Hypothyroidism is one of the most common endocrine disorders in dogs, causing metabolic slowdown and a wide range of symptoms that significantly affect quality of life when undiagnosed.
Hypothyroidism causes insidious welfare compromise as metabolic slowdown affects every body system. Affected dogs experience lethargy that owners often attribute to normal aging, mental dullness, exercise intolerance, and the discomfort of skin infections and poor coat condition. Neurological signs in severe cases include facial nerve paralysis and vestibular disease that are profoundly disorienting. The response to treatment is one of the most rewarding in veterinary medicine - owners frequently describe their dogs as 'coming back to life' within weeks of starting levothyroxine. The welfare impact of undiagnosed hypothyroidism is significant because dogs live in a chronically compromised state while owners may attribute changes to normal aging rather than a treatable medical condition.