We have two female aussies and they go into heat every 6 to 6 1/2 months so if you take away the 63 days of pregnancy its 4 to 4 1/2 months after litter is born.
In this case yes. I have a silky terrier that goes into heat every six months. You can set your watch by that girl. Yet again, age and size of dog can have an impact.
even pure breeds get euthanized
