What Happens If You Separate Dogs While Mating. It is important that you never try to separate the dogs because it can seriously hurt them. Seek the help of a veterinarian straightaway after an unplanned mating to avoid having pups.

If two male dogs mate with the female on the same day, it's a straight swimming race between the sperm as to which reaches the ovum first and fertilizes it. Depending on how long ago your dog was neutered, yes he can still breed a female after neutering. The tie does not always occur, but when it does, it may last for as long as 30 minutes.