Gestation of
miniature mare

The gestation period fore mare is about 342 days, but we notice in miniature mares it's often a little shorter with an average of 330 days, and a gap which generally goes from 320 to 360 days. A gestation period of 280 days with survival of the premature foal is reported as being, at the time, the shortest ever recorded in the miniatures.

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Means of detection

The first way to detect gestation in your mare is to observe her heat cycle and see if she shows signs 2 to 3 weeks after the last breeding. It is a simple but limited method because some mares show very discreet heat, others continue to show signs even during their gestation, finally, it involves having a stallion in the herd or nearby to trigger the heat.

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Internal ultrasounds (rectally) are rarely performed in miniature mares because the probes and especially the hands of the practitioners are generally too large to guarantee the safety of the mare. However, some experienced veterinarians use this method which makes it possible to confirm a gestation as early as 18 days after fertilization.

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External ultrasounds (trans-abdominal) are one of the best ways to confirm that your mare is in foal. They do not present a physical risk for the mare and allow to have a reliable image of the fetus on the ultrasound machine. The limits of this method generally lie in the equipment which veterinarians do not always have (portable ultrasound system with a large dog probe) and the time before they can be carried out. For an experienced practitioner, detection can be done as early as 30 days but it is much more reliable after 2-3 months of gestation.

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Finally, blood tests are one of the most used methods in large breeds and in miniatures although. Indeed, the blood test consists in measuring the concentration levels of one or more hormones and in particular estrogen. In miniature horses, it has been observed that the measurement of this hormone alone is not enough to have a reliable result, it is the concentration of estrogen and HGC which makes it possible to confirm a gestation between 45 and 60 days after fertilization.

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Gestation monitoring

Throughout her gestation, it is essential to observe your mare and to spot any physical or psychological changes. Some mares radically change their behavior. A supply of concentrated feed of the granule type, in addition to fibers (grass or hay depending on the region) may be necessary. It should be kept in mind that a mare who will have been well cared for throughout her gestation is a mare who will have an easier time to give birth correctly and to produce milk, especially a quality one.

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While it is important to ensure that your mare does not lose condition during this period, she should also not be in excess because a mare that is too fat is a mare that may have more difficulty foaling correctly.

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In the last few weeks before the expected foaling date, if you can and wish, it is beneficial to bring your mare back to the stall for the night. This will allow her to familiarize herself with the place,  you will be able to adapt her ration and have a little more surveillance by observing the physical changes that take place.

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In addition, a mare produces antibodies adapted to her environment which she transmits to her fetus, it is not recommended to move her in the last 4 weeks of her gestation so that the foal is born in a place facing which her organism is well armed. You may have noticed that early season foals are hairier than those born in June or July for example. Nature is generally well done and the mother's organism sends the right messages to her foal, to prepare him as well as possible for his arrival. If a mare must foal in a different environment, it will be necessary to plan to transport her there 4 to 6 weeks before the expected foaling date.

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Abortion

The causes of an abortion can be multifactorial and are unfortunately not always identified. Miniature horses appear to be more prone to abortions compared to larger breeds. Basically, there are key periods in gestation when an abortion can occur more easily, this is particularly the case at 3, 6 and 9 months of gestation.

In any case, when one is confronted with such an event, it is important to carry out analyzes with your veterinarian to try to determine the reason (s) : infection, malformation of the fetus, placental abruption, torsion of the umbilical cord, genetic diseases, EHV1 type rhinopneumonia, etc. Some mares can abort after great stress, others because of mild poisoning. If the cause is due to a situation or to an element of her environment, you will be able to prevent the risks on future gestations.

A pregnant mare should not be fed fescue (whether standing or dried as fodder). This plant has the particularity of increasing the risk of abortion, lack of lactation and obstructed foaling in pregnant mares.