German Shepherd dog

I have a female who has a history of poor heat cycles. She is six years old and has only produced on litter, and she has only come into standing heat two times. The one litter she produced was outstanding. I have a senior male I would really like to breed her to while his sperm analysis is still good, but she will not come in heat. I have kept her with other females in heat, with this male, and other males....I've tried everything I can think of. She did start into heat once, bled a couple of weeks, then went out without swelling or standing for my male. I am wondering if there is a shot that I can get to bring her into heat? I've heard of this before, but never used it or done much research on it, so wondered if anyone here has any experience with it.

 Why would you want to create a litter from a bitch so hard to breed? is this a trait you would want to pass to puppies? obviously she took once so she will stand thats not a problem but what medical reasons makes her heat cycles so weak, I would have to rethink using her to breed.  

Forcing a poor breeding female to go into heat  with hormone injection is sooooooooo immoral and very irresponsible.

If the bitch has problems, why pass it to the pups, as what Bob mention above? If you dont want to accept her as a family pet, please sell (or give her away) her to someone who will not only spay her but also care and love her for the rest of her life.

 Do the female a favor if you do sell or place her have her spayed your self just to make sure someone else doesnt think hey i,ll try it once. Viagra and Roofies thats funny.