A number of non-infectious causes can result in diarrhea. These include lactose intolerance, irritable bowel syndrome, non-celiac gluten sensitivity, celiac disease, inflammatory bowel disease, hyperthyroidism, and a number of medications. In most cases, stool cultures to confirm the exact cause are not required.
Most dogs are first bred between the 10th and 14th day after the onset of proestrus. As long as the bitch will accept the male, mating every other day for a total of two or three matings is generally considered sufficient. However, signs of proestrus are not obvious in some bitches.
Eight weeks old is when training should start. These days reputable breeders are starting their puppy imprinting at 3 weeks until the dog goes to their new homes. Obedience training can be started immediately. You do not have to wait until the dog is mature in order to train them.