Join Date: Nov 2011
Location: Alberta, Canada
• Horses: 0
It really depends, and your Vet would easily be able to give you a better idea after some breeding exams.
I know of a mare who was infertile at 7, while I know others who conceived for the first time at 19 years old.
That being said, personally I would be nervous to breed any horse over 15 if they haven't had a foal in the past 3 years.
As mares age, they lose elasticity and therefor are more prone to rips and tears, which can lead to infection, and of course many more issues could arise.
When breeding any mare over 10, they should generally be 'flushed out' by a Veterinarian, to prevent infection, blockage and so on.
There are many precautions that need to be taken when breeding an older mare - including their weight, feet, muscular/skeletal structure (do they easily get sore, etc) and so on.
I hope I helped :)