We rescued a male mini dachsund that is now 5½ months old. We already had a 2 year old female mini dachshund. We inteneded on getting him neutered, but the vet said he needed to be 6 months old. Well, I walked in the room today and they were locked together. It couldn't have been more than 15 minutes. My question is, Is he old enough to create sperm to impregnate her? And is there a abortion pill for dogs? I hate to do that, but I know there are too many unwanted dogs, and far too many loser owners that are neglectful/abusive, so I wouldn't want to place them with some bum.

There is a chance that he could get her pregnant, if they had sex and ejaculated than yes, she could be. There is a morning after pill, but it is only good up to 48 hours after sex.

There are spay aborts, which might be your last option. It won't cause any additional harm to your female, and spaying and neutering is always the best option :)

As Bella said, yes it is definitely possible.

The injection to stop a pregnancy only works up to 48 hours after the mating so you need to get in quick.
The other option is booking your b*tch in to be spayed, easy fix and even if you only neuter the male, he will still more than likely get upset when she comes into season.

He is definitely old enough.

You have options to weigh here. She technically is old enough to have puppies. But the question is do you want this? Daschunds are prone to many boney (mainly spinal) issues, so it is pretty important they have proper genetic testing done before they are bred.
Also the idea of the fact that there are a lot of dogs out there, and do you really need to add more? Daschunds are a pretty popular breed, and because of that there are a lot in shelters (see here: Search Results: Error. )

The mismate shot needs to be done pretty soon after tying for it to work. Your best bet would be to get her spayed, which in the long run is the best thing to do.

I have nothing to add, I just want to let you know that I admire the fact that you don't want this pregnancy to continue, and that you are being a responsible pet owner by asking this question.

Please let us know how it goes, or what you decide.