Canine Hypothyroidism: Thyroid Welfare Updated 2025

Key Welfare Facts

Hypothyroidism affects approximately 0.2-0.6% of dogs and is the most common endocrine disorder in canine medicine.
Signs include weight gain, lethargy, cold intolerance, coat changes, and in some cases neurological complications.
Affected dogs may show marked behavioural changes including reduced activity, depression, and increased anxiety.
Diagnosis requires measurement of total T4 and ideally free T4 by equilibrium dialysis for accurate confirmation.
Levothyroxine replacement therapy is highly effective, with most dogs showing significant improvement within weeks.
Lifelong treatment with regular thyroid level monitoring is required for optimal welfare management.

Welfare Assessment

Hypothyroidism is a highly treatable condition that causes significant welfare compromise if undiagnosed or undertreated. Annual screening in at-risk breeds and prompt treatment when confirmed allows affected dogs to return to excellent quality of life.

What You Can Do

Discuss thyroid screening with your vet if your dog shows signs of lethargy, weight gain, or coat change
Commit to lifelong levothyroxine treatment and regular monitoring once diagnosed
Monitor for recurrence of signs as a guide to whether medication dose needs adjustment
Screen at-risk breeds including Dobermanns, Golden Retrievers, and Boxers from middle age