The Germany time line is quite correct for the northern hemisphere My Singers begin heat cycles in August and the second a few months later and sometimes a third end in mid winter I have a male pup from a third heat cycle that was born in early spring like a wolf or coyote This breeding only occurred because I had them separated for the first  cycles thinking them over then put them back together Then the third happened with pregnancy as the result  Heat periods in  months or less is quite remarkable for any canine