Our 8 year old mare just seems not quite grown up enough yet to handle the stress of the campaign, and so she will coem back for foal this year, and we will restart her afetrwards. Seems like it can be emotional - I know, I know - anthropomorphizing.... but she tends to be a quiet mare, internalizing things I think - and much like her older great aunt, may just need the time. She was treated for a peekaboo case of beginning ulcers, seems good to go but we will always want to monitor her. Perhaps she will be an endurance horse - perhaps she will not. We will see - but if not, she wouldn't run on drugs. Ever.