Canine Autoimmune ThyroiditisCanine Autoimmune Thyroiditis

An Overview for Dog BreedersAn Overview for Dog Breeders

Canine HypothyroidismCanine Hypothyroidism• A thyroid condition in which a dogA thyroid condition in which a dog’’s thyroid gland s thyroid gland

does not produce enough thyroid hormonedoes not produce enough thyroid hormone• This can cause obesity, sluggishness, hair loss, cold This can cause obesity, sluggishness, hair loss, cold

intolerance, weakness, skin disease, a poor coat, intolerance, weakness, skin disease, a poor coat, infertility and even failure to thrive in puppiesinfertility and even failure to thrive in puppies

• Hypothyroidism is primarily caused by a genetic Hypothyroidism is primarily caused by a genetic disease known as Canine Autoimmune Thyroiditisdisease known as Canine Autoimmune Thyroiditis

A Tale of Two Dogs:A Tale of Two Dogs:

Hypothyroid NormalHypothyroid Normal

How does this affect my dogs?How does this affect my dogs?• Canine Autoimmune Thyroiditis is hereditary so a dog Canine Autoimmune Thyroiditis is hereditary so a dog

inherits the disease from the sire or daminherits the disease from the sire or dam• Some hereditary diseases are easily controlled through Some hereditary diseases are easily controlled through

selective breeding practices. However autoimmune selective breeding practices. However autoimmune thyroiditis does not usually show symptoms until years thyroiditis does not usually show symptoms until years after a dog is bred.after a dog is bred.

• This means a single untested dog born with Canine This means a single untested dog born with Canine Autoimmune Thyroiditis can have many litters before it Autoimmune Thyroiditis can have many litters before it develops the first symptoms, passing the disease along to develops the first symptoms, passing the disease along to its pupsits pups

Hypothyroid SymptomsHypothyroid Symptoms• Hair loss and/or hair pulling up from the roots easilyHair loss and/or hair pulling up from the roots easily• Patches of scaly or red skinPatches of scaly or red skin• Lethargy and slownessLethargy and slowness• ObesityObesity• Cold sensitivity (Cold intolerance)Cold sensitivity (Cold intolerance)• LamenessLameness

……and in breeding damsand in breeding dams• Reproductive problemsReproductive problems

– Decreased number of pupsDecreased number of pups– Decreased puppy viabilityDecreased puppy viability– Decreased birth weightDecreased birth weight– Higher interval between deliveriesHigher interval between deliveries– Longer duration of uterine contractionsLonger duration of uterine contractions

* Chester & Hightower* Chester & Hightower

* Panciera et al., J Vet Int Med, 2012* Panciera et al., J Vet Int Med, 2012

• Canine Autoimmune Thyroiditis is much more common in Canine Autoimmune Thyroiditis is much more common in some breeds than others. High incidence breeds include Irish some breeds than others. High incidence breeds include Irish Setters, Golden Retrievers, Cocker Spaniels, Shetland Setters, Golden Retrievers, Cocker Spaniels, Shetland Sheepdogs, Beagles, and Dobermans.Sheepdogs, Beagles, and Dobermans.

• However, this disorder is found in virtually all dog breeds.However, this disorder is found in virtually all dog breeds.

How common is thyroid How common is thyroid disease in my breed?disease in my breed?

What can we do to reduce the What can we do to reduce the incidence of thyroid disease?incidence of thyroid disease?

• Hypothyroidism cannot be diagnosed with only a total assay of T4 (Thyroxine.) Broader profiles that include FT4, TSH, TgAA, and T3 are more specific in diagnosing thyroid disease.

• Thyroglobulin Autoantibody (TgAA) is produced when a dogThyroglobulin Autoantibody (TgAA) is produced when a dog’’s s immune system attacks its own thyroid. Hence, TgAA has been immune system attacks its own thyroid. Hence, TgAA has been shown to be a reliable test to help you identify the disease years shown to be a reliable test to help you identify the disease years before it becomes clinically apparent. before it becomes clinically apparent.

• This information may help you make better informed decisions This information may help you make better informed decisions when breeding, by selecting sires and dams with the healthiest when breeding, by selecting sires and dams with the healthiest qualities in the future generations of your breed.qualities in the future generations of your breed.

““Breed to ImproveBreed to Improve””

• Thyroglobulin Autoantibody (TgAA) is produced by dogs in the Thyroglobulin Autoantibody (TgAA) is produced by dogs in the early stages of Canine Autoimmune Thyroiditis. These dogs early stages of Canine Autoimmune Thyroiditis. These dogs typically develop symptoms from typically develop symptoms from 3 to 6 years of age!3 to 6 years of age!

