Hypothyreosis

is the same disease as humans also do have. The thyroid gland is not working enough. In dogs the symptoms are getting fat and flegmatic, feeling cold easily, fur not renewing and turning more reddish in the time. Hypothyreosis can easily be diagnosed by a blood test. Treatment is pills, and when the dose is correct the dog becomes normal again and has no symptoms of the disease so long the medicine is taken daily.

For further reading: O.F.A.