Hypothyroidism is a common endocrine disease in dogs that causes significant but reversible welfare impacts including lethargy, weight gain, and skin disease when not adequately treated.
Untreated hypothyroidism causes chronic and progressive welfare impacts that can substantially reduce a dog quality of life. Profound lethargy means dogs that were previously active and engaged become reluctant to exercise and lose interest in play and social interaction. Weight gain despite normal food intake creates additional joint stress and metabolic complications. Skin changes including thick, dry coat, hair loss, and hyperpigmentation are uncomfortable and indicate systemic hormonal disruption. Neurological signs including peripheral neuropathy cause weakness and discomfort in some dogs. Because these signs develop gradually, owners often attribute them to ageing rather than disease. The welfare tragedy is that effective treatment with inexpensive daily medication produces dramatic reversal of most signs within weeks. Regular thyroid screening of predisposed breeds would identify the disease earlier and prevent prolonged suffering.