Breeding

I've just been reading an article about why back to back breeding is better for the bitch than missing seasons between breeding. Apparently the uterus is never more healthy than after a litter, or maybe that's their excuse for excessive breeding? They tell us that with every season that is missed the uterus becomes less functional and fertility drops. Well ... no one told Sammi! She has been mated twice, approaching her third birthday she had three pups and then just after her 6 birthday and she had nine pups. Now I take on board what they say, I do, I'm willing to learn but there must be more to living with bitches and breeding than the condition of the uterus? 
I totally understand that the uterus has to be fit for function, but what about everything else? What about the mental state of the bitch? What about her quality of life? Her walks in the park? Her swims in the lake? Do they not count? There must be more for a female than producing puppies. Generally Blanik bitches have one litter, Sammi is the first to have two litters since Krizzie in 2003/05. To be honest it was only late last Summer that I decided I would breed from her again - after all she hadn't exactly flooded the market! She has been an excellent mother, but I do hope she will be firmer with the pup who stays this time than she has been with Kaiah though, she has let her run riot!
Talking of the mini Angel, she is in season. Obviously no trip to Suffolk for her this time .. but she'd be quite happy to settle for Ross. Odd isn't it, she wants to kill Loki for his advances but fancies the pants off Ross! Mrs S says NO Kaiah!