Overbreeding a bitch

We breed Coton De Tulear dogs. My question has to do with the number of litters our bitch can safely have before she should be spayed? Is there a recommended number and if so why? Is it related to age? We sincerely love our female and would NOT want to jeopardize her health by overbreeding her!

The current thinking by the vets I have contact with is that you can not over breed a dog as long as she has a healthy uterus When a female reaches the age of 6-8 years the litter size starts to decrease, that is the time to think about stopping breeding & spaying a dog. You need to find a good breeding vet for advice and help

Thanks, that is pretty much what my new Vet said. Bitches, as long as they are healthy will produce their maximum number of puppies. When that number drops, quit!
   
Thanks Again!