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.
Large Dog Breeds: 18 to 24 months old; Small Dog Breeds: 12 to 18 months old; Medium Dog Breeds: 15 to 18 months old; While a dog may reach sexual maturity in the first year and a half of life, it's best to wait until it's at least two years old before mating. This is especially true for bitches, who should not breed during their first year of heat.