cycle after a litter

Question
Hi,
 My Black Lab had a litter of puppies in January and weaned in March...I assumed she wouldn't have another heat for 6 months after she stopped nursing, however, she's showing all the signs of beginning her heat now 6 months after the delivery.  What is the typical cycle?  I don't want her to have another litter so soon, but don't want to separate her from her mate unless necessary......Help!?
Thanks,
Chris

Answer
Dogs usually stay on their same cycle regardless of being bred.  They will tend to come in again about 6-8 months from the time the cycle started on which they were bred.  So it could seem like only 4 months from whelping.  

Dogs don't have "mates" the way other animals mate for life.  Crate her when she comes in, crate the male, just separate them.  It's not that difficult.  You are the HUMAN, the OWNER, it's YOUR DECISION.  If you do not crate them, you WILL have another litter again.  What you have is a male and female who will breed non-stop, please do not be irresponsible about this.  

Just wanted to add that I hope you made sure that both your dogs have passed all the necessary health clearances that are necessary for labradors before you allowed that first litter.  OFA's for hips, elbows and hearts.  CERF and Optigen for eyes.  If they have not been checked, please do that as soon as possible.  Because to have any more litters in the future without tested parents is irresponsible!