As a human who went for years without treatment for a slow thyroid (hypothyroid), I have the human experience of how it affected my own behavior. Before I finally received proper treatment that included natural thyroid supplementation, my symptoms of ill health grew to three pages long. A lot of my hair fell out; I was lethargic and testy; I’d even say I was overly reactive to other human beings. The brain fog was among the worst symptom. The day I got on desiccated thyroid medication was so important I wrote it down and now celebrate it each year: March 7, 2007. I got my hair, my brain, my energy, and my active life back.

Having such a health turnaround for myself made me sympathetic to how a dog might be feeling with low thyroid levels. Could being hypothyroid cause a dog to be “snippy”? To feel sluggish or the other extreme, hyperactive?

I went to the foremost authority of canine thyroid function, Dr. Jean Dodds, DVM, for answers. Her book, The Canine Thyroid Epidemic: Answers You Need for Your Dog (co-authored with Diana R. Laverdure through DogWise Publishing, 2011) walks owners, trainers, and veterinarians through the complexity that is the thyroid gland. It is a must-read for dog owners with reactive dogs or for anyone who suspects that their dog might have a thyroid condition.

Dr. Dodds received her veterinary degree from the Ontario Veterinary College in 1964. After working for several decades in upstate New York doing non-invasive studies of animal models of inherited bleeding diseases, she moved to southern California in 1986 to start Hemopet, the first nonprofit national animal blood bank. Today, Hemopet’s range of nonprofit services and educational activities include:

• Providing canine blood components and blood bank supplies
• Adopting retired Greyhound blood donors as companions through Pet Life-Line
• Contributing to the social needs of the less fortunate through volunteer and interactive programs with the Greyhounds
• Specialized diagnostic testing using all “green” patented technology and consulting in clinical pathology through Hemolife, Hemopet’s diagnostic division

Dr. Dodds and Diana R. Laverdue have a new book recently published by Dogwise: Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health.

I was thrilled that Dr. Dodds found time in her busy schedule to answer questions about the canine thyroid epidemic for Dogster.

Dogster: How did you become interested in researching and writing about the topic of canine thyroid disease?

Dr. Dodds: After years of studying and researching the hematologic and immunologic diseases of animals as models for their human counterparts, I realized that I needed to look more at the body as a whole and what regulated it. The pituitary-thyroid axis connection then became the obvious answer for further study.

What are the physical symptoms owners should be on the lookout for with their dogs in terms of having low thyroid levels?

The classical symptoms are the overweight, lazy dog who dislikes the cold and usually has chronic skin disease and a poor coat. But, these signs don’t show up until at least 70 percent of thyroid gland function has been impaired. Other signs include but are not limited to:

• Lethargy
• Weight gain
• Mental dullness
• Cold intolerance
• Mood swings
• Aggression
• Hyperexcitability
• Stunted growth
• Seizures
• Dry, scaly skin and dandruff
• Chronic offensive skin odor
• Infertility
• Weak, dying, or stillborn pups

What are the behavioral symptoms?

Typical clinical signs: unprovoked aggression, sudden onset seizure disorder, disorientation, moodiness, erratic temperament, hyperactivity, hypo-attentiveness, depression, fearfulness, phobias, anxiety, passivity, submissiveness, compulsiveness, and irritability.

It seems like there are more dogs than ever who have thyroid issues. Do you think it is increasing in dogs?

It appears to be a combination of a real increase and an increased awareness of the condition followed by appropriate diagnostic testing. More inbreeding and line breeding of dog breeds and cross-breeds known to be historically at risk for thyroid disorders combined with the environmental pollution, depletion of the ozone layer around us, and the increased use of pesticides, herbicides, other chemicals, and even over-vaccination.

Are some breeds more prone to thyroid issues than others?

Yes. The top 25 affected breeds list fluctuates a little, but usually includes (in alphabetical order): Alaskan Klee Kai, Beagle, Borzoi, Boxer, Chesapeake Bay Retriever, Cocker Spaniel, Dalmatian, Doberman Pincher, English Setter (the highest), Eurasier, German Wirehaired Pointer, Giant Schnauzer, Golden Retriever, Great Dane, Havanese, Irish Setter, Kuvasz, Labrador Retriever, Leonberger, Maltese, Nova Scotia Duck Tolling Retriever, Old English Sheepdog, Rhodesian Ridgeback, Shetland Sheepdog, and Staffordshire Terrier.

What’s the earliest age thyroid disease can be detected?

Typically, affected dogs are at puberty or young adults before the disorder is detected.

Can stress affect the thyroid?

Yes, stress affects most body functions.

Is there anything owners can do to reduce the odds that their dog will become hypothyroid?

Yes: Feed them with fresh whole foods or premium grain-free commercial diets, avoid over-vaccination, vaccinate only for the prevent diseases in your area and rabies vaccine as legally required, and avoid pesticide and herbicide exposures, whenever possible. Use other chemical preventives for heartworm, fleas, and ticks, only if exposure risk warrants their use in your area.

What do you advise dog owners do if their veterinarian refuses to do a thyroid test?

Pet guardians need to remember that they are paying for this testing; if their veterinarian does not wish to perform the requested diagnostic testing after polite insistence, then go to another veterinarian.

Thanks, Dr. Dodds. One thing I’ve done ever since I read Dr. Dodds’ book is to have my local veterinarian draw my dog’s blood (if I suspect a thyroid concern), and my vet ships the sample to Dr. Dodds’ Hemopet Laboratory for a complete thyroid exam. You can ask your vet to do the same; it doesn’t cost much more to have this expert rule in or rule out a thyroid issue. Visit Dr. Dodds’ website for more information.

Read more by Annie Phenix:

• A Dog Trainer Answers the Question: What Makes a Dog “Good” or “Bad”?
• As a Dog Trainer, Here Are Three Things I Wish Veterinarians Would Do Differently
• Are You One of the Few Who Train Their Dog?
• How Do Dogs Show Affection to Humans?

About the author: Annie Phenix, CPDT-KA, is a force-free professional dog trainer enjoying her mountain-filled life in Colorado. She is a member of the Pet Professional Guild and the National Association of Canine Scent Work. She takes her highly trained dogs with them everywhere dogs are welcome because of their exceptionally good manners. Join Annie on her dog-training Facebook page.