What is the maximum age that a miniature Yorkshire Terrier should be used for breeding?

There's no definitive "maximum age" for breeding a miniature Yorkshire Terrier, but it's generally recommended to retire them from breeding after their second heat cycle, which usually occurs around 1-2 years of age.

Here's why:

* Health: Older dogs are more susceptible to health issues, which could be passed down to their puppies. They also may not be able to handle the physical demands of pregnancy and birthing.

* Puppy quality: Puppies from older mothers are more likely to have health problems.

* Ethics: It's considered unethical to breed dogs past their prime reproductive years, as it puts both the mother and potential puppies at risk.

Factors to consider:

* Individual dog's health: A healthy dog may be able to breed later than others.

* Breeding program goals: Some breeders may choose to breed older dogs if they have specific goals in mind.

It's important to consult with a veterinarian and experienced breeder to determine the best breeding schedule for your individual dog.

Ultimately, the decision of when to retire a dog from breeding should be based on the dog's individual health and well-being.