Blood testing is generally done about 6 hours after the morning pill is given. Some breeders of purebred dogs are trying to lower the occurence of the disease by selective breeding. One of the steps in this process is, of course, to identify affected dogs and not to breed them. This is similar to what is being done in attempt to decrease the number of cases of hip dysplasia , another common disease with a strong genetic component. However, the registry has not been accepted by everyone in the veterinary world.
Hypothyroidism is very rare in cats, especially naturally occuring cases.
In a few instances it occurs as a sequelae to treating hyperthyroidism with radioiodine.