Hypothyroidism is one of the most commonly diagnosed hormone disorders in dogs. As of Sept 2012, the Orthopedic Foundation for Animals (OFA) at OFFA.org, lists 26 dogs tested, with 11.5% abnormal. It is important to note that those numbers are not meant to be a percentage of WPG’s with thyroiditis. The numbers are biased by the reasons for submission, and by the numbers of owners/breeders willing to have results (anonymously) posted. The numbers do indicate that the disease occurs in the WPG. Hyperthyroidism is quite uncommon in dogs, and will not be included here at this time.
Symptoms of hypothyroidism often mimic those of other diseases, and that sometimes includes behavioral problems. Dog owners are most often not aware of clinical signs of the disease, and both they and the veterinarians might have difficulty sorting out symptoms leading to diagnosis and treatment. The OFA website is the best source of information on hypothyroidism, including disease description, testing procedures, and databases for individual breeds. Searching the database for testing results for individual dogs is available there.
If you are breeding a dog, both parents should be tested within a year before breeding, and should be tested annually. If you are buying a dog, and the dogs have not been tested, or testing is not documented, ask the breeder why not.
An excellent overview: Schaer, Michael, Hypothyroidism in the Dog, University of Florida College of Veterinary Medicine, July 29, 2000, can be found at: Hypothyroidism in the Dog 2000
The Canine Thyroid Epidemic: Answers You Need for Your Dog, W. Jean Dodds DVM and Diana R. Laverdure (Dogwise Publishing, 2011) provides the dog owner with comprehensive up-to-date information on thyroid disease.