Aussie Genetics Fact Sheet: Thyroid Disease by C.A. Sharp Thyroid disease, specifically auto-immune thyroiditis, is becoming more and more common in dogs, including Australian Shepherds. Weight gain, skin problems and a tendency to seek heat are some of the more common signs, but they may also be signs of other problems. Therefore, a thorough veterinary exam and testing are called for. The disease is becoming common enough in Aussies that all breeding stock should be screened. Thyroid screening isn't as simple as taking an OFA e-ray or a CERF exam. A single type of screening is insufficient. Like the clinical signs of Disease, test reuslts are variable. If an animal is sick (from something other than thyroid disease), injured, pregnant or in heat, its condition can throw off the test results. It is entirely possible to have a clinically normal dog with abnormal test results, or the opposite. A gathering of experts in the disease at UC Davis in 1997 concluded that for the most useful results, measures should be taken of: total T4 free T4 measured by equilibrium dialysis thyrogobulin autoantibodies canine thyroid stimulating hormone If results are normal and the dog has no clinical signs or family history of thyroid disease, it is probably clear of the disease and can be bred. If a healthy dog tests normal but comes from a line with a history of disease it should be re-tested annually. A clinically normal dog with abnormal test results should be re-tested in 6 months. It should not be bred in the interim and if it continues to have abnormal tests it should not be bred at all. A dog showing clinical signs but which has normal tests should be re-tested in 2-6 months. It should not be bred unless it becomes clinically normal and has normal test results. Clinically affected dogs with abnormal tests results should not be bred.