• Idiopathic Hypothyroidism: Some older dogs with thyroid Idiopathic Hypothyroidism: Some older dogs with thyroid disease (low T4, high TSH), have low levels of TgAA after the disease (low T4, high TSH), have low levels of TgAA after the thyroid is destroyed. But, by then, the disease is readily thyroid is destroyed. But, by then, the disease is readily apparent.apparent.

What the TgAA results meanWhat the TgAA results mean

• Negative: The dog has no antibodies to TgAA.– NOTE: Young dogs may still develop thyroid disease, so it is best to screen NOTE: Young dogs may still develop thyroid disease, so it is best to screen

them regularly if they are in a breeding program.them regularly if they are in a breeding program.– TgAA levels may also decline in older dogs (over 7 years) with thyroid disease TgAA levels may also decline in older dogs (over 7 years) with thyroid disease

(e.g. idiopathic thyroiditis)(e.g. idiopathic thyroiditis)

• Positive: The dog has thyroid disease and should not be bred.Positive: The dog has thyroid disease and should not be bred.– NOTE: in some rare cases, a positive result may be due to non-specific binding NOTE: in some rare cases, a positive result may be due to non-specific binding

(NSB) of dog antibodies to the test matrix. OFA approved laboratories will (NSB) of dog antibodies to the test matrix. OFA approved laboratories will confirm positive results by performing a Non-specific binding test, and report confirm positive results by performing a Non-specific binding test, and report only true positive results.only true positive results.

• Inconclusive: The levels of TgAA are slightly elevatedInconclusive: The levels of TgAA are slightly elevated– Is the elevated TgAA due to thyroid disease?Is the elevated TgAA due to thyroid disease?– If the NSB is high the apparent elevation may be caused by something else – If the NSB is high the apparent elevation may be caused by something else –

like recent vaccination.like recent vaccination.– If the NSB is very low, and the dog is young, it may be an early sign of If the NSB is very low, and the dog is young, it may be an early sign of

autoimmune thyroid disease. We recommend NOT breeding the dog and autoimmune thyroid disease. We recommend NOT breeding the dog and testing again in 6 months.testing again in 6 months.

How can we help?How can we help?• The Oxford Laboratories TgAA test has been widely The Oxford Laboratories TgAA test has been widely

validated and used for over 20 years for the validated and used for over 20 years for the diagnosis of canine autoimmune thyroiditis. It is diagnosis of canine autoimmune thyroiditis. It is recognized by the recognized by the Orthopedic Foundation for Orthopedic Foundation for AnimalsAnimals for inclusion of dogs in its thyroid registry. for inclusion of dogs in its thyroid registry.

• The TgAA test, and thyroid test panels work very The TgAA test, and thyroid test panels work very well - but they are not inexpensive, and dogs in well - but they are not inexpensive, and dogs in breeding programs should be tested regularly.breeding programs should be tested regularly.

• The TgAA screening kit is easy to use and can help The TgAA screening kit is easy to use and can help you check for this disease on a regular basis.you check for this disease on a regular basis.

The TgAA screening kitThe TgAA screening kit• Easy to use, without the need for a veterinary visit. The kit provides Easy to use, without the need for a veterinary visit. The kit provides

everything you need for a preliminary screening at home. everything you need for a preliminary screening at home.

1)1) When trimming a dog’s nails, have the When trimming a dog’s nails, have the test kit handy. test kit handy.

2)2) When bleeding occurs, apply the test When bleeding occurs, apply the test card to the site and completely fill each card to the site and completely fill each printed circle on the test card with printed circle on the test card with blood.blood.

3)3) Complete the information on the test Complete the information on the test card and the information sheet.card and the information sheet.

4)4) Place everything in the envelope and Place everything in the envelope and mail it in. mail it in.

5)5) Results are typically send to you within Results are typically send to you within 10 days.10 days.

ResourcesResources• Oxford Laboratories websitewebsite

– Prevalence of Thyroid Disease in Pedigreed DogsPrevalence of Thyroid Disease in Pedigreed Dogs– TgAA screening kitTgAA screening kit

• Orthopedic Foundation for Animals websiteOrthopedic Foundation for Animals website– OFA breed statistics for major health issuesOFA breed statistics for major health issues

• Contact info: Oxford Laboratories Contact info: Oxford Laboratories – http://www.oxfordlabs.com/http://www.oxfordlabs.com/– E-mail: Info@oxfordbiomed.comE-mail: Info@oxfordbiomed.com– Phone: 800-692-4633Phone: 800-692-4633

– Website: Website: http://www.oxfordlabs.com/http://www.oxfordlabs.com/