This article is from the Keeshonden Breed FAQ, by firstname.lastname@example.org (Kimberly J. Eashoo).
Keeshonden are subject to hypothyroidism and allergic skin diseases,
both of which can often be treated. Sometimes skin diseases are a
result of thyroid dysfunction. Current research indicates maternal
antibodies as a major cause of hypothyroiditis. An untested mother, if
affected by the disease and not demonstrating visible symptoms, will
have circulating antibodies to the disease. When the fetus begins
developing its own thyroid tissue, the antibodies attack brain tissue.
In humans, it causes mental retardation but in dogs, it is believed to
cause behavior problems. Once the fetus begins nursing, additional
antibodies are passed to the newborn in the colostrum, eventually
damaging the thyroid gland of the recipient. Studies indicate a
euthyroid (normal on medication) mother is no longer circulating
antibodies, thereby producing normal offspring. If each female is
tested BEFORE breeding, in 5-10 generations, lymphocytic
hypothyroiditis could greatly diminish. A complete thyroid panel,
including T3, T4, free T3, free T4 and an antibody test are important.
A subclinical bitch may not be showing visible symptoms therefore,
only a blood test could determine an affected bitch.