How many years can a mare be breed?

A mare can be bred until she reaches about 20 years old. Mares generally reach their peak reproductive years between the ages of 6-12, with the ideal age for breeding being around 8-9 years old. Fertility starts to decline after the age of 12, and there are increased risks associated with breeding mares over the age of 15. After the age of 20, it becomes increasingly difficult for a mare to produce healthy offspring.