My questions are:
1.What are the genetic health issues with this breed?
2.What health certifications should he be looking for in the parents?
3.I have noticed that a lot of breeders only register with the UKC. Should the breeding stock be registered AKC FSS or is UKC enough?
4.What health guarrantees should he expect in a puppy contract?(i.e. OFA-hips/elbows/heart/thyroid, CERF)
5.And lastly, What are some main questions he should be asking a breeder?
Hi, I own and show DDB and have for the last 7 years, but am also a rottie owner. My first suggestion is that you go to the national breed clubs website at www.ddbs.org. As for your questions here is my opinion
Health issues - orthopedic as with any large breed, elbows, pasterns and hips are a problem
Health certificates - look at the stars program on the DDBS website, these should include heart, hips, elbows, thyroid and eyes for the basics
As for registration - this can be tricky, first off does he want to compete with his dog? the breed is now in Misc class with AKC so you would want a dog that has a proven 3 generation pedigree with AKC or FCI so that when the breed moves to the Working group it can continue to compete and also be used for a breeding program if that is what he has in mind. While we are in Misc class AKC will except the UKC pedigree, but all 3 generations must have UKC numbers - many have blanks in them as UKC will issue pedigrees that are not complete.
Health guarentees - same as other health questions
Questions of the breeder - should be same as with any breed dog. Much will depend on what he is looking for as far as competing. As with rotties and other breeds different bloodlines will have some differences in temperament. Some bloodlines are big couch potatoes and that might be what you are looking for, but there are a few bloodlines that have been breeding for working temperment as these dogs are capable of doing obedience, rally, carting and french ring sport. Do be aware that this breed like many others can be dog/animal aggressive. This does not mean they can't have manners, but may never be friendly to other dogs. Any breeder that says their pups will never be dog aggressive can not in my opinion guarantee that.
Feel free to email me with more questions if you want as I am one of the contact people listed on the parent club's website as the AKC Liaison.

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Val.
proudly owned by
Majic the Rotten
Purl - the Nottweiler (Dogue de Bordeaux)
Quest - the otherweiler (DDB)
Chrissy & Tina who have earned their wings