dog breeds in and why you should own one. You have all the knowledge about the friendly personality and unique qualities of the dog breeds included, and you have also learned the common behavioral problems you might have to deal with, when you buy the dog from the wrong family or breeder.

I hope that, by now, you have decided which dog breed is the best for you! It is important to be aware of the problems that can arise, as you already know that the dog traits are unique, and one dog will not be exactly the same as another.

Good luck choosing your pet dog! Remember, the perfect dog breed is the one that will suit your lifestyle, your family, and your financial situation.