I had a 13 year old lab that I had to put down several years ago. She kept having seizures. Vet said she had a stoke. She couldn't eat, contol her bowels and lots of other problems. Was the hardest thing I've ever done to decide to have her put to sleep. I can still see it. Very peaceful for the animal, but terrible for the owner. I still tear up when I think about it and wonder if I did the right thing. I remember thinking "Why can't people have the option of going out peacefully?" Thirteen is getting up there for a lab. Always tough deciding how long to prolong their life. It gets pretty expensive and usually doesn't help much. They never are the same again. None of us really are when we start that slippery slide. Best of luck to you in dealing with your dog.