I also think it has to do with the bitch, herself, and how she handles a litter.
I was fortunate to have a bitch who, with pups eight weeks old, did not look or act like she had whelped. She was very athletic, in very good shape, was a wonderful mom, and worked during and after pregnancy with no problems (she was not a FT dog! but had no problem swimming (and swimming, and swimming)).
She had two litters of one pup (stud was pretty much sterile), which I did not really count at all - they did not tire her out for a day!
I hope this isn't taken to mean that I think you should just repeatedly breed a bitch; I just think it also depends on her health, attitude, etc.
I was fortunate to have a bitch who, with pups eight weeks old, did not look or act like she had whelped. She was very athletic, in very good shape, was a wonderful mom, and worked during and after pregnancy with no problems (she was not a FT dog! but had no problem swimming (and swimming, and swimming)).
She had two litters of one pup (stud was pretty much sterile), which I did not really count at all - they did not tire her out for a day!
I hope this isn't taken to mean that I think you should just repeatedly breed a bitch; I just think it also depends on her health, attitude, etc.
