* Lack of accurate records: Records of births in horses, particularly in older times, were not always kept meticulously.
* Variations in definitions: The definition of "oldest" can be interpreted differently. Some might consider the mare's age at the time of giving birth, while others might consider the overall age of the mare.
* Ethical considerations: It is not considered ethical to breed mares at very advanced ages due to the risks associated with pregnancy for older mares.
However, there are some notable cases of older mares giving birth.
* In 2017, a 30-year-old mare named "Lady" gave birth to a healthy foal in Germany. This was considered a remarkable achievement.
It is important to remember that older mares are more susceptible to complications during pregnancy and labor. Veterinarians generally advise against breeding mares after a certain age.