Last Updated on February 20, 2022 by Griselda M.
Breeding horses can be a tricky business, and it is a risky time for both the mare and the foal. But exactly how long is a horse pregnant for?
Knowing how long a horse is pregnant can help us to guess when she is due to foal. Let’s find out everything you need to know about how long a horse is pregnant, and more!
How Long Is A Horse Pregnant For?
The average pregnancy of a horse lasts for 11 months. During this time, she will carry the growing foal in her uterus, and by the time it is born it will be one-tenth of its adult weight.
The reason that a horse is pregnant for so long is that they need to produce a foal that can survive in the wild. A young foal is very vulnerable, and easy prey for predators. It is important that the foal is big, strong, and can run with the herd as soon as possible.
In a situation where horses lived in the wild, it was also sensible to only have one foal per year. The mare would normally be mated by the stallion in early summer, to produce a foal in the spring of the following year. This gives the foal a much higher chance of survival than one born during the winter months.
How Many Days Is A Horse Pregnant?
The average length of a mare pregnancy is 330 days. It is unusual for a mare to have her foal early unless there is a medical reason that causes her to abort the growing fetus. However, she may foal anytime from 320 days of her pregnancy.
The mare might not foal early, but the length of her pregnancy can be extended by a considerable amount of time! A horse pregnancy can last for up to 390 days, which is more than a whole year.
If a mare has never had a foal before, it will be impossible to predict how long her pregnancy will be. Once a mare has had her first foal, it becomes easier to predict when she will give birth in the future. However, there are some factors that may influence how long is a horse pregnant.
Firstly, ponies tend to have a shorter pregnancy than larger horses. A first-time mother will tend to have a longer pregnancy than any future gestation period. Some horse breeders believe that a mare will often have a similar pregnancy length to that of its own mother.
Another factor that affects how long a mare is pregnant is when she was mated. Mares that are covered earlier in the season tend to have a longer pregnancy than those covered later.
Scientists also believe that climate conditions can affect the length of a horse’s pregnancy, along with the levels of nutrition that the mare receives.
What Happens During A Mare Pregnancy?
One of the most fascinating things about a horse pregnancy is the way in which the foal develops. The vast majority of the growth of the foal takes place during the last few months of pregnancy. During the first seven months, the foal will only reach around 7 kilograms in weight. When it is born, it will be about 50 kilograms!
The foal might be tiny during the first two trimesters of pregnancy, but many other amazing things are happening. At just 24 days after conception, a heartbeat will be detectable in the growing embryo. By the time it is 46 days old, it will be able to move its head and limbs.
During the second trimester, the foal will start to develop hairs, including eyelashes! At this stage, it will already have tiny hooves, and the major joints in the skeletal system will be evident. In the sixth month of pregnancy, the growing fetus will have a mane and tail.
It is in the third trimester that the foal starts to grow rapidly. For this reason, if you have a mare that is pregnant, she will need additional nutrition during the last four months of the gestation period.
Towards the end of the pregnancy, the foal will start to turn and move into the correct position for a successful birth. At this stage, your mare will look obviously pregnant, with a distended abdomen. You will also see her mammary glands start to develop as they fill with milk in preparation for the birth.
Read more about How To Tell If Your Mare Is Pregnant?
So, as we have learned, a horse is pregnant for 11 months or 330 days, but this can vary by several weeks. Factors that can affect how long is a horse pregnant include the size of the mare and whether it is her first foal. It is important to know the signs that a mare is approaching her foaling date so that we can monitor her for any potential problems.
We’d love to hear your thoughts on how long is a horse pregnant! Have you ever been caught out by a foal arriving early? Or maybe you want to try and calculate when your mare will give birth? Leave a comment below and we’ll get back to you!
How Long Does It Take To See If A Horse Is Pregnant?
A veterinarian will be able to perform an ultrasound scan 16 days after mating or insemination to see if a horse is pregnant.
Alternatively, some people choose to wait and see if the mare comes back into heat again. If she comes into heat 20 days after mating then she is not pregnant, and if she does not come into heat then she is most likely in foal.
How Long Is A Mini Horse Pregnant?
A mini horse pregnancy is no different to any other type of horse, and is on average 330 days long. As with all horses, this can vary widely, from 300 to 380 days.
However, mini horses can often have difficulty foaling, so it is important to check regularly for signs that her pregnancy is coming to an end. This will help you to get assistance during foaling if required.
How Long Is A Horse Pregnant With A Mule?
When a horse mare is covered by a donkey stallion, she becomes pregnant with a mule and will have a shorter pregnancy than when having a horse foal. A horse pregnancy with a mule will last between 316 and 365 days.