How long do I have to keep my dogs apart to prevent pregnancy?

you will know........watch the actions of the male, when he becomes agitated (about two weeks into the heat cycle) and attempts mounting......and most important when the bi tch is willing and standing,  that is the time to separate them.  you must remove one of them from your home at that time for a period of about 5 or 6 days....hopefully you have a great responsible relative or friend to take one of them....you might try the male but sometimes males become unmanageable away from home, then it must be the female.   you need not separate them the first weeks you will not notice your males agitation YET and that is your signal to get one packing.....

At LEAST three weeks how cruel for your entire adult male to be in same environment as a ***** on heat. When this has passed and if you’ve been extremely lucky get her fixed. The world doesn’t need more puppies believe me. Why on earth would you want to keep an entire pair together anyway ? Did you consider this when you got the dogs. Be a responsible owner and get your dogs sorted.

21 days from the fist heat day

Absolutely no less than 21 days.

three weeks or 21 days or more.

You really need to get them spayed & neutered. You do not want the label of being a stupid, ignorant, lying, cheating, scamming BYBer by breeding your pets.

If you had intentions of breeding them, I sure hope that it does not happen. People breeding their pets is what has caused the pet population to EXPLODE BOOM BIG TIME. Just because people breed their pets for all the wrong reasons.

You need to get on google & do some research & learn a little bit about dogs. Look up what a responsible dog owner is. Look up the difference between a Backyard Breed & a Reputable breeder.

I am glad you don't want puppies now & I appreciate you efforts to prevent pregnancy now but could you make it forever?

Right up until your VETERINARIAN either gives you advice or spays/neuters them.

Spay and neuter them and you will never have to worry about ill bred mutt puppies

Until her heat cycle is over and the best thing to do is to find somewhere else for the male to live while she is in heat or you are going to have consistant whining from the male who could damage anything to get to her, stop eating and be a real pain

Until the heat is complete. Allow 3 weeks from the 12th. Call the vet and schedule a spay for her when they feel it's appropriate - it's unfair to your male to torment him with a dog in heat, and sooner or later he's going to get to her!

Until she is no longer in heat. The length of heat cycles can vary. It is usually about three weeks, but can be longer. If he's still showing interest in her, they need to stay apart.