Spring is the estrous period for mares when the weather is warm and bright. If you have a mare and it has mated with a male horse, you will most likely have to check whether it is pregnant or not.
Thus, how do you know if your horse is pregnant and how long are horses pregnant? Typically, a horse’s pregnancy cycle will last about 11 to 12 months. However, it may take longer, and that is normal.

How long are horses pregnant?
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How Long Is A Horse Pregnant?
As you know, people get pregnant within nine months and ten days, which is a time of utter misery. However, many animals have a longer gestation period, namely horses.
Thus, how many days can a horse pregnancy last?
Typically, a horse will be pregnant within about 11 months, corresponding to the standard time from 320 to 340 days. However, many mares have a more extended gestation period, up to 370 days or more. So, you do not need to worry because the foal born late is still healthy.
By contrast, premature foals regularly have health problems. Therefore, they need to see a doctor to monitor and care for them. In the unfortunate case, premature horses can die within a few hours after being born.
How Do You Know If Your Horse Is Pregnant?
You can quickly check to see whether your horse is pregnant by using both chemical and non-chemical methods.
1. Using Non-chemical Methods
Check The Behavior Of Female With Male Horses
You can expose a mare to a male horse after 14 days of mating to observe their actions. If pregnant, the mare will most likely refuse the male’s advance, and it will not bring the anus towards the male as it did during estrus.
However, the horse may also reject the male even during the estrus cycle for other reasons.
Watch For Signs Of Estrus
When females lift their tails, open and close their vulva, and bend their legs to urinate or spit mucus from inside, these are signs of the estrous cycle. If they exhibit these symptoms after 21 days of fertilization, they are not pregnant.
Invite The Veterinarian To Conduct Rectal Palpation
Veterinarians may perform rectal touch after 16 to 19 days of mating. The doctor will insert his hand into the horse’s rectum to examine the uterus for evidence of gestation. These signs include the size, and shape of the uterus, and swelling in the ovaries.
Use Ultrasound Machine
Ultrasound is the most commonly used method for controlling the pregnancy of horses as this is the most reliable method.
This will require the doctor to insert a probe into the rectum so that you can know whether a female horse is pregnant or not. After 16 days of mating, the fetus can be detected, and when the fetus is 55 to 70 days of age, the doctor can determine its sex.
2. Using Chemical Methods
Conduct A Blood Test
You can determine the fertility of mares through the pregnancy hormone test. This is especially useful for those who do not like to check a pregnancy by non-chemical method because their rectum is too small.
The veterinarian will take a blood sample and send it to the lab for analysis. They will analyze the serum concentration (PMSG) of mares after 40 to 100 days of mating.
However, in case your horse miscarried, then this test may provide inaccurate results. Also, oestrone sulfate levels rise when the horse is pregnant, but this level will return to normal if the fetus is lost.
Have the Urine Test
When verifying pregnancy, you can find oestrone sulfate in the urine of mares. Thus, you can do urine testing at home with a veterinarian or farmer.
First, you need to buy a home pregnancy test device from grocery stores or online. After that, check the horse’s urine after 110 to 300 days of mating. Then, cut a container about 2 to 3.8 liters in half and use the bottom to hold the horse’s urine.
Finally, act according to the instructions listed on the pregnancy test equipment to evaluate horse urine. It usually takes about 10 minutes to get results.
Confirm Pregnancy Test Results
The chemical tests described above can tell you if your horse is pregnant, but it is best to be done by a veterinarian. Whether it is a chemical or non-chemical test, a doctor’s intervention is needed to get the best results and make sure it does not have a miscarriage.
Horses Gestation Period
The pregnant horse will go through three main stages.
Stage 1
The first stage begins with mating and is usually checked after two weeks. This is also the most crucial period, so you should have a veterinarian regularly check and monitor the health of your pregnant horse.
After about three weeks, the veterinarian may perform an ultrasound to detect the horse’s heartbeat. At this point, they will confirm if your horse is pregnant with twins. Usually, the mare is only single pregnant, and twins are a rare occurrence.
By the third month of pregnancy, the shape of the foal begins to form, and the doctor can identify the gender of the fetus.
Stage 2
The second stage can start from day 114 of gestation. During this time, you should ask the doctor to vaccinate your horse. Besides, you also need to add more food to provide the nutrients necessary for better development.
Stage 3
The final phase is for more than the last three months. You need to pay special attention to the behavior of pregnant horses because this is the end of pregnancy. They can have reproductive signs at any time.
In particular, you need to remember that your horse should be born in a spacious, comfortable, and clean space for the birth process to take place most smoothly.
Conclusion
Honestly, “How long are horses pregnant?” is an interesting question. Our article not only helps you understand the maternity process of a mare but also provides fascinating information to help you improve your horse breeding technique.
In general, a mare is usually pregnant for 11 months. However, that time may change sooner or later due to many factors. Therefore, you should pay close attention and take care of your pregnant horse regularly.