When does the mother dog stops producing milk?

It is possible but with the correct diet and a heavy demand on her from the pups, she should have enough milk. Make sure she is on a good name Puppy Food, not some generic cheap food. Make sure the pups nurse all they want off of her. If she is not cooperating then sit with her and make her lay on her side while the pups nurse. If you think she is not healthy, then take her to your Veterinarian for a check up. Make sure she gets lots of the Puppy Food and is healthy looking.