we faced this last year our old boy was about 30 , he was very arthritic and having the maximum dose of bute daily but was getting worse ,the vet came out to see him and said it was a downhill slope he was happy to let him carry on a bit longer but said that winter was coming and before long i would find him down in the mud and rain and unable to get up , so i made the decision to let him go ,he was put to sleep in his paddock with the sun on his back munching grass and polos it broke my heart , but it was the best i could do for him , he is buried in his paddock ,it didnt take long to bury him we had a man come in with a digger he dug a really deep hole we lined it with straw and laid one of his rugs in then they lifted him in with the digger and we covered him with another rug and the digger filled in , you are doing your best for him , i will be thinking of you tomorrow xxx