A “maiden mare” is one who has never carried her own foal to term; “maiden” can also be used to describe a mare who has never been bred. The inherent fertility of mares remains high until approximately 12 to 15 years of age, after which there is a slow progressive decline in pregnancy and foaling rates until mares are in their mid- to late 20s. A majority of mares are bred to carry a foal well before they reach their mid-teens. However, occasionally a mare is bred for the first time at a relatively advanced age.
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