Unlike humans, mares do not go through menopause. They do not experience menopause or “change of life,” but their eggs are depleted, and they can no longer become pregnant. Research has shown that the mare’s reproductive age depends on the number of eggs present in her ovaries at birth. Therefore, the mare’s actual age is not the same as her reproductive age.
In women, menopause occurs when the hormone estrogen decreases. This decrease is responsible for well-known symptoms such as hot flashes, dizziness, mood swings, and similar effects. Additionally, the stimulation of the uterine lining is reduced, and menstrual bleeding ceases.
Mares do not bleed like women, and there is no evidence that they experience symptoms of menopause. They simply become more infertile with age.
ARE THEY STILL IN HEAT?
A mare’s cycle lasts for 21 days, and she is often in heat for about 5-8 days, with ovulation occurring within the last day of estrus. The duration of a mare’s heat depends on her genetics, conditions, and season. If a mare is in poor condition, extremely stressed, or ill, her heat cycle can be automatically paused. This is also recognized in humans. The mare’s heat period is paused during winter, and the ovaries become inactive. This prevents her from foaling in the middle of winter since mares have a gestation period of approximately 11 months.
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Most mares experience their first heat cycle between one to two years of age and remain fertile until around 20 to 25 years old. There have been cases where some mares go into heat at 35 years old, but they cannot become pregnant as there are no more eggs remaining in their ovaries. After the age of 20 to 25, it is common for a mare’s cycle to become more irregular, and the symptoms of heat can vary. However, it is rare for mares to completely stop showing signs of being in heat.
AT WHAT AGE CAN A MARE BE BRED?
Since the mare’s actual age may not correspond to her reproductive age, it means that the ability to breed varies individually for each mare. It is not uncommon for breeders to breed mares up to 23 years old, but it is once again an individual decision that also depends on the mare’s health and physique. When a mare is over 20 years old, the process of breeding and the likelihood of a successful birth become more risky, so it must be a carefully considered choice. Some mares can breed without issues until they are 25 years old.
If a mare has never had a foal before, she should be bred by around 15 years old. If the mare gets older, the risk of tragic complications becomes too high.
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Similar to humans, a mare’s cycle and hormones can vary. It is observed that some mares’ performance and willingness to cooperate can change depending on their cycle. Furthermore, some mares may have a disrupted cycle, either with very long estrus or no estrus at all. This can also affect the mare’s behavior in various ways. In such cases, interventions can be made to assist the mare with supplements. A veterinarian can provide suggestions for supplements and preparations, but natural remedies can also be sought with the help of most equine nutritionists. However, it is recommended to consult a veterinarian if natural remedies are not sufficient to support the mare comfortably through her cycle. Never attempt any interventions without consulting a veterinarian, equine nutritionist, or other qualified professionals in the field.
Ball, B., “Reproduction in the Geriatric Mare” University of Kentucky, 2015: https://equine.ca.uky.edu/news-story/reproduction-geriatric-mare
Seges Innovation “Hoppens brunstcyklus“ Landbrugsinfo.dk, 2015
Netdoktor.dk: Hormoner & Progesteron
Approved by veterinarian Elisabeth Pontoppidan from Hestepraksis Nord https://hestepraksisnord.dk/