i had to make the decision at the begining of the year to have my old terrier put to sleep and it broke my heart. i looked at it like this, is it worth giving medications that are just going to mask the symptoms its sad but you cant save a dog from old age and its not going to get better its just hideing whats there. Dogs are hard especially those that have lived and worked a lifetime and even when they are old and infirm they still try to get up and please there master, its hard to make the decision but you will know when the dog has had enough. dont feel guilty you have given her everthing s