Download Presentation for Breed Clubs

Canine Autoimmune Thyroiditis
An Overview for Dog Breeders
Canine Hypothyroidism
• A thyroid condition in which a dog’s thyroid gland
does not produce enough thyroid hormone
• This can cause obesity, sluggishness, hair loss, cold
intolerance, weakness, skin disease, a poor coat,
infertility and even failure to thrive in puppies
• Hypothyroidism is primarily caused by a genetic
disease known as Canine Autoimmune Thyroiditis
A Tale of Two Dogs:
Hypothyroid
Normal
How does this affect my dogs?
• Canine Autoimmune Thyroiditis is hereditary so a dog
inherits the disease from the sire or dam
• Some hereditary diseases are easily controlled through
selective breeding practices. However autoimmune
thyroiditis does not usually show symptoms until years
after a dog is bred.
• This means a single untested dog born with Canine
Autoimmune Thyroiditis can have many litters before it
develops the first symptoms, passing the disease along to
its pups
Hypothyroid Symptoms
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Hair loss and/or hair pulling up from the roots easily
Patches of scaly or red skin
Lethargy and slowness
Obesity
Cold sensitivity (Cold intolerance)
Lameness
* Chester & Hightower
…and in breeding dams
• Reproductive problems
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Decreased number of pups
Decreased puppy viability
Decreased birth weight
Higher interval between deliveries
Longer duration of uterine contractions
* Panciera et al., J Vet Int Med, 2012
How common is thyroid
disease in my breed?
• Canine Autoimmune Thyroiditis is much more common in
some breeds than others. High incidence breeds include Irish
Setters, Golden Retrievers, Cocker Spaniels, Shetland
Sheepdogs, Beagles, and Dobermans.
• However, this disorder is found in virtually all dog breeds.
What can we do to reduce the
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
dog’s immune system attacks its own thyroid. Hence, TgAA
has been shown to be a reliable test to help you identify
the disease years before it becomes clinically apparent.
• This information may help you make better informed
decisions when breeding, by selecting sires and dams with
the healthiest qualities in the future generations of your
breed.
“Breed to Improve”
• Thyroglobulin Autoantibody (TgAA) is produced by dogs in the
early stages of Canine Autoimmune Thyroiditis. These dogs
typically develop symptoms from 3 to 6 years of age!
• Idiopathic Hypothyroidism: Some older dogs with thyroid
disease (low T4, high TSH), have low levels of TgAA after the
thyroid is destroyed. But, by then, the disease is readily
apparent.
What 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
them regularly if they are in a breeding program.
– TgAA levels may also decline in older dogs (over 7 years) with thyroid disease
(e.g. idiopathic thyroiditis)
• 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
(NSB) of dog antibodies to the test matrix. OFA approved laboratories will
confirm positive results by performing a Non-specific binding test, and report
only true positive results.
• Inconclusive: The levels of TgAA are slightly elevated
– Is the elevated TgAA due to thyroid disease?
– If the NSB is high the apparent elevation may be caused by something else –
like recent vaccination.
– 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
testing again in 6 months.
How can we help?
• The Oxford Laboratories TgAA test has been widely
validated and used for over 20 years for the
diagnosis of canine autoimmune thyroiditis. It is
recognized by the Orthopedic Foundation for
Animals for inclusion of dogs in its thyroid registry.
• The TgAA test, and thyroid test panels work very
well - but they are not inexpensive, and dogs in
breeding programs should be tested regularly.
• The TgAA screening kit is easy to use and can help
you check for this disease on a regular basis.
The TgAA screening kit
• Easy to use, without the need for a veterinary visit. The kit provides
everything you need for a preliminary screening at home.
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When trimming a dog’s nails, have the
test kit handy.
When bleeding occurs, apply the test
card to the site and completely fill each
printed circle on the test card with
blood.
Complete the information on the test
card and the information sheet.
Place everything in the envelope and
mail it in.
Results are typically send to you within
10 days.
Resources
• Oxford Laboratories website
– Prevalence of Thyroid Disease in Pedigreed Dogs
– TgAA screening kit
• Orthopedic Foundation for Animals website
– OFA breed statistics for major health issues
• Contact info: Oxford Laboratories
– http://www.oxfordlabs.com/
– E-mail: [email protected]
– Phone: 800-692-4633
– Website: http://www.oxfordlabs.com/