I have a female daschund 5 1/2 month old how old does she has to be before she could start breeding?

She will not come into season until about 8 months. She can get pregnant then. You may shocked at the creative, strenuous efforts she makes to get loose and go find a male, any male. At 8 months, very few dogs have proven themselves to be the exceptional examples of the breed that should be selected for breeding. They haven't had near the time for personality and physical defects to show. I don't think OFA will accept X-rays for a dog under a year old. AKC has a limit on the ages of the parents to register dogs. No OFA and AKC, and the puppies won't be worth much.

You would be best off spaying her now. If you insist, spend the next year doing serious research on Dachshunds, their problems, and breeding dogs in general. A good place to start is www.akc.org. Be sure to read every word of their page on responsible breeding. Also work with her, seeing what she might be good at. There is much more than the AKC breed standards. You could see how she does in obedience or agility competition.