i dont know ,every dog ive ever had has stayed with me till it died , .but thats just my way , i think some folks expectations are to high , ive heard about certain folk taking dogs out for a race , it hasnt killed so fk it and left it in the field , not good in my eyes , you cant run a unfit dog and expect it to be at its best on strong winter stuff ,so my view is its alot to do with the owner to give the dog the or get the best from his dog .