Deja has given you some great advice. I have 3 dogs, 2 are dachshunds actually! If I am reading correctly, this is a petstore dog that was older? Ok.. heres what I have learned. I got Kahlua my blk tan doxie, from a friend, and he was trained to go outside since he was little, and we crate trained him and he was great, never once pooped in there the whole time. I thought this is great, he learned so fast!!!!! Then, we were clueless about petstore puppies and how they could come from puppy mills, the health issues,etc Well unfortunatley we learned the hard way with our Jasmine. She is the cutest little girl, a papillon. We had problems with her since the beginning, we were at the vet all the time. And most of the time this was why.. they kept telling me over and over it was Colitis, like you had with Buddy. She was terrible with potty training, she would go in her cage all the time no matter what schedule we had with her, and would lay in it and litterally not care!!! I learned that's b/c she was a petstore dog and they are raised that way and thats the only way they know to go potty. We tried it all, making the cage smaller, praising her outside when she went, you name it, and she just wouldn't get it. I couldn't understand it, thats all they kept saying, colitis. Her stools were never normal, and we rushed once to the emergency vet b.c there was blood in it. What do they tell me ..colitis! We were thinking too that she was sick alot and thats why she would go in the cage. They thought she had kidney problems, she had tests done all the time, but after a trip to the specialist and a couple $1000 later, they tell me she has a food allergy! This has been the problem the whole time, I couldn't believe they were telling me this. I was sooo thankful it wasnt a kidney problem or anything serious, but I didn't understand thats what it had been the whole time, her allergic to that food!! I fed them all science diet, and was told by 1 vet(i took her to 2) to keep her on the food and NOT change b.c we didn't want to go to the protien diet yet and wanted to see how her BUN levels stayed with the same food as we started(didn't know if there was kidney problems at the time) and so they said keep her on it. If only I had known about how crappy this food really was I would never have fed her it and saved her alot of anguish. So I read up on foods and switched to an all natural diet that is so much better for cats and dogs, it doesn't have all those gross by products and preservatives in it. Jasmine has been a different dog since then!!!!!! Her stools have been totally normal, and we aren't there yet(and she almost 1 1/2), but since her tummy was adjusting to this food better, she was better at controlling all the times she had to go poop and has learned to kindof go on a schedule. Have you thought about changing the food? This could be part of the issue, I would give it a try. The food I feed mine are Solid gold. The other great ones out there are Innova, Flint River Ranch and Natural Balance. Alot of people also feed their dogs a raw diet.
To me Buddy seems alot like Jasmine, we were so frustrated and couldn't understand why she just didn't get it. Also, it could be some behavorial issues as well, have you thought about signing Buddy up for a obdience class, or talk to a pet behavoralist? We just signed Jasmine up last week, she gave some tips on house training as well. That could be good too. I know how frustrating it is, believe me!!! Deja gave some great advice too. And yes as bad as it sounds, sometimes the blanket or bed has to come out, we learned that. She hides it in there and she would be so good, and I'd give her a new bed and oopps there we go again, an accident! I have a 3rd dog,Penny a piebald dachshund. Before we knew about puppymills and petstores, we got her from another petstore a few months after Jasmine, spur of the moment, and I admit it was harder to teach her too, but she learned ALOT quicker than Jasmine.
Dachshunds are very smart and quick at learning. They can be stubborn too,lol. Kahlua just learned one day "ok I gotta go, so I wait by the door and whine and mommy will know.."! Now how do I get the other 2 to learn that lol. And let me guess, you take him out and he screws around sniffing ever blade of grasss, taking their good ol time?? Yup, its a dachshund thing.LOL
Different dogs have to go at different time and amounts, etc. My dachshunds normally only have a bowel movement 2-3 times a day., where as Jasmine is more like 4, but smaller amounts if that sounds right. Different bodies and statures. Are you on a set feeding schedule, how many times a day do they eat?I REALLY think maybe a change in diet and talking with a dog trainer/behavoralist could really help you. Hope I could help!!!