However, it's important to note that:
* Individual variation exists: Some mares may be fertile for longer or shorter periods than this average.
* Breeding longevity depends on factors like:
* Breed
* Overall health
* Nutrition
* Management practices
* Breeding frequency
While it's possible for a mare to be fertile for over 20 years, it's generally recommended to retire mares from breeding around 15-18 years old. This helps to ensure the mare's health and well-being, and can also prevent the risk of complications related to pregnancy in older mares.