Parvo and difficulty in breeding.

Question
We have a beautiful 2 yo Jack Russell Terrier female that has been in heat twice.  When she was around 6 mo. old she almost died from parvo.  We would like to breed her and let her have one litter of puppies and then have her spayed.  Her heat cycle has only lasted about 4-6 days on both occasions.  Is this a normal length of time for her to be in heat?  Could this be connected in some way with her serious bout with parvo at an early age?  Could this cause her to be infertile?  We, in no way, want to breed her multiple times for profit.  She is our "child" and not a baby factory.  Does parvo have lingering effects such as this?  Thank you for this site and your time.
Concerned mom of a JRT baby  

Answer
A normal heat cycle is about 3 weeks.  I am not sure if this could be connected to Parvo.  When she is in heat, I would take her to the Vet. to have a vaginal smear collected and evaluated for estrus status.  They could tell you at the time if she is ovulating and ready to breed.  They might be able to run more tests to determine if she can become pregnant.  I wish I could help you more